Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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661
FXUS61 KPHI 221524
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1124 AM EDT FRI MAY 22 2015

.SYNOPSIS...
A COLD FRONT WILL CROSS OUR REGION LATER THIS AFTERNOON, THEN HIGH
PRESSURE BUILDS IN SATURDAY BEFORE SHIFTING OFFSHORE SATURDAY NIGHT
AND SUNDAY. A WARM FRONT IS FORECAST TO LIFT NORTH ACROSS OUR AREA
DURING MONDAY. A COLD FRONT IS THEN ANTICIPATED TO REMAIN WELL TO
OUR NORTH AND WEST WEDNESDAY AND THURSDAY AS HIGH PRESSURE REMAINS
ANCHORED IN THE WESTERN ATLANTIC.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
NO CHANGES TO THE OVERALL FORECAST FOR TODAY. MOSTLY SUNNY SKIES
THIS MORNING WILL BECOME PARTLY CLOUDY BY THIS AFTERNOON AS A
MOSTLY DRY COLD FRONT SWEEPS THROUGH THE AREA. MODELS, ESPECIALLY
THE HRRR, DO SHOW AN ISOLATED SHOWER OR SPRINKLE MOVING ACROSS
THE AREA THIS AFTERNOON BETWEEN 2-6 PM, BUT MOST PLACES SHOULD
REMAIN PRECIPITATION FREE.

WIND GUSTS ARE BEGINNING TO INCREASE INTO THE LOW 20S, AND SHOULD
REACH THE 25-35 MPH RANGE BY THIS AFTERNOON. WEST WINDS WILL
BECOME NORTHWEST BEHIND THE FRONT LATER THIS AFTERNOON/EARLY
EVENING.

TEMPS REBOUND AFTER YDYS 12 TO 18 BELOW NORMAL MAX TEMPS WITH
THIS AFTNS TEMPS ABOUT 15-20 DEGREES WARMER COMPARED TO THURSDAY
AFTN (NEAR NORMAL MAX`S).

FORECAST GENERATED GENERALLY FROM A 5050 BLEND OF 00Z/22 NCEP MOS
GUIDANCE (GFS/NAM).

CONFIDENCE: ABOVE AVERAGE.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
CLEAR AND TURNING CHILLY AS THE CFP NEAR I-80 (NE PA/NNJ) IN THE
6P TIME FRAME SLIPS DOWN TO VCNTY KACY-KPHL AROUND 11P WITH A
PERIOD OF GUSTY NORTH-NORTHWEST WINDS OF 20-25 MPH EXPECTED EARLY
AT NIGHT THEN DECOUPLING-RAPIDLY DIMINISHING WIND LATE AS TEMPS
FALL RAPIDLY.

WILL CONTINUE A TOUCH OF SCT FROST FROM WARREN-SUSSEX COUNTIES IN
NW NJ INTO MONROE AND CARBON COUNTIES OF NE PA. JUST NOT ENOUGH
COVERAGE EXPECTED FOR A FROST ADVY. ALSO WITH FULL GREENUP, PROBABLY
ENOUGH LEAF COVER TