Extended Streamflow Guidance
Issued by NWS Middle Atlantic RFC

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FLOOD POTENTIAL STATEMENT
MIDDLE ATLANTIC RIVER FORECAST CENTER (MARFC)
NATIONAL WEATHER SERVICE STATE COLLEGE PA
 856 PM EDT WED MAR 19 2014

WINTER/SPRING RIVER FLOOD POTENTIAL OUTLOOK
NWS MIDDLE ATLANTIC RIVER FORECAST CENTER

OUTLOOK NUMBER 14-07 - MARCH 19, 2014

THIS OUTLOOK IS VALID FOR THE TWO-WEEK PERIOD MARCH 20-APRIL 3, 2014.

THIS OUTLOOK ESTIMATES THE POTENTIAL FOR RIVER FLOODING (NOT FLASH
FLOODING) TO DEVELOP DURING THE NEXT TWO WEEKS ACROSS THE MARFC AREA
OF RESPONSIBILITY (MID-ATLANTIC REGION) BASED ON A CURRENT ASSESSMENT
OF HYDROMETEOROLOGICAL FACTORS WHICH CAN CONTRIBUTE TO RIVER FLOODING.
ACROSS THE MARFC AREA THESE FACTORS INCLUDE FUTURE WEATHER CONDITIONS,
RECENT PRECIPITATION, SOIL MOISTURE, SNOW COVER AND SNOW WATER
EQUIVALENT, RIVER ICE, STREAMFLOW, AND OTHERS.  THIS OUTLOOK DOES NOT
ADDRESS THE SEVERITY/EXTENT OF ANY FUTURE RIVER FLOODING.

REMEMBER, IN THE MID-ATLANTIC REGION HEAVY RAINFALL IS THE PRIMARY
FACTOR WHICH LEADS TO RIVER FLOODING.  HEAVY RAINFALL CAN RAPIDLY
CAUSE RIVER FLOODING ANY TIME OF THE YEAR, EVEN WHEN OVERALL RIVER
FLOOD POTENTIAL IS CONSIDERED TO BE LOW OR BELOW AVERAGE.

TWO-WEEK RIVER FLOOD POTENTIAL - BELOW AVERAGE FOR THE FIRST WEEK,
THEN AVERAGE.  THE POTENTIAL FOR RIVER FLOODING DURING THE NEXT TWO
WEEKS WITHIN THE MARFC SERVICE AREA IS CONSIDERED SOMEWHAT BELOW
AVERAGE FOR THE FIRST WEEK OF THIS OUTLOOK PERIOD DUE TO AN EXPECTED
LACK OF SIGNIFICANT RAINFALL AND COOL TO COLD TEMPERATURES WHERE
SIGNIFICANT SNOW REMAINS.  THE POTENTIAL WILL INCREASE TO AVERAGE FOR
THE SECOND WEEK.  FACTORS WHICH CONTRIBUTE TO RIVER FLOOD POTENTIAL
ARE ADDRESSED BELOW.

CURRENT FLOODING - NONE.

RECENT PRECIPITATION - BELOW TO MUCH-BELOW NORMAL.  PRECIPITATION
DURING THE LAST 30 DAYS (FEBRUARY 17-MARCH 18, 2014) HAS NOW DROPPED
TO THE BELOW-NORMAL TO MUCH-BELOW-NORMAL RANGE ACROSS THE ENTIRE MARFC
REGION.  IN GENERAL ONLY 1-3 INCHES OF PRECIPITATION HAS FALLEN DURING
THE LAST 30 DAYS, WHICH IS 1-3 INCHES BELOW NORMAL, DEPENDING ON
LOCATION.  MOST AREAS HAVE OBSERVED PRECIPITATION THAT IS 25-75
PERCENT BELOW AVERAGE FOR THE LAST 30 DAYS.  GO TO
WWW.ERH.NOAA.GOV/ER/MARFC FOR ADDITIONAL PRECIPITATION INFORMATION.

