658  
FXUS61 KPHI 291323  
AFDPHI  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ  
923 AM EDT WED MAR 29 2017  
   
SYNOPSIS
 
 
HIGH PRESSURE NEAR HUDSON'S BAY WILL BUILD INTO OUR REGION  
THROUGH WEDNESDAY NIGHT. LOW PRESSURE MOVING THROUGH THE OHIO  
VALLEY ON FRIDAY WILL REDEVELOP NEAR THE NEW JERSEY COAST  
FRIDAY NIGHT AND MOVE OFFSHORE ON SATURDAY. HIGH PRESSURE  
WILL MOVE INTO THE AREA FOR SUNDAY AND MONDAY. LOW PRESSURE  
OVER THE OHIO VALLEY AND ITS ASSOCIATED FRONTS WILL APPROACH  
OUR REGION ON TUESDAY.  
 

 
   
NEAR TERM /UNTIL 6 PM THIS EVENING/
 
 
LOW PRESSURE SOUTH AND EAST OF MONTAUK POINT WILL CONTINUE TO  
DRIFT OUT TO SEA TODAY AS HIGH PRESSURE OVER HUDSON'S BAY BUILDS  
EAST. THE PRESSURE GRADIENT TIGHTENS UP A BIT THIS MORNING, AND  
WITH SLIGHT CAA, CAN EXPECT NW WINDS 15-20 MPH WITH GUSTS UP TO  
25 MPH THIS MORNING. WINDS ABATE BY LATE MORNING/EARLY  
AFTERNOON AS GRADIENT RELAXES.  
 
CLOUDS OVER EASTERN AND SOUTHERN NJ, AND DOWN INTO DE WILL  
CONTINUE TO SCATTER OUT, AND MOSTLY SUNNY SKIES WILL DEVELOP  
ACROSS THE WHOLE CWA BY LATE MORNING/EARLY AFTERNOON.  
 
MAX TEMPS IN THE MID 40S IN THE POCONOS, AND IN THE LOW 50S  
ACROSS NORTHERN NJ. OTHERWISE, HIGHS IN THE UPPER 50S TO LOW 60S  
ACROSS CENTRAL/SOUTHERN NJ, SE PA, AND IN THE LOW TO MID 60S IN  
MD/DE.  
 

 
   
SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/
 
 
CLEAR OR MOSTLY CLEAR SKIES, A FEW FRAGMENTS OF SC IN THE EARLY  
EVE AND POSSIBLY A LITTLE CIRRUS. SOME RADIATIONAL COOLING  
EXPECTED. LIGHT NORTH WIND. NORMAL OR SLIGHTLY BELOW NORMAL  
MINS.  
 
FORECAST BASIS: 50 50 BLENDED 00Z/29 GFS/NAM MOS GUIDANCE. APPLIED  
MINOR 1-2F COOLER THAN GUIDANCE ADJUSTMENTS IN OUR 330 AM FCST  
FOR TONIGHT.  
 

 
   
LONG TERM /THURSDAY THROUGH TUESDAY/
 
 
THE PRIMARY PLAYERS DURING THE LONG TERM WILL BE TWO SOUTHERN  
STREAM SYSTEMS THAT ARE EXPECTED TO IMPACT OUR REGION IN THE  
FRIDAY-SATURDAY AND TUESDAY TIME FRAMES.  
 
THE FIRST SYSTEM MAY PRODUCE 1 TO 1.5 INCHES OF RAIN ACROSS  
PORTIONS OF THE REGION, ESPECIALLY IN THE DELAWARE VALLEY. WHILE  
THERE COULD BE SOME URBAN AND POOR DRAINAGE FLOODING, WE DO NOT  
EXPECT ANY MAJOR IMPACTS ON RIVERS AND STREAMS. THERE IS ALSO A  
CONSISTENT SIGNAL IN THE MODELS FOR MIXED PRECIP NORTH OF I-80,  
WITH SLEET AND FREEZING RAIN THE PRIMARY CONCERNS, DURING THE  
FRIDAY NIGHT AND SATURDAY MORNING PERIOD. WE HAVE MENTIONED THIS  
IN THE HWO.  
 
LOOKING AHEAD TO EARLY NEXT WEEK, THE NEXT SYSTEM IS EXPECTED TO  
BRING MORE PRECIP TO OUR REGION MONDAY NIGHT INTO TUESDAY. THIS  
SETUP LOOKS WARMER, GIVEN THE ABSENCE OF HIGH LATITUDE BLOCKING,  
AND WOULD FAVOR PREDOMINANTLY RAIN.  
 

 
   
AVIATION /13Z WEDNESDAY THROUGH SUNDAY/
 
 
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,  
KILG, KMIV, KACY AND SURROUNDING AREAS.  
 
TODAY...MVFR CIGS ACROSS EASTERN/SOUTHERN NJ, MAINLY AT  
KMIV/KACY, WILL BECOME VFR BY 14-15Z. OTHERWISE, VFR. SCT CLOUDS  
AT 3500 FT POSSIBLE THIS AFTERNOON.  
 
