Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000
FXUS61 KPHI 211645
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1245 PM EDT THU MAY 21 2015

.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL TRACK SOUTH AND EAST OF OUR REGION
LATE TODAY AND TONIGHT, THEN A COLD FRONT CROSSES OUR AREA LATER
FRIDAY. HIGH PRESSURE BUILDS IN SATURDAY BUT THEN SHIFTS OFFSHORE
SATURDAY NIGHT AND SUNDAY. THE NEXT COLD FRONT DROPS INTO OUR AREA
SUNDAY NIGHT INTO MONDAY, THEN AS LOW PRESSURE TRACKS FROM THE
PLAINS TO THE GREAT LAKES REGION THE FRONT LIFTS BACK NORTH AS A
WARM FRONT LATE MONDAY INTO TUESDAY. A COLD FRONT IS FORECAST TO
REMAIN WELL TO OUR WEST DURING WEDNESDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE LATEST MODEL GUIDANCE SUGGESTS THAT THE FARTHEST NORTHWARD
EXTENT OF THE RADAR ECHOES IN AND NEAR OUR REGION HAS ALREADY
OCCURRED. AS A RESULT, IT CONTINUES TO APPEAR AS THOUGH THE BETTER
CHANCES FOR RAIN DURING THE AFTERNOON HOURS WILL BE FROM THE
PHILADELPHIA METROPOLITAN AREA AND CENTRAL NEW JERSEY SOUTHWARD.

RAINFALL AMOUNTS OF 0.25 TO 0.75 INCHES ARE EXPECTED ACROSS MUCH
OF NORTHEASTERN MARYLAND, DELAWARE AND SOUTHERN NEW JERSEY THROUGH
THIS EVENING. A TOTAL OF 0.10 TO 0.20 INCHES IS POSSIBLE AS FAR
NORTH AS PHILADELPHIA WITH LESSER AMOUNTS ANTICIPATED FOR THE
CITY`S NORTHERN SUBURBS INTO CENTRAL NEW JERSEY.

THE SKY WILL BE OVERCAST FOR MOST OF THE DAY WITH PERHAPS SOME
BREAKS UP NORTH. THE WIND SHOULD FAVOR THE NORTHEAST AND EAST IN
OUR SOUTHERN COUNTIES DUE TO THE CIRCULATION AROUND THE LOW IN THE
CAROLINAS. THE WIND MAY SETTLE INTO THE SOUTHWEST IN MUCH OF
EASTERN PENNSYLVANIA AND NORTHERN NEW JERSEY. SPEEDS SHOULD BE
LESS THAN 10 MPH.

TODAY`S TEMPERATURE FORECAST REMAINS TRICKY. THE STEADY RAIN
SHOULD KEEP READINGS MAINLY IN THE 50S IN THE SOUTH. THE WARMEST
TEMPERATURES IN OUR FORECAST AREA WILL LIKELY BE IN THE VALLEYS UP
NORTH WHERE HIGHS SHOULD GET INTO THE LOWER OR MIDDLE 60S.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM FRIDAY/...
LEFTOVER RAIN ALONG THE COAST AND A CHANCE OF A PERIOD OF RAIN OR
SHOWERS ELSEWHERE EARLY, THEN CLEARING TOWARD DAWN AS THE
RELATIVELY STRONG 500MB SHORT WAVE SEEN AS AN -80M 12 HR HFC
PASSES THROUGH E PA REACHING LI BY DAYBREAK FRIDAY.

PATCHY FOG POSSIBLE TOWARD DAWN IF IT CLEARS FAST ENOUGH AND IT
REMAINS DECOUPLED THROUGH THE NIGHT.

