National Weather Service United States Department of Commerce

Winter/Spring River Flood Potential Outlook
NWS Middle Atlantic River Forecast Center (MARFC)
State College, PA
3:28 pm EDT Wed, March 17, 2021

Outlook Number 21-06 - March 17, 2021


This Winter/Spring River Flood Potential Outlook is valid for the two-week period March 18 - April 1, 2021.

This outlook estimates the potential for river flooding (not flash flooding) to develop during the next two weeks across the Middle Atlantic River Forecast Center`s (MARFC) area of responsibility (Mid- Atlantic Region) based on a current assessment of hydrometeorological factors which can contribute to river flooding. Across the MARFC area these factors include future weather conditions, recent precipitation, soil moisture, snow cover and snow water equivalent, river ice, streamflow and other factors. This outlook does not address the severity/extent of any future river flooding. Remember, in the Mid-Atlantic region heavy rainfall is the primary factor which leads to river flooding. Heavy rainfall can rapidly cause river flooding any time of the year, even when overall river flood potential is considered to be low or below average.

TWO-WEEK RIVER FLOOD POTENTIAL - SOMEWHAT ABOVE AVERAGE THEN AVERAGE

The river flood potential for the entire MARFC area of responsibility starts out as average to somewhat above-average for the first few days of this two-week outlook period due to widespread significant rainfall anticipated for much of the region from late tonight into Friday. After the rain ends on Friday, a dry period is anticipated area-wide through the weekend into the middle of next week. The river flood potential will therefore gradually return to "average" area-wide later next week as streamflow recedes from this next rain event and vegetation slowly begins to emerge from winter dormancy from south-to-north. Factors which contribute to this assessment of river flood potential are discussed in some detail below.

CURRENT RIVER FLOODING - NONE

There is currently no river flooding occurring at any river forecast points within the MARFC service area.

RECENT PRECIPITATION - MOSTLY BELOW NORMAL TO NORMAL

During the last 30 days (February 15 - March 16, 2021) observed precipitation across most of the MARFC region has been near normal to below normal. Some small areas across the south have seen slightly above-normal precipitation. All of the MARFC service area has seen a very dry month of March so far. The dry weather has helped southern portions of the region dry out some from the very persistent wetness experienced by that region for much of the last year. Further north, considerable snow has melted during the dry spell with no river flooding, and the river flood potential is now reduced some since much of the snow has already melted. Total precipitation during the last 30 days has ranged from around an inch in south-central NY to 4 inches on the Delmarva Peninsula. Precipitation departure data is found at www.weather.gov/marfc/Precipitation_Departures.

SNOW CONDITIONS - ABOUT NORMAL TO SOMEWHAT BELOW NORMAL

As of this morning (March 17, 2021), generally continuous snow covers the ground only across about 10-20 percent of the MARFC service area and is limited to portions of extreme northeastern PA and portions of southern NY. Even here, exposed and lower elevations have pretty much lost the snow, with the most snow found in wooded areas or on north-facing slopes and in the highest elevations. Further south in PA and northwestern NJ the snow quickly becomes patchy in nature, while no snow is found across the southern half to two-thirds of the region. The areal extent of the current snow cover is fairly typical for mid-March. In terms of snow amounts, the deepest snow is found in northeastern PA and southern NY where depths are mostly less than 6 inches with isolated reports of up to a foot. Here the water contained in the snow is mostly an inch or less with isolated water equivalent values of 2-3 inches. These snow depths and water equivalent values are near normal to somewhat below normal for southern NY and northeastern PA for mid-March. Elsewhere where patchy snow is still seen on the ground it is generally of no/very limited hydrologic significance. Snow information can be found at www.weather.gov/marfc/Snow and www.nohrsc.noaa.gov.

RIVER ICE - AVERAGE TO BELOW AVERAGE

Currently there is no significant river ice remaining on or in MARFC rivers. The loss of river ice is perhaps a little early for portions of NY and northern PA, but not at all unusual.

STREAMFLOW CONDITIONS - VARIABLE

As of this morning data from the United States Geological Survey (USGS) indicates current streamflow conditions are rather variable within the MARFC region. Across the north where snow has recently melted and continues to melt, such as within portions of the Susquehanna and Delaware River Basins, streamflow ranges from average to above average. Meanwhile, further south streamflow conditions have gradually decreased to the average to below-average range for the Juniata and Schuylkill River Basins in PA as well as across most other basins within the MARFC service area, including rivers and streams in NJ, DE and the Potomac, Rappahannock, Shenandoah, James and Appomattox River Basins in MD, WV and VA. For current streamflow conditions please visit waterdata.usgs.gov/nwis/rt.

SOIL MOISTURE CONDITIONS - STILL VERY WET ACROSS THE SOUTHEAST

Soils remain extremely moist across southeastern portions of the MARFC service area, though some drying has occurred. The long-term Palmer drought severity index is useful to estimate deep soil moisture conditions. The March 13 map (cpc.ncep.noaa.gov/products/analysis_monitoring/regional_monitoring/palmer.gif) still suggests deep soils remain extremely moist across portions of central/southeast VA and some of the Delmarva Peninsula. Outside of this very wet area, the map shows soil moisture conditions in the normal to somewhat above-normal range. Additional soil moisture data confirms the very wet soils across southeastern portions of the area. For the latest conditions please visit www.cpc.ncep.noaa.gov/products/Soilmst_Monitoring/ and then click on U.S. Monitoring.

GROUNDWATER - NORMAL TO MUCH-ABOVE NORMAL

Within the MARFC service area, real-time USGS groundwater monitoring wells indicate current groundwater levels are generally around normal in the north including southern NY and the northern third of PA. South of this area, groundwater levels are above or much-above normal for mid-March. To see groundwater levels visit groundwaterwatch.usgs.gov/usgsgwnetworks.asp.

RESERVOIR CONDITIONS - AVERAGE

Most major reservoirs within the MARFC region are holding storages that are about average for this time of year. For example, reservoirs in the Delaware River Basin that supply NYC with water are showing near-average storages presently.

FUTURE WEATHER CONDITIONS - WET THIS THURSDAY INTO FRIDAY

Significant rainfall of 0.5-2.0 inches, with locally higher amounts, is anticipated for most of the region beginning overnight tonight and lasting into Friday. The rain may be heavy enough to result in some scattered, mostly minor river flooding. A dry spell is anticipated for this weekend into the middle of next week. Fairly typical early spring weather is currently anticipated for the second week of this outlook period. The latest (March 17, 2021) 6-10 and 8-14 day weather outlooks issued by the NWS Climate Prediction Center suggest a good chance of normal to above-normal temperature and normal to above-normal precipitation for the region when averaged over the entire 9-day period March 23-31, 2021. Please visit www.cpc.ncep.noaa.gov/ for the latest outlooks.

