National Weather Service United States Department of Commerce

Outlook #6 released on March 13, 2019


Winter/Spring River Flood Potential Outlook
National Weather Service Middle Atlantic River Forecast Center (MARFC)
State College, PA
2:35 pm EDT Wed, Mar 13, 2019

Outlook Number 19-06 - March 13, 2019 (outlook map)

This Winter/Spring River Flood Potential Outlook is valid for the one-week period March 14-21, 2019.

This outlook estimates the potential for river flooding (not flash flooding) to develop during the next week 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 others.  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.

ONE-WEEK RIVER FLOOD POTENTIAL - ABOUT AVERAGE

The river flood potential during just the next week (through March 21) is about average.  This outlook will be updated in one week, on or about March 20-21.  Factors which contribute to this assessment of river flood potential are discussed in some detail below.

ONE-MONTH RIVER FLOOD POTENTIAL - VARIABLE

The river flood potential for the next 30 days through April 11, 2019, shows a somewhat below average potential for flooding compared to normal for about the northern third of the region.  This is due to recent precipitation, snow conditions and streamflow all being somewhat below normal there now.  Further south, the longer-range flood potential increases to about normal across the central third of the region, to above normal across the southern third of the region.

CURRENT FLOODING - NONE

There is currently no river flooding occurring within the MARFC service area.

RECENT PRECIPITATION - VARIABLE

During the last 30 days (February 11 - March 12, 2019) observed precipitation has been below average to average across NY, northern PA and northwestern NJ.  Across the remainder of the MARFC service area, 30-day observed precipitation has been above average to much-above average.  Portions of southwestern PA, WV, VA, MD, DE, and southern NJ have been the wettest compared to normal.  To view precipitation departure data please visit https://www.weather.gov/marfc/Precipitation_Departures.

SNOW CONDITIONS - ABOUT AVERAGE

As of 9am this morning (March 13) snow covers the ground within the MARFC region across roughly the northern third of the area.  This includes NY, approximately the northern half of PA and roughly the northwestern third of NJ.  Patchy, generally insignificant snow is also found in the higher elevations of southwestern PA, western MD and northeastern WV.  In all areas, higher elevations are holding on to the snow better while deeper river valleys have little snow remaining.  The most significant snow remains across portions of the Chenango, North Branch Susquehanna and Upper Delaware Basins in NY.  Current snow depths range from 1-12 inches while current snow water equivalent values range from 0.25-2.50 inches.  Isolated locations have deeper snow and higher equivalent values.  Snow conditions are fairly close to average in most areas for late winter.  Maximum temperatures in the 50s and 60s Thursday and Friday will melt considerable snow in all areas where snow still remains.  Snow information can be found at https://www.weather.gov/marfc/Snow and https://www.nohrsc.noaa.gov.

RIVER ICE - BELOW AVERAGE TO AVERAGE

Recent observations from ice observers and satellite photos currently indicate that only minimal river ice exists on portions of streams and rivers mainly in NY and extreme northern PA.   River ice conditions are somewhat below average for late winter across roughly the northwestern third of the MARFC region.  Elsewhere, the current lack of river ice is not uncommon for late winter.

STREAMFLOW CONDITIONS - LOWER NORTH, HIGHER SOUTH

The latest data from the United States Geological Survey (USGS) indicate below-median to median streamflow conditions across roughly the northern third of the MARFC region.  Meanwhile, across the southern two-thirds of the region streamflow conditions are in the median to above-median range.  Please visit https://waterdata.usgs.gov/nwis/rt.

SOIL MOISTURE CONDITIONS - GENERALLY MUCH-ABOVE AVERAGE

The long-term Palmer drought severity index is useful to estimate deep soil moisture conditions.  The March 9, 2019 chart (found at https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/regional_monitoring/palmer.gif) suggests deep soils across most of the MARFC service area contain moisture that continues to be much-above normal for this time of year.  Additional more detailed soil moisture information continues to support the idea that soils are extremely wet across nearly all of the MARFC area.  Go to https://www.cpc.ncep.noaa.gov/products/Soilmst_Monitoring/ and then click on U.S. Monitoring to view this soil moisture information.

GROUNDWATER - VARIABLE

Within the MARFC area, real-time USGS groundwater monitoring wells indicate groundwater levels increase from below normal/normal across about the northern third of the region, to above normal/much above normal elsewhere.  Please visit https://groundwaterwatch.usgs.gov.

RESERVOIR CONDITIONS - AVERAGE TO ABOVE AVERAGE

Most major reservoirs within the MARFC region are holding storages that are average to above average for this time of year.

FUTURE WEATHER CONDITIONS - MILD THEN COOLER, LIGHT-MODERATE RAIN EVENT ON FRIDAY

Mild temperatures are expected across the region through Friday, with maximum temperatures ranging from the low 50s north to the low 70s south both Thursday and Friday.  These temperatures will cause considerable snowmelt where snow still exists, with scattered river flooding possible in NY due to snowmelt combined with predicted light-moderate rain.  Cooler weather spreads across the region on Saturday and persists into midweek next week.  Precipitation wise, light-moderate rain is expected Thursday evening through Friday night with the heaviest amounts expected over southern and eastern regions where little or no snow remains.  Only scattered light precipitation is expected Saturday through next Wednesday.  At this time no widespread heavy rain events are anticipated during this one-week outlook period.  The latest (March 12) longer-range weather outlook issued by the NWS Climate Prediction Center suggests below-average temperatures and precipitation for the MARFC region for the five-day period March 18-22, 2019.  Long-range outlooks can be viewed at https://www.cpc.ncep.noaa.gov/.

