Extended Streamflow Guidance
Issued by NWS Middle Atlantic RFC

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FGUS61 KRHA 051847
ESGRHA

FLOOD POTENTIAL STATEMENT
MIDDLE ATLANTIC RIVER FORECAST CENTER (MARFC)
NATIONAL WEATHER SERVICE STATE COLLEGE PA
 147 PM EST THU MAR 05 2015

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

OUTLOOK NUMBER 15-05 - MARCH 5, 2015

THIS FIFTH OUTLOOK IS VALID FOR THE ONE WEEK PERIOD MARCH 5-12,
2015.

THIS OUTLOOK ESTIMATES THE POTENTIAL FOR RIVER FLOODING (NOT FLASH
FLOODING) TO DEVELOP DURING THE NEXT WEEK 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.

ONE-WEEK RIVER FLOOD POTENTIAL - THERE IS A DECENT THREAT OF MINOR
RIVER FLOODING DEVELOPING DURING THE NEXT COUPLE OF DAYS ALONG THE
LOWER JAMES RIVER IN VA DUE TO RECENT RAIN AND SNOWMELT.  OTHERWISE,
THE RIVER FLOOD POTENTIAL DURING JUST THE NEXT WEEK RANGES FROM BELOW
AVERAGE ACROSS ABOUT THE NORTHWESTERN HALF OF THE MARFC REGION TO ABOUT
AVERAGE ELSEWHERE.  THE RIVER FLOOD POTENTIAL FOR THE NORTHWESTERN HALF
OF THE MARFC REGION RISES TO ABOVE AVERAGE AFTER THIS ONE-WEEK OUTLOOK
PERIOD AS WARMER AND WETTER WEATHER EVENTUALLY ACTS UPON THE
ABOVE-AVERAGE SNOW AND RIVER ICE CONDITIONS THAT CURRENTLY EXIST IN
THIS REGION.  FACTORS WHICH CONTRIBUTE TO RIVER FLOOD POTENTIAL ARE
DISCUSSED BELOW.

CURRENT FLOODING - NONE.

RECENT PRECIPITATION - BELOW NORMAL WEST. NEAR NORMAL EXTREME EAST.
PRECIPITATION (LIQUID EQUIVALENT) DURING THE LAST 30 DAYS
(FEBRUARY 2-MARCH 3, 2015) WAS BELOW TO MUCH-BELOW NORMAL ACROSS MUCH
OF THE MARFC REGION, ESPECIALLY ALONG AND EAST OF THE APPALACHIAN
MOUNTAINS.  MANY LOCATIONS RECEIVED 1-3 INCHES OF PRECIPITATION WHICH
WAS 10-75 PERCENT BELOW NORMAL.  MEANWHILE PRECIPITATION DURING THE
LAST 30 DAYS WAS NEAR TO SOMEWHAT ABOVE NORMAL ACROSS EASTERN PORTIONS
OF THE MARFC SERVICE AREA, INCLUDIING EASTERN NY, EASTERN PA, CENTRAL
AND SOUTHERN NJ, THE DELMARVA PENINSULA AND SOUTHEASTERN VA.  A SMALL
AREA IN WEST-CENTRAL VA ALSO HAD NEAR-NORMAL PRECIPITATION.  IN THESE
AREAS 2-4 INCHES OF PRECIPITATION FELL, WHICH IS 0-25 PERCENT ABOVE
NORMAL.  PLEASE VISIT WWW.ERH.NOAA.GOV/ER/MARFC.

SNOW CONDITIONS - MOSTLY ABOVE NORMAL.  CURRENTLY SNOW STILL COVERS
MUCH OF THE GROUND WITHIN THE MARFC SERVICE AREA, THANKS IN PART TO
SIGNIFICANT SNOW FALLING AT THE TIME OF THIS WRITING ACROSS CENTRAL
PORTIONS OF THE REGION.  THE ONLY AREAS LACKING SNOW INCLUDE SOUTHERN
PORTIONS OF THE DELMARVA PENINSULA AND PORTIONS OF SOUTHEASTERN AND
CENTRAL VA.  THE GREATEST SNOW DEPTHS ARE STILL FOUND ACROSS PORTIONS
OF NY WHERE 8-24 INCHES WITH LOCALLY GREATER DEPTHS EXIST.  ACROSS
NORTHERN PA AND NORTHERN NJ, DEPTHS OF 6-18 INCHES ARE COMMON, AGAIN
WITH LOCALLY HIGHER AMOUNTS.  LASTLY, ACROSS THE REMAINING PORTIONS OF
THE MARFC REGION THAT HAVE SNOW, DEPTHS OF 2-10 INCHES PREVAIL.  WITH
RESPECT TO SNOW WATER EQUIVALENT VALUES, 2.5-5.0 INCHES WITH LOCALLY
HIGHER AMOUNTS EXIST IN NY AND ACROSS WEST-CENTRAL AND NORTHERN PA AS
WELL AS IN THE POCONO REGION OF NORTHEASTERN PA ON INTO NORTHERN NJ.
HEADING SOUTH, 1-3 INCHES IS COMMON ACROSS THE REMAINDER OF PA EASTWARD
INTO CENTRAL NJ.  OVER THE REMAINDER OF THE MARFC SERVICE AREA WHERE
SNOW EXISTS, SNOW WATER EQUIVALENT VALUES ARE AROUND AN INCH OR LESS,
WITH LOCALLY HIGHER AMOUNTS IN THE HIGHER ELEVATIONS.  THE SNOW
CONDITIONS IN NY, AND ACROSS MUCH OF PA AND THE NORTHERN HALF OF
NJ ARE SIGNIFICANT ENOUGH TO BE A CONSIDERABLE FACTOR IN THE FUTURE
DEVELOPMENT OF RIVER FLOODING, ESPECIALLY IF RAPID SNOWMELT IS COMBINED
WITH SIGNIFICANT RAINFALL.  HOWEVER, RAPID SNOWMELT AND SIGNIFICANT
RAINFALL IS CURRENTLY NOT ANTICIPATED IN THESE REGIONS DURING THE NEXT
WEEK.  THE SNOW CURRENTLY FALLING ACROSS CENTRAL PORTIONS OF THE MARFC
REGION WILL LIKELY MELT WITH LIMITED HYDROLOGIC IMPACT DURING THE NEXT
WEEK.  FOR DETAILED SNOW INFORMATION PLEASE VISIT WWW.NOHRSC.NOAA.GOV
AND WWW.WEATHER.GOV/MARFC.

RIVER ICE - ABOVE AVERAGE TO AVERAGE.  NORTHERN/WESTERN REGIONS ARE
STILL OBSERVING QUITE EXTENSIVE AND THICK RIVER ICE.  MANY STREAMS AND
RIVERS NORTH OF THE MD/PA STATE LINE HAVE SIGNIFICANT ICE, WHILE MUCH
OF THE RIVER ICE IN THE POTOMAC RIVER BASIN HAS DIMINISHED FROM TWO
WEEKS AGO.  SHOULD A RAPID ICE BREAKUP OCCUR IN EITHER THE SUSQUEHANNA
OR DELAWARE RIVER BASINS, THE RIVER ICE IS THICK ENOUGH AND EXTENSIVE
ENOUGH THAT ICE JAMS WOULD LIKELY FORM AND SOME LOCALIZED ICE JAM
FLOODING COULD OCCUR.  HOWEVER, RAPID RIVER ICE BREAKUP IS UNLIKELY IN
THESE TWO BASINS DURING THE NEXT WEEK.  RATHER A MORE GRADUAL
DETERIORATION IN RIVER ICE CONDITIONS IS EXPECTED.

STREAMFLOW CONDITIONS - VARIABLE.  LATEST DATA FROM THE U.S. GEOLOGICAL
SURVEY (USGS) INDICATES THAT STREAMFLOW ACROSS THE MARFC REGION VARIES
CONSIDERABLY.  ACROSS NY AND MUCH OF CENTRAL PA, STREAMFLOW IS BELOW
MEDIAN TO MEDIAN.  MANY GAGES IN THIS REGION REMAIN AFFECTED BY RIVER
ICE AND THEREFORE DO NOT REPRESENT ACTUAL STREAMFLOW CONDITIONS.
MEANWHILE, ACROSS THE REMAINDER OF THE MARFC SERVICE AREA, WHERE RECENT
RAIN AND SNOWMELT HAS OCCURRED, STREAMFLOW IS CURRENTLY ABOVE MEDIAN TO
MUCH-ABOVE MEDIAN.  PLEASE VISIT WWW.USGS.GOV/WATER.

SOIL MOISTURE CONDITIONS - MOSTLY ABOUT NORMAL.  THE LONG-TERM PALMER
DROUGHT SEVERITY INDEX IS WIDELY USED TO INFER DEEP SOIL MOISTURE
CONDITIONS.  THE MOST RECENT (FEBRUARY 28, 2015) INDEX CHART
(WWW.CPC.NOAA.GOV/PRODUCTS) SUGGESTS SOILS ACROSS MOST OF THE MARFC
SERVICE AREA CONTAIN MOISTURE THAT IS NEAR NORMAL FOR THIS TIME OF
YEAR.  VISIT WWW.CPC.NCEP.NOAA.GOV/PRODUCTS/SOILMST_MONITORING/US FOR
ADDITIONAL SOIL MOISTURE INFORMATION.

GROUND WATER - BELOW NORMAL TO NEAR NORMAL.  USGS GROUND WATER
MONITORING WELLS ACROSS THE MARFC REGION ARE CURRENTLY INDICATING THAT
GROUND WATER LEVELS ARE GENERALLY IN THE BELOW NORMAL TO NEAR NORMAL
RANGE.  NORTHEASTERN PA, NORTHWESTERN NJ, AND SOUTH-CENTRAL NY HAVE THE
GREATEST CONCENTRATION OF WELLS WITH BELOW-NORMAL LEVELS AT THIS TIME.
VISIT HTTP://GROUNDWATERWATCH.USGS.GOV FOR MONITORING INFORMATION.

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 - AS OF THIS WRITING SIGNIFICANT SNOW WAS
FALLING ACROSS CENTRAL PORTIONS OF THE MARFC REGION.  PRECIPITATION IN
THIS REGION WILL END DURING THE NEXT 12 HOURS OR SO.  COLD AND MOSTLY
DRY WEATHER FOLLOWS THIS STORM FOR A COUPLE OF DAYS.  THEN A WARMING
TREND BEGINS BY EARLY NEXT WEEK WHICH SHOULD PROVIDE MOST OF THE MARFC
REGION WITH NEARLY NORMAL TEMPERATURES FOR MOST OF NEXT WEEK ALONG
WITH ONLY LIGHT, IF ANY, PRECIPITATION.  THESE CONDITIONS SHOULD
FINALLY INITIATE SOME LIMITED, DAILY SNOWMELT ACROSS EVEN NORTHERN AND
WESTERN PORTIONS OF THE MARFC SERVICE AREA NEXT WEEK.  PLEASE VISIT
WWW.CPC.NCEP.NOAA.GOV TO VIEW LONGER-RANGE WEATHER OUTLOOKS.

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 5-19, 2015) AHPS RIVER FORECASTS INDICATE THAT THE
LIKELIHOOD OF RIVER FLOODING WITHIN THE MARFC SERVICE AREA IS PRETTY
CLOSE TO NORMAL FOR MOST MARFC RIVER BASINS.  HOWEVER, THE AHPS
FORECASTS ARE SHOWING A PRETTY HIGH CHANCE OF MINOR FLOODING ALONG THE
LOWER JAMES RIVER IN VA DUE TO THE RECENT RAIN AND SNOWMELT IN THAT
BASIN.  PLEASE VISIT WWW.WEATHER.GOV/AHPS/.