LIGHT WIND TREND W-NW OVERNIGHT.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
THE SYNOPTIC SETUP IS COMPRISED OF A CLOSED LOW ACROSS EASTERN
CANADA THAT SHIFTS EASTWARD FRIDAY AND OVER THE WEEKEND AS ENERGY
STARTS TO EJECT INTO THE CENTRAL AND SOUTHERN PLAINS. THE LATTER
WILL TEND TO BUILD A RIDGE FROM NEAR FLORIDA NORTHWESTWARD TOWARD
THE MIDWEST SATURDAY INTO MONDAY. THE RIDGE THEN STRENGTHENS SOME
AS IT SHIFTS EASTWARD MONDAY AND TUESDAY, HOWEVER IT SHOULD
FLATTEN SOME ON ITS NORTHERN SIDE. THE MAIN FEATURE OF INTEREST IS
A COLD FRONT THAT DROPS DOWN LATE SUNDAY INTO MONDAY, BUT THEN IT
LIFTS BACK NORTH AS A WARM FRONT AS THE RIDGE BUILDS. IT LOOKS TO
TURN RATHER WARM TO EVEN HOT NEXT WEEK AS THE UPPER-LEVEL RIDGE IS
IN PLACE. WE USED A MODEL BLEND FOR FRIDAY THROUGH SUNDAY, THEN
THE 00Z WPC GUIDANCE WITH CONTINUITY THEREAFTER. SOME TWEAKS WERE
THEN MADE FOLLOWING ADDITIONAL COLLABORATION WITH OUR NEIGHBORING
OFFICES.

FOR FRIDAY AND SATURDAY...THE CLOSED LOW TO OUR NORTH IS FORECAST
TO BE SHIFTING EASTWARD DURING THIS TIME FRAME AS ENERGY EJECTS
INTO THE CENTRAL AND SOUTHERN PLAINS. THIS WILL TAKE SURFACE LOW
PRESSURE INTO THE CANADIAN MARITIMES FRIDAY AND A COLD FRONT
THROUGH OUR AREA LATE IN THE DAY. WHILE THERE IS SOME INCREASE IN
MOISTURE AHEAD OF THE FRONT AND ALSO SOME LOWER LEVEL INSTABILITY
FORECAST, THE DEEP WESTERLY FLOW SHOULD TEND TO LIMIT THE
CONVERGENCE. WHILE SOME ISOLATED SHOWERS CANNOT BE RULED OUT, WE
OPTED TO KEEP THE FORECAST FRIDAY DRY ATTM. THE PRESSURE GRADIENT
TIGHTENS WITH BREEZY CONDITIONS DURING FRIDAY, THEN THIS GRADUALLY
RELAXES LATER FRIDAY NIGHT AND SATURDAY AS SURFACE HIGH PRESSURE
MOVES IN. A MUCH DRIER AIR MASS FOLLOWS THE FRONT, AND THIS WILL
SET THE STAGE FOR A CHILLY FRIDAY NIGHT AND EARLY SATURDAY. THERE
COULD BE SOME FROST FORMATION EARLY SATURDAY MORNING ACROSS
PORTIONS OF THE NORTHERN ZONES, PENDING WE DECOUPLE. FOR NOW, WE
INCLUDED A PATCHY FROST MENTION. HIGH PRESSURE THEN BEGINS TO
SHIFT OFFSHORE SATURDAY NIGHT AS RIDGING BUILDS TO OUR WEST.

FOR SUNDAY AND MONDAY...A RIDGE TO OUR WEST WILL GRADUALLY BUILD
EASTWARD. SOME ENERGY SLIDING SOUTHEASTWARD ACROSS NEW ENGLAND
WILL DROP A COLD FRONT INTO OUR AREA SUNDAY NIGHT AND MONDAY. THIS
FEATURE GENERALLY LOOKS TO BE ON THE WEAK SIDE, AND THERE IS SOME
GUIDANCE THAT HOLDS THIS FRONT FARTHER TO THE NORTH IN THE FORM OF
A WARM FRONT. THE FRONT DOES NOT LOOK TO STAY IN PLACE LONG AS THE
BUILDING RIDGE ALOFT ALONG WITH SURFACE HIGH PRESSURE TO OUR EAST
WILL HELP REINFORCE A SOUTHWESTERLY FLOW. THEREFORE THE BOUNDARY
SHOULD MOVE NORTH AS A WARM FRONT DURING MONDAY AND MONDAY NIGHT.
THERE MAY BE SOME CONVECTION RIDING ALONG OR NEAR THIS FRONT,
HOWEVER THIS MAY NOT BE UNTIL LATE MONDAY AS THE RIDGE AXIS MOVES
ACROSS. A WARMER AIR MASS SHOULD OVERSPREAD THE AREA ESPECIALLY
MONDAY AS AN EXPANDING WARM SECTOR MOVES NORTH, AND SOME INCREASE
IN THE DEW POINTS WILL ALSO OCCUR.