ENSEMBLE RIVER FORECASTS - A LIMITED THREAT OF RIVER FLOODING DEVELOPING IN NY DURING THE NEXT FEW DAYS

The most recent runs (March 13, 2019) of the short-term (one week) ensemble river forecasts, which take into account anticipated future weather conditions including precipitation and temperatures, show a limited threat of river flooding developing mainly in NY.  A snowmelt/rainfall event is anticipated during the next few days, and this event could result in scattered river flooding developing in NY Friday-Sunday.  Heavier rain than currently anticipated could result in more significant and widespread river flooding.  Longer-range (30-day) ensemble river forecasts still show a somewhat elevated risk (compared to normal) of river flooding developing for rivers located in about the southern half of the MARFC region during the next 30 days.  This elevated longer-range risk reflects the very wet soils and generally above-median streamflow conditions that still exist across especially the southern half of the MARFC region.  Please visit https://www.weather.gov/erh/mmefs for short-term ensemble river forecasts.

SUMMARY

The risk of river flooding during just the next week for streams and rivers within the MARFC service area is about average.  Snowmelt combined with light-moderate rain during the next few days could result in some scattered river flooding developing mainly in NY, where snowmelt may be the greatest.  Elsewhere, significant rainfall would be necessary for river flooding to develop, and for this one-week outlook period no widespread, heavy rain events are currently anticipated.  Please monitor your local NWS forecasts during the next few days for updated information regarding this next snowmelt/rainfall event.

WATER SUPPLY OUTLOOK

According to the latest (March 5) U.S. Drought monitor (https://droughtmonitor.unl.edu), there are currently no drought conditions within the MARFC service area.  Visit https://www.drought.gov, https://www.cpc.ncep.noaa.gov and https://www.weather.gov/marfc/wro_north for additional drought and water supply information.  Assuming near-normal precipitation for the next few months, no water supply shortages are anticipated anywhere within the MARFC region through at least mid-June, 2019.

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

The next Outlook will be issued by this office March 20 or 21, 2019.

 

Outlook #5 released on March 7, 2019


Winter/Spring River Flood Potential Outlook
National Weather Service Middle Atlantic River Forecast Center (MARFC)
State College, PA
12:20 pm EST Thu, March 7, 2019

Outlook Number 19-05 - March 7, 2019 (outlook map)

This Winter/Spring River Flood Potential Outlook is valid for the one-week period March 7-14, 2019.

This outlook estimates the potential for river flooding (not flash flooding) to develop during the next week 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 others.  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.

ONE-WEEK RIVER FLOOD POTENTIAL - BELOW AVERAGE NORTH, ABOUT AVERAGE ELSEWHERE

The river flood potential during just the next week (through March 14) ranges from below average across roughly the northern third of the MARFC service area, to average across the remainder of the region.  This outlook will be updated in one week, since flood potential may rise in many areas a week from now.  Factors which contribute to this assessment of river flood potential are discussed in some detail below.

CURRENT FLOODING - NONE

There is currently no river flooding occurring within the MARFC service area.

RECENT PRECIPITATION - VARIABLE

During the last 30 days (February 5 - March 6, 2019) observed precipitation has been about average across NY and northern PA.  to the south, it has been wetter, ranging from above average to much-above average.  Portions of southwestern PA, VA, MD, DE, and southern NJ have been the wettest compared to normal.  To view precipitation departure data please visit https://www.weather.gov/marfc/Precipitation_Departures.

SNOW CONDITIONS - ABOUT AVERAGE

Currently, snow covers the ground within the MARFC region across roughly the northern two-thirds of the area.  This includes NY, nearly all of PA, the northern half of NJ, western MD, northeastern WV, and the highest elevations of extreme western VA.  Current snow depths range from 1-15 inches while current snow water equivalent values range from 0.25-2.25 inches.  The most significant snow remains across portions of the Chenango, North Branch Susquehanna and Upper Delaware Basins in NY and portions of the West Branch Susquehanna and Juniata Basins in central PA.  Snow conditions are fairly close to average for this time of winter.  Snow information can be found at https://www.weather.gov/marfc/Snow and https://www.nohrsc.noaa.gov.

RIVER ICE - BELOW AVERAGE TO AVERAGE

Recent observations from ice observers and satellite photos currently indicate that only minimal river ice exists on streams and rivers, limited mainly to New York and perhaps isolated locations in northern PA.   River ice conditions are somewhat below average for this time of year across roughly the northwestern half of the region.  Meanwhile, across the southeastern half of the region, the lack of river ice is fairly common for early March.

STREAMFLOW CONDITIONS - LOWER NORTH, HIGHER SOUTH

The latest data from the United States Geological Survey (USGS) indicate below-median to median streamflow conditions across roughly the northern half of the MARFC region.  Meanwhile, across the southern half of the region streamflow conditions are in the median to above-median range.  Conditions have decreased some from two weeks ago.  Please visit https://waterdata.usgs.gov/nwis/rt.

SOIL MOISTURE CONDITIONS - GENERALLY MUCH-ABOVE AVERAGE

The long-term Palmer drought severity index is useful to estimate deep soil moisture conditions.  The March 3, 2019 chart (found at https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/regional_monitoring/palmer.gif) suggests deep soils across most of the MARFC service area contain moisture that continues to be much-above normal for this time of year.  Additional more detailed soil moisture information continues to support the idea that soils are extremely wet across nearly all of the MARFC area.  Go to https://www.cpc.ncep.noaa.gov/products/Soilmst_Monitoring/ and then click on U.S. Monitoring to view this soil moisture information.

GROUNDWATER - VARIABLE

Within the MARFC area, real-time USGS groundwater monitoring wells indicate groundwater levels increase from below normal/normal across about the northern third of the region, to above normal/much above normal across the southern two-thirds.  Please visit https://groundwaterwatch.usgs.gov.

RESERVOIR CONDITIONS - AVERAGE TO ABOVE AVERAGE

Most major reservoirs within the MARFC region are holding storages that are average to above average for this time of year.

FUTURE WEATHER CONDITIONS - TYPICAL FOR MARCH

Weather conditions during the next week are expected to be rather typical for early March, which means fluctuating temperatures and generally light-moderate precipitation.  A light precipitation event moves through the region Friday, while a more significant event is anticipated this weekend.  The weekend event will generate some snowmelt along with generally moderate amounts of precipitation.  Mostly rain is expected, with some mixed precipitation across the north at the beginning of the event.  This system should be monitored for the potential to produce heavier rain than currently anticipated.  Cooler and drier weather follows the weekend system into midweek, with increasingly milder and wetter conditions developing around midweek and beyond.  The latest (March 6) longer-range weather outlook issued by the NWS Climate Prediction Center suggests above-average temperatures and precipitation for the MARFC region for the five-day period March 12-16, 2019.  Long-range outlooks can be viewed at https://www.cpc.ncep.noaa.gov/.

ENSEMBLE RIVER FORECASTS - A LIMITED THREAT OF RIVER FLOODING DEVELOPING DURING THE NEXT WEEK

The most recent runs (March 7, 2019) of the short-term (one week) ensemble river forecasts, which take into account anticipated future weather conditions including precipitation and temperatures, show a limited threat of river flooding developing within the MARFC service area.  A snowmelt/rainfall event is anticipated this weekend, but at the present time this event does not look significant enough to produce river flooding.  Still, this event should be monitored since heavier rain than currently anticipated could result in some river flooding.  Longer-range ensemble river forecasts do show an elevated risk of river flooding developing for many areas, compared to normal, for the next 30 days.  This elevated longer-range risk reflects the very wet soils and generally above-median streamflow conditions that still exist across much of the region.  Please visit https://www.weather.gov/erh/mmefs for short-term ensemble river forecasts.

SUMMARY

The risk of river flooding during just the next week for streams and rivers within the MARFC service area is about average, except for northern portions of PA and NY, where the risk is somewhat below average.  However, this outlook will be updated next Wednesday or Thursday, March 13-14.  It is likely that many areas will see the river flood risk increase at that time.  The most significant weather event during this one-week outlook period will occur over the weekend, when some snowmelt and a moderate rainfall are anticipated.  At this time this weekend’s event does not appear as though it will cause river flooding, but if more snow melts or rain is heavier than anticipated, some flooding could develop.  Please monitor NWS forecasts during the next couple of days for updated information regarding this weekend’s snowmelt/rainfall event.

WATER SUPPLY OUTLOOK

According to the latest (March 5) U.S. Drought monitor (https://droughtmonitor.unl.edu), there are currently no drought conditions within the MARFC service area.  Visit https://www.drought.gov, https://www.cpc.ncep.noaa.gov and https://www.weather.gov/marfc/wro_north for additional drought and water supply information.  Assuming near-normal precipitation for the next few months, no water supply shortages are anticipated anywhere within the MARFC region through at least mid-June, 2019.

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

The next Winter/Spring Flood Outlook will be issued by this office in one week on or about March 13-14, 2019.

 

Outlook #4 released on February 21, 2019


Winter/Spring River Flood Potential Outlook
National Weather Service Middle Atlantic River Forecast Center (MARFC)
State College, PA
11:30 am EST Thu, Feb 21, 2019

Outlook Number 19-04 - February 21, 2019 (outlook map)

This Winter/Spring River Flood Potential Outlook is valid for the two-week period February 21-March 7, 2019.

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 others.  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 during the next two weeks (through March 7) varies from somewhat above-average across most of the southern half of the MARFC service area, then decreases to near-average or even somewhat below average across the northern half.  Factors which contribute to this assessment of river flood potential are discussed in some detail below.

CURRENT FLOODING - NONE

There is currently no river flooding occurring within the MARFC service area.

RECENT PRECIPITATION - NEAR TO ABOVE AVERAGE

During the last 30 days (January 22 - February 20, 2019) observed precipitation has been mostly average to above average across the MARFC service area.  Portions of western and central PA have been the wettest compared to normal, while portions of VA and the Delmarva Peninsula have been the driest compared to normal.  To view precipitation departure data please visit https://www.weather.gov/marfc/Precipitation_Departures.