ENSEMBLE RIVER FORECASTS - A DECENT THREAT OF MINOR RIVER FLOODING DOES
EXIST ACROSS THE LOWER PORTIONS OF THE JAMES RIVER DURING THE NEXT
THREE DAYS DUE TO THE RECENT RAIN AND SNOWMELT THAT OCCURRED IN THE
JAMES RIVER BASIN.  PLEASE REFER TO WARNINGS AND STATEMENTS FROM YOUR
LOCAL NWS OFFICE CONCERNING THIS NEAR-TERM RIVER FLOOD THREAT.
OTHERWISE THE MOST RECENT RUNS (MARCH 5, 2015) OF THE ENSEMBLE RIVER
FORECASTS DO NOT SHOW ANY THREAT OF RIVER FLOODING DEVELOPING DURING
THE NEXT SEVERAL DAYS WITHIN THE MARFC SERVICE AREA.  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 DURING THE NEXT
WEEK IS QUITE VARIABLE.  THERE IS A DECENT THREAT OF MINOR RIVER
FLOODING ALONG THE LOWER JAMES RIVER DURING THE NEXT THREE DAYS DUE TO
THE RECENT RAIN AND SNOWMELT IN THAT BASIN.  MEANWHILE, ACROSS THE
REMAINDER OF THE SOUTHEASTERN HALF OF THE MARFC SERVICE AREA, INCLUDING
UPPER AND MIDDLE PORTIONS OF THE JAMES, APPOMATTOX, RAPPAHANNOCK, LOWER
POTOMAC, SCHUYLKILL, RARITAN AND PASSAIC BASINS, THE RIVER FLOOD
POTENTIAL DURING THE NEXT WEEK IS ABOUT NORMAL.  THIS INCLUDES THE
SMALLER STREAMS AND RIVERS LOCATED OUTSIDE OF THESE BASINS BUT STILL
LOCATED IN THE SOUTHEASTERN HALF OF THE REGION.  FINALLY ACROSS THE
NORTHWESTERN HALF OF THE MARFC REGION, INCLUDING THE SUSQUEHANNA AND
DELAWARE RIVER BASINS, AS WELL AS THE PASSAIC BASIN IN NJ, THE RIVER
FLOOD POTENTIAL DURING JUST THE NEXT WEEK IS BELOW AVERAGE DUE TO
WEATHER CONDITIONS THAT ARE PREDICTED TO PRODUCE ONLY LIGHT
PRECIPITATION AND NO UNUSUALLY WARM TEMPERATURES.  HOWEVER, BEYOND THE
NEXT WEEK THE RIVER FLOOD POTENTIAL FOR THIS SAME AREA IS ABOVE NORMAL
DUE TO THE SIGNIFICANT SNOW AND RIVER ICE CONDITIONS THAT STILL EXIST
THERE.

WATER SUPPLY OUTLOOK - ACCORDING TO THE LATEST (MARCH 3, 2015) U.S.
DROUGHT MONITOR, ABNORMALLY DRY CONDITIONS ARE STILL FOUND ACROSS
PORTIONS OF THE MARFC SERVICE AREA.  THIS INCLUDES PORTIONS OF NY, NJ,
PA, MD, WV AND VA.  HOWEVER NO TRUE DROUGHT CONDITIONS CURRENTLY EXIST
WITHIN THE MARFC SERVICE AREA, NOR ARE ANY EXPECTED TO DEVELOP 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 MAY, 2015.  PLEASE
SEE WWW.DROUGHT.GOV, WWW.CPC.NCEP.NOAA.GOV AND
WWW.WEATHER.GOV/MARFC/WRO_UPDATE FOR ADDITIONAL DROUGHT AND WATER
SUPPLY INFORMATION.

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

THE NEXT WINTER/SPRING FLOOD OUTLOOK WILL BE ISSUED BY THIS OFFICE IN
ONE WEEK, ON THURSDAY, MARCH 12, 2015.

SK
$$

....END MARFC....
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