ENSEMBLE RIVER FORECASTS - SOME SHORT-TERM THREAT OF RIVER FLOODING

The most recent runs (March 17, 2021) of the short-term (6-10 day) ensemble river forecasts, which take into account anticipated future weather conditions including precipitation and temperatures, do show some limited threat of scattered, mostly minor river flooding developing within the MARFC service area during the next few days. This threat is due to high confidence in a moderate-heavy rain event mainly Thursday into Friday (March 18-19) across much of the region, with expected rainfall of 0.50-2.0 inches with locally heavier amounts. Please visit www.weather.gov/erh/mmefs. Once this short-term river flood threat passes, current longer-term river forecasts show a normal to below-normal threat of river flooding for most of the region during the next 30 days. All future river flooding will now require heavy rainfall since much of the significant snow has now melted within the region.

SUMMARY

A significant rain event during the next two days could result in the development of some scattered, mostly minor river flooding during the next few days anywhere within the MARFC region. At the same time there is also a good chance that no river flooding will occur, and conversely a very small chance that isolated moderate river flooding could occur. The exact location, extent and duration of heavy rainfall tomorrow and tomorrow night will determine if and where any river flooding may develop. Once this limited short-term river flood threat passes, the river flood potential will gradually return to normal, meaning all future river flooding will depend entirely upon the occurrence of heavy rainfall. Only small pockets of significant snow remain within the MARFC region, so snowmelt will very soon be eliminated as a factor that can increase the potential for river flooding. River ice is done for this winter season.

WATER SUPPLY OUTLOOK

According to the latest (March 9, 2021) U.S. Drought Monitor (droughtmonitor.unl.edu), abnormally dry conditions persist across a small portion of south-central NY and north-central PA. However, assuming near-normal precipitation over the next few months, no water supply shortages are anticipated within the MARFC region through at least May, 2021.

Please visit www.drought.gov, www.cpc.ncep.noaa.gov and www.weather.gov/marfc/WRO for additional drought and water supply information. Please visit the NWS MARFC homepage at www.weather.gov/marfc or find us on Facebook at www.facebook.com/nwsmarfc/?REF=aymt_homepage_panel and on Twitter @nwsmarfc.

This will be the final winter/spring river flood outlook product issued by this office for the 2021 season unless unusual conditions occur which warrant an additional release.

SK

 

Winter/Spring River Flood Potential Outlook
NWS Middle Atlantic River Forecast Center (MARFC)
State College, PA
11:38 am EST Thu, March 4, 2021

Outlook Number 21-05 - March 4, 2021


This Winter/Spring River Flood Potential Outlook is valid for the two-week period March 4 - March 18, 2021.

This outlook estimates the potential for river flooding (not flash flooding) to develop during the next two weeks across the Middle Atlantic River Forecast Center`s (MARFC) area of responsibility (Mid- Atlantic Region) based on a current assessment of hydrometeorological factors which can contribute to river flooding. Across the MARFC area these factors include future weather conditions, recent precipitation, soil moisture, snow cover and snow water equivalent, river ice, streamflow and other factors. This outlook does not address the severity/extent of any future river flooding. Remember, in the Mid-Atlantic region heavy rainfall is the primary factor which leads to river flooding. Heavy rainfall can rapidly cause river flooding any time of the year, even when overall river flood potential is considered to be low or below average.

TWO-WEEK RIVER FLOOD POTENTIAL - VARIABLE

The river flood potential for the entire MARFC area of responsibility starts out as below average to average for the first week of this two-week outlook period - through the morning of Thursday, March 11. This is due to high confidence in below-normal precipitation area wide for the first week, and only gradual snowmelt where snow still exists. Then during the second week of this outlook period (March 11-18) the river flood potential increases to average to above average. This is because warmer weather is expected and thus more snowmelt, along with a more active weather pattern which could produce moderate or heavy periods of rain in some areas. During the second week the above-average river flood potential area includes portions of south-central NY, central and northeast PA, and northern NJ. Factors which contribute to this assessment of river flood potential are discussed in some detail below.

CURRENT RIVER FLOODING - NONE

Flooding from earlier this week has ended and no river flooding is currently occurring at any forecast points within the MARFC service area.

RECENT PRECIPITATION - MOSTLY ABOVE/MUCH-ABOVE NORMAL EXCEPT FAR NORTH

During the last 30 days (February 1 - March 2, 2021) observed precipitation across most of the MARFC region has been above normal to much-above normal. The exception has been far northern portions of the region where normal or even somewhat below-normal precipitation has been observed. Eastern and coastal portions of the MARFC service area have been the wettest. In this area precipitation amounts have been 1.5 to 4.0 inches above normal which is 50 to 100 percent above normal. Otherwise, most of the rest of the service area has received somewhat above-normal precipitation, or 10-65 percent above normal. Total precipitation during the last 30 days has ranged from less than 2 inches in south-central NY to 7 inches on the Delmarva Peninsula. Precipitation departure data is found at www.weather.gov/marfc/Precipitation_Departures.

SNOW CONDITIONS - NORMAL TO ABOVE NORMAL

As of this morning (March 4, 2021), generally continuous snow covers the ground across about 40 percent of the MARFC service area. The line that roughly separates snow from no snow runs approximately along and north of Interstate 80 in PA and NJ. However in eastern PA the snow does extend further southward to near the Pennsylvania Turnpike. Some snow also exists in portions of the Appalachian Mountains. The current extent of snow is fairly typical for early March, which is usually the time of winter when snow within the MARFC region is at its maximum extent and contains the most water. Except for light-moderate lake effect snow in the usual areas of NY, no significant snow is forecast for the next week or so. Within the MARFC service area, snow conditions are above normal for this time of year across much of NY, much of northern PA and northern NJ. In this region snow depths this morning were generally in the 3-10 inch range, with scattered greater depths. Corresponding snow water equivalent values in this same region range generally from 1-4 inches, again with locally higher values. Elsewhere where snow exists depths are generally 1-5 inches, with up to about an inch of snow water equivalent. These conditions are about normal for early March. Finally, across the south little or no snow remains across VA, most of WV, most of MD, southern PA, the Delmarva Peninsula and southern NJ, which is also about normal for early March. Snow information can be found at www.weather.gov/marfc/Snow and www.nohrsc.noaa.gov.

RIVER ICE - AVERAGE TO BELOW AVERAGE

Currently the most river ice is found in streams and rivers in mainly upper portions of the Susquehanna and Delaware River Basins in NY and northern PA, which is pretty typical for early March. The river ice is not being reported as unusually thick or extensive for this time of year, and is actually somewhat below normal. Ice jam flooding is unlikely with the amount of river ice that still exists, and little or no additional river ice formation is expected for the remainder of this winter season. Elsewhere, no river ice exists which is normal for this time of year.

STREAMFLOW CONDITIONS - NORMAL TO MUCH-ABOVE NORMAL

As of this morning data from the United States Geological Survey (USGS) indicates current streamflow conditions within the MARFC region range from normal to much-above normal for early March. Highest flows compared to normal are across the southern two-thirds of the region, whereas near-normal streamflow conditions exist across the northern third. For current streamflow conditions please visit waterdata.usgs.gov/nwis/rt.

SOIL MOISTURE CONDITIONS - STILL VERY WET ACROSS THE SOUTHEAST

Soils remain extremely moist across southeastern portions of the MARFC service area. The long-term Palmer drought severity index is useful to estimate deep soil moisture conditions. The February 27, 2021 map (seen at cpc.ncep.noaa.gov/products/analysis_monitoring/regional_monitoring/palmer.gif) suggests deep soils remain extremely moist across central/southeast VA and much of the Delmarva Peninsula. Outside of this very wet area, the map shows soil moisture conditions in the normal to somewhat above-normal range. Additional soil moisture data confirms the very wet soils across southeastern portions of the area. Visit www.cpc.ncep.noaa.gov/products/Soilmst_Monitoring and then click on U.S. Monitoring.

GROUNDWATER - NORMAL TO MUCH-ABOVE NORMAL

Within the MARFC service area, real-time USGS groundwater monitoring wells indicate current groundwater levels are generally around normal in the north including southern NY and the northern third of PA. South of this area, groundwater levels are above or much-above normal for early March. To see groundwater levels visit groundwaterwatch.usgs.gov/usgsgwnetworks.asp.

RESERVOIR CONDITIONS - AVERAGE

Most major reservoirs within the MARFC region are holding storages that are about average for this time of year. For example, reservoirs in the Delaware River Basin that supply NYC with water are showing near-average storages presently.

FUTURE WEATHER CONDITIONS - MOSTLY DRY FIRST WEEK, THEN MILDER WITH SOME RAIN

A dry spell is anticipated for most of the MARFC region during the first week of this outlook period. The dry spell will be most welcome across the southern half of the region where it has been unusually wet for quite some time, as evidenced by scattered river flooding that occurred there recently. There currently are no indications of any significant rain events for at least the first week of this outlook period, through next Wednesday, March 10, 2021. Seasonable temperatures early in the period will be followed by milder weather next week which will increase snowmelt where snow still exists. Also in the second week of this outlook period a more active but still rather mild weather pattern may develop, with periods of moderate or heavy rain possible in some areas. The latest (March 3, 2021) 6-10 and 8-14 day weather outlooks issued by the NWS Climate Prediction Center suggest that both temperatures and precipitation may be above normal when averaged over the entire 9-day period March 9-17, 2021. Please visit www.cpc.ncep.noaa.gov for the latest outlooks.

ENSEMBLE RIVER FORECASTS - SOME THREAT OF RIVER FLOODING

The most recent runs (March 4, 2021) of the short-term (6-10 day) ensemble river forecasts, which take into account anticipated future weather conditions including precipitation and temperatures, do show some threat of river flooding developing across northern portions of the service area during the second week of this outlook period. The threat is due to a milder weather pattern developing, which will most likely melt some or much of the snow remaining within the MARFC service area. A more active weather pattern is also likely for the second week of this outlook period, which could result in periods of moderate to heavy rain in some areas, possibly accompanying or following the snowmelt. Please visit www.weather.gov/erh/mmefs. Current longer-term river forecasts also suggest a somewhat increased chance for river flooding compared to normal during the next 30 days, most notably in upper portions of the Susquehanna River Basin. This is primarily due to the above-average snow conditions that currently exist in portions of NY and northern PA. Any future river flooding will depend on shorter-term weather conditions, such as widespread heavy rainfall and/or rapid snowmelt.

SUMMARY

After some flooding that occurred earlier this week across mostly the southern half of the region due to snowmelt combined with significant rainfall, the focus for potential river flooding during the next two weeks shifts further north where significant snow remains. The good news is that there are currently no indications of any widespread heavy rain events for the first week of this outlook period. It is the second week of the period when warmer temperatures and the possibility of periods of moderate or heavy rain could result in some river flooding developing across mainly the northern half of the region. Still, heavy rain anywhere in the region could also cause river flooding to develop, including the south where it has been unusually wet. As such, conditions will need to be monitored closely for the rest of this winter into early spring. It does seem unlikely that ice jam flooding will occur since river ice is not as extensive or thick as usual at this time, and new ice formation is unlikely.

WATER SUPPLY OUTLOOK

According to the latest (March 2, 2021) U.S. Drought Monitor (droughtmonitor.unl.edu), abnormally dry conditions persist across a small portion of southern NY and northern PA. However, assuming near-normal precipitation over the next few months, no water supply shortages are anticipated within the MARFC region through at least May, 2021.

Please visit www.drought.gov, www.cpc.ncep.noaa.gov and www.weather.gov/marfc/WRO for additional drought and water supply information. Please visit the NWS MARFC homepage at www.weather.gov/marfc or find us on Facebook at www.facebook.com/nwsmarfc/?REF=aymt_homepage_panel and on Twitter @nwsmarfc.

The next winter/spring river flood outlook product will be issued by this office March 17-18, 2021, unless conditions warrant an intermediate release on March 10-11, 2021.

Winter/Spring River Flood Potential Outlook
NWS Middle Atlantic River Forecast Center (MARFC)
State College, PA
4:34 pm EST Wed, February 17, 2021

Outlook Number 21-04 - February 17, 2021


This Winter/Spring River Flood Potential Outlook is valid for the two-week period February 18 - March 4, 2021.

This outlook estimates the potential for river flooding (not flash flooding) to develop during the next two weeks across the Middle Atlantic River Forecast Center`s (MARFC) area of responsibility (Mid- Atlantic Region) based on a current assessment of hydrometeorological factors which can contribute to river flooding. Across the MARFC area these factors include future weather conditions, recent precipitation, soil moisture, snow cover and snow water equivalent, river ice, streamflow and other factors. This outlook does not address the severity/extent of any future river flooding. Remember, in the Mid-Atlantic region heavy rainfall is the primary factor which leads to river flooding. Heavy rainfall can rapidly cause river flooding any time of the year, even when overall river flood potential is considered to be low or below average.

TWO-WEEK RIVER FLOOD POTENTIAL - ABOVE AVERAGE TO AVERAGE

The river flood potential during the next two weeks (through March 4, 2021) is above average for late February across southern and eastern portions of the MARFC area of responsibility, and average elsewhere. The line separating the two categories runs roughly from southeast NY southwestward into west-central PA. Factors which contribute to this assessment of river flood potential are discussed in some detail below.

CURRENT RIVER FLOODING - NONE

As of this afternoon (Wednesday, February 17, 2021) minor flooding was occurring along a portion of the lower James River in VA. Flooding will end here this evening.

RECENT PRECIPITATION - WET SOUTH, NORMAL/BELOW NORMAL ELSEWHERE

During the last 30 days (January 18 - February 16, 2021) observed precipitation across the MARFC region has been above normal to much-above normal across far southern portions of the MARFC service area, including portions of central VA and the lower half of the Delmarva Peninsula. In this area amounts have been 1-2.5 inches above normal which is 25 to 75 percent above average. Otherwise, most of the rest of the service area has received below-normal to normal precipitation, 50-125 percent of average. Precipitation departure data is found at www.weather.gov/marfc/Precipitation_Departures.

SNOW CONDITIONS - NORMAL TO MUCH-ABOVE NORMAL

As of this afternoon (February 17, 2021), snow covers the ground across roughly 70 percent of the MARFC service area. The snow/no snow line runs roughly from near/along the WV/VA border, east through central MD and into central/southern NJ. The current snow cover extends somewhat further east than what is typical for mid February. In addition, moderate amounts of new snow are expected across much of the MARFC service area during the next two days. Within the MARFC service area, snow conditions are above normal to much-above normal for this time of year across much of NY, much of PA, northern NJ and portions of WV and MD. In this region snow depths this morning were generally in the 10-20 inch range, with scattered greater depths. Corresponding snow water equvialent values in this same region range generally from 1-4 inches, with isolated values of 4.5 inches. Snow depths in the remaining areas where snow exists are generally 1-8 inches, with 0.25-1.0 inches of snow water equivalent. These conditions are about normal for mid February. Little or no snow remains across most of VA, the Delmarva Peninsula and southern NJ, which is also about normal. But to repeat, moderate snowfall is expected across much of this region during the next two days. Snow information can be found at www.weather.gov/marfc/Snow and www.nohrsc.noaa.gov.

RIVER ICE - AVERAGE TO SOMEWHAT BELOW AVERAGE

Currently most streams and rivers in NY, much of PA, portions of NJ, western MD, eastern WV and northwestern VA have at least some ice in them. This is a fairly typical area for river ice to be observed in the second half of February. The most river ice is found in streams and rivers throughout the Susquehanna and Delaware River Basins, which is also typical for mid-late February. The river ice is not being reported as unusually thick or extensive for this time of year. Some additional river ice formation is possible for at least the first week of this outlook period. Then a gradually milder weather pattern appears likely to evolve later in this outlook period, preventing additional river ice formation.

STREAMFLOW CONDITIONS - HIGH SOUTH AND EAST, OTHERWISE NORMAL

The latest data from the United States Geological Survey (USGS) indicates current streamflow conditions within the MARFC region are much-above median across roughly the southeastern two-thirds of the region. Streamflow conditions then generally gradually decrease heading west and north from this area and are generally fairly close to median for mid February. For current streamflow conditions please visit waterdata.usgs.gov/nwis/rt.

SOIL MOISTURE CONDITIONS - WET SOUTHEAST, OTHERWISE NEAR NORMAL

Soils remain extremely moist across southeastern portions of the MARFC service area. The long-term Palmer drought severity index is useful to estimate deep soil moisture conditions. The February 13, 2021 map (seen at cpc.ncep.noaa.gov/products/analysis_monitoring/regional_monitoring/palmer.gif) suggests deep soils remain extremely moist across central/southeast VA and much of the Delmarva Peninsula. Outside of this very wet area, the map shows near-normal values. Additional soil moisture data confirms the very wet soils across southeastern portions of the area. Visit www.cpc.ncep.noaa.gov/products/Soilmst_Monitoring/ and then click on U.S. Monitoring.

GROUNDWATER - VARIABLE

Within the MARFC service area, real-time USGS groundwater monitoring wells indicate current groundwater levels generally range from below average in the far north, gradually increasing to above or even much-above normal in the south for this time of year. To see groundwater levels visit groundwaterwatch.usgs.gov/usgsgwnetworks.asp.

RESERVOIR CONDITIONS - AVERAGE

Most major reservoirs within the MARFC region are holding storages that are about average for this time of year. For example, reservoirs in the Delaware River Basin that supply NYC with water are showing near-average storages presently.

FUTURE WEATHER CONDITIONS - CHANGEABLE

A winter storm will produce widespread moderate amounts of snow, sleet and freezing rain over much of the region tonight through Friday. The system should be monitored for the possibility of producing just enough rain to cause some flooding again across lower portions of the James and Appomattox River Basins in VA. After the storm, seasonable weather conditions will likely prevail for the first week of this two-week period. However, a milder weather pattern appears likely to develop during the second week. After the storm moves out Friday, there currently are no strong indications of any widespread heavy rain events for the rest of the first week of this outlook period. The latest (February 17, 2021) weather outlooks issued by the NWS Climate Prediction Center suggest that both temperatures and precipitation will be normal or above normal when averaged over the entire nine-day period February 23-March 3, 2021. Please visit www.cpc.ncep.noaa.gov for the latest outlooks.

ENSEMBLE RIVER FORECASTS - SOME THREAT OF RIVER FLOODING

The most recent runs (February 17, 2021) of the short-term (6-10 day) ensemble river forecasts, which take into account anticipated future weather conditions including precipitation and temperatures, do show some threat of river flooding developing across southern portions of the service area. The threat is due to the possibility of locally heavy rain early in the outlook period, followed by snowmelt/additional rain later in the period. Please visit www.weather.gov/erh/mmefs. Current longer-term forecasts also suggest a somewhat increased chance for river flooding compared to normal during the next 30 days for some river basins within the MARFC service area, most notably the Potomac River Basin. This is primarily due to what is now above-average snow conditions in portions of that river basin. Any future river flooding will depend on shorter-term weather conditions, such as the widespread heavy rainfall and/or rapid snowmelt.

