128  
FGUS61 KRHA 141848  
ESGRHA  
 
WINTER/SPRING RIVER FLOOD POTENTIAL OUTLOOK  
MIDDLE ATLANTIC RIVER FORECAST CENTER  
NATIONAL WEATHER SERVICE STATE COLLEGE, PA  
1:45 PM EST WED FEB 14 2018  
 
OUTLOOK NUMBER 18-04 - FEBRUARY 14, 2018  
 
THIS WINTER/SPRING RIVER FLOOD POTENTIAL OUTLOOK IS VALID FOR THE  
TWO-WEEK PERIOD FEBRUARY 15-MARCH 1, 2018.  
 
THIS OUTLOOK ESTIMATES THE POTENTIAL FOR RIVER FLOODING (NOT FLASH  
FLOODING) TO DEVELOP DURING THE NEXT TWO WEEKS ACROSS THE MIDDLE  
ATLANTIC RIVER FORECAST CENTER'S (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 - THE RIVER FLOOD POTENTIAL FOR MARFC  
RIVERS DURING THE NEXT TWO WEEKS IS SOMEWHAT ABOVE AVERAGE. FACTORS  
WHICH CONTRIBUTE TO THIS ASSESSMENT OF RIVER FLOOD POTENTIAL ARE  
DISCUSSED IN SOME DETAIL BELOW.  
 
CURRENT FLOODING - NONE.  
 
RECENT PRECIPITATION - VARIABLE. PRECIPITATION HAS INCREASED  
CONSIDERABLY ACROSS MUCH OF THE MARFC SERVICE AREA RECENTLY. THANKS  
TO THE RECENT STORM, SOUTHERN AND EASTERN AREAS ARE NOW, AT LEAST  
FOR THE TIME BEING, RATHER WET. OVER THE LAST 30 DAYS (JANUARY 15-  
FEBRUARY 13) PRECIPITATION WAS BELOW NORMAL/NORMAL ACROSS SOUTHERN  
NY, PORTIONS OF CENTRAL PA, IN WESTERN MD AND NORTHEASTERN WV.  
ELSEWHERE, PRECIPITATION HAS BEEN ABOVE NORMAL/MUCH ABOVE NORMAL.  
THE RECENT WET WEATHER WILL HELP REDUCE THE DRYNESS THAT HAS EXISTED  
ACROSS MUCH OF THE SOUTHEASTERN HALF OF THE MARFC REGION FOR SEVERAL  
MONTHS. TOTAL PRECIPITATION DURING THE LAST 30 DAYS RANGED FROM  
AROUND 1.5 INCHES IN SOUTH-CENTRAL NY TO 4-7 INCHES ACROSS MUCH OF  
VA, THE DELMARVA REGION AND NJ. PRECIPITATION DEPARTURE DATA CAN BE  
VIEWED AT WWW.WEATHER.GOV/MARFC/PRECIPITATION_DEPARTURES.  
 
SNOW CONDITIONS - BELOW AVERAGE/AVERAGE. SNOW PRESENTLY COVERS THE  
GROUND ACROSS ABOUT THE NORTHWESTERN THIRD OF THE MARFC REGION. THE  
MOST SIGNIFICANT SNOW IS FOUND ACROSS UPPER PORTIONS OF BOTH THE  
SUSQUEHANNA AND DELAWARE BASINS IN NY AND NORTHERN PA. HERE SNOW  
DEPTHS RANGE FROM 3-10 INCHES WHILE SNOW WATER EQUIVALENT VALUES ARE  
GENERALLY 1.0-2.0 INCHES. ISOLATED LOCATIONS HAVE SOMEWHAT HIGHER  
VALUES. OUTSIDE OF THIS REGION SNOW DEPTHS DECREASE HEADING  
SOUTHWARD TO 1-4 INCHES WHILE WATER EQUIVALENT VALUES DECREASE TO  
LESS THAN AN INCH. SNOW CONDITIONS ARE GENERALLY BELOW AVERAGE FOR  
THIS TIME OF WINTER NORTHWEST OF A LINE FROM ABOUT ROANOKE VA TO  
NEAR FREDERICK MD TO ABOUT POUGHKEEPSIE NY. SOUTHEAST OF THAT LINE  
SNOW CONDITIONS ARE ABOUT AVERAGE, MEANING LITTLE OR NO SNOW EXISTS  
WHICH IS FAIRLY TYPICAL FOR THIS REGION. SNOW INFORMATION CAN BE  
FOUND AT WWW.WEATHER.GOV/MARFC/SNOW AND WWW.NOHRSC.NOAA.GOV.  
 