SNOW CONDITIONS - VARIABLE

Due to yesterday’s storm, at the time of this writing snow/sleet covers the ground across nearly all of the MARFC service area.  Only lower portions of the Delmarva Peninsula and southeastern VA have little or no snow/sleet on the ground.  However, most if not all of the snow/sleet across southern and eastern areas will melt during the next few days.  Current snow depths range from 1-10 inches while current snow water equivalent values range from a minimum of about 0.25 inches across the eastern edge of the snow cover to a maximum of around 2.25 inches across portions of the Chenango, North Branch Susquehanna and Upper Delaware Basins in NY and portions of the West Branch Susquehanna in central PA.  Snow conditions are somewhat below average for this time of winter across NY and northern PA.  Elsewhere, conditions are fairly close to average for this time of winter.  The snow/sleet across the far south and east is a little unusual, but it will melt in the next day or two and is generally hydrologically insignificant.  Snow information can be found at https://www.weather.gov/marfc/Snow and https://www.nohrsc.noaa.gov.

RIVER ICE - BELOW AVERAGE TO AVERAGE

Recent observations from ice observers and satellite photos currently indicate that little river ice exists on streams and rivers within the MARFC region.  As such, river ice conditions are below average for this time of year across roughly the northwestern half of the region.  Meanwhile, across the southeastern half of the region, the lack of river ice is fairly typical for late February.

STREAMFLOW CONDITIONS - ABOVE MEDIAN TO MUCH-ABOVE MEDIAN

The latest data from the United States Geological Survey (USGS) indicate above normal to much-above normal streamflow conditions across most of the MARFC region.  Streamflow conditions are currently highest relative to normal across southern and eastern portions of the region.  Please visit https://waterdata.usgs.gov/nwis/rt for current streamflow data.

SOIL MOISTURE CONDITIONS - GENERALLY MUCH-ABOVE AVERAGE

The long-term Palmer drought severity index is useful to estimate deep soil moisture conditions.  The February 16, 2019 chart (found at https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/regional_monitoring/palmer.gif) suggests deep soils across most of the MARFC service area contain moisture that continues to be much-above normal for this time of year.  Additional more detailed soil moisture information supports the idea that soils are extremely wet across nearly all of the MARFC area.  Go to https://www.cpc.ncep.noaa.gov/products/Soilmst_Monitoring/ and then click on U.S. Monitoring to view this soil moisture information.

GROUNDWATER - ABOVE NORMAL TO MUCH ABOVE NORMAL

Throughout the MARFC area, most USGS groundwater monitoring wells continue to measure above-normal to much-above-normal groundwater levels.  Please visit https://groundwaterwatch.usgs.gov.

RESERVOIR CONDITIONS - AVERAGE TO ABOVE AVERAGE

Most major reservoirs within the MARFC region are holding storages that are average to above average for this time of year.

FUTURE WEATHER CONDITIONS - MILD AND WET, THEN COOLER AND DRIER 

Snowmelt is anticipated across much of the MARFC region during the next few days, but especially across the southern half of the region.  Additionally, a moderate-to-heavy rain event seems likely this weekend, again mainly across the southern half of the region.  This weather pattern has a decent chance of causing river flooding to develop during the next several days in this region, including the Potomac, Shenandoah, Rappahannock, James and Appomattox River Basins.  Beyond the next few days, a gradually cooler and drier weather pattern looks likely for most of the MARFC region.  This would act to decrease the chances for river flooding to some degree.  The latest (February 20) longer-range weather outlook issued by the NWS Climate Prediction Center suggests the second week of this two-week period may see below-average temperatures and about normal precipitation for most of the MARFC region.  Long-range outlooks can be viewed at https://www.cpc.ncep.noaa.gov/.

ENSEMBLE RIVER FORECASTS - A FAIR THREAT OF RIVER FLOODING DEVELOPING ACROSS THE SOUTH

The most recent runs (February 21, 2019) of the short-term (one week) ensemble river forecasts, which take into account anticipated future weather conditions including precipitation and temperatures, show fairly high chances of river flooding developing during the next several days, mainly across the southern half of the MARFC service area.   Longer-range ensemble river forecasts also show a somewhat elevated risk of river flooding, compared to normal, for the next 30 days - again mainly for the southern half of the region.  This elevated longer-range risk reflects the very wet soils and high streamflow conditions that currently exist across the region.  Please visit https://www.weather.gov/erh/mmefs for short-term ensemble river forecasts.

SUMMARY

An elevated risk of river flooding - above average for this time of winter - currently exists across much of the southern half of the MARFC region.  Melting snow during the next few days, combined with a threat of moderate to heavy rain this weekend, are helping to create the short-term river flood threat.  Some of the flooding could reach moderate levels.  Beyond the next few days, the river flood potential remains somewhat above average across the south through this outlook period ending March 7.  With the wet soils and high streamflow in this region, any additional heavy rain events later in this outlook period could easily result in river flooding.  Meanwhile, across the northern half of the region, the river flood potential during this two-week outlook period is average or even somewhat below average.  Snowmelt further north will be less impressive, and the weekend rain event at this time looks to impact southern regions more than northern regions.  In general, weather conditions after this weekend look to turn gradually cooler and drier across most of the MARFC region.  The latest long-range weather outlook issued by the NWS Climate Prediction Center can be seen at https://www.cpc.ncep.noaa.gov/.

