Flood Potential Outlook
Issued by NWS

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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-
049-051-061-069-077-093-103-161430-

WINTER/SPRING FLOOD POTENTIAL OUTLOOK
NATIONAL WEATHER SERVICE PITTSBURGH PA
1020 AM EDT THU APR 14 2016

THE FLOOD POTENTIAL IS NEAR TO BELOW NORMAL ACROSS WATERSHEDS IN
THE UPPER OHIO VALLEY.


A NEAR NORMAL FLOOD POTENTIAL MEANS OCCASIONAL FLOODING COULD OCCUR
WITH WATER LEVELS HAVING MINOR IMPACTS.

A BELOW NORMAL FLOOD POTENTIAL MEANS FLOODING IS UNLIKELY.

FOR THE LONG-RANGE RIVER OUTLOOKS AND THE PROBABILITY OF
EXCEEDING FLOODSTAGE 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 ON THE
LEFT HAND SIDE OF THE PAGE. CLICK ON FLOOD CHC VS NORMAL TO VIEW
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
HYDROMETEOROLOGICAL CONDITIONS AND TO ASSESS THE POTENTIAL FOR
WINTER/SPRING FLOODING. THE OUTLOOKS ARE BASED ON CURRENT AND
FORECAST CONDITIONS DURING THE OUTLOOK PERIOD.

IN ADDITION...A 90-DAY WATER RESOURCE OUTLOOK IS ISSUED MONTHLY.

FACTORS CONSIDERED IN ASSESSING FLOOD POTENTIAL ARE (1) ANTECEDENT
CONDITIONS (2) PAST PRECIPITATION (3) RECENT STREAMFLOWS AND
RESERVOIR LEVELS (4) SOIL MOISTURE (5) WATER CONTENT OF THE SNOW
PACK (6) ICE CONDITIONS ON THE RIVERS AND (7) FUTURE PRECIPITATION.

METEOROLOGICALLY...THE PREVAILING STORM TRACK HAS RESEMBLED AN EL
NINO SIGNATURE ACROSS THE U.S...WITH STORM SYSTEMS HITTING THE WEST
COAST OF NORTH AMERICA...THEN MOVING ACROSS THE DEEP SOUTH BEFORE
CURVING UP THE EAST COAST OR OUT INTO THE WESTERN NORTH ATLANTIC
BASIN. THE LACK OF PHASING OF THE POLAR AND SUBTROPICAL JET STREAMS
HAS RESULTED IN MAINLY LIGHT TO MODERATE PRECIPITATION EVENTS IN THE
OHIO VALLEY.

SINCE EARLY FEBRUARY...THE OHIO RIVER BASIN HAS HAD A STRONG
GRADIENT IN THE PRECIPITATION FIELD. MOST WATERSHEDS IN THE UPPER
OHIO VALLEY HAVE HAD ONLY 1/2 TO 3/4 OF THE NORMAL
PRECIPITATION...WHILE DRAINAGES IN THE MIDDLE PART OF THE OHIO RIVER
BASIN AND LOWER OHIO VALLEY HAVE HAD NEARLY 1 1/2 TO 2 TIMES THE
NORMAL RAINFALL.

HYDROLOGICALLY...THE DRYNESS IN THE UPPER OHIO VALLEY SHOWS UP QUITE
WELL WHEN LOOKING AT STREAMFLOWS. AVERAGE STREAMFLOWS DURING THE
EARLY PART OF SPRING ARE MUCH BELOW NORMAL(LESS THAN THE 10TH
PERCENTILE) FROM THE HEADWATERS OF ALL BASINS IN WV TO THE
TRIBUTARIES OF WESTERN PENNSYLVANIA.

...SPRING FLOOD OUTLOOK/SUMMARY...

AN ACTIVE STORM TRACK HAS PREDOMINANTLY SKIRTED THE OHIO RIVER
BASIN SINCE LAST WINTER. OCCASIONALLY...PHASING OF THE
SUBTROPICAL AND POLAR JET STREAMS OCCURRED PRODUCING DEEPENING LOW
PRESSURE SYSTEMS MOVING THROUGH THE OHIO VALLEY LEADING TO HEAVY
RAINFALL AND MINOR FLOODING WITH THE HEAVIEST RAINS FROM THIS
STORMY SCENARIO OCCURRING IN THE LOWER OHIO VALLEY.

EL NINO IS EXPECTED TO GRADUALLY WEAKEN DURING THE SPRING/EARLY
SUMMER. SPRING RAINFALL IS FORECAST TO BE NORMAL TO BELOW NORMAL
FROM WEST TO EAST ACROSS THE OHIO VALLEY LEADING TO A BELOW NORMAL
FLOOD POTENTIAL IN THE UPPER OHIO VALLEY...AND NEAR NORMAL POTENTIAL
FOR FLOODING OVER THE REMAINDER OF THE OHIO RIVER BASIN.

THIS WILL BE THE FINAL WINTER/SPRING FLOOD POTENTIAL OUTLOOK FOR
2016.


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