Flood Potential Outlook
Issued by NWS Binghamton, NY

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WINTER/SPRING FLOOD POTENTIAL OUTLOOK
NATIONAL WEATHER SERVICE BINGHAMTON NY
112 PM EST THU FEB 19 2015

...WINTER/SPRING FLOOD POTENTIAL OUTLOOK NUMBER 4...

THIS IS THE FOURTH IN A SERIES OF REGULARLY SCHEDULED HYDROLOGIC OUTLOOKS
ISSUED DURING THE WINTER AND SPRING SEASON. THIS OUTLOOK IS DESIGNED
TO PROVIDE A GENERALIZED ASSESSMENT OF THE FLOOD POTENTIAL ACROSS CENTRAL
NEW YORK AND NORTHEAST PENNSYLVANIA.

...SUMMARY...
.FLOOD POTENTIAL NEXT TWO WEEKS...BELOW AVERAGE.
THE NEXT TWO WEEKS WILL FEATURE A CONTINUATION OF BELOW NORMAL
TEMPERATURES WITH MOST PRECIPITATION CONTINUING TO BE IN THE FORM
OF SNOW. GIVEN THE LOW PROBABILITY OF A SIGNIFICANT WARM UP WITH
RAIN...THE FLOOD POTENTIAL IS LOW.

.FLOOD POTENTIAL THROUGH APRIL...ABOVE AVERAGE.
THE THREE MONTH LONG RANGE OUTLOOK SUGGESTS THE SPRING TEMPERATURES
AND PRECIPITATION ARE EXPECTED TO BE NEAR CLIMATOLOGY. THIS IMPLIES
A GREATER LIKELIHOOD FOR A GRADUAL SPRING THAW...HOWEVER...THERE
ALWAYS REMAINS A CHANCE FOR A RAPID WARM SPELL WITH A SIGNIFICANT
RAINFALL. GIVEN THE ANTECEDENT CONDITIONS LISTED BELOW...THE LONG
LOOK FLOOD POTENTIAL SUGGESTS A SLIGHTLY HIGHER THAN AVERAGE
POTENTIAL FOR HIGH FLOWS AND POSSIBLE MINOR FLOODING THIS SPRING.

...DETAILS ON CURRENT CONDITIONS...

.PRECIPITATION...VARIABLE BY BASIN. SINCE THE BEGINNING OF THE WATER
YEAR ON OCTOBER 1ST...PRECIPITATION AMOUNTS RANGE FROM APPROXIMATELY
5 TO 10 INCHES IN THE CHEMUNG AND MUCH OF THE FINGER LAKES BASINS.
FOR THE REMAINDER OF THE SUSQUEHANNA...UPPER DELAWARE AND OSWEGO
BASINS...AMOUNTS RANGE FROM 10 TO 20 INCHES. LIQUID PRECIPITATION
AMOUNTS ARE BASICALLY WITHIN AN INCH OF NORMAL FOR THE SUSQUEHANNA
AND OSWEGO BASINS...BUT ARE AS MUCH AS 4 TO 6 INCHES BELOW NORMAL
IN THE CHEMUNG AND PORTIONS OF THE UPPER DELAWARE REGION. THIS HAS
BEEN ENOUGH TO PROMPT THE U.S. DROUGHT MONITOR TO DECLARE THESE
DEFICIT AREAS AS ABNORMALLY DRY.

.SNOW COVER AND WATER EQUIVALENT...ABOVE NORMAL. AS OF FEBRUARY 19TH...
SNOW COVER RANGES FROM APPROXIMATELY 8 TO 16 INCHES ACROSS NORTHEASTERN
PENNSYLVANIA AND THE CHEMUNG BASIN IN NEW YORK...WITH SPOTTY AMOUNTS
NEAR 20 INCHES OVER HIGHER TERRAIN. THE REMAINDER OF THE UPPER
SUSQUEHANNA...UPPER DELAWARE...FINGER LAKES AND OSWEGO BASINS ARE
AVERAGING 15 TO 30 INCHES OF SNOW COVER WITH SOME HIGHER AMOUNTS
IN THE TULLY-HEIBERGS AND CATSKILLS. ON AVERAGE...THIS IS ABOUT 5
TO 10 INCHES ABOVE NORMAL FOR THIS TIME IN THE SEASON. THE WATER
EQUIVALENT OF THE SNOW PACK IN THE HEAVIER COVERED AREAS RANGES
FROM 2 TO 6 INCHES. THE CHEMUNG BASIN AND UPPER MAIN STEM SUSQUEHANNA
IN PENNSYLVANIA ARE SHOWING APPROXIMATELY 1 TO 4 INCHES OF LIQUID
IN THE SNOW.

.RIVER ICE COVER...ABOVE NORMAL. AS OF FEBRUARY 19TH...OUR RIVER ICE
OBSERVER NETWORK CONTINUES TO REPORT MANY OF THE MAIN STEM RIVER CHANNELS
AND ASSOCIATED TRIBUTARIES HAVE SUBSTANTIAL ICE COVER...WITH SEVERAL
AREAS FROZEN SOLID. MOST REPORTED CHANNEL OPENINGS ARE 20 PERCENT OR
LESS. THE ACCUMULATED FREEZING DEGREE DAY INDEX WAS RUNNING ABOVE NORMAL
AT ALL ASOS STATIONS. USING THIS INDEX TO CALCULATE A THEORETICAL ICE
THICKNESS SUGGESTED THAT RIVER ICE SHOULD BE BETWEEN 10-15 INCHES THICK.
THE USGS AND OTHER SOURCES HAVE REPORTED RIVER ICE MEASUREMENTS RANGING
FROM 1 TO 1.5 FEET AROUND NEW YORK. AS ICE THICKNESS APPROACHES...OR
EXCEEDS ONE FOOT...THE CHANCES FOR ICE JAMMING DURING THAW EVENTS
BECOMES HIGH.

