ZCZC CRWESGTIR CES TTAA00 KTIR DDHHMM WATER RESOURCES OUTLOOK NATIONAL WEATHER SERVICE OHIO RIVER FORECAST CENTER, WILMINGTON OH 252 PM EDT Wednesday, May 1, 2013 THE FOLLOWING IS THE 30-DAY WATER RESOURCES OUTLOOK FOR THE MONTH OF MAY .WATER RESOURCES STREAMFLOW OUTLOOK... STREAMFLOWS ARE EXPECTED TO AVERAGE NORMAL TO ABOVE NORMAL IN THE OHIO RIVER BASIN/LAKE ERIE DRAINAGE. ABOVE NORMAL STREAMFLOWS ARE FOCUSED IN THE WESTERN AND SOUTHWEST BASIN WITH NORMAL IN OTHER LOCATIONS. ..................................................................... .HYDROLOGIC FLOOD AND DROUGHT POTENTIAL... ANTECEDENT CONDITIONS ARE ABOVE NORMAL IN THE WESTERN AND SOUTHWEST BASIN WITH MAINLY NORMAL CONDITIONS ELSEWHERE. FLOOD POTENTIAL IS MODERATE GIVEN THAT CLIMATOLOGICALLY MINOR FLOOD IS NORMAL FOR SPRING IN THE OHIO RIVER BASIN. ..................................................................... .PAST 30 DAY HYDROLOGICAL AND METEOROLOGICAL REVIEW... RAINFALL DEPARTURES... PRECIPITATION WAS AS MUCH AS 200 TO 300 PERCENT OF NORMAL IN AREAS OF CENTRAL AND NORTHERN INDIANA. 150 TO 200 PERCENT OF NORMAL WAS OBSERVED ACROSS MUCH OF THE WESTERN BASIN AS WELL AS AREAS OF SOUTHWEST KENTUCKY AND WESTERN PORTIONS OF MIDDLE TENNESSEE. CONVERSELY, LARGE AREAS OF WEST VIRGINIA, SOUTHEAST OHIO, AND WESTERN PA RECEIVED 50 PERCENT OR LESS OF NORMAL APRIL PRECIPITATION. HTTP://WWW.ERH.NOAA.GOV/ER/OHRFC/DROUGHT.HTML SOIL MOISTURE CONDITIONS... AREAS OF SOUTHERN KENTUCKY, MIDDLE TENNESSEE, AND INDIANA SAW A WET APRIL AND SUBSEQUENT WETTER THAN NORMAL SOILS. MOST OF THE OHIO RIVER FORECAST BASIN IS RUNNING FAIRLY NORMAL SOIL MOISTURE CONDITIONS. HTTP://WWW.CPC.NCEP.NOAA.GOV/SOILMST/W.SHTML STREAMFLOW CONDITIONS... MUCH OF THE WESTERN AND SOUTHWEST BASIN IS EXPERIENCING ABOVE NORMAL STREAMFLOWS FOR THIS TIME OF YEAR. AREAS OF THE WABASH AND CUMBERLAND WATERSHEDS ARE UP TO THE 90TH PERCENTILE. AREAS OF THE UPPER OHIO VALLEY, HOWEVER, ARE CURRENTLY BELOW NORMAL...PARTICULARLY WEST VIRGINIA WATERSHEDS. MANY OTHER AREAS OF THE BASIN ARE RELATIVELY NORMAL GIVEN THIS TIME OF YEAR. HTTP://WATERMONITOR.GOV ..................................................................... .ATMOSPHERIC TELECONNECTION AND OSCILLATION FORECASTS FOR THE NEXT MONTH... TELECONNECTION/OSCILLATION PATTERN ARCTIC OSCILLATION TRENDING POSITIVE EARLY = WETTER FIRST HALF OF MONTH NORTH ATLANTIC OSCILLATION NEUTRAL TO NEGATIVE = NORMAL TO BELOW PACIFIC/NORTH AMERICAN TELECONNECTION TRENDING POSITIVE = TRENDING ABOVE ENSO - EL NINO/LA NINA OSCILLATION NEUTRAL = NORMAL HTTP://WWW.CPC.NCEP.NOAA.GOV ..................................................................... .TECHNICAL DISCUSSION... ANTECEDENT CONDITIONS ARE ABOVE NORMAL FOR MANY AREAS OF THE WESTERN OHIO RIVER FORECAST BASIN. THAT COUPLED WITH A GENERALLY ACTIVE OUTLOOK FOR THE FIRST COUPLE OF WEEKS OF MAY GIVES RISE TO A ABOVE NORMAL OUTLOOK FOR THOSE SAME AREAS FOR THE MONTH OF MAY. THERE DOESN'T SEEM TO BE A WHOLE LOT OF EVIDENCE FOR A BELOW NORMAL MAY IN THE ATMOSPHERIC TELECONNECTIONS OR ELSEWHERE, THUS THE NORMAL OUTLOOK FOR THE EASTERN HALF OF THE BASIN. PRECIPITATION IN MAY TYPICALLY IS MORE CONVECTIVE IN NATURE VERSUS THE EARLIER SPRING SO FLOODING CAN SOMETIMES FOLLOW A MORE LOCALIZED PATTERN. THUS SOME SUB-BASINS WILL BE WELL ABOVE NORMAL FOR THE MONTH WHILE A NEIGHBORING BASIN WILL BE NORMAL OR BELOW. THESE MONTHLY OUTLOOKS ARE OBVIOUSLY GENERALIZED. ....................................................................... VISIT OUR WATER RESOURCES WEBSITE AT www.weather.gov/ohrfc/WRO.shtml IN ADDITION TO A 30-DAY STREAMFLOW OUTLOOK...YOU CAN ALSO OBTAIN A 60- AND 90-DAY OUTLOOK AT THE WEBSITE $$ NNNN