346  
FXUS61 KPHI 050126  
AFDPHI  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ  
926 PM EDT WED MAY 4 2016  
   
SYNOPSIS
 
 
A TROUGH OF LOW PRESSURE WILL EXTEND EASTWARD FROM THE OHIO VALLEY  
TO THE MID-ATLANTIC COASTLINE TONIGHT. DUAL LOW PRESSURE SYSTEMS  
LOCATED JUST OFFSHORE AND ACROSS THE OHIO VALLEY WILL BE SLOW TO  
MOVE THROUGH THE REGION FOR THE LATER HALF OF THIS WEEK. A LOW  
PRESSURE SYSTEM IS LIKELY TO LINGER JUST OFFSHORE INTO THE  
WEEKEND. BY SUNDAY, A COLD FRONT IS EXPECTED TO MOVE SOUTHEAST  
THROUGH THE REGION. THIS WILL BE FOLLOWED BY WELCOMED HIGH  
PRESSURE BUILDING NORTHEAST INTO THE REGION FOR THE FIRST PART OF  
NEXT WEEK.  
 

 
   
NEAR TERM /UNTIL 6 AM THURSDAY MORNING/
 
 
CONTINUE TO KEEP A DRY FCST INTO TONIGHT, EXCEPT PSBLY FOR SOME  
DZ.  
 
OTHERWISE, TEMPS AND CLOUD COVER LOOK GOOD.  
 
LOW PRESSURE WILL REMAIN ALONG AND OFF THE MIDDLE ATLANTIC COAST  
TONIGHT.  
 
ANOTHER AREA OF LOW PRESSURE WAS CENTERED OVER SOUTHEASTERN  
MICHIGAN AT MID AFTERNOON. THE LOW WILL SHIFT SOUTHEASTWARD AND  
IT IS EXPECTED TO MERGE WITH THE COASTAL LOW LATE TONIGHT.  
 
THE SURFACE WEATHER PATTERN IS EXPECTED TO MAINTAIN A NORTHEAST FLOW  
IN OUR REGION. AS A RESULT, WE WILL CONTINUE TO HAVE LOW CLOUDS AND  
PATCHY DRIZZLE TONIGHT ALONG WITH ISOLATED LIGHT SHOWERS. PATCHY FOG  
IS POSSIBLE IN THE ELEVATED TERRAIN.  
 
MINIMUM TEMPERATURES WILL FAVOR THE MIDDLE AND UPPER 40S.  
 

 
   
SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/
 
 
A PRIMARY SURFACE LOW IS FORECAST TO PROGRESS NORTHEASTWARD TO THE  
WATERS OFF NEW ENGLAND ON THURSDAY. MEANWHILE, A LINGERING AREA OF  
LOW PRESSURE SHOULD REMAIN OFF THE MIDDLE ATLANTIC COAST. AS A  
RESULT, WE WILL EXPERIENCE ANOTHER DAY OF NORTHEASTERLY WIND ALONG  
WITH LOW CLOUDS. SCATTERED SHOWERS ARE POSSIBLE, MAINLY IN OUR  
NORTHWESTERN COUNTIES.  
 
MAXIMUM TEMPERATURES ARE ANTICIPATED TO BE IN THE 50S.  
 

 
   
LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/
 
 
THURSDAY NIGHT THROUGH SATURDAY: DUAL LOW PRESSURES WILL CONTINUE  
THE GRAY AND DREARY PATTERN ACROSS THE REGION IN THIS TIMEFRAME. THE  
FIRST AREA OF LOW PRESSURE WILL LIKELY BE DEPARTING TO THE NORTHEAST  
OFF CAPE COD WITH THE SECOND LOW PRESSURE SYSTEM IN THE CAROLINAS.  
THESE LOW PRESSURE SYSTEMS WILL PROVIDE LIFT AND MOISTURE WITH  
ONSHORE FLOW LEADING TO ADDITIONAL PERIODS OF SHOWERS. THE HIGHEST  
CHANCES CURRENTLY ARE LIKELY TO OCCUR ON FRIDAY WHEN THE TRAILING  
LOW PRESSURE SYSTEMS LOCATED JUST TO OUR SOUTHWEST. RIGHT NOW  
MODELING IS FOCUSING THE HEAVIEST AND STEADIEST SHOWERS ACROSS  
NORTHERN PORTIONS OF THE REGION ON FRIDAY. QPF COULD REACH HALF AN  
INCH BY FRIDAY NIGHT IN NORTHERN PARTS OF THE REGION. WITH THE  
EXCESSIVE CLOUD COVER IN PLACE WENT A LITTLE COOLER IN THE DAYS  
WITH HIGHS THAN WHAT MET/MAV GUIDANCE WOULD SUGGEST AND WARMER AT  
NIGHT,HIGHS WILL LIKELY STAY IN THE 50'S FOR MOST OF THE REGION.  
 