SUMMARY

A winter storm is expected across most of the MARFC service area beginning tonight (Wednesday, February 17) and lasting well into Friday. The storm will add to the already substantial snow conditions that exist across roughly the northwestern half of the region, and put down some new snow across much of the southern half of the region. The storm should be monitored for the possibility of producting just enough rain across portions of the James and Appomattox River Basins to produce some additional river flooding, though that possibility seems fairly low due to the cold temperatures. Meanwhile, in the longer range, while there are currently no strong indications of widespread heavy rainfall or widespread rapid snowmelt after this first storm departs late Friday, snow and to some degree river ice conditions have increased enough to be of some concern, especially over about the northwestern half of the MARFC region. A milder weather pattern is now expected to develop sometime during the second week of this outlook period, but it is too soon to tell if/where significant snowmelt will occur, and whether or not widespread heavy rainfall will occur. Needless to say, the river flood potential is becoming more elevated with time as we get closer to March, the month when river flooding due to snowmelt and/or heavy rainfall is fairly common. As such, conditions will need to be monitored closely for the rest of this winter into early spring, until such time that most of the snow has melted.

WATER SUPPLY OUTLOOK

According to the latest (February 9, 2021) U.S. Drought Monitor (droughtmonitor.unl.edu), abnormally dry conditions persist across a small portion of southern NY and northern PA. However, assuming near-normal precipitation over the next few months, no water supply shortages are anticipated within the MARFC region through May, 2021.

Please visit www.drought.gov, www.cpc.ncep.noaa.gov and www.weather.gov/marfc/WRO for additional drought and water supply information. Please visit the NWS MARFC homepage at www.weather.gov/marfc or find us on Facebook at www.facebook.com/nwsmarfc/?REF=aymt_ homepage_panel and on Twitter @nwsmarfc.

The next winter/spring river flood outlook product will be issued by this office March 3-4, 2021.

Winter/Spring River Flood Potential Outlook
NWS Middle Atlantic River Forecast Center (MARFC)
State College, PA
10:12 pm EST Wed, February 3, 2021


Outlook Number 21-03 - February 3, 2021


This Winter/Spring River Flood Potential Outlook is valid for the two-week period February 4 - February 18, 2021.

This outlook estimates the potential for river flooding (not flash flooding) to develop during the next two weeks across the Middle Atlantic River Forecast Center`s (MARFC) area of responsibility (Mid- Atlantic Region) based on a current assessment of hydrometeorological factors which can contribute to river flooding. Across the MARFC area these factors include future weather conditions, recent precipitation, soil moisture, snow cover and snow water equivalent, river ice, streamflow and other factors. This outlook does not address the severity/extent of any future river flooding. Remember, in the Mid-Atlantic region heavy rainfall is the primary factor which leads to river flooding. Heavy rainfall can rapidly cause river flooding any time of the year, even when overall river flood potential is considered to be low or below average.

TWO-WEEK RIVER FLOOD POTENTIAL - BELOW AVERAGE TO AVERAGE

The river flood potential during the next two weeks (through February 18, 2021) is about average for early February across southern and eastern portions of the MARFC area of responsibility, and somewhat below average elsewhere. This is very similar to the outlook issued two weeks ago. The line separating the two categories runs roughly from extreme northwest NJ southwestward into south-central PA. western MD, eastern WV and west-central VA. Factors which contribute to this assessment of river flood potential are discussed in some detail below.

CURRENT RIVER FLOODING - NONE

No river flooding is currently occurring within the MARFC service area.

RECENT PRECIPITATION - BELOW AVERAGE

During the last 30 days (January 4 - February 2, 2021) observed precipitation across most of the MARFC region has been below average to much-below average by generally 0.5 to 1.5 inches, or about 20 to 70 precent below average. Precipitation departure data can be seen at www.weather.gov/marfc/Precipitation_Departures.

SNOW CONDITIONS - NORMAL TO MUCH-ABOVE NORMAL

As of this evening (February 3, 2021), snow covers the ground across roughly 85 percent of the MARFC service area. The snow/no snow line runs roughly from Roanoke, VA northeast across the central Delmarva Peninsula and across extreme southeastern NJ. The snow cover currently extends somewhat further south and considerably further east than what is typical for early February, thanks to the recent snowstorm. Within the MARFC service area, snow conditions are above normal to much-above normal for this time of year across much of NY, much of PA and much of NJ. In this region snow depths this morning were generally in the 10-20 inch range, with scattered reports of 20-30 inches. Corresponding snow water equvialent values in this same region range generally from 1-3 inches, with isolated values of 3.5 inches. In portions of central and eastern MD, eastern WV and northern VA, 3-12 inches of snow exists which equates to about 1-1.5 inches of water. These conditions are somewhat above normal for early February. Then along and near the western border of our service area, from south-central NY southward through the Appalachian Mountains, snow conditions are normal/above normal with snow depths of 5-15 inches and water equivalent values mostly in the 1-2 inch range with locally higher amounts. Much of the light snow cover that existed across central VA and the southern half of the Delmarva Peninsula melted today, and more will melt during the next couple of days in northern VA, across the Delmarva Peninsula and across southeastern NJ. Snow information can be found at www.weather.gov/marfc/Snow and www.nohrsc.noaa.gov.

RIVER ICE - AVERAGE TO SOMEWHAT BELOW AVERAGE

Currently, most streams and rivers in NY, much of PA, northwestern NJ, western MD, eastern WV and northwestern VA have at least some ice in them. This is a fairly typical area for river ice to be observed in early February. The most river ice is found in streams and rivers throughout the Susquehanna and Delaware River Basins, which is also typical for early February. The river ice is not unusually thick or extensive for this time of year, but has increased a fair amount from just two weeks ago. In areas not specifically mentioned, little or no river ice exists, which is also normal for those areas. Additional river ice formation is expected during the next two weeks, as the coldest temperatures of this winter appear likely. Today`s NWS Climate Prediction Center`s 6-10 and 8-14 day (through February 17) temperature outlooks both strongly favor below-normal temperatures for our region.

STREAMFLOW CONDITIONS - VARIABLE

The latest data from the United States Geological Survey (USGS) indicates current streamflow conditions within the MARFC region range from above median across central and southeastern VA, the Delmarva Peninsula and southeastern NJ. Streamflow conditions then generally gradually decrease heading west and north from this area and are in the median to below-median range. For current streamflow conditions please visit waterdata.usgs.gov/nwis/rt.

SOIL MOISTURE CONDITIONS - WET SOUTHEAST, OTHERWISE NEAR NORMAL

Soils remain extremely moist across southeastern portions of the MARFC service area. The long-term Palmer drought severity index is useful to estimate deep soil moisture conditions. The January 30, 2021 map (seen at www.cpc.ncep.noaa.gov/products/ analysis_monitoring/regional_monitoring/palmer.gif) suggests deep soils are extremely moist across central/southeast VA and the lower Delmarva Peninsula. Outside of this very wet area, the map shows near-normal values. Additional soil moisture data confirms the very wet soils across southeastern portions of the region. Please visit www.cpc.ncep.noaa.gov/products/Soilmst_Monitoring/ and then click on U.S. Monitoring.

GROUNDWATER - VARIABLE

Within the MARFC service area, real-time USGS groundwater monitoring wells indicate current groundwater levels generally range from below average in the far north, gradually increasing to above or even much-above normal in the south for this time of year. To see groundwater levels visit groundwaterwatch.usgs.gov/usgsgwnetworks.asp.

RESERVOIR CONDITIONS - AVERAGE

Most major reservoirs within the MARFC region are holding storages that are about average for this time of year. For example, reservoirs in the Delaware River Basin that supply NYC with water are showing near-average storages presently.

FUTURE WEATHER CONDITIONS - UNFAVORABLE FOR HEAVY RAIN

At the present time, due to seasonable winter temperatures and only weak storm systems, there are no strong indications of any widespread heavy rain or substantial snowmelt events for the MARFC region for about the next 5-7 days. After a brief warmup, a cold front is expected to pass through the MARFC region Friday. Mixed light-moderate precipitation is expected. Sunshine on Thursday and milder temperatures ahead of the front will likely melt some snow across southeastern portions of our service area, but only minor rises in river levels are expected from the snowmelt. Afterwards, a generally colder and perhaps drier weather pattern looks likely in the longer range, The latest (February 3, 2021) weather outlooks issued by the NWS Climate Prediction Center strongly suggest that temperatures will be below normal when averaged over the entire nine-day period February 9-17, 2021. The outlooks also show a good chance that precipitation will end up being below average for that same nine-day period. Please visit www.cpc.ncep.noaa.gov/.

ENSEMBLE RIVER FORECASTS - VERY LIMITED THREAT OF RIVER FLOODING

The most recent runs (February 3, 2021) of the short-term (6-10 day) ensemble river forecasts, which take into account anticipated future weather conditions including precipitation and temperatures, show little threat of any river flooding developing during the next 6-10 days (through the morning of February 13, 2021) within the MARFC region. Widespread river flooding in February is uncommon within the MARFC region, but is still possible. Please visit www.weather.gov/erh/mmefs. Longer-term forecasts currently suggest no apparent increased chance for river flooding compared to normal into mid-February. However, with a fairly widespread and substantial snowpack now in place across much of the MARFC region, and river ice conditions increasing, it is likely that the river flood potential will increase for portions of the region after mid month. Any future river flooding will depend primarily on shorter-term weather conditions, such as the occurrence of rapid snowmelt and/or widespread heavy rainfall.

SUMMARY

The recent major east coast storm just brought moderate-heavy amounts of precipitation - mostly snow - region-wide. Now a substantial snowpack - above to much-above normal for early February - exists across a respectable portion of the region. Additionally, river ice has increased within the Susquehanna and Delaware River Basins from two weeks ago and is expected to increase and expand further during the next two weeks. Meanwhile, southeast portions of the region continue to have wet soils and above-median streamflows, though they have little/no snow or river ice. While these conditions suggest a normal or above-normal river flood potential for much of the region, the mitigating factor is that there are currently no strong indicators for heavy rainfall or significant snowmelt that could initiate river flooding during the next 5 to 7 days. On the contrary, the overall weather pattern for the next two weeks strongly suggests below-normal temperatures and a good chance of below-normal precipitation. Due to the predicted lack of warm, wet weather systems, the river flood potential for the next two weeks is being held at average to below average, similar to two weeks ago. But weather patterns can change quickly this time of year and should be monitored now that a significant snowpack exists across a portion of the region. Additionally, concern is increasing that a higher river flood potential may develop beyond this two-week period.

WATER SUPPLY OUTLOOK

According to the latest (January 26, 2021) U.S. Drought Monitor (droughtmonitor.unl.edu), two small areas of abnormally dry conditions and spotty restrictions on water use continue in PA and NY. Assuming near normal precipitation over the next few months, no water supply shortages are anticipated within the MARFC region through May, 2021. Please visit www.drought.gov, www.cpc.ncep.noaa.gov and www.weather.gov/marfc/WRO for additional drought and water supply information.

Please visit the NWS MARFC homepage at www.weather.gov/marfc or find us on Facebook at www.facebook.com/nwsmarfc/?REF=aymt_ homepage_panel and on Twitter @nwsmarfc.

The next winter/spring river flood outlook product will be issued by this office February 17-18, 2021.

SK/WJM

Winter/Spring River Flood Potential Outlook
NWS Middle Atlantic River Forecast Center (MARFC)
State College, PA
11:59 am EST Thu, January 21, 2021

Outlook Number 21-02 - January 21, 2021


This Winter/Spring River Flood Potential Outlook is valid for the two-week period January 21-February 4, 2021.

This outlook estimates the potential for river flooding (not flash flooding) to develop during the next two weeks across the Middle Atlantic River Forecast Center`s (MARFC) area of responsibility (Mid- Atlantic Region) based on a current assessment of hydrometeorological factors which can contribute to river flooding. Across the MARFC area these factors include future weather conditions, recent precipitation, soil moisture, snow cover and snow water equivalent, river ice, streamflow and other factors. This outlook does not address the severity/extent of any future river flooding.

Remember, in the Mid-Atlantic region heavy rainfall is the primary factor which leads to river flooding. Heavy rainfall can rapidly cause river flooding any time of the year, even when overall river flood potential is considered to be low or below average.

TWO-WEEK RIVER FLOOD POTENTIAL - AVERAGE TO BELOW AVERAGE

The river flood potential during the next two weeks (through February 4, 2021) is about average across southern and eastern portions of the MARFC area of responsibility, and below average for late January for the remainder of the region. Factors which contribute to this assessment of river flood potential are discussed in some detail below.

CURRENT RIVER FLOODING - NONE

No river flooding is currently occurring within the MARFC service area.

RECENT PRECIPITATION - NEAR AVERAGE

During the last 30 days (December 21, 2020 - January 19, 2021) observed precipitation across the entire MARFC region has been about average plus or minus up to an inch or so. Areas most likely to have been above average are southern New York and central Pennsylvania. Areas most likely to have been below average are the eastern panhandle of West Virginia and western Virginia. Precipitation departure data can be seen at www.weather.gov/marfc/Precipitation_Departures.

