000
FGUS71 KPBZ 211241
ESFPBZ
MDC023-OHC013-019-029-031-059-067-081-111-119-121-157-PAC003-005-
007-019-031-051-053-059-063-065-073-085-121-125-129-WVC009-029-
049-051-061-069-077-093-103-041245-

WINTER/SPRING FLOOD POTENTIAL OUTLOOK
NATIONAL WEATHER SERVICE PITTSBURGH PA
841 AM EDT THU MAR 21 2013

...FLOOD POTENTIAL IS EXPECTED TO BE NEAR NORMAL TO SLIGHTLY ABOVE...

NORMAL FLOOD POTENTIAL MEANS AT LEAST MINOR FLOODING IS POSSIBLE. 
ABOVE NORMAL FLOOD POTENTIAL MEANS WIDESPREAD FLOODING COULD OCCUR 
WITH FLOODING POSSIBLY REACHING MODERATE OR MAJOR LEVELS AT SOME 
LOCATIONS.

FOR THE LONG-RANGE RIVER OUTLOOKS AND THE PROBABILITY OF
EXCEEDING FLOOD STAGE OR THE CHANCES OF FLOODING RELATIVE TO
NORMAL AT SPECIFIC FORECAST POINTS DURING THE NEXT 90-DAYS...
REFER TO WWW.WEATHER.GOV/OHRFC AND CLICK ON THE 90-DAY RIVER
OUTLOOK IN THE LEFT HAND COLUMN. CLICK ON FLOOD CHC VS. NORMAL TO
SEE THE RISK OF FLOODING WITH RESPECT TO NORMAL.

FLOOD OUTLOOKS ARE ISSUED BI-WEEKLY BY THE NATIONAL WEATHER
SERVICE DURING WINTER AND EARLY SPRING TO SUMMARIZE BASIN
HYDROMETEROLOGICAL CONDITIONS AND TO ASSESS THE POTENTIAL FOR
WINTER/SPRING FLOODING. THE OUTLOOKS ARE BASED ON CURRENT AND
EXPECTED CONDITIONS ACKNOWLEDGING THAT ACTUAL CONDITIONS COULD
CHANGE DURING THE OUTLOOK PERIOD.

IN ADDITION...90-DAY WATER RESOURCES OUTLOOKS ARE ISSUED MONTHLY.
FACTORS CONSIDERED IN ASSESSING FLOOD POTENTIAL ARE...

ANTECEDENT CONDITIONS

PAST PRECIPITATION 
OVER THE PAST 30 DAYS...PRECIPITATION HAS BEEN 40% TO 50% OF
NORMAL IN ALLEGHENY RIVER BASIN...50% TO 75% OVER THE MONONGAHELA
AND CHEAT RIVER BASINS AND 75% TO 100% ACROSS THE UPPER OHIO AND
100% TO 130% ACROSS THE MUSKINGUM BASINS.

OVER THE PAST 60 DAYS...PRECIPITATION HAS BEEN 70% TO 105% OF
NORMAL IN ALLEGHENY RIVER BASIN...75% TO 144% OVER THE 
MONONGAHELA...CHEAT...UPPER OHIO AND MUSKINGUM RIVER BASINS.

OVER THE PAST 90 DAYS...PRECIPITATION HAS BEEN 70 TO 125 OF NORMAL 
ACROSS THE ENTIRE UPPER OHIO AND MUSKINGUM BASINS.

SOILS ARE CURRENTLY MOIST TO WET ACROSS MUCH OF THE REGION DUE TO
CONSISTENT LIGHT TO MODERATE PRECIPITATION ACROSS THE REGION.
 
SNOW PACK IS LIMITED TO THE MOUNTAINOUS TERRAIN OF THE CHEAT BASIN 
IN WEST VIRGINIA WITH SNOW WATER EQUIVALENTS  AROUND 1.0 INCH. 
ACROSS THE HEADWATERS OF THE ALLEGHENY BASIN SNOW WATER EQUIVALENTS 
LESS THAN 1/2 INCH.

STREAMFLOW CONDITIONS 
STREAM FLOWS DURING THE LAST 30 DAYS HAVE AVERAGED NEAR NORMAL IN 
THE UPPER OHIO VALLEY.

ICE CONDITIONS 
RIVER ICE IS VIRTUALLY NON EXISTENT OVER THE AREA.

RESERVOIR CAPACITIES
MOST RESERVOIRS IN THE USACE PITTSBURGH DISTRICT WERE GRADUALLY 
INCREASING POOL LEVELS WITH 6 OF THE 17 RESERVOIRS REPORTING FLOOD 
STORAGE CAPACITIES OF 10 PERCENT TO 43 PERCENT. THESE VALUES HAVE 
BEEN STEADILY TRENDING UP OVER THE PAST 30 DAYS AS THE USACE 
PREPARES FOR SUMMER POOLS. THE RESERVOIRS IN THE HUNTINGDON USACE 
DISTRICT ARE AT NORMAL WINTER POOL TO ALERT POOL LEVELS. THIS IS 
UNCHANGED OVER THE PAST TWO WEEKS.

WEATHER AND PRECIPITATION OUTLOOK
THE OUTLOOK FOR THE NEXT 2 WEEKS HAS AN ACTIVE STORM TRACK OVER THE 
AREA WITH EXPECTATIONS OF NORMAL PRECIPITATION THROUGH THE PERIOD. 
NORMAL PRECIPITATION FOR THE 14 DAY PERIOD IS ABOUT 1.55 INCHES. 
TEMPERATURES ARE EXPECTED TO AVERAGE WELL BELOW NORMAL FOR THE NEXT 
TWO WEEKS. NORMAL TEMPERATURES FOR THE NEXT 14 DAYS ARE HIGHS 
RANGING THROUGH THE 50S AND LOWS IN THE 30S. THE WEATHER PATTERN 
INDICATES FREQUENT BUT RELATIVELY QUICK MOVING STORMS. FLUCTUATIONS 
IN TEMPERATURES WILL BRING PRECIPITATION IN THE FORM OF BOTH SNOW 
AND RAIN FOR THE NEXT 2 WEEKS. THE FLOOD POTENTIAL WILL REMAIN NEAR 
NORMAL.

SUMMARY...
RAINFALL IS THE PRIMARY FACTOR LEADING TO FLOODING. HEAVY OR
EXCESSIVE RAINFALL CAN CAUSE FLOODING ANY TIME OF THE YEAR...EVEN
WHERE THE FLOOD POTENTIAL IS BELOW NORMAL.

THE NEXT WINTER/SPRING FLOOD POTENTIAL OUTLOOK WILL BE ISSUED BY
APRIL 04.

$$