WATER SUPPLY OUTLOOK

According to the latest (February 19) U.S. Drought monitor (https://droughtmonitor.unl.edu), there are currently no drought conditions within the MARFC service area.  Visit https://www.drought.gov, https://www.cpc.ncep.noaa.gov and https://www.weather.gov/marfc/wro_north for additional drought and water supply information.  Assuming near-normal precipitation for the next few months, no water supply shortages are anticipated anywhere within the MARFC region through at least May, 2019.

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

The next Winter/Spring Flood Outlook will be issued by this office in two weeks, on or about March 6-7, 2019.

SK

Outlook #3 released on February 7, 2019


Winter/Spring River Flood Potential Outlook
National Weather Service Middle Atlantic River Forecast Center (MARFC)
State College, PA
9:25 am EST Thu, Feb 07, 2019

 

Outlook Number 19-03 - February 07, 2019 (outlook map)

This Winter/Spring River Flood Potential Outlook is valid for the two-week period February 7-21, 2019. 

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 others.  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 - GENERALLY ABOVE AVERAGE

Wet soils, high streamflow, and a weather pattern that favors above-average precipitation during the next two-week period all add up to a generally above-average river flood potential across most of the MARFC region.  Factors which contribute to this assessment of river flood potential are discussed in some detail below.

CURRENT FLOODING - NONE

There is currently no river flooding occurring within the MARFC service area.

RECENT PRECIPITATION - VARIABLE

During the last 30 days (January 7 - February 5, 2019) observed precipitation has been quite variable across the MARFC service area.  The northern third of the region (NY, northern PA, northwestern NJ) has recorded above to much-above normal precipitation.  Further south, the central third of the region (southern PA, most of NJ, central MD, northeastern WV and northern VA) has, in general, received near-normal precipitation during the last 30 days.  Finally, the southern third of the region (western MD, most of VA, and central portions of the Delmarva Peninsula) has generally seen below average precipitation.  To view precipitation departure data please visit https://www.weather.gov/marfc/Precipitation_Departures.

SNOW CONDITIONS - AVERAGE TO BELOW AVERAGE

Presently within the MARFC service area snow covers the ground generally north and west of a line that extends from roughly Port Jervis, NY/Matamoras, PA to near Cumberland, MD to near Elkins, WV.  The greatest snow depths of about 3-14 inches are found in the Chenango, North Branch Susquehanna and Upper Delaware River Basins in NY.  From here, depths decrease gradually heading southward to just a couple or few inches across central PA, western MD and northeastern WV.  Snow water equivalent values range from about 0.75-2.00 inches across the Chenango, North Branch Susquehanna and Upper Delaware Basins in NY.  The remaining snowpack in NY, PA, MD and WV has snow water equivalent values of generally less than an inch.  Snow conditions are somewhat below average for the date across about the northwestern half of the MARFC region, where water equivalent values of 1-4 inches are more typical for this time of year.  Elsewhere, the current lack of snow across the southeastern half of the region is about average for early February.  Snow information can be found at https://www.weather.gov/marfc/Snow and https://www.nohrsc.noaa.gov.

RIVER ICE - BELOW AVERAGE TO AVERAGE

Recent observations from ice observers, along with recent satellite photos, confirm that river ice continues to be observed along sections of some streams and rivers, mainly across northern portions of the MARFC region.  Where river ice exists, the river ice is not particularly widespread or thick for early February.  As such, river ice conditions are generally somewhat below average for early February across the north.  Meanwhile, across about the southern half of the region, little if any river ice is being observed which is about normal.

STREAMFLOW CONDITIONS - MOSTLY ABOVE MEDIAN

The latest data from the United States Geological Survey (USGS) indicate above normal to much-above normal streamflow conditions continue across much of the MARFC region.  Some scattered areas, including southeastern VA and lower portions of the Delmarva Peninsula, have streamflow conditions that are about median for the date.  Some gages across the north are still being affected by ice.  Please visit https://waterdata.usgs.gov/nwis/rt for current streamflow data.

SOIL MOISTURE CONDITIONS - GENERALLY MUCH-ABOVE AVERAGE

The long-term Palmer drought severity index is useful to estimate deep soil moisture conditions.  The February 02, 2019 chart (found at https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/regional_monitoring/palmer.gif) suggests deep soils across most of the MARFC service area contain moisture that continues to be much-above normal for this time of year.  Additional more detailed soil moisture information supports the idea that soils are extremely wet across nearly all of the MARFC area.  Go to https://www.cpc.ncep.noaa.gov/products/Soilmst_Monitoring/ and then click on U.S. Monitoring to view this soil moisture information.

GROUNDWATER - ABOVE NORMAL TO EXTREMELY HIGH

Throughout the MARFC area, most USGS groundwater monitoring wells continue to measure above normal to extremely high groundwater levels.  Please visit https://groundwaterwatch.usgs.gov.

RESERVOIR CONDITIONS - AVERAGE TO ABOVE AVERAGE

Most major reservoirs within the MARFC region are holding storages that are average to above average for this time of year.