FOR TUESDAY AND WEDNESDAY...WE SHOULD BE IN THE WARM SECTOR
DURING THIS TIME FRAME AS A SHORT WAVE ALOFT AND SURFACE LOW
TRACKS TO OUR NORTH, WHICH WILL FLATTEN THE RIDGE SOME. WHILE THE
SURFACE COLD FRONT IS CURRENTLY FORECAST TO STAY TO OUR WEST, SOME
CONVECTION CANNOT BE RULED OUT AS THERE ARE SOME INDICATIONS OF A
LEE SIDE TROUGH DEVELOPING IN THE PRESENCE OF A WARM TO HOT
AIR MASS ALONG WITH AN INCREASE IN THE HUMIDITY. SOME PLACES HAVE
A GOOD CHC OF REACHING 90 DEGREES EACH AFTERNOON.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.

CONDITIONS REMAINED VFR AT ALL EIGHT OF OUR TAF SITES AROUND
1630Z. RAIN WILL CONTINUE TO OVERSPREAD KILG, KPHL, KPNE, KTTN,
KMIV AND KACY. BOTH KRDG AND KABE SHOULD REMAIN RAIN-FREE.

THE PRECIPITATION IS EXPECTED TO BRING CONDITIONS DOWN INTO THE
MVFR CATEGORY AT KILG, KPHL, KPNE AND KTTN FOR A TIME FROM LATE
THIS AFTERNOON INTO THIS EVENING. MVFR CONDITIONS ARE FORECAST
FROM MID AFTERNOON UNTIL ABOUT MIDNIGHT FOR KMIV AND KACY WHERE
THE IMPACTS OF THE RAIN WILL LAST THE LONGEST IN OUR REGION.

GRADUAL CLEARING IS ANTICIPATED FOR LATE TONIGHT. PATCHY FOG IS
POSSIBLE, ESPECIALLY IN THE LOCATIONS THAT RECEIVE SEVERAL HOURS
OF STEADY RAINFALL.

VFR CONDITIONS ARE EXPECTED FOR FRIDAY WITH A MOSTLY SUNNY SKY.

A VARIABLE WIND AT 6 KNOTS OR LESS IS FORECAST FOR THIS AFTERNOON
INTO THIS EVENING. THE WIND IS EXPECTED TO SETTLE INTO THE
NORTHWEST TONIGHT AT 8 KNOTS OR LESS. A GUSTY NORTHWEST WIND
SHOULD DEVELOP FOR FRIDAY. SUSTAINED SPEEDS ARE ANTICIPATED TO
RANGE FROM 12 TO 16 KNOTS WITH GUSTS INTO THE 20S.

OUTLOOK...
FRIDAY...VFR OVERALL. A COLD FRONT MOVES THROUGH LATER IN THE DAY
WITH PERHAPS AN ISOLATED BRIEF SHOWER. WEST WINDS BECOMING
NORTHWEST AND GUSTING UP TO 25 KNOTS MAINLY DURING THE AFTERNOON
AND EVENING, THEN DIMINISHING.

SATURDAY...VFR. NORTHWEST WINDS AROUND 10 KNOTS.

SUNDAY...VFR. SOUTHWEST WINDS 10 TO 15 KNOTS, THEN TENDING TO
BECOME LIGHT AND VARIABLE AT NIGHT AS A FRONT DROPS NEAR OR INTO
THE AREA.

