Flood Potential Outlook
Issued by NWS Mt. Holly, NJ

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000
FGUS71 KPHI 192131
ESFPHI
DEC001-003-005-MDC011-015-029-035-041-NJC001-005-007-009-011-015-
019-021-023-025-027-029-033-035-037-041-PAC011-017-025-029-045-
077-089-091-095-101-052130-

WINTER/SPRING FLOOD POTENTIAL OUTLOOK
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
425 PM EST THU FEB 19 2015

WINTER/SPRING FLOOD POTENTIAL OUTLOOK...NUMBER 4

THIS IS THE FOURTH IN A SERIES OF ANNUAL WINTER/SPRING FLOOD
POTENTIAL STATEMENTS INTENDED TO PROVIDE INSIGHT INTO THE LIKELIHOOD
OF RIVER FLOODING (NOT FLASH FLOODING) OVER THE MIDDLE/LOWER
DELAWARE, LEHIGH, SCHUYLKILL, PASSAIC AND RARITAN RIVER BASINS.
THESE STATEMENTS WILL PROVIDE INFORMATION ON FLOOD THREAT CONDITIONS
SUCH AS RECENT PRECIPITATION, SOIL MOISTURE, SNOW COVER AND ITS
WATER EQUIVALENT, RIVER ICE CONDITIONS, STREAMFLOW, FUTURE
PRECIPITATION AND OTHERS.

THIS OUTLOOK DOES NOT ADDRESS THE SEVERITY OR EXTENT OF ANY FUTURE
RIVER FLOODING.

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

THIS OUTLOOK IS VALID FOR THE TWO-WEEK PERIOD, FEBRUARY 19 TO MARCH
5, 2015.

IN THE MOUNT HOLLY, NEW JERSEY HYDROLOGIC SERVICE AREA (HSA), THE
OVERALL RIVER FLOOD POTENTIAL FOR THE NEXT TWO WEEKS IS SLIGHTLY
ABOVE NORMAL.

NOTE - FOR THE HEADWATERS OF THE DELAWARE RIVER, SEE THE STATEMENT
(FGUS71 KBGM ESFBGM) FROM OUR BINGHAMTON (BGM), NEW YORK OFFICE.

CURRENT FLOODING - NONE.

RECENT PRECIPITATION - BELOW NORMAL. BETWEEN 2.0 AND 5.0 INCHES OF
LIQUID HAVE BEEN RECORDED OVER THE LAST 30 DAYS WHICH IS GENERALLY
10 TO 25 PERCENT BELOW NORMAL. PRECIPITATION DEPARTURE MAPS CAN BE
FOUND AT WWW.WEATHER.GOV/MARFC (UNDER THE WATER SUPPLY TAB).

SNOW COVER - ABOVE NORMAL. DEPTHS GENERALLY RANGE BETWEEN THREE AND
TWELVE INCHES. SNOW WATER EQUIVALENTS GENERALLY RANGE BETWEEN ONE
AND THREE INCHES. THESE SNOW CONDITIONS ARE SIGNIFICANT ENOUGH TO BE
A FACTOR IN THE DEVELOPMENT OF RIVER FLOODING, ESPECIALLY IF RAPID
SNOWMELT IS COMBINED WITH SIGNIFICANT RAINFALL. WHILE RAPID SNOWMELT
AND SIGNIFICANT RAINFALL IS CURRENTLY NOT ANTICIPATED ACROSS THE
SNOWPACK DURING THE NEXT TWO WEEKS, MILDER TEMPERATURES AND RAINFALL
MAY REDUCE OR ELIMINATE THE LESS SIGNIFICANT SNOW THAT EXISTS ACROSS
SOUTHERN AND FAR EASTERN PORTIONS OF THE REGION THIS WEEKEND. SNOW
DEPTH AND BASIN-AVERAGE WATER EQUIVALENT ESTIMATES CAN BE FOUND AT
WWW.WEATHER.GOV/MARFC (UNDER THE SEASONAL INTEREST TAB) OR
WWW.NOHRSC.NOAA.GOV (UNDER THE NATIONAL ANALYSES TAB).

RIVER ICE - ABOVE NORMAL. ICE HAS FURTHER INCREASED OVER THE LAST
TWO WEEKS. SHOULD A RAPID ICE BREAKUP OCCUR, THE RIVER ICE IS THICK
ENOUGH AND EXTENSIVE ENOUGH THAT ICE JAMS WOULD LIKELY FORM. THIS
COULD CAUSE SOME LOCALIZED FLOODING. A SIGNIFICANT BREAKUP DURING
THE NEXT TWO WEEKS IS UNLIKELY WITH CONTINUED COLD TEMPERATURES
PREDICTED FOR MOST OF THE OUTLOOK PERIOD.