FUTURE WEATHER CONDITIONS - GENERALLY MILD AND WET 

The next week, and possibly beyond, is suggestive of a fairly wet and generally mild weather pattern.  During the next 24 hours periods of light-moderate rain will continue across the region until a cold front pushes through Thursday night/Friday morning.  The heaviest rainfall is expected across the northern half of the MARFC service area, where additional rainfall of 0.25-1.00 inches is possible through 7am EST Friday.  This rain/snowmelt event could result in some scattered, mostly minor flooding to develop within the Susquehanna River Basin in NY and northern PA during the next couple of days.  After a dry but chilly weekend, another precipitation event begins Sunday night and persists into Tuesday night, bringing rain to the south and mixed precipitation to the north.  Amounts could be moderate-heavy with this event.  A third event is possible toward the end of next week.  The latest (February 6, 2019) longer-range weather outlook issued by the NWS Climate Prediction Center suggests the second week of this two-week period may see above-normal precipitation continue and have normal or above normal temperatures.  Long-range outlooks can be viewed at https://www.cpc.ncep.noaa.gov/.

ENSEMBLE RIVER FORECASTS - SOME THREAT OF RIVER FLOODING DEVELOPING

The most recent runs (February 7, 2019) of the short-term (one week) ensemble river forecasts, which take into account anticipated future weather conditions including precipitation and temperatures, show some mostly minor flooding is possible during the next 2-3 days across mainly northern portions of the MARFC service area.  Beyond the next 2-3 days, longer-range ensemble river forecasts also show an elevated risk of river flooding, compared to normal, for the next 30 days.  This elevated risk reflects the very wet soils and high streamflow conditions that currently exist across the region.  Please visit https://www.weather.gov/erh/mmefs for short-term ensemble river forecasts.

SUMMARY

Scattered river flooding, mostly minor, is possible during the next 2-3 days, mainly across northern portions of the MARFC service area.  This is due to the rain/snowmelt event expected to continue through tonight across the north.  Beyond this event, additional significant precipitation events seem possible during this outlook period, one next Monday-Tuesday and another toward the end of next week.  The anticipated wet weather pattern (and snowmelt where snow exists) combined with very wet soils and high streamflow conditions lead to a generally above-average river flood potential across most of the MARFC region during this two-week outlook period ending February 21, 2019.  The latest long-range weather outlook issued by the NWS Climate Prediction Center can be seen at https://www.cpc.ncep.noaa.gov/.

WATER SUPPLY OUTLOOK

According to the latest (January 31, 2019) U.S. Drought monitor (https://droughtmonitor.unl.edu), there are currently no drought conditions within the MARFC service area.  Visit https://www.drought.gov, https://www.cpc.ncep.noaa.gov and https://www.weather.gov/marfc/wro_north for additional drought and water supply information.  Assuming near-normal precipitation for the next few months, no water supply shortages are anticipated anywhere within the MARFC region through at least April, 2019.

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

The next Winter/Spring Flood Outlook will be issued by this office in two weeks, on or about February 20-21, 2019.

SK

 

Outlook #2 released on January 24, 2019


Winter/Spring River Flood Potential Outlook
National Weather Service Middle Atlantic River Forecast Center (MARFC)
State College, PA
1:15 pm EST Thu, Jan 24, 2019

 

Outlook Number 19-02 - January 24, 2019 (outlook map)

This Winter/Spring River Flood Potential Outlook is valid for the two-week period January 24-February 7, 2019.

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 others.  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 THEN DIMINISHING TO AVEREAGE/BELOW AVERAGE

Current MARFC river forecasts indicate a high likelihood of mostly minor flooding developing today along portions of several small streams and rivers as a result of the current rainfall/snowmelt event.  For the remainder of this outlook period, after this next 2-3 days, the river flood potential across the MARFC area of responsibility will quickly diminish to average or below average due to an expected colder and drier weather pattern for much of the next two weeks.  Factors which contribute to this assessment of river flood potential are discussed in some detail below.

CURRENT FLOODING - MINOR FLOODING EXPECTED TO BEGIN SOON ALONG SEVERAL STREAMS AND RIVERS

Current MARFC river forecasts indicate a high likelihood of mostly minor flooding developing today along portions of several small streams and rivers as a result of the current rainfall/snowmelt event. This flooding will continue for the next 2-3 days at some locations.  To see current detailed river forecasts go to our homepage at www.weather.gov/marfc/ or the NWS Advanced Hydrologic Prediction Service (AHPS) web page at https://water.weather.gov/ahps.

RECENT PRECIPITATION - MOSTLY ABOVE AVERAGE

During the last 30 days (December 25, 2018 - January 23, 2019) the wet precipitation pattern has continued.  With the exception of southeastern VA and portions of the Delmarva Peninsula, precipitation during the last 30 days was above average to much-above average across the entire MARFC region.ar average.  To view precipitation departure data please visit https://www.weather.gov/marfc/Precipitation_Departures.

SNOW CONDITIONS - ABOUT AVERAGE

Presently within the MARFC service area snow covers the ground north and west of a line that extends from northwest NJ to near Harrisburg, PA to near Moorefield, WV.  The greatest snow depths of about 4-14 inches are found in NY and northern PA.  Depths decrease gradually heading southward to just a couple or few inches across southern and southeastern PA, northern NJ, western MD and northeastern WV.  Snow water equivalent values range from about 0.75-2.50 inches across NY and much of PA, with the heaviest amounts across eastern NY and northern PA.  Further south and east, values drop to about 0.50 inches or less in WV and MD.  Snow conditions are now considered about average for most of the MARFC region for the date, although a fair amount of snow has melted just during the last 24 hours across the entire MARFC region.  Snow information can be found at https://www.weather.gov/marfc/Snow and https://www.nohrsc.noaa.gov.

