National Weather Service Text Product Display

Flood Potential Outlook
Issued by NWS Cleveland, OH
Versions: 1 2 3

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FGUS71 KCLE 211537
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WINTER/SPRING FLOOD POTENTIAL OUTLOOK
NATIONAL WEATHER SERVICE CLEVELAND OH
1137 AM EDT THU MAR 21 2013


...WINTER/SPRING FLOOD OUTLOOK NUMBER 6...

...THE FLOOD THREAT IS EXPECTED TO BE NEAR NORMAL ACROSS
NORTHWEST PENNSYLVANIA AND NORTHERN OHIO THROUGH EARLY APRIL...

THIS IS THE SIXTH ISSUANCE OF THE WINTER AND SPRING FLOOD OUTLOOK
ISSUED BY THE NATIONAL WEATHER SERVICE IN CLEVELAND. FLOOD
OUTLOOKS ARE ISSUED BIWEEKLY DURING THE WINTER AND EARLY SPRING TO
SUMMARIZE CURRENT CONDITIONS AND ASSESS THE POTENTIAL FOR FLOODING
ACROSS NORTHERN OHIO AND NORTHWEST PENNSYLVANIA.

FACTORS TO CONSIDER WHEN ASSESSING FLOOD POTENTIAL THIS TIME OF
YEAR ARE CURRENT RIVER AND RESERVOIR LEVELS...SNOW PACK DEPTH AND
WATER CONTENT...ICE COVERAGE ON AREA RIVERS AND THE LAKE...SOIL
MOISTURE...AND WIDESPREAD HEAVY RAINFALL POTENTIAL.

...OVERVIEW...
THE FLOOD THREAT FOR THE UPCOMING TWO WEEKS IS NEAR NORMAL. THE
SNOW PACK OVER THE SNOWBELT CONTINUES TO GROW AS A WEATHER PATTERN
SUPPORTS LAKE EFFECT SNOW AND MINIMAL MELTING. THE WEATHER PATTERN
IS ALSO KEEPING THE RISK OF HEAVY RAIN AT A MINIMUM. THE COMBINATION
OF THESE FACTORS LEADS TO A NORMAL THREAT OF FLOODING. THE RISK OF
MAJOR FLOODING IS LOW.

...CURRENT RIVER AND RESERVOIR LEVELS...
THE RESERVOIR LEVELS ARE RUNNING AT OR SLIGHTLY ABOVE NORMAL
WINTER POOL LEVELS.

...SNOW COVER...
THE SNOW PACK OVER THE SNOWBELT IS MOST PROMINENT IN NORTHWEST
PENNSYLVANIA WHERE DEPTHS AS OF THIS ISSUANCE WERE AS HIGH AS A
FOOT BUT AVERAGED AROUND 6 INCHES. THE WATER EQUIVALENT OF THIS
SNOW PACK IS AROUND AN INCH FOR THE FRENCH CREEK BASIN. ACROSS
NORTHEASTERN OHIO THE SNOW PACK IS AVERAGING LESS THAN AN INCH OF
WATER EQUIVALENT. WITH TEMPERATURES FORECASTED TO REMAIN BELOW
NORMAL IT CAN BE EXPECTED THAT THERE WILL BE LIMITED MELTING AT
LEAST IN THE FIRST WEEK.

ICE COVERAGE...
THE LAKE AND RIVERS HAVE PASSED THEIR CLIMATOLOGICAL PEAK ICE
PERIOD AND THE ICE COVERAGE CONTINUES TO RECEDE. AT THE TIME OF
THIS ISSUANCE THE ICE COVERAGE WAS ABOUT 10% ON LAKE ERIE WITH
OPEN WATERS ALONG THE NORTHERN SHORE. NO NOTABLE ICE HAS DEVELOPED
ALONG AREA RIVERS.

...SOIL MOISTURE...
THE TOP SOILS ARE SATURATED AS IS TYPICAL IN LATE MARCH. WITH THE
COLD TEMPERATURES OF THE LAST WEEK...AND FORECASTED TEMPERATURES
BELOW FREEZING FOR THE NEXT WEEK...THE GROUND COVER WILL SEE
PERIODIC FREEZES. FROZEN GROUND COVER CAN ACT LIKE CONCRETE AS IT
IS UNABLE TO ABSORB RAINFALL...AN CAN BE A CATALYST TO SPRING
FLOODS.

...PRECIPITATION AND TEMPERATURE FORECASTS...
THE CLIMATE PREDICTION CENTER`S SHORT TERM FORECASTS PREDICT
TEMPERATURES LIKELY BEING BELOW NORMAL FOR THE NEXT TWO WEEKS. AS
A RESULT THE PRECIPITATION ALONG THE SNOW BELT MAY BE ABOVE NORMAL
DUE TO THE ENHANCEMENT OF LAKE EFFECT SNOW. MEANWHILE THE REST OF THE
REGION IS LIKELY TO EXPERIENCE PRECIPITATION NEAR NORMAL...IF NOT
BELOW NORMAL...AS THESE COLDER AIRMASSES TEND TO HAVE LESS MOISTURE
TO SUPPORT HEAVY RAIN.

...LONG TERM OUTLOOKS...
THE ENSO CYCLE IN THE PACIFIC OCEAN IS EXPECTED TO CONTINUE TO
REMAIN NEUTRAL AND NOT PLAY A NOTABLE ROLE ON THE LARGE SCALE
WEATHER PATTERN OVER THE U.S. THIS SPRING. THE CLIMATE PREDICTION
CENTER(CPC) IS PREDICTING A TURN AROUND IN TEMPERATURES BY NEXT
MONTH WITH A HIGHER CHANCE OF ABOVE NORMAL TEMPERATURES. THIS
FORECAST IS DRIVEN BY THE MODEL PREDICTIONS THAT THE NORTH
ATLANTIC OSCILLATION (NAO) WILL SWITCH FROM NEGATIVE AS IT HAS
BEEN SINCE MID FEBRUARY TO POSITIVE. THIS STATE OF THE NAO IS LESS
SUPPORTIVE FOR THE NORTHERN JET INFLUENCE ON THE LOWER 48 STATES.
HOWEVER THIS WEATHER PATTERN SHIFT COULD ALSO SUPPORT MORE ACTIVE
WEATHER INCLUDING THE RISK OF HEAVY RAIN. CPC`S PRECIPITATION
FORECAST SUPPORTS AN ABOVE NORMAL CHANCE FOR PRECIPITATION OVER
THE LAKE ERIE AND OHIO RIVER BASINS FOR APRIL.

...FLOOD POTENTIAL SUMMARY AND OUTLOOK...
IN SUMMARY...WITH THE ANTECEDENT CONDITIONS OF A FROZEN GROUND
COVER AND THE MINIMAL SNOW PACK THERE IS A NEAR NORMAL CHANCE FOR
FLOODING THROUGH THE END OF MARCH. BY APRIL CONDITIONS COULD TURN
TO SUPPORT A WARMER AND MORE ACTIVE WEATHER PATTERN.

REAL TIME RIVER INFORMATION AND PROBABILISTIC FORECASTS FOR
SPECIFIC LOCATIONS ALONG RIVERS ACROSS NORTHERN OHIO AND
NORTHWEST PENNSYLVANIA CAN BE FOUND ON THE INTERNET AT
HTTP://WWW.ERH.NOAA.GOV/CLE/ AND CLICKING THE /RIVERS AND LAKES
AHPS/ LINK ON THE LEFT HAND SIDE.



$$
National Weather Service Weather Forecast Office