SNOW CONDITIONS - NORMAL TO BELOW NORMAL

As of this morning (January 21, 2021), snow is found on the ground across approximately the northern third of the MARFC region. The snow/no-snow line is roughly close to U.S. Route 220 in the Appalachians, then along Interstate 99, then near Interstate 80 in PA, and northeastward near Interstate 84 in NY. Typically for mid to late January, the snow/no snow line extends roughly 50 to 75 miles further south and east of the current line. Snow conditions are about normal for this time of year across some portions of northern PA and NY, where snow water equivalent values of 1-2 inches are common with isolated higher values. Snow depths in this region are mostly 1-8 inches with isolated deeper amounts. Elsewhere where snow exists, water equivalent values are less than an inch and depths are a few inches or less. Outside of northern PA and NY, snow conditions range from normal to below normal for mid to late January. Snow information can be found at www.weather.gov/marfc/Snow and www.nohrsc.noaa.gov.

RIVER ICE - NONE

Currently, no significant river ice exists on rivers within the MARFC service area. Some river ice formation is likely during the next two weeks given that this next two weeks is typically the coldest two weeks of the year, and the latest NWS Climate Prediction Center`s 6-10 and 8-14 day temperature outlooks both suggest colder than normal temperatures.

STREAMFLOW CONDITIONS - NEAR TO ABOVE MEDIAN

The latest data from the United States Geological Survey (USGS) indicates current streamflow conditions within the entire MARFC region are near to above median for the date. For current streamflow conditions please visit waterdata.usgs.gov/nwis/rt.

SOIL MOISTURE CONDITIONS - WET SOUTHEAST, OTHERWISE NEAR NORMAL

Soils remain extremely moist across southeastern portions of the MARFC service area. The long-term Palmer drought severity index is useful to estimate deep soil moisture conditions. The January 16, 2021 map (seen at www.cpc.ncep.noaa.gov/products/analysis_monitoring/regional_ monitoring/palmer.gif) suggests deep soils are unusually moist to extremely moist across central/southeast VA and the middle and lower Delmarva Peninsula. Outside of this very wet area, the map shows near-normal to unusually moist values. Additional soil moisture data confirms the very wet soils across southern and eastern portions of the region. Visit www.cpc.ncep.noaa.gov/products/Soilmst_Monitoring/ and then click on U.S. Monitoring.

GROUNDWATER - AVERAGE TO ABOVE AVERAGE

Within the MARFC service area, real-time USGS groundwater monitoring wells indicate current groundwater levels generally range from average to above average for this time of year. To see groundwater levels visit groundwaterwatch.usgs.gov/usgsgwnetworks.asp.

RESERVOIR CONDITIONS - AVERAGE TO ABOVE AVERAGE

Most major reservoirs within the MARFC region are holding storages that are average or somewhat above average for this time of year. For example, reservoirs in the Delaware River Basin that supply NYC with water are showing above-average storage for this time of year.

FUTURE WEATHER CONDITIONS -

At the present time there are no strong indications of any widespread heavy rain events for the MARFC region for about the next 5-7 days. A storm system across the Southeast next Monday-Tuesday should be monitored for the potential of heavy rain/snow should the storm track shift further north than currently predicted. A colder weather pattern looks likely in the longer range. The latest (January 20, 2021) weather outlooks issued by the NWS Climate Prediction Center suggest that both temperatures and precipitation may be below normal when averaged over the entire nine-day period January 25-February 3, 2021. Visit www.cpc.ncep.noaa.gov/ to view the outlooks.

ENSEMBLE RIVER FORECASTS - VERY LIMITED THREAT OF RIVER FLOODING

The most recent runs (January 21, 2021) of the short-term (6-10 day) ensemble river forecasts, which take into account anticipated future weather conditions including precipitation and temperatures, show little threat of any river flooding developing during the next 6-10 days (through the morning of January 30, 2021) within the MARFC region. Widespread river flooding in January and early February is uncommon within the MARFC region, but is still possible. Please visit www.weather.gov/erh/mmefs. Longer-term forecasts suggest no apparent increased chance for river flooding compared to normal for early February. Any future river flooding will depend primarily on shorter-term weather conditions, such as the occurrence of widespread heavy rainfall.

SUMMARY

Average or somewhat above average soil moisture and streamflow conditions region-wide indicate a slow drying of the MARFC region over the past two weeks. Though southeastern portions of the region are still the wettest, there are currently no strong indicators for heavy rainfall here that could result in river flooding during the next 5 to 7 days. That being said a weather system tracking across the Southeast Monday into Tuesday should be monitored in case the current predicted track of that system shifts northward with time. Rivers are free of river ice at this time, though some ice will likely form in the next two weeks. The only significant snow on the ground at this time within the MARFC region is across portions of northern PA and NY. There are no indications of any fast snowmelt events for this region at the present time, as temperatures are likely to be pretty close to normal or below normal for the next couple of weeks.

WATER SUPPLY OUTLOOK

According to the latest (January 14, 2021) U.S. Drought Monitor (droughtmonitor.unl.edu), scattered areas of abnormally dry conditions and spotty restrictions on water use are all that remain of a fairly significant summer/fall drought that existed over portions of PA and NY. Assuming near-normal precipitation over the next few months, no water supply shortages are anticipated within the MARFC region through May, 2021. Please visit www.drought.gov, www.cpc.ncep.noaa.gov and www.weather.gov/marfc/WRO for additional drought and water supply information.

Please visit the NWS MARFC homepage at www.weather.gov/marfc or find us on Facebook at www.facebook.com/nwsmarfc/?REF=aymt_homepage_panel and on Twitter @nwsmarfc.

The next winter/spring river flood outlook product will be issued by this office February 3-4, 2021, SK/WJM

 

Winter/Spring River Flood Potential Outlook
NWS Middle Atlantic River Forecast Center (MARFC)
State College, PA
1:25 pm EST Wed, January 6, 2021

Outlook Number 21-01 - January 6, 2021


This Winter/Spring River Flood Potential Outlook is valid for the two-week period January 7-21, 2021.

This outlook estimates the potential for river flooding (not flash flooding) to develop during the next two weeks across the Middle Atlantic River Forecast Center`s (MARFC) area of responsibility (Mid- Atlantic Region) based on a current assessment of hydrometeorological factors which can contribute to river flooding. Across the MARFC area these factors include future weather conditions, recent precipitation, soil moisture, snow cover and snow water equivalent, river ice, streamflow and other factors. This outlook does not address the severity/extent of any future river flooding.

