000
FGUS71 KPBZ 241654
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-
049-051-061-069-077-093-103-071700-

WINTER/SPRING FLOOD POTENTIAL OUTLOOK
NATIONAL WEATHER SERVICE PITTSBURGH PA
1154 AM EST THU JAN 24 2013

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

THE FLOOD POTENTIAL FOR THE PITTSBURGH HYDROLOGIC SERVICE AREA IS
FOR ABOVE NORMAL THROUGH 7 FEBRUARY. 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 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 
THE UPPER OHIO RIVER BASIN EXPERIENCED SLIGHTLY ABOVE NORMAL
PRECIPITATION DURING THE AUTUMN IN 2012 SINCE 1 JANUARY 2013...
PRECIPITATION HAS BEEN 30%-95% OF NORMAL IN UPPER OHIO RIVER
BASIN. OVER THE PAST 60 DAYS...PRECIPITATION ACROSS THE UPPER OHIO
RIVER BASIN HAS RANGED FROM 85%-175% OF NORMAL. SOILS ARE CURRENTLY
FROZEN ACROSS MUCH OF THE REGION BUT CONTAIN ABOVE NORMAL SOIL
MOISTURE.
 
SNOW COVER AND SNOW WATER CONTENT
AN ARCTIC AIR MASS HAS SETUP LAKE EFFECT SNOWS ACROSS THE UPPER
OHIO VALLEY SINCE THIS PAST WEEKEND. EVEN THOUGH SNOWS HAVE BEEN
HEAVY IN SOME LOCATIONS...THE HIGH RATIOS OF SNOWFALL TO LIQUID HAVE
KEPT WATER EQUIVALENTS TO 0.50 TO 0.75 INCH IN THE UPPER
ALLEGHENY...CHEAT...CLARION RIVER BASINS.


STREAMFLOW CONDITIONS 
STREAM FLOWS FOR THE PAST 14 DAYS HAVE RANGED FROM NORMAL TO MUCH
ABOVE NORMAL THROUGHOUT THE OHIO VALLEY SINCE EARLY DECEMBER 2012.

ICE CONDITIONS 
ICE COVERAGE ACROSS PORTIONS OF THE UPPER ALLEGHENY RIVER RANGES
FROM 45 TO 100 PERCENT. ACROSS THE LOWER ALLEGHENY ONLY SPOTTY SHORE
ICE HAS BEEN OBSERVED. ICE ON OTHER RIVERS HAS BEEN NEGLIGIBLE.

RESERVOIR CAPACITIES
ALL RESERVOIRS IN THE USACE PITTSBURGH DISTRICT WERE USING 6
PERCENT OR LESS OF THEIR CAPACITY. THIS IS UP 2 PERCENT IN THE
PAST TWO WEEKS. THE RESERVOIRS IN THE HUNTINGDON USACE DISTRICT
EITHER AT OR NEAR NORMAL WINTER POOL LEVELS. THIS IS UNCHANGED
OVER THE PAST TWO WEEKS.

WEATHER AND PRECIPITATION OUTLOOK
IN THE NEAR TERM...ANOTHER WARMING TREND WITH TEMPERATURES
WARMING TO WELL ABOVE NORMAL WITH A MIXTURE OF RAIN AND SNOW FOR
THE OHIO VALLEY DURING THE NEXT WEEK. FOR THE SECOND HALF OF THE
FORECAST...THERE IS A GOOD DEAL OF UNCERTAINTY WITH WIDELY VARYING
SOLUTIONS. WITH THIS MUCH UNCERTAINTY...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 ON
FEBRUARY 7 2013.
 

$$