MONDAY...MAINLY VFR. LIGHT AND VARIABLE WINDS BECOMING SOUTHWEST
AROUND 10 KNOTS. A FEW SHOWERS AND THUNDERSTORMS ARE POSSIBLE
ESPECIALLY IN THE AFTERNOON.

&&

.MARINE...
SAFE BOATING WEEK CONTINUES THROUGH FRIDAY MORNING.

THERE IS A NEW USCG SAFETY APP THAT SHOULD BE OF VALUE TO
MARINERS AND WAS JUST UNVEILED THIS WEEK:

HTTP:/WWW.USCG.MIL/MOBILE

THIS APP PROVIDES ADDITIONAL SAFE BOATING RESOURCES FOR MOBILE
DEVICE USERS. WHEN LOCATION ENABLED, USERS CAN RECEIVE THE LATEST
WEATHER REPORTS FROM THE CLOSEST NOAA BUOY AS WELL AS REPORT THE
LOCATION OF A HAZARD ON THE WATER. IT FEATURES AN EMERGENCY
ASSISTANCE BUTTON, WHICH CAN CALL THE CLOSEST CG COMMAND CENTER.

THE FORECAST:

ISSUED SCA FOR THE DE BAY ATLC WATERS TONIGHT. NCAROLINA LOW
INTENSIFIES IN ITS DEPARTURE AND SHOULD DEVELOP MARGINAL 5 FT
HAZARDOUS SEAS AND A FEW SCA GUSTS AROUND 25 KT OVERNIGHT NEAR
44009.

OTHERWISE NO MARINE HEADLINE ANTICIPATED THROUGH TONIGHT.

WINDS TEND NORTHEAST NORTHEAST-EAST THEN ONSHORE SOUTHEAST THIS
AFTERNOON. WINDS EVENTUALLY BECOMING NORTHWEST EVERYWHERE LATER
THIS THURSDAY NIGHT.

OUTLOOK...
FRIDAY...A COLD FRONT MOVES THROUGH THE AREA LATE IN THE DAY AND
THE EVENING AS LOW PRESSURE MOVES AWAY, WITH A NORTHWEST WIND IN
ITS WAKE. PRIOR TO THIS, SOME GUSTS TO NEAR 25 KNOTS SHOULD LINGER
ACROSS THE FAR SOUTHERN COASTAL WATERS EARLY. THE FORECAST
SOUNDINGS SHOW BETTER MIXING MOSTLY NEARSHORE DURING THE DAY, THEN
EXPANDING TO OFFSHORE AT NIGHT AS COLDER AIR MOVES IN AND
THEREFORE A SMALL CRAFT ADVISORY MAY BE NEEDED FOR LATER FRIDAY
NIGHT.

SATURDAY AND SUNDAY...NORTHWEST WIND GUSTS TO 25 KNOTS MAY OCCUR
TO START SATURDAY, OTHERWISE THE CONDITIONS SHOULD BE BELOW
ADVISORY CRITERIA.

MONDAY...A SOUTHWESTERLY FLOW IS ANTICIPATED TO INCREASE SOME,
HOWEVER THE CONDITIONS OVERALL SHOULD BE BELOW ADVISORY CRITERIA.
SOME SHOWERS AND THUNDERSTORMS ARE POSSIBLE.

&&

.FIRE WEATHER...
FOR FRIDAY AFTERNOON, THERE MAY BE THE RISK FOR ENHANCED WILDFIRE
SPREAD AS WEST-NORTHWEST WINDS GUST TO 20-25 MPH AT TIMES. IN
ADDITION, THIS WILL COMBINE WITH RELATIVE HUMIDITY VALUES DROPPING
TO AROUND 30 PERCENT IN SOME AREAS ALONG WITH DRY FINE FUELS. THIS
WILL DEPEND ON HOW MUCH WETTING OCCURS LATER TODAY ESPECIALLY
ACROSS THE SOUTHERN AREAS.