SNOW CONDITIONS - NORMAL TO SOMEWHAT ABOVE NORMAL.  CURRENTLY WITHIN
THE MARFC SERVICE AREA SIGNIFICANT SNOW IS NOW LIMITED TO PORTIONS OF
THE UPPER SUSQUEHANNA RIVER BASIN IN NY, ACROSS THE POCONO/CATSKILL
REGION, AND ACROSS NORTHERN NJ.  IN THESE AREAS SNOW DEPTHS OF A FEW
INCHES REMAIN (WITH LOCALLY HIGHER AMOUNTS).  ELSEWHERE, THERE IS
RATHER PATCHY SNOW COVER OF UP TO A FEW INCHES, INCLUDING SOUTHERN
AREAS THAT RECEIVED SEVERAL INCHES OF SNOW EARLIER THIS WEEK.  WITH
RESPECT TO SNOW WATER EQUIVALENT (SWE) VALUES, 1.0-2.5 INCHES REMAIN
ACROSS PORTIONS OF THE UPPER SUSQUEHANNA RIVER BASIN IN NY, ACROSS THE
POCONO/CATSKILL REGION, AND ACROSS NORTHERN NJ.  ISOLATED SWE VALUES
OF 3-4 INCHES ARE STILL FOUND IN THE CATSKILL MOUNTAINS AND ACROSS
EXTREME NORTHERN PORTIONS OF THE MARFC SERVICE AREA IN NY.  SNOW
CONDITIONS ARE NORMAL TO SOMEWHAT ABOVE NORMAL FOR THE DATE IN NY AND
ACROSS NORTHERN PA AND NORTHERN NJ, AND NEAR NORMAL ELSEWHERE.  WHILE
SOUTHERN AREAS RECEIVED SIGNIFICANT LATE-SEASON SNOW EARLIER THIS
WEEK, THIS SNOW IS HYDROLOGICALLY INSIGNIFICANT AND SHOULD DIMINISH
QUICKLY.  FOR DETAILED SNOW INFORMATION VISIT WWW.NOHRSC.NOAA.GOV AND
WWW.ERH.NOAA.GOV/ER/MARFC.  APPRECIATION IS EXTENDED TO ALL PEOPLE AND
ORGANIZATIONS WHO HAVE PROVIDED THIS AND OTHER NWS OFFICES WITH SNOW
AND RIVER ICE REPORTS AND DATA THIS WINTER, INCLUDING VOLUNTEERS, THE
U.S. ARMY CORPS OF ENGINEERS, THE NWS NATIONAL OPERATIONAL HYDROLOGIC
REMOTE SENSING CENTER IN MN, OTHER NWS OFFICES, THE U.S. GEOLOGICAL
SURVEY, AND MANY OTHER PRIVATE AND PUBLIC ORGANIZATIONS AT THE LOCAL,
STATE AND REGIONAL LEVELS.

RIVER ICE - AVERAGE TO SOMEWHAT ABOVE AVERAGE.  SOME RIVER ICE REMAINS
WITHIN THE SUSQUEHANNA AND DELAWARE RIVER BASINS OF NORTHERN PA AND
NY, WHICH IS AVERAGE TO SOMEWHAT ABOVE AVERAGE FOR MID MARCH.  THE
RIVER ICE CONTINUES TO GRADUALLY DECAY, WEAKEN AND DIMINISH WHILE THE
THREAT OF ICE JAMS AND ASSOCIATED ICE JAM FLOODING ALSO SLOWLY
DECREASES.  STILL, ISOLATED ICE JAMS/ICE JAM FLOODS REMAIN REMOTELY
POSSIBLE WITHIN UPPER PORTIONS OF THE SUSQUEHANNA AND DELAWARE RIVER
BASINS DURING THE NEXT TWO WEEKS, MAINLY ALONG SMALLER STREAMS AND
RIVERS.

STREAMFLOW CONDITIONS - GENERALLY NEAR MEDIAN.  ACCORDING TO THE
U.S. GEOLOGICAL SURVEY (USGS) THE CURRENT STREAMFLOW ACROSS MOST OF
THE MARFC REGION IS RELATIVELY CLOSE TO MEDIAN FOR THE DATE.  A FEW
STREAM GAGES ACROSS THE NORTH ARE STILL BEING AFFECTED BY RIVER ICE.
REAL-TIME WATER DATA CAN BE FOUND BY VISITING THE USGS AT
WWW.USGS.GOV/WATER.