RIVER ICE - BELOW AVERAGE TO AVERAGE

Due to the recent cold weather, some ice has formed during the last week or so along sections of some streams and rivers, mainly across northern portions of the MARFC region.  The river ice is not widespread or thick, and the current rain/snowmelt event is flushing much of the ice out of the streams and rivers.  As such, river ice conditions are generally below average for mid-winter across the north.  Meanwhile, across the southeastern half of the region, minimal river ice is being observed which is about normal.

STREAMFLOW CONDITIONS - MOSTLY ABOVE MEDIAN

The latest data from the United States Geological Survey (USGS) indicate above normal to much-above normal streamflow conditions continue across much of the MARFC region.  Some scattered areas, including southeastern VA and lower portions of the Delmarva Peninsula, have streamflow conditions that are about median for the date.  Some ice has formed in the last week, but much of it is being flushed out by the current rain/snowmelt event.  Please visit https://waterdata.usgs.gov/nwis/rt for current streamflow data.

SOIL MOISTURE CONDITIONS - GENERALLY MUCH-ABOVE AVERAGE

The long-term Palmer drought severity index is useful to estimate deep soil moisture conditions.  The January 19, 2019 chart (found at http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/regional_monitoring/palmer.gif) suggests deep soils across most of the MARFC service area contain moisture that continues to be much-above normal for this time of year.  Additional more detailed soil moisture information supports the idea that soils are extremely wet across nearly all of the MARFC area.  Go to http://www.cpc.ncep.noaa.gov/products/Soilmst_Monitoring and then click on U.S. Monitoring to view this soil moisture information.

GROUNDWATER - ABOVE NORMAL TO EXTREMELY HIGH

USGS groundwater monitoring wells continue to measure above normal to extremely high groundwater levels across nearly all of the MARFC area.  Please visit https://groundwaterwatch.usgs.gov.

RESERVOIR CONDITIONS - AVERAGE TO ABOVE AVERAGE

Most major reservoirs within the MARFC region are holding storages that are average to above average for this time of year.

FUTURE WEATHER CONDITIONS 

The current rain/snowmelt event will end later today.  This event is expected to cause some scattered, mostly minor flooding along smaller streams and rivers to develop today and persist for the next 2-3 days at a few locations.  A cold and drier weather pattern is expected across the MARFC region for most of the next two weeks.  Most precipitation that falls during the next week will likely be only light-moderate and will likely be snow at most locations.  No heavy rain events are expected for at least the next week.  Indeed, current longer-range weather outlooks suggest the second week of this two-week period may be colder than normal, while precipitation is most likely to be normal or below normal.  Long-range outlooks can be viewed at http://www.cpc.ncep.noaa.gov/products/predictions/610day.

ENSEMBLE RIVER FORECASTS - HIGH THREAT OF MOSTLY MINOR RIVER FLOODING DEVELOPING TODAY AND CONTINUING FOR A DAY OR TWO

The most recent runs (January 24, 2019) of the ensemble river forecasts, which take into account anticipated future weather conditions including precipitation and temperatures, show minor flooding is likely during the next couple of days at several MARFC river forecast points as a result of the current rain/snowmelt event.  This near-term river flood threat is also detailed in current MARFC river forecasts.  Beyond this high near-term flood threat, additional river flooding seems unlikely for the remainder of this outlook period within the MARFC region.  Please visit https://www.weather.gov/erh/mmefs for ensemble river forecasts.

SUMMARY

Scattered minor river flooding is expected to develop today at several MARFC forecast points due to the current rain/snowmelt event.  Detailed river forecasts can be seen at www.weather.gov/marfc/. Beyond this high near-term river flood threat, additional river flooding seems unlikely for the remainder of this two week outlook period, through February 7, 2019.  Much colder and generally drier weather conditions are anticipated, with no hint of any heavy rain events for at least the next week.  The latest long-range weather outlook issued by the NWS Climate Prediction Center can be seen at http://www.cpc.ncep.noaa.gov/.

WATER SUPPLY OUTLOOK

According to the latest (January 17, 2019) U.S. Drought monitor (http://droughtmonitor.unl.edu), there are currently no drought conditions within the MARFC service area.  Visit https://www.drought.gov, https://www.cpc.ncep.noaa.gov and https://www.weather.gov/marfc/wro_north for additional drought and water supply information.  Assuming near-normal precipitation for the next few months, no water supply shortages are anticipated anywhere within the MARFC region through at least April, 2019.

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

The next Winter/Spring Flood Outlook will be issued by this office in two weeks, on or about February 6-7, 2019.

SK

 

 

Outlook #1 released on January 9, 2019


Winter/Spring River Flood Potential Outlook
National Weather Service Middle Atlantic River Forecast Center (MARFC)
State College, PA
1:30 pm EST Wed, Jan 9, 2019

 

Outlook Number 19-01 – January 9, 2019 (outlook map).

This Winter/Spring River Flood Potential Outlook is valid for the two-week period January 9-23, 2019.

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 others.  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 ABOVE AVERAGE

The river flood potential across the MARFC area of responsibility for the next two weeks is average to above average.  Factors which contribute to this assessment of river flood potential are discussed in some detail below.

CURRENT FLOODING – NONE

There is no river flooding within the MARFC service area presently.