THERE IS SOME OPTIMISM THAT SATURDAY AFTERNOON/EVENING COULD BE  
DRIER THAN INDICATED IN THE VARIOUS ENSEMBLE PACKAGES. HOWEVER, AN  
EQUAL POSSIBILITY IS PRESENT THAT THE SECOND LOW WILL LINGER  
OFFSHORE THROUGH SATURDAY. THE CLOUDS AND SHOWERS SHOULD KEEP LOW  
TEMPERATURES WARMER AT NIGHT AND COOLER IN THE DAY THAN WHAT VARIOUS  
GUIDANCE PACKAGES INDICATE. TEMPERATURES WILL START A GRADUAL  
WARMING TREND ON SATURDAY.  
 
SATURDAY NIGHT THROUGH SUNDAY NIGHT: A COLD FRONTAL BOUNDARY WILL  
LIKELY BE THE ULTIMATE KICKER FOR THE STUBBORN LOW PRESSURE JUST  
OFFSHORE. HOWEVER, TIMING REMAINS UNCERTAIN AT THIS POINT. THE COLD  
FRONT WILL BE A FOCUS FOR YET ADDITIONAL SCATTERED LIGHT SHOWERS LATE  
SATURDAY NIGHT AND SUNDAY. A BREAK BETWEEN SYSTEMS WITH SOME  
CLEARING IS LIKELY TO OCCUR BEFORE THE NEXT ROUND OF SHOWERS  
ARRIVES.  
 
MONDAY THROUGH WEDNESDAY: ON MONDAY HIGH PRESSURE WILL BUILD  
NORTHEAST INTO THE REGION. THIS WILL ALLOW FOR A FEW DRY DAYS AND A  
GRADUAL WARMING TREND THROUGH THE FIRST HALF OF NEXT WEEK AS A  
NORTHWESTERLY FLOW GRADUALLY BECOMES SOUTHERLY BY WEDNESDAY. THE  
CHALLENGE IN THIS PERIOD WILL BE A WARM FRONT DIVIDING A COOLER  
MORE MARINE AIRMASS AND SOUTHERLY FLOW SENDING MORE SUMMERLIKE  
TEMPERATURES INTO OUR REGION. RIGHT NOW THE LOCATION AND TIMING OF  
THIS WARM FRONT EARLY NEXT WEEK IS STILL UNCERTAIN. HOWEVER, IT DOES  
LOOK LIKE THE FRONT MAKES IT NORTH OF THE REGION. THIS WOULD  
POTENTIALLY RESULT IN HIGH TEMPERATURES INTO THE 80'S BY WEDNESDAY.  
FOR NOW, HAVE TEMPERED THIS CHANGE IN MODELING KEEPING SOME  
CONTINUITY GIVEN THE UNCERTAINTY. LOW PRESSURE ALONG THE FRONT WILL  
MOVE TOWARD OUR REGION ON WEDNESDAY. THERE IS A POTENTIAL FOR  
OVERLAP OF INSTABILITY AND OVER 30 KNOTS OF 0-6 KM BULK SHEAR,  
BUT IT'S TO EARLY TO ACCESS THE DEGREE OF ANY SEVERE WEATHER.  
 

 
   
AVIATION /01Z THURSDAY THROUGH MONDAY/
 
 
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,  
KILG, KMIV, KACY AND SURROUNDING AREAS.  
 
CEILINGS GENLY REMAIN IN THE 1000 TO 1500 FT RANGE. THERE ARE  
SOME SUB 100 FT VALUES AS WELL. THE EXPECTED TREND IS DOWNWARD  
INTO IFR AND EVEN LIFR OVERNIGHT. HOWEVER, DOWNWARD TREND MAY BE  
SLOWER FCST. IF THERE IS ANY DRIZZLE THAT OCCURS, THERE COULD BE  
BRIEF VSBY REDUCTIONS AS WELL. HOWEVER, SCATTERED LIGHT SHOWERS  
AND PATCHY DRIZZLE FROM TONIGHT INTO THURSDAY MAY BRIEFLY REDUCE  
THE VISIBILITY TO 5 MILES OR LESS IN SPOTS.  
 