&&

.RIP CURRENTS...
SST`S ABOVE NORMAL AND JUST OFF THE COAST SSTS WELL ABOVE NORMAL
BY ALMOST 3C. THIS IS NOT GOOD ONCE IT TURNS HOT AND BEACHES ARE
UNGUARDED, SWIMMERS MAY TAKE CHANCES AT UNGUARDED LOCATIONS. BE
SMART ABOUT ANY SWIMMING EARLY THIS SEASON. ATLANTIC COASTAL WATER
TEMPS ARE WARMING --UPPER 50S TO MID 60S.

RIP CURRENT AWARENESS WEEK FOR MT HOLLY IS JUNE 7-13 WITH PSAS
VIA PUBLIC INFORMATION STATEMENTS, SOCIAL MEDIA, NOAA WEATHER
RADIO AND ANY MEDIA INTERVIEWS DESIRED (CONTACT OFFICE).

FOR RIP CURRENTS: DESPITE ANTICIPATED PROJECTIONS OF LOW OR
MODERATE RISK THROUGH THE MEMORIAL DAY WEEKEND, EARLY SEASON
FATALITIES OCCUR WHEN SWIMMING AT UNGUARDED TIMES/LOCATIONS.
WEAKER SWIMMERS OR SWIMMING IN AREAS WHERE RIP CURRENTS ARE
STRONGER (JETTIES) CAN QUICKLY BECOME LIFE THREATENING. WHEN
TRAINED LIFEGUARDS ARE NOT NEARBY, TIMELY RESCUE IS MUCH LESS
LIKELY. LETS GET THROUGH THE MONTH OF MAY WITH ALL SWIMMERS SAFE!
SWIM IN THE PRESENCE OF LIFE GUARDS! THANK YOU.

&&

.CLIMATE...
**TOP 10 WARMEST MAY CONTINUES LIKELY IN PORTIONS OF THE
FORECAST AREA**

THE FIRST 19 DAYS OF MAY IN OUR FORECAST AREA WERE AVERAGING
WITHIN ABOUT 1/2 DEGREE OF 7 DEGREES ABOVE NORMAL.

BASED ON THE ENSEMBLE AND A FORECAST THAT IS DETERMINISTICALLY
CONSERVATIVE INCLUDING OUR 330 PM MAY 20 PROJECTIONS THROUGH THE
27TH AND THEN THE 00Z/21 CONSERVATIVE FTPRHA THEREAFTER THROUGH
THE 31ST...EASILY OUTLOOKS A TOP 10 WARMEST MAY ON RECORD.

FOR PHILADELPHIA...PERIOD OF RECORD BACK TO 1874. PROJECTING AN
AVG TEMP OF 68.7 TO 69.3 OR AROUND 5 DEGREES ABOVE NORMAL AND AT
THE LEAST, 3RD WARMEST ON RECORD. WARMEST WAS 70.8 IN 1991. THEN
69.2 2004.

FOR ALLENTOWN...POR TO 1922. YESTERDAY WE WERE PROJECTING 65.0 OR
5.1 DEGREES ABOVE NORMAL AND 8TH WARMEST ON RECORD. WARMEST WAS
67.2 IN 1991.

POSTED BECAUSE WE`RE EXPECTING OUR FIRST 90 IN PHILADELPHIA BY
THE MIDDLE OF NEXT WEEK.

NORMAL FIRST DATE OF 90 OR HIGHER.

PHILADELPHIA MAY 29
ALLENTOWN MAY 30
WILMINGTON JUNE 4
ATLANTIC CITY JUNE 11.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 8 AM EDT
     FRIDAY FOR ANZ455.

&&

$$

SYNOPSIS...GORSE
NEAR TERM...IOVINO
SHORT TERM...DRAG
LONG TERM...GORSE
AVIATION...GORSE/IOVINO
MARINE...DRAG/GORSE
FIRE WEATHER...GORSE
RIP CURRENTS...DRAG
CLIMATE...DRAG



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