RECENT PRECIPITATION – ABOVE TO MUCH-ABOVE AVERAGE

The MARFC region experienced widespread near-record to record precipitation during calendar year 2018.  The frequent doses of heavy precipitation led to a record number of flood events at the 175 official hydrologic forecast points within the MARFC service area.  More recently, during the last 30 days (December 10, 2018 – January 8, 2019) the wet precipitation pattern has continued.  With the exception of a portion of NY, precipitation during the last 30 days was above average to much-above average across the entire MARFC region.  In a small portion of NY precipitation was near average.  To view precipitation departure data please visit https://www.weather.gov/marfc/Precipitation_Departures.

SNOW CONDITIONS – BELOW AVERAGE TO AVERAGE

Presently the only snow on the ground within the MARFC service area is across portions of NY and northern PA.  In these areas snow depths are 3 inches or less, with snow water equivalent values of less than a half inch.  Snow conditions in NY, across much of PA and along the Appalachians are best described as being below average for early January.  Across the southeastern half of the MARFC region, no snow exists which is about average for that region.  Additional accumulations of lake-effect snow are expected during the next two days across northern PA and NY, where some locations could pick up several inches.  Snow information can be found at https://www.weather.gov/marfc/Snow and https://www.nohrsc.noaa.gov.

RIVER ICE – BELOW AVERAGE TO AVERAGE

No river ice is currently being observed within the MARFC region which is below normal for about the northwestern third of the MARFC service area, and about normal elsewhere.

STREAMFLOW CONDITIONS – MOSTLY ABOVE MEDIAN

The latest data from the United States Geological Survey (USGS) indicate above normal to much-above normal streamflow conditions across most of the MARFC region.  The exception is across southeastern VA and lower portions of the Delmarva Peninsula where streamflow conditions are closer to median for the date.  Please visit https://waterdata.usgs.gov/nwis/rt for current streamflow data.

SOIL MOISTURE CONDITIONS - NORMAL/BELOW NORMAL

The long-term Palmer drought severity index is used to estimate deep soil moisture conditions.  The January 5, 2019 chart (found at http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/regional_monitoring/palmer.gif) suggests deep soils across most of the MARFC service area contain moisture that is much-above normal for this time of year.  This reflects just how extremely wet 2018 was across the MARFC region.  Additional more detailed soil moisture information supports the idea that soils are extremely wet across all of the MARFC area.  Go to http://www.cpc.ncep.noaa.gov/products/Soilmst_Monitoring and then click on U.S. Monitoring to view this soil moisture information.

GROUNDWATER – ABOVE NORMAL TO EXTREMELY HIGH

USGS groundwater monitoring wells are currently indicating above normal to extremely high groundwater levels across nearly all of the MARFC area.  Please visit https://groundwaterwatch.usgs.gov.

RESERVOIR CONDITIONS – AVERAGE TO ABOVE AVERAGE

Most major reservoirs within the MARFC region are holding storages that are average to above average for this time of year.

FUTURE WEATHER CONDITIONS 

Seasonably cool temperatures and generally light-moderate precipitation events are expected for about the next week across the MARFC region.  Some significant lake-effect snow will accumulate across portions of NY and PA during the next two days.  A storm system may impact portions of the MARFC region Saturday night-Sunday night, bringing what currently looks to be light-moderate amounts of snow and mixed precipitation to the region.  A drier and somewhat milder pattern looks possible around midweek next week.  Then a more significant storm system may impact the region toward the end of next week.  Indeed, current longer-range weather outlooks suggest the second week of this two-week period may have wetter than normal weather conditions.  Long-range outlooks can be viewed at http://www.cpc.ncep.noaa.gov/products/predictions/610day.

ENSEMBLE RIVER FORECASTS – NEGLIGIBLE THREAT OF RIVER FLOODING DEVELOPING THROUGH JANUARY 15, 2019

The most recent runs (January 9, 2019) of the ensemble river forecasts, which take into account anticipated future weather conditions including precipitation and temperatures, show little chance of river flooding developing within the MARFC region for about the next week through January 15, 2019.  Please visit https://www.weather.gov/erh/mmefs for ensemble river forecasts.

SUMMARY

For the next two weeks the river flood potential for rivers in the MARFC region is average to above average for this time of year.  Although snow and river ice conditions are currently negligible, soils are wet and streamflow is high across the entire region.  A single, widespread heavy rain event of 2-3 inches in 6-24 hours would likely result in some river flooding within the MARFC region.  The good news is that there are currently no strong indications of any widespread heavy rain events for at least the first week of this outlook period, through next Wednesday, January 16, 2019.  For the second week of this outlook period, the latest long-range weather outlook issued by the NWS Climate Prediction Center suggests precipitation could once again be above average across the MARFC region.  Long-range outlooks are seen at http://www.cpc.ncep.noaa.gov/.

WATER SUPPLY OUTLOOK

According to the latest (January 1, 2019) U.S. Drought monitor (http://droughtmonitor.unl.edu), there are currently no drought conditions within the MARFC service area.  Visit https://www.drought.gov, https://www.cpc.ncep.noaa.gov and https://www.weather.gov/marfc/wro_north for additional drought and water supply information.

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

The next Winter/Spring Flood Outlook will be issued by this office in two weeks, on January 23, 2019.

SK