Remember, in the Mid-Atlantic region heavy rainfall is the primary factor which leads to river flooding. Heavy rainfall can rapidly cause river flooding any time of the year, even when overall river flood potential is considered to be low or below average.

TWO-WEEK RIVER FLOOD POTENTIAL - ABOVE AVERAGE SOUTH AND EAST

The river flood potential during the next two weeks (through January 21, 2021) is somewhat above average across southern and eastern portions of the MARFC service area, and about average for early January for the remainder of the region. Factors which contribute to this assessment of river flood potential are discussed in some detail below.

CURRENT RIVER FLOODING - NONE

No flooding is currently occurring within the MARFC service area.

RECENT PRECIPITATION - ABOVE TO MUCH-ABOVE AVERAGE

During the last 30 days (December 6, 2020 - January 4, 2021) observed precipitation across the entire MARFC region has been above to much-above average. Precipitation departure data can be seen at www.weather.gov/marfc/Precipitation_Departures.

SNOW CONDITIONS - ABOVE NORMAL FAR NORTH, OTHERWISE NEAR NORMAL

As of this morning (January 6, 2021), snow is found on the ground across roughly the northern third of the MARFC region. The snow/no-snow line is roughly close to U.S. Route 220 in the Appalachians, then along Interstate 99, then near Interstate 80 in PA, and northeastward near Interstate 84 in NY. This is a fairly typical location of the snow/no-snow line for early January. Snow conditions are somewhat above normal for this time of year across portions of northern PA and NY, where snow water equivalent values of 1-2 inches are common, with isolated higher values. Snow depths in this region are mostly 2-10 inches with isolated deeper amounts. Elsewhere where snow exists, water equivalent values are less than an inch and depths are a few inches or less. Outside of northern PA and NY, snow conditions are fairly close to normal for early January for most of the remainder of the MARFC region. Snow information can be found at www.weather.gov/marfc/Snow and www.nohrsc.noaa.gov.

RIVER ICE - NONE

Currently, no river ice exists on rivers within the MARFC service area and river ice formation during the next two weeks is currently expected to be limited due to the relative absence of arctic air. The lack of river ice at this time is somewhat below normal for rivers across roughly the northwestern third of the MARFC service area.

STREAMFLOW CONDITIONS - ABOVE TO MUCH-ABOVE MEDIAN

The latest data from the United States Geological Survey (USGS) indicates current streamflow conditions within the entire MARFC region are above to much-above median for the date. This is especially true for rivers in southern and eastern portions of the region. For current streamflow conditions please visit waterdata.usgs.gov/nwis/rt.

SOIL MOISTURE CONDITIONS - WET SOUTH AND EAST

Soils remain extremely moist across southern and eastern portions of the MARFC service area. The long-term Palmer drought severity index is useful to estimate deep soil moisture conditions. The January 2, 2021 map (seen at www.cpc.ncep.noaa.gov/products/analysis_monitoring/regional_ monitoring/palmer.gif) suggests deep soils are unusually moist to extremely moist across large portions of the region, especially in central/southeast VA, the Delmarva Peninsula, southeast PA and southern NJ. Outside of this very wet area, the map shows near-normal to unusually moist values. Additional soil moisture data confirms the very wet soils across southern and eastern portions of the region. Visit www.cpc.ncep.noaa.gov/products/Soilmst_Monitoring/ and then click on U.S. Monitoring.

GROUNDWATER - AVERAGE TO ABOVE AVERAGE

Within the MARFC service area, real-time USGS groundwater monitoring wells indicate current groundwater levels generally range from average to above average for this time of year. To see groundwater levels visit groundwaterwatch.usgs.gov/usgsgwnetworks.asp.

RESERVOIR CONDITIONS - AVERAGE TO ABOVE AVERAGE

Most major reservoirs within the MARFC region are holding storages that are average or somewhat above average for this time of year. For example, reservoirs in the Delaware River Basin that supply NYC with water are showing somewhat above-average storage for this time of year.

FUTURE WEATHER CONDITIONS 

At the present time there are no strong indications of any widespread heavy rain events for the MARFC region for about the next 5-7 days. Only light-to-moderate precipitation is currently anticipated, though southern storms will need to be monitored late this week and again before midweek next week. Either/both of these storms could clip southern/eastern portions of the MARFC region with significant rain and/or snow if the predictions of their tracks shift northwestward much. A somewhat colder weather pattern looks possible at least briefly toward the end of next week. In the longer range, the latest (January 5, 2021) weather outlooks issued by the NWS Climate Prediction Center suggest that both temperatures and precipitation may be near normal when averaged over the entire nine-day period January 11-19, 2021. Visit www.cpc.ncep.noaa.gov/ to view the outlooks.

ENSEMBLE RIVER FORECASTS - VERY LIMITED THREAT OF RIVER FLOODING

The most recent runs (January 6, 2021) of the short-term (6-10 day) ensemble river forecasts, which take into account anticipated future weather conditions including precipitation and temperatures, show little threat of river flooding developing during the next 6-10 days (through the morning of January 15, 2021) within the MARFC region. Widespread river flooding in January is uncommon, but still possible within the MARFC region. Please visit www.weather.gov/erh/mmefs. Longer-term forecasts suggest a somewhat elevated chance for river flooding compared to normal later this month, mainly due to currently high streamflows and wet soils in some regions. Any future river flooding will depend primarily on shorter-term weather conditions, such as the occurrence of widespread heavy rainfall.

SUMMARY

Wet soils and unusually high streamflow conditions across southern and eastern portions of the region result in a somewhat above-average chance of river flooding developing during the next two weeks in the MARFC region. However, at this time there are no strong indications of any widespread heavy rain events for at least the next five days. Rivers are free of river ice at this time, and the only significant snow on the ground within the MARFC region is across portions of northern PA and NY. There are no indications of any fast snowmelt events for this region at the present time, as temperatures are likely to be pretty close to normal for January for the next couple of weeks.

WATER SUPPLY OUTLOOK

According to the latest (December 31, 2020) U.S. Drought monitor (droughtmonitor.unl.edu), abnormally dry conditions are all that remain of a fairly significant summer/fall drought that existed over portions of PA and NY. Please visit www.drought.gov, www.cpc.ncep.noaa.gov and www.weather.gov/marfc/WRO for additional drought and water supply information.

Please visit the NWS MARFC homepage at www.weather.gov/marfc or find us on Facebook at www.facebook.com/nwsmarfc/?REF=aymt_homepage_panel and on Twitter @nwsmarfc.

The next winter/spring river flood outlook product will be issued by this office January 20-21, 2021.

SK