.STREAMFLOW CONDITIONS...BELOW NORMAL. AVERAGE MONTHLY STREAMFLOW
TO DATE AT USGS GAUGES WITHIN THE SERVICE AREA WAS NEAR TO BELOW
NORMAL. MUCH OF THESE BELOW NORMAL FLOWS ARE DUE TO LOSS OF FLOW
FROM PROLONGED COLD WEATHER LIMITING RUNOFF AND FREEZING
TRIBUTARIES AND CERTAIN MAIN STEM CHANNELS.

.SOIL CONDITIONS...NORMAL. THE GROUND IS FROZEN. FROST DEPTHS ARE IN EXCESS
OF 18 INCHES AT NWS BINGHAMTON...AND SOME ANECDOTAL REPORTS FROM
TOWN/COUNTY PUBLIC WORKS FOLKS INDICATE THE FROST LINE MAY BE OVER
4 FEET DEEP IN SOME AREAS. PALMER DROUGHT INDEX SUGGESTS THAT LONG
TERM REGIONAL SOIL MOISTURE WAS GENERALLY NORMAL ACROSS THE
REGION...WITH SOME INDICATION OF ABNORMALLY HIGH MOISTURE STILL IN
THE FINGER LAKES REGION.

.RESERVOIR AND LAKE LEVELS...VARIABLE. THE ARMY CORPS FLOOD CONTROL
RESERVOIRS IN THE SUSQUEHANNA BASIN APPEAR TO BE RUNNING WITH NEAR
TO SLIGHTLY ABOVE NORMAL POOL HEIGHTS. CAYUGA LAKE WAS ABOVE THE
HIGH SNOW PACK TARGET LEVEL...BUT ALL OTHER FINGER LAKES APPEARED
TO HAVE NORMAL WINTER POOLS. THE LAKE WALLENPAUPACK LEVEL WAS ON
TARGET. THE NYC DELAWARE BASIN WATER SUPPLY STORAGE WAS CURRENTLY
WELL BELOW THE LONG TERM MEDIAN POOL LEVEL.

...FORECAST OUTLOOK...

.FUTURE WEATHER CONDITIONS - THE 6 TO 14 DAY OUTLOOK CALLS FOR A
CONTINUATION OF MUCH COLDER THAN AVERAGE TEMPERATURES WITH NEAR
TO BELOW NORMAL PRECIPITATION. MEDIUM RANGE METEOROLOGICAL MODELS
THROUGH THE NEXT 10 DAYS ALSO SUGGEST A CONTINUATION OF THE COLD
PATTERN IN THE NORTHEAST. A SLIGHT MODERATION MAY OCCUR DURING THE
SECOND WEEK OF THIS OUTLOOK...BUT STILL GENERALLY BE COLDER THAN
NORMAL.

.LONG RANGE RIVER MODELING AND PROBABILITY FORECASTS - MULTI-MODEL ENSEMBLE
FORECASTS DO NOT SUGGEST ANY FLOODING IN THE SERVICE AREA FOR THE NEXT
TWO WEEKS. PROBABILITY GUIDANCE FROM THE ADVANCED HYDROLOGIC PREDICTION
SERVICE SUGGESTS GENERALLY BELOW NORMAL CHANCES OF FLOODING WHEN COMPARED
TO WHAT HAS HAPPENED IN THE PAST DURING THIS TIME OF YEAR.

...IN CONCLUSION...
THE OUTLOOK ESTIMATES THE POTENTIAL FOR RIVER AND LAKE FLOODING BASED ON A
CURRENT ASSESSMENT OF GENERALIZED HYDRO-METEOROLOGICAL FACTORS WHICH
CONTRIBUTE TO FLOODING DURING THE SPRING THAW.

IT IS IMPORTANT TO NOTE THAT SIGNIFICANT FLOODING DOES NOT OCCUR
FROM SNOW MELT ALONE. SHORT TERM HEAVY RAIN EVENTS...THE INTENSITY
OF ANY MILD SPELLS...WIND SPEED AND RAPID INCREASES IN HUMIDITY
ARE THE MOST IMPORTANT FACTORS IN DETERMINING THE OCCURRENCE AND
SEVERITY OF SPRING FLOODING. SPECIFIC FORECASTS OF HEAVY RAINFALL
AND FLASH FLOODING ARE NOT INCLUDED IN THIS OUTLOOK.

THE NEXT WINTER/SPRING FLOOD OUTLOOK WILL BE ISSUED BY THIS OFFICE IN TWO
WEEKS, ON MARCH 5, 2015. IF CONDITIONS CHANGE IN THE INTERIM...FLOOD
WATCHES...WARNINGS OR ADVISORIES WILL BE ISSUED AS NECESSARY.

$$

JAB




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