RIVER ICE - GENERALLY BELOW AVERAGE. RIVER ICE CONDITIONS ARE  
PRESENTLY BELOW NORMAL FOR THIS TIME OF WINTER. WHILE RIVER ICE IS  
BEING OBSERVED ACROSS ABOUT THE NORTHERN THIRD OF THE MARFC REGION,  
THE ICE IS NEITHER THICK NOR EXTENSIVE. WITH A WARMER-THAN-NORMAL  
WEATHER PATTERN POSSIBLE FOR MUCH OF THE NEXT TWO WEEKS, LITTLE IF  
ANY NEW RIVER ICE IS EXPECTED TO FORM DURING THE NEXT TWO WEEKS. IT  
ALSO SEEMS UNLIKELY THAT TEMPERATURES WILL GET COLD ENOUGH FOR ANY  
SUBSTANTIAL RIVER ICE TO REFORM FOR THE REST OF THIS WINTER.  
 
STREAMFLOW CONDITIONS - AVERAGE/ABOVE AVERAGE. SOME STREAMGAGES,  
MAINLY IN NY, CONTINUE TO BE AFFECTED BY ICE. THE LATEST DATA FROM  
THE UNITED STATES GEOLOGICAL SURVEY (USGS) INDICATE NEAR-NORMAL TO  
ABOVE-NORMAL STREAMFLOW CONDITIONS THROUGHOUT THE MARFC REGION.  
PLEASE VISIT HTTPS://WATERDATA.USGS.GOV/NWIS/RT FOR CURRENT  
STREAMFLOW DATA.  
 
SOIL MOISTURE CONDITIONS - NORMAL/BELOW NORMAL. THE LONG-TERM  
PALMER DROUGHT SEVERITY INDEX IS USED TO INFER DEEP SOIL MOISTURE  
CONDITIONS. THE FEBRUARY 10, 2018 CHART (FOUND AT  
WWW.CPC.NCEP.NOAA.GOV/PRODUCTS/ANALYSIS_MONITORING/  
REGIONAL_MONITORING/PALMER.GIF) SUGGESTS DEEP SOILS ACROSS MUCH OF  
THE MARFC SERVICE AREA CONTAIN MOISTURE THAT IS ABOUT NORMAL FOR  
THIS TIME OF YEAR. HOWEVER, OTHER DETAILED SOIL MOISTURE  
INFORMATION (GO TO WWW.CPC.NCEP.NOAA.GOV/PRODUCTS/SOILMST_MONITORING  
AND THEN CLICK ON U.S. MONITORING) INDICATES SOIL MOISTURE DEFICITS  
REMAIN ACROSS SOUTHERN AND EASTERN REGIONS. THESE AREAS DID RECEIVE  
2-4 INCHES OF RAIN FROM THE MOST RECENT RAIN EVENT WHICH WILL  
CERTAINLY HELP TO DECREASE THE DRYNESS.  
 
GROUNDWATER - NORMAL/BELOW NORMAL. USGS GROUNDWATER MONITORING  
WELLS ARE CURRENTLY INDICATING NEAR-NORMAL GROUNDWATER LEVELS ACROSS  
ABOUT THE NORTHWESTERN TWO-THIRDS OF THE REGION, AND BELOW-NORMAL  
LEVELS ELSEWHERE. PLEASE VISIT HTTPS://GROUNDWATERWATCH.USGS.GOV.  
 
RESERVOIR CONDITIONS - AVERAGE/BELOW AVERAGE. MOST MAJOR RESERVOIRS  
WITHIN THE MARFC REGION ARE HOLDING STORAGES THAT ARE AVERAGE/BELOW  
AVERAGE FOR THIS TIME OF YEAR. FOR EXAMPLE RESERVOIR STORAGE IN THE  
UPPER DELAWARE RIVER BASIN IN NY IS SLIGHTLY BELOW THE LONG-TERM  
MEDIAN BUT STILL WELL WITHIN THE NORMAL RANGE.  
 