STREAMFLOW - BELOW NORMAL TO NORMAL. REAL TIME WATER DATA IS
AVAILABLE FROM THE UNITED STATES GEOLOGICAL SURVEY BY VISITING
HTTP://WATER.USGS.GOV.

SOIL MOISTURE - ABOUT NORMAL. SOIL MOISTURE MONITORING CHARTS FROM
NOAA`S CLIMATE PREDICTION CENTER CAN BE FOUND AT THE FOLLOWING
WEBSITES...
WWW.CPC.NCEP.NOAA.GOV/PRODUCTS/SOILMST_MONITORING/US/SOILMST/SOILMST.
SHTML AS WELL AS WWW.DROUGHT.GOV.

GROUND WATER - USGS MONITORING WELLS INDICATE THAT CURRENT GROUND
WATER LEVELS ACROSS THE REGION ARE VARIABLE, RANGING FROM BELOW
NORMAL NORMAL. ADDITIONAL INFORMATION CAN BE FOUND AT
HTTP://GROUNDWATERWATCH.USGS.GOV.

RESERVOIR CONDITIONS - WATER SUPPLY AND FLOOD CONTROL RESERVOIRS IN
THE AREA ARE RUNNING NEAR NORMAL TO NORMAL.

FUTURE WEATHER CONDITIONS - HIGH PRESSURE OVER THE OHIO VALLEY WILL
BUILD INTO THE REGION THRU FRIDAY. LOW PRESSURE OVER THE LOWER
MISSISSIPPI VALLEY ON SATURDAY WILL MOVE INTO THE SAINT LAWRENCE
VALLEY ON SUNDAY...LEADING TO A STRONG COLD FRONTAL PASSAGE LATE
SUNDAY. AN ARTIC COLD FRONTAL PASSAGE WILL OCCUR LATE MONDAY. LOW
PRESSURE MAY DEVELOP JUST OFFSHORE DURING THE TUESDAY AND WEDNESDAY
TIME FRAME OF NEXT WEEK. THE 8 TO 14 DAY OUTLOOK CALLS FOR BELOW
NORMAL TEMPERATURES AND ABOVE NORMAL PRECIPITATION. PLEASE VISIT
WWW.CPC.NCEP.NOAA.GOV.

ADVANCED HYDROLOGIC PREDICTION SERVICE (AHPS) - NEAR NORMAL FOR THIS
TIME OF YEAR. ANOTHER TOOL USED TO ASSESS THE POTENTIAL FOR
WINTER/SPRING FLOODING IS CALLED AHPS, ADVANCED HYDROLOGIC
PREDICTION SERVICE. ONE COMPONENT OF AHPS IS THE GENERATION OF
PROBABILISTIC RIVER FORECASTS BASED ON CURRENT BASIN CONDITIONS
(RIVER LEVELS, SOIL MOISTURE, EXTENT AND CONDITION OF SNOWPACK)
ALONG WITH 50 YEARS OF HISTORIC TEMPERATURE AND PRECIPITATION DATA.

FOR THIS OUTLOOK, THE AHPS TECHNIQUE HAS BEEN APPLIED TO THE
DELAWARE, PASSAIC AND RARITAN RIVER SYSTEMS. FOURTEEN DAY
PROBABILISTIC FORECASTS GENERATED FOR THESE BASINS SHOW THAT THE
LIKELIHOOD OF FLOODING IS NEAR NORMAL COMPARED TO WHAT HAS BEEN
HISTORICALLY OBSERVED. PLEASE VISIT WWW.WEATHER.GOV/AHPS.

IT SHOULD BE NOTED THAT AHPS PROBABILISTIC FORECASTS DO NOT TAKE INTO
ACCOUNT FUTURE PRECIPITATION.

SUMMARY - TAKING ALL OF THE INCLUDED VARIABLES INTO CONSIDERATION,
THE OVERALL FLOOD POTENTIAL OVER THE NEXT TWO WEEKS IS SLIGHTLY
ABOVE NORMAL.

FOR COMPLETE WEATHER INFORMATION, VISIT OUR WEB SITE AT:
WWW.WEATHER.GOV/PHI

$$

SUMMARY/OVERVIEW OF FLOOD POTENTIAL THROUGH MARCH 5, 2015:

OVERALL FLOOD POTENTIAL...SLIGHTLY ABOVE NORMAL
CURRENT FLOODING...NONE
RECENT PRECIPITATION...BELOW NORMAL
SNOW COVER...ABOVE NORMAL
RIVER ICE...ABOVE NORMAL
STREAMFLOW...BELOW NORMAL
SOIL MOISTURE...BELOW NORMAL
GROUND WATER...BELOW NORMAL TO NORMAL
RESERVOIR CONDITIONS...NEAR NORMAL TO NORMAL
AHPS...NEAR NORMAL

$$

KRUZDLO



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