Skip Navigation Linkswww.nws.noaa.gov 
NOAA logo - Click to go to the NOAA homepage National Weather Service Forecast Office   NWS logo - Click to go to the NWS homepage
Philadelphia/Mount Holly banner image
 
 

Area Forecast Discussion
Latest Versions  [Current][-1][-2][-3][-4]



000
FXUS61 KPHI 191404
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1004 AM EDT TUE AUG 19 2014

.SYNOPSIS...
QUASI-STATIONARY FRONTAL BOUNDARY TO THE SOUTH OF THE REGION WILL 
SLOWLY SLIP FARTHER SOUTH THIS WEEK AS SEVERAL WAVES OF LOW PRESSURE 
MOVE EASTWARD ALONG IT. NEW ENGLAND HIGH PRESSURE NOSES IN OVER THE 
WEEKEND AND REMAINS NEARLY STATIONARY THROUGH EARLY NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THIS MORNING'S SURFACE ANALYSIS SHOWED WEAK LOW PRESSURE JUST OFF
OF THE VIRGINIA CAPES. AS MENTIONED BY THE PREVIOUS SHIFT, THE
TRACK OF THIS LOW HAS BEEN A TAD FARTHER SOUTH AND FASTER THAN
PREVIOUS MODEL GUIDANCE HAD PROGGED. THUS, THE BULK OF THE PRECIP
WITH THE LOW HAS STAYED SOUTH OF DE AND EASTERN MD, FOR THE MOST
PART. HOWEVER, AT THIS TIME, WE CANNOT COMPLETELY RULE OUT AN
ISOLATED SHOWER OR TWO AS THERE HAVE BEEN EARLIER TODAY, AND WE HAVE
KEPT SLIGHT CHANCE POPS IN THROUGH THE MORNING OVER SOUTHERN
PORTIONS OF OUR DELMARVA AREA. WE ALSO ADJUSTED SKY COVER SOME
ACROSS THE SOUTHERN DELMARVA, FAR SOUTHERN NJ, AND ALONG THE
MONMOUTH TO OCEAN COUNTY COASTS WHERE SOME LOWER CLOUDS REMAIN,
BUT THE OVERALL TREND WILL BE FOR THE CLOUDS TO ERODE SOMEWHAT
THROUGH THE DAY. ONLY SOME MINOR ADJUSTMENTS TO HOURLY TEMPS AND
DEWPOINTS WERE NEEDED THROUGH MORNING AND INTO THE AFTERNOON, AND
TODAY'S MAXIMUM TEMPERATURES LOOK ON TRACK AFTER CHECKING 12Z
REGIONAL SOUNDING DATA. 

OTHERWISE, SKY COVER WAS RANGING FROM OVERCAST IN FAR SOUTHERN NJ
AND THE DELMARVA TO FEW IN NORTHERN NJ BEFORE DRIER AIR MOVES IN
BEHIND THE SYSTEM AND CLOUDS ERODE. THE ONE EXCEPTION TO THE CLOUD
COVER WILL BE OUT TOWARD MQS-RDG-MPO. THESE LOCATIONS ARE
POSITIONED NEAR OR JUST WEST OF H8 RIDGE AXIS, WHERE BACKING WINDS
OUT OF THE SOUTH WILL RESULT IN WEAK ISENTROPIC LIFT AND CLOUDS.
AN ISO SHOWER MAY DEVELOP ACROSS THE HIGHER TERRAIN OF PA LATE IN
THE AFTERNOON, BUT MOST OF THIS ACTIVITY SHOULD BE FOCUSED DEEPER
WITHIN LLVL THETA-E RIDGE, WHICH WILL BE SITUATED WEST OF THE CWA.

USED A BLEND OF MAV/MET GUIDANCE FOR MAX TEMPS TODAY BUT WITH 
ONSHORE FLOW DEVELOPING, UNDERCUT TEMPS A COUPLE OF DEGREES NEAR THE 
COAST. TEMPS TODAY WILL BE SLIGHTLY BELOW NORMAL, WHICH FITS THE 
PATTERN ACROSS THE REGION FOR MUCH OF THE MONTH.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
WEAK HIGH PRESSURE OVER NEW ENGLAND WILL START TO NOSE DOWN TOWARD 
THE NORTHERN MID-ATLANTIC REGION TONIGHT AS LOW PRESSURE MOVES 
FARTHER OFF THE NC COAST. MOST OF THE FORECAST AREA SHOULD BE ABLE 
TO CLEAR OUT EXCEPT IN THE FAR WEST. WILL ALSO NEED TO WATCH FOR THE 
POTENTIAL FOR THE DEVELOPMENT OF LOW CLOUDS/FOG LATE TONIGHT IN 
COASTAL NJ/DE WITH A PERSISTENT ONSHORE FLOW. MIN TEMPS RANGE FROM 
THE UPPER 50S IN THE POCONOS TO MID 60S NEAR THE COAST AND IN THE 
URBAN I-95 CORRIDOR.

&&

.LONG TERM /WEDNESDAY THROUGH TUESDAY/... 
HEMISPHERIC PATTERN SHOWS RIDGING OFF THE EAST COAST WITH A CLOSED
LOW FEATURE OVER THE CANADIAN MARITIMES. WEAK MID-LEVEL RIDGING
OVER THE GREAT LAKES WITH A MEANDERING CUT-OFF LOW OVER THE UPPER
MID-WEST SLOWLY MOVES EASTWARD WITH TIME AND BECOMES ABSORBED BY
THE OPENING OF THE CLOSED LOW OVER THE CANADIAN MARITIMES BY THE
WEEKEND. RIDGING MOVES OVERHEAD BY LATE THIS WEEKEND INTO NEXT
WEEK.

WEDNESDAY...THE 00Z GUIDANCE HAS COME IN A BIT FASTER THAN THE 12Z 
WITH THE SHORTWAVE ENERGY MOVING ACROSS THE REGION AND THE 
ASSOCIATED SURFACE BOUNDARY. THAT BEING SAID, THE GUIDANCE STILL 
KEEPS THE BETTER CHANCES FOR SHOWERS UNTIL THE OVERNIGHT TIMEFRAME 
AND MOSTLY ACROSS OUR WESTERN ZONES...EASTERLY UPSLOPE FLOW WILL 
HELP INCREASE CHANCES LATE.

THURSDAY - FRIDAY...INCREASING CHANCES FOR SCATTERED SHOWERS AS THE 
SHORTWAVE MOVES DIRECTLY OVERHEAD ON THURSDAY...LOOKS LIKE THE 
WETTEST DAY OF THE LONGTERM. MODEST SURFACE BASED CAPE OF 1000J/KG, 
SOUTHERLY FLOW OUT AHEAD OF THE APPROACHING LOW, COMBINED WITH COLD 
POOL ALOFT AND STEEPER MID-LEVEL LAPSE RATES, SHOULD BE ENOUGH FOR 
SCATTERED CONVECTION TO OCCUR...PRIMARILY DIURNALLY DRIVEN. SLOWER 
MOVEMENT OF THE OPENING MID-LEVEL LOW COULD KEEP SHOWERS AROUND, 
MOSTLY ACROSS THE SOUTHERN HALF, THROUGH THE FIRST PART OF FRIDAY 
BEFORE CLEARING OUT.  

SATURDAY - SUNDAY...NEW ENGLAND HIGH PRESSURE BETTER ESTABLISHES 
ITSELF PUSHING A RIDGE AXIS DOWN THROUGH OUR REGION. PERSISTENT 
ONSHORE FLOW SHOULD BE ENOUGH TO KEEP A MAJORITY OF THE REGION 
STABLE ENOUGH TO OMIT THUNDER FROM THE FORECAST OVER THE WEEKEND. 
MID-LEVEL LOW/TROUGH WILL BE TO THE SOUTHEAST OF THE REGION WITH 
MID-LEVEL RIDGING TRYING TO WORK IN FROM THE SOUTHWEST. SURFACE 
CONVERGENCE LOOKS TO STAY JUST TO THE WEST OF THE REGION AS MORE 
SHORTWAVE ENERGY DIVES SOUTHEAST WITHIN THE CYCLONIC FLOW 
ALOFT...RING OF FIRE ACTION IS CLOSE BY. WE KEEP THE FORECAST MOSTLY 
DRY AT THIS TIME, BUT CONFIDENCE IS LOWER TO OUR WEST AND SOUTH, 
CLOSER TO THE SURFACE BOUNDARY. 

