National Weather Service United States Department of Commerce
WATER RESOURCES OUTLOOK NATIONAL WEATHER SERVICE OHIO RIVER FORECAST CENTER WILMINGTON OH 1014 AM EDT Wednesday August 30 2017 THE FOLLOWING IS THE 30-DAY WATER RESOURCES OUTLOOK FOR THE MONTH OF SEPTEMBER .WATER RESOURCES STREAMFLOW OUTLOOK... The Water Resources Outlook for the Ohio Valley in September is a bit of a mixed bag. The forecast calls for above normal streamflows in the far southern reaches while the northwest portion is trending a bit below average. However, the vast majority of the Ohio River forecast basin will likely fall within the normal streamflow range for September. ..................................................................... .HYDROLOGIC FLOOD AND DROUGHT POTENTIAL... The very beginning of September will see the tropical remnants of Harvey impacting the basin, with heavy rain forecast in the far southern reaches in Tennessee. There is some flood potential with this passage, particularly in the more flashy streams. The beginning of September also sees a bit of dryness in the far western basin, which could be exacerbated a bit by a dry September. Certainly nothing very widespread or extreme though in that area. ..................................................................... .PAST 30 DAY HYDROLOGICAL AND METEOROLOGICAL REVIEW... RAINFALL DEPARTURES... August saw the northern half of the Ohio River forecast basin with below normal rainfall totals (25 to 75% of normal) and the southern half more normal to even a bit above normal. Above normal locations were concentrated in central and eastern Kentucky and ran about 125 to 150% of normal. http://www.weather.gov/ohrfc/images/dynamic/latest30day.jpeg SOIL MOISTURE CONDITIONS... Most of the area's soil moisture conditions are near normal for the vast majority of the basin. The far western basin shows a bit drier than normal and eastern Kentucky is showing slightly above normal. http://www.cpc.noaa.gov/soilmst/w.shtml STREAMFLOW CONDITIONS... Streamflows for the month of August averaged below normal for the far western portions of the Ohio River forecast basin and above normal for eastern Kentucky and portions of western Ohio. The vast majority of the basin stayed pretty close to normal. http://watermonitor.gov ..................................................................... .ATMOSPHERIC TELECONNECTION AND OSCILLATION FORECASTS FOR THE NEXT MONTH... TELECONNECTION/OSCILLATION PATTERN ARCTIC OSCILLATION Neutral = Normal precipitation NORTH ATLANTIC OSCILLATION Neutral = Normal precipitation to slightly above PACIFIC/NORTH AMERICAN TELECONNECTION Neutral = Normal precipitation ENSO - EL NINO/LA NINA OSCILLATION Neutral = Normal precipitation http://www.cpc.noaa.gov ..................................................................... .TECHNICAL DISCUSSION... In putting together September's water resource outlook, there were not a whole lot of strong indicators to hang the proverbial hat on. Long term models like the NMME, CFSv2, and CCSM4 models were sending mixed messages amongst each other, while the teleconnections shown above were canceling themselves out in their neutrality. Therefore, there was a particularly heavy lean on the mid-range models which take us well into the first and second weeks of the month and how they were setting the table. Sure enough, the very beginning of September will see the remnants of an exteremly potent tropical system (Harvey) bringing heavy rains to the far southern reaches...Tennessee and Kentucky. In fact, there are forecasts for the first few days of the month to see the entirety of the average monthly totals. It is September though...one of the climatologically driest months. In Tennessee and southern Kentucky's case, that translates to 2.5 to 4 inches. The liklihood that these areas can see above normal then for the month seems a good bet. The forecast for the smattering of below normal streamflows for areas of the western and northwest basins, comes from a look at the mid-term models as well as a little heavier lean on the CCSM4 and NMME longer term models. They were a bit more on point for August...subsequently they are also a bit drier for Illinois and northern Indiana for September. ....................................................................... VISIT OUR WATER RESOURCES WEBSITE AT http://www.weather.gov/ohrfc/WRO IN ADDITION TO A 30-DAY STREAMFLOW OUTLOOK...YOU CAN ALSO OBTAIN A 60- AND 90-DAY OUTLOOK AT THE WEBSITE $$