000
FGUS71 KPBZ 021337
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-
049-051-061-069-077-093-103-041345-

WINTER/SPRING FLOOD POTENTIAL OUTLOOK
NATIONAL WEATHER SERVICE PITTSBURGH PA
937 AM EDT THU MAY 2 2013

...WINTER/SPRING FLOOD POTENTIAL OUTLOOK...

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

NORMAL FLOOD POTENTIAL MEANS AT LEAST MINOR FLOODING IS POSSIBLE. 

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 CHANCE 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 HYDRO 
METEOROLOGICAL 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 35% TO 100% OF NORMAL 
ACROSS THE ALLEGHENY RIVER...MONONGAHELA...CHEAT AND UPPER OHIO 
BASINS. ACROSS THE MUSKINGUM BASIN...RAINFALL WAS BETWEEN 50% TO 
100% OF NORMAL.

OVER THE PAST 60 DAYS...PRECIPITATION HAS BEEN 28% TO 95% OF NORMAL 
ACROSS OUR ENTIRE FORECAST REGION.

OVER THE PAST 90 DAYS...PRECIPITATION HAS BEEN 45% TO 95% OF NORMAL 
FOR MOST OF THE REGION. 

THE EARLY SPRING WEATHER PATTERN FOR THE OHIO RIVER BASIN HAS BEEN 
MOSTLY PROGRESSIVE...PRODUCING LIGHT TO MODERATE PRECIPITATION 
EVENTS RESULTING IN GENERALLY MOIST SOIL CONDITIONS.
 
SNOW PACK HAS MELTED ACROSS THE REGION.

STREAMFLOW CONDITIONS 
STREAM FLOWS AVERAGED NEAR NORMAL DURING THE PAST 30 DAYS. THERE WAS 
AN AREA ACROSS SOUTHEAST OHIO AND NORTHWEST WEST VIRGINIA WITH BELOW 
NORMAL STREAM FLOWS FOR THE PAST 20 DAYS. 

ICE CONDITIONS 
THERE IS NO RIVER ICE OVER THE AREA.

RESERVOIR CAPACITIES
RESERVOIRS IN THE USACE PITTSBURGH DISTRICT WERE GRADUALLY 
INCREASING POOL LEVELS WITH 12 RESERVOIRS REPORTING FLOOD STORAGE 
CAPACITIES LESS THAN SIX PERCENT. THREE RESERVOIRS REPORTED TEN TO 
TWENTY EIGHT PERCENT OF FLOOD STORAGE BEING USED. THESE VALUES WILL 
BE STEADILY TRENDING UP OVER THE NEXT 30 DAYS AS THE USACE PREPARES 
FOR SUMMER POOLS. TEN RESERVOIRS IN THE HUNTINGDON USACE DISTRICT 
ARE AT OR NEAR NORMAL SUMMER POOL LEVELS. THE EXCEPTIONS ARE 
LEESVILLE THAT REPORTED ABOVE ALERT POOL AND TAPPAN WHICH IS ONE TO 
THREE FEET BELOW NORMAL.

WEATHER AND PRECIPITATION OUTLOOK
THE OUTLOOK FOR THE NEXT 2 WEEKS IS FOR NEAR NORMAL TEMPERATURES AND 
BELOW NORMAL PRECIPITATION. FOR THE COMING WEEK...FAIR...DRY WEATHER 
WILL DOMINATE THE REGION THROUGH THE WEEKEND. AT THE BEGINNING OF 
NEXT WEEK A STRONG...SLOW MOVING WEATHER SYSTEM MOVES INTO THE MID 
ATLANTIC REGION BRINGING SOMEWHAT UNSETTLED WEATHER TO THE REGION 
THROUGH THE END OF THE WEEK. NORMAL PRECIPITATION FOR THE 14 DAY 
PERIOD IS ABOUT 1.65 INCHES. TEMPERATURES ARE EXPECTED TO TREND FROM 
NORMAL  TO SLIGHTLY ABOVE NORMAL FOR THE NEXT TWO WEEKS. NORMAL 
HIGHS FOR THE PERIOD RANGE FROM THE MID 60S TO LOW 70S0S. NORMAL 
LOWS RANGE FROM THE MID TO UPPER 40S. 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 MAY 
16 2013.


$$