THE WIND SHOULD CONTINUE TO FAVOR THE NORTHEAST AT 6 TO 12 KNOTS.  
GUSTS NEAR 20 KNOTS ARE POSSIBLE FROM AROUND KPHL EAST AND SOUTHWARD  
ON THURSDAY.  
 
OUTLOOK...  
 
THURSDAY NIGHT THROUGH SATURDAY: FREQUENT MVFR/IFR CEILINGS AND  
VSBYS WITH SCATTERED SHOWERS. EASTERLY WINDS UP TO 10 KNOTS WITH  
HIGHER GUSTS UP TO 20 KNOTS ON FRIDAY.  
 
SATURDAY NIGHT THROUGH SUNDAY NIGHT: MAINLY VFR WITH SCATTERED  
SHOWERS. SOUTHWEST WINDS INCREASING WITH GUSTS AROUND 20 KNOTS  
SUNDAY AFTERNOON. WINDS SHIFTING TO NORTHWEST DURING THE DAY SUNDAY.  
 
MONDAY: VFR, WEST TO NORTHWEST WINDS AROUND 10 KNOTS WITH HIGHER  
GUSTS.  
 

 
   
MARINE
 
 
LOW PRESSURE ALONG AND OFF THE MIDDLE ATLANTIC COAST WILL MAINTAIN A  
NORTHEASTERLY FLOW ON OUR COASTAL WATERS FOR TONIGHT AND THURSDAY.  
WAVE HEIGHTS ON OUR OCEAN WATERS SHOULD BUILD TO 4 TO 7 FEET AND  
GUSTS NEAR 25 KNOTS ARE POSSIBLE. THE SMALL CRAFT ADVISORY HAS BEEN  
EXPANDED TO INCLUDE OUR WATERS OFF DELAWARE.  
 
OUTLOOK...  
 
AN SCA IS NOW IN EFFECT THROUGH FRIDAY AFTERNOON. SEAS WILL REMAIN  
AT OR JUST OVER FIVE FEET THROUGH SATURDAY. SEAS WILL DECREASE FOR  
THE EARLY PART OF NEXT WEEK. A PERIOD OF EASTERLY WIND GUSTS AROUND  
20 KNOTS IS LIKELY FRIDAY ALONG WITH A PERIOD OF NORTHWESTERLY WIND  
GUSTS AROUND 20 KNOTS ON SUNDAY.  
 

 
   
TIDES/COASTAL FLOODING
 
 
THE TIDAL SURGE RANGED FROM +0.7 TO +1.0 FOOT ALONG THE NEW JERSEY  
AND DELAWARE COAST DURING THIS MORNING'S HIGH TIDE. THE PERSISTENT  
NORTHEAST FLOW WILL LIKELY CAUSE THE TIDAL SURGE TO BE AROUND +1.0  
TO +1.3 FEET FOR THIS EVENING'S HIGH TIDE. THOSE VALUES ALONG WITH  
THE INCREASING ASTRONOMICAL TIDES AS WE APPROACH FRIDAY'S NEW MOON  
SHOULD RESULT IN MINOR TIDAL FLOODING ALONG THE NEW JERSEY AND  
DELAWARE COASTS THIS EVENING. THE COASTAL FLOOD ADVISORY REMAINS IN  
EFFECT.  
 
MINOR TIDAL FLOODING IS ALSO LIKELY TO EXTEND INTO THE HIGH TIDE  
CYCLES THURSDAY AND FRIDAY NIGHT CYCLES.  
 

 
   
PHI WATCHES/WARNINGS/ADVISORIES
 
 
PA...NONE.  
NJ...COASTAL FLOOD ADVISORY UNTIL 11 PM EDT THIS EVENING FOR  
NJZ012>014-020>027.  
DE...COASTAL FLOOD ADVISORY UNTIL 11 PM EDT THIS EVENING FOR  
DEZ002>004.  
MD...NONE.  
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EDT FRIDAY FOR ANZ450>455.  
 

 
 

 
SYNOPSIS...GAINES  
NEAR TERM...IOVINO/NIERENBERG  
SHORT TERM...IOVINO  
LONG TERM...GAINES  
AVIATION...GAINES/IOVINO/NIERENBERG  
MARINE...GAINES/IOVINO  
TIDES/COASTAL FLOODING...  
 
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