NW WINDS AROUND 15 KT WITH 20-25 KT GUSTS THIS MORNING,  
DIMINISHING TO 10-15 KT BY LATE AFTERNOON.  
 
TONIGHT...VFR WITH FRAGMENTS OF SC IN THE EVENING AND MAYBE SOME  
THIN CIRRUS AT TIMES. LIGHT NORTH WIND.  
 
OUTLOOK...  
 
PREDOMINANTLY VFR, EXCEPT MVFR POSSIBLE FRIDAY INTO SATURDAY.  
 

 
   
MARINE
 
 
OCNL 25 KT GUSTS POSSIBLE UNTIL 11 AM OR SO ON THE OCEAN WATERS  
THIS MORNING, BUT 25 KT GUSTS SHOULD NOT BE FREQUENT ENOUGH OR  
WIDESPREAD ENOUGH TO WARRANT A SCA.  
 
SCA MAY BE NEEDED FOR ANZ450-51 (NNJ TONIGHT).  
ELSEWHERE...GUSTY NORTH WIND THROUGH THE NIGHT TO AROUND 20-22  
KT.  
 
OUTLOOK...  
 
SCA LIKELY FRIDAY INTO SATURDAY, WITH THE POTENTIAL FOR GALE  
FORCE SOUTHEASTERLY WIND GUSTS FRIDAY NIGHT, MAINLY ACROSS THE  
NORTHERN NJ WATERS. OTHERWISE, SUB-SCA.  
 

 
   
TIDES/COASTAL FLOODING
 
 
THOUGH ASTRONOMICAL TIDES WILL BE GRADUALLY DIMINISHING THROUGH  
THE WEEK NOW THAT WE ARE PAST THE NEW MOON, THE THREAT OF MINOR  
TIDAL FLOODING ALONG THE NJ AND DE ATLANTIC COASTS INCREASES  
LATE IN THE WEEK. THIS IS A RESULT OF A LOW PRESSURE SYSTEM  
BRINGING A PROLONGED PERIOD OF ONSHORE FLOW. THE TIDE OF MOST  
CONCERN AT THIS POINT IS THE HIGH TIDE ON FRIDAY EVENING/LATE  
FRIDAY NIGHT. BY THIS TIDE CYCLE, IT WILL TAKE A SURGE OF 0.8 TO  
1.0 FEET TO REACH MINOR FLOODING THRESHOLDS, WHICH IS POSSIBLE  
BUT STILL UNCERTAIN (IT WILL BE DEPENDENT ON HOW QUICKLY THE ON  
SHORE FLOW DEVELOPS AND HOW STRONG IT WILL BE BY THEN). AT LEAST  
ONE SOURCE OF GUIDANCE SHOWS WATER LEVELS REACHING MINOR TIDAL  
FLOODING THRESHOLDS WITH THE THURSDAY EVENING/NIGHT HIGH TIDE,  
BUT THAT SEEMS UNLIKELY AS THE LATEST FORECAST DEPICTS ONSHORE  
FLOW EITHER DEVELOPING RIGHT AROUND OR JUST AFTER THE TIME OF  
THAT HIGH TIDE.  
 
WE HAVE MENTIONED THE POTENTIAL OF MINOR FLOODING ALONG THE  
NORTHERN NJ COAST IN THE HWO, WHERE THE THREAT IS GREATEST  
DURING THE FRIDAY EVENING/LATE FRIDAY NIGHT HIGH TIDE CYCLE.  
 

 
   
CLIMATE
 
 
MO AVG TEMPS  
 
MARCH DEP FEB DEP  
ABE 38.0 -1.1 39.2 +8.5  
 
ACY 41.6 -0.6 43.0 +7.7  
 
ILG 41.7 -1.3 43.1 +8.0  
 
PHL 42.2 -1.3 44.2 +8.5  
 
THIS MARCH WILL BE A BELOW NORMAL MONTH FOR TEMPS.... ONE OF  
THE VERY FEW THE LAST TWO YEARS.  
 
WE APPRECIATE THAT THIS IS POSSIBLY OLD NEWS, BUT MARCH TEMPERATURES  
WILL AVERAGE COLDER THAN THE FEB AVERAGE AT ALL 4 LONG TERM CLIMATE  
LOCATIONS. THE LAST TIME THIS OCCURRED, 1984.  
 

 
   
PHI WATCHES/WARNINGS/ADVISORIES
 
 
PA...NONE.  
NJ...NONE.  
DE...NONE.  
MD...NONE.  
MARINE...NONE.  
 

 
 

 
SYNOPSIS...FRANCK  
NEAR TERM...MPS  
SHORT TERM...DRAG  
LONG TERM...FRANCK  
AVIATION...DRAG/FRANCK/MPS  
MARINE...DRAG/FRANCK  
TIDES/COASTAL FLOODING...  
CLIMATE...  
 
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