MONDAY - TUESDAY...BETTER CHANCE THAT WE WILL BE DRY FOR THE END OF 
THE LONGTERM AS THE UPPER LOW MOVES FARTHER TOWARDS THE EAST AND 
RIDGING OVERRIDES THE REGION. A COLD FRONT MAY NEAR FROM THE 
NORTHWEST SOMETIME ON TUESDAY.

&&

.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, 
KMIV, KACY AND SURROUNDING AREAS.

SOME SCT-BKN CLOUDS ASSOCIATED WITH LOPRES IN THE SRN MID ATLANTIC
WILL IMPACT AREAS THROUGH SOUTHERN NJ AND THE SOUTHERN DELMARVA THIS
MRNG, INCLUDING KACY AND KMIV, BUT ANY CIGS WILL BE IN VFR RANGE.
NO FLIGHT RESTRICTIONS EXPECTED THIS AFTN AND EVE. EASTERLY FLOW
5-10 KT WILL DEVELOP TODAY. THERE IS STILL A POTENTIAL FOR LOW
CLOUDS AND/OR FOG TO DEVELOP NEAR ACY/MIV AFTER 06Z TONIGHT UNDER
THE INFLUENCE OF ONSHORE FLOW.

OUTLOOK...
WEDNESDAY...CHANCE OF SOME MVFR CIGS SERN AIRPORTS AND TERMINALS  
WED MORNING. CONFIDENCE NOT HIGH. PRIMARILY VFR ELSEWHERE.
 
WEDNESDAY NIGHT - THURSDAY NIGHT...CHANCE FOR SHRA/TSRA AS A SERIES 
OF DISTURBANCES MOVE THRU THE REGION. LOCAL/TEMPORARY FLIGHT MVFR 
RESTRICTIONS POSSIBLE.

FRIDAY THROUGH SATURDAY...PREDOMINATELY VFR CONDITIONS.

&&

.MARINE...
THE PRESSURE GRADIENT BETWEEN WEAK HIPRES OVER NEW ENGLAND AND 
LOPRES MOVING OFF THE VA-NC COAST WILL TIGHTEN TODAY. EASTERLY WINDS 
WILL STRENGTHEN AS A RESULT LATER THIS MORNING AND AFTERNOON. THE 
STRONGEST WINDS WILL BE IN THE COASTAL DE WATERS, WHERE WINDS 
INCREASE TO AROUND 15-20 KT. WINDS GRADUALLY SUBSIDE TONIGHT AS THE 
LOW PULLS AWAY.

OUTLOOK...
WEDNESDAY - THURSDAY...ONSHORE FLOW CONTINUES BUT WILL 
WEAKEN OVER TIME. TSRA POSSIBLE IN SOUTHERN WATERS ON THURSDAY.

FRIDAY - SATURDAY...SUB SMALL CRAFT ADVISORY WINDS
EXPECTED. THE PERSISTENT ONSHORE FLOW MIGHT BRING SEAS TO SMALL
CRAFT ADVISORY LEVELS FRIDAY AND POSSIBLY MORE LIKELY ON SATURDAY.

&&

.RIP CURRENTS...
EASTERLY FLOW CONTINUES TO STRENGTHEN THIS MORNING AND 10 SECOND 
SWELLS HAVE BEEN REPORTED FROM BUOY 44009. THESE CONDITIONS WILL 
PRODUCE A MODERATE RISK OF RIP CURRENTS FOR THE NEW JERSEY BEACHES 
AND LOW FOR DELAWARE BEACHES TODAY.

&&

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

&&

$$
SYNOPSIS...HEAVENER
NEAR TERM...KLEIN/KLINE
SHORT TERM...KLEIN
LONG TERM...HEAVENER 
AVIATION...HEAVENER/KLEIN/KLINE
MARINE...HEAVENER/KLEIN 
RIP CURRENTS...KLEIN






National Weather Service
Disclaimer Privacy Policy