FUTURE WEATHER CONDITIONS - AN ACTIVE WEATHER PATTERN SEEMS LIKELY  
TO CONTINUE FOR THE NEXT TWO WEEKS. NUMEROUS WEATHER SYSTEMS SEEM  
LIKELY TO PASS NEAR/THROUGH THE REGION, AND EACH HAS THE APPEARANCE  
OF BEING ABLE TO PRODUCE AT LEAST MODERATE PRECIPITATION ACROSS  
PORTIONS OF THE REGION. SOME HEAVY RAINFALL SEEMS UNAVOIDABLE  
DURING THIS NEXT TWO-WEEK PERIOD. IN ADDITION, A VERY MILD PERIOD  
SEEMS LIKELY FOR AT LEAST THE FIRST HALF OF NEXT WEEK, WHICH WILL  
UNDOUBTEDLY CAUSE SNOWMELT WHERE SNOW STILL EXISTS. THE COMBINATION  
OF RATHER FREQUENT PERIODS OF MODERATE-HEAVY RAIN, AND SNOWMELT,  
COULD EASILY PRODUCE SOME RIVER FLOODING ALMOST ANYWHERE WITHIN THE  
MARFC REGION DURING THE NEXT TWO WEEKS. THE FACT THAT STREAMFLOWS  
ACROSS MOST OF THE REGION ARE NOW ELEVATED AND SOILS MORE MOIST  
SUPPORTS THE IDEA OF AN INCREASED FLOOD POTENTIAL DURING THIS  
PERIOD. FINALLY, LONGER-RANGE WEATHER OUTLOOKS ALSO SUGGEST THIS  
NEXT TWO-WEEK PERIOD WILL LIKELY BE MILDER AND WETTER THAN NORMAL  
(VISIT WWW. CPC.NCEP.NOAA.GOV/PRODUCTS/PREDICTIONS/610DAY).  
 
ENSEMBLE RIVER FORECASTS - A LIMITED THREAT OF RIVER FLOODING  
DEVELOPING. THE MOST RECENT RUNS (FEBRUARY 14, 2018) OF THE  
ENSEMBLE RIVER FORECASTS, WHICH TAKE INTO ACCOUNT ANTICIPATED FUTURE  
WEATHER CONDITIONS INCLUDING PRECIPITATION AND TEMPERATURES, DO SHOW  
SOME CHANCE OF RIVER FLOODING DEVELOPING WITHIN THE MARFC REGION  
DURING THE NEXT WEEK. PLEASE VISIT WWW.WEATHER.GOV/ERH/MMEFS FOR  
ENSEMBLE RIVER FORECASTS.  
 
SUMMARY - FOR THE NEXT TWO WEEKS THE RIVER FLOOD POTENTIAL FOR  
RIVERS IN THE MARFC REGION IS ABOVE AVERAGE. HIGHER STREAMFLOWS,  
WETTER SOILS, AND A POTENTIALLY ACTIVE WEATHER PATTERN CAPABLE OF  
PRODUCING PERIODS OF HEAVY RAIN (AND SNOWMELT) ARE ALL FACTORS  
LEADING TO THE ABOVE-AVERAGE POTENTIAL.  
 
WATER SUPPLY OUTLOOK - ACCORDING TO THE LATEST (FEBRUARY 6, 2018)  
U.S. DROUGHT MONITOR (HTTP://DROUGHTMONITOR.UNL.EDU), LARGE PORTIONS  
OF THE MARFC SERVICE AREA CONTINUE TO SHOW CONDITIONS THAT RANGE  
FROM ABNORMALLY DRY TO EVEN SEVERE DROUGHT. DRIEST REGIONS ARE  
ACROSS THE SOUTH AND EAST. HOWEVER, THIS CHART DOES NOT TAKE INTO  
ACCOUNT THE RECENT HEAVY RAIN EVENT THAT IMPACTED THOSE SAME  
REGIONS. A NEW CHART WILL BE RELEASED THIS WEEK, AND SOME  
IMPROVEMENT IN DROUGHT CONDITIONS WITHIN THE MARFC REGION IS  
ANTICIPATED. VISIT WWW.DROUGHT.GOV, WWW.CPC.NCEP.NOAA.GOV AND  
WWW.WEATHER.GOV/MARFC/WRO_NORTH FOR ADDITIONAL DROUGHT AND WATER  
SUPPLY INFORMATION.  
 
PLEASE VISIT THE NWS MARFC HOMEPAGE AT WWW.WEATHER.GOV/MARFC OR FIND  
US ON FACEBOOK AT WWW.FACEBOOK.COM/NWSMARFC/?REF=AYMT_HOMEPAGE_PANEL  
AND ON TWITTER @NWSMARFC.  
 
THE NEXT WINTER/SPRING FLOOD OUTLOOK WILL BE ISSUED BY THIS OFFICE  
IN TWO WEEKS ON MARCH 1, 2018.  
 
SK  

 
   
...END MARFC.
 
 
NNNN  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab RFC Page Main Text Page