SOIL MOISTURE CONDITIONS - NORMAL TO EXTREMELY MOIST.  THE LONG-TERM
PALMER DROUGHT SEVERITY INDEX IS WIDELY USED TO INFER DEEP SOIL
MOISTURE CONDITIONS.  THE MARCH 15, 2014 INDEX CHART
(WWW.CPC.NOAA.GOV/PRODUCTS) SUGGESTS SOILS ACROSS THE MARFC SERVICE
AREA CONTAIN MOISTURE THAT RANGES FROM NORMAL TO EXTREMELY MOIST FOR
THIS TIME OF YEAR.  AT THIS TIME THE WETTEST SOILS ARE INDICATED IN
NY, SOUTHEASTERN PA, CENTRAL MD AND NORTHERN VA, WHILE THE DRIEST
SOILS ARE ACROSS PORTIONS OF PA.  SOILS ACROSS MUCH OF THE MARFC
REGION HAVE BEEN GRADUALLY DRYING DURING THE LAST COUPLE OF WEEKS.
PLEASE VISIT WWW.CPC.NCEP.NOAA.GOV/PRODUCTS/SOILMST_MONITORING/US FOR
ADDITIONAL SOIL MOISTURE INFORMATION.

GROUND WATER - GENERALLY NEAR NORMAL.  USGS GROUND WATER MONITORING
WELLS ACROSS MOST OF THE MARFC REGION ARE INDICATING NEAR NORMAL
LEVELS.  HOWEVER, SOME BELOW NORMAL GROUNDWATER CONDITIONS CONTINUE
ACROSS PORTIONS OF NORTHERN PA AND SOUTHERN NY.  PLEASE VISIT
HTTP://GROUNDWATERWATCH.USGS.GOV.

RESERVOIR CONDITIONS - GENERALLY ABOUT AVERAGE.  IN GENERAL, MOST
MAJOR RESERVOIRS WITHIN THE MARFC REGION ARE HOLDING STORAGES THAT ARE
FAIRLY CLOSE TO AVERAGE FOR THIS TIME OF YEAR.

FUTURE WEATHER CONDITIONS - FAIRLY TYPICAL LATE WINTER WEATHER IS
EXPECTED FOR THE MARFC REGION DURING THE NEXT FEW DAYS.  THEN A COLD
FRONT CROSSING THE REGION SUNDAY WILL USHER IN ANOTHER ROUND OF
UNSEASONABLY COLD AIR THAT WILL PERSIST MUCH OF NEXT WEEK ACROSS THE
ENTIRE REGION.  A STORM SYSTEM MAY FORM NEAR OR OFF THE EAST COAST
AROUND MID WEEK NEXT WEEK WHICH COULD PRODUCE MORE WINTRY
PRECIPITATION FOR PORTIONS OF THE REGION.  A WARMING TREND MAY BEGIN
TOWARDS THE END OF NEXT WEEK.  AT THIS TIME THERE ARE NO INDICATIONS
OF ANY WIDESPREAD HEAVY RAIN EVENTS OR SIGNIFICANT WARM-UPS FOR AT
LEAST THE NEXT WEEK.  THE LATEST (MARCH 19, 2014) 6-10 AND 8-14 DAY
EXTENDED WEATHER OUTLOOKS ISSUED BY THE NWS CLIMATE PREDICTION CENTER
(CPC) AGAIN BOTH SUGGEST A CONTINUATION OF BELOW NORMAL TEMPERATURES
FOR THE ENTIRE MARFC REGION WHEN AVERAGED OVER THE 9-DAY PERIOD FROM
MARCH 25-APRIL 2, 2014.  MEANWHILE PRECIPITATION WILL MOST LIKELY END
UP ABOVE NORMAL ACROSS THE MARFC REGION FOR THE SAME NINE-DAY PERIOD.

AHPS RIVER FORECASTS - MOSTLY NEAR NORMAL.  THE ADVANCED HYDROLOGIC
PREDICTION SERVICE (AHPS) GENERATES PROBABILISTIC RIVER FORECASTS
BASED ON CURRENT BASIN CONDITIONS (RIVER LEVELS, SOIL MOISTURE, EXTENT
AND CONDITION OF ANY SNOWPACK) ALONG WITH 50 YEARS OF HISTORIC
TEMPERATURE AND PRECIPITATION DATA.  REMEMBER, AHPS RIVER FORECASTS DO
NOT TAKE INTO ACCOUNT ACTUAL FUTURE WEATHER CONDITIONS.  FOR THE NEXT
TWO WEEKS (MARCH 20-APRIL 3, 2014) AHPS RIVER FORECASTS INDICATE THAT
THE LIKELIHOOD OF RIVER FLOODING WITHIN THE MARFC SERVICE AREA IS
PRETTY CLOSE TO NORMAL ACROSS MOST RIVER BASINS.  PLEASE VISIT
WWW.WEATHER.GOV/AHPS/.

ENSEMBLE RIVER FORECASTS - A MINIMAL THREAT OF ISOLATED RIVER FLOODING
DURING THE NEXT FEW DAYS.  THE MOST RECENT RUNS (MARCH 19, 2014) OF
THE ENSEMBLE RIVER FORECASTS SHOW A MINIMAL THREAT OF ISOLATED RIVER
FLOODING DEVELOPING WITHIN PORTIONS OF THE UPPER SUSQUEHANNA RIVER
BASIN IN NEW YORK DURING THE NEXT FEW DAYS.  THIS THREAT IS MAINLY
ASSOCIATED WITH SOME MILDER TEMPERATURES (AND SUBSEQUENT SNOWMELT)
BEING INDICATED BY A FEW OF THE WEATHER MODELS LATER THIS WEEK AHEAD
OF A WEEKEND COLD FRONT.  REMEMBER THAT ENSEMBLE RIVER FORECASTS DO
NOT ACCOUNT FOR RIVER ICE CONDITIONS AND THEREFORE DO NOT PREDICT ICE
JAMS/ICE JAM FLOODING.  PLEASE VISIT WWW.ERH.NOAA.GOV/MMEFS.

SUMMARY - THE RIVER FLOOD POTENTIAL IN THE MARFC REGION WILL BE BELOW
AVERAGE DURING THE NEXT WEEK, THEN INCREASE TO AVERAGE.  SIGNIFICANT
RAINFALL WOULD BE REQUIRED TO INITIATE FLOODING IN MOST BASINS, EXCEPT
MAYBE IN NY WHERE SIGNIFICANT SNOWMELT COULD ALSO INITIATE FLOODING.
NEITHER SIGNIFICANT RAIN NOR SIGNIFICANT SNOWMELT IS PRESENTLY
EXPECTED FOR AT LEAST THE FIRST WEEK OF THIS OUTLOOK PERIOD.  MILDER
WEATHER AND RAIN IS POSSIBLE DURING THE SECOND WEEK THOUGH, AND
CONDITIONS WILL THEREFORE NEED TO BE MONITORED AT THAT TIME.

WATER SUPPLY OUTLOOK - ACCORDING TO THE LATEST (MARCH 11, 2014)
U.S. DROUGHT MONITOR, ABNORMALLY DRY CONDITIONS STILL LINGER ACROSS
SMALL PORTIONS OF EAST-CENTRAL PA AND IN THE CATSKILL MOUNTAINS.
HOWEVER NO DROUGHT CONDITIONS CURRENTLY EXIST NOR ARE ANY EXPECTED TO
DEVELOP ANYWHERE WITHIN THE MARFC SERVICE AREA DURING THE NEXT FEW
MONTHS.  LIKEWISE ASSUMING NEAR-NORMAL PRECIPITATION DURING THE NEXT
FEW MONTHS, NO WATER SUPPLY SHORTAGES ARE EXPECTED ANYWHERE WITHIN THE
MARFC REGION THROUGH AT LEAST JUNE, 2014.  PLEASE SEE WWW.DROUGHT.GOV
AND WWW.CPC.NCEP.NOAA.GOV.

FINALLY, PLEASE VISIT THE NWS MARFC HOMEPAGE AT
WWW.ERH.NOAA.GOV/ER/MARFC FOR OTHER HYDROMETEOROLOGICAL INFORMATION.

IF NECESSARY, THE NEXT WINTER/SPRING FLOOD OUTLOOK WILL BE ISSUED BY
THIS OFFICE IN TWO WEEKS, ON APRIL 3, 2014.

SK
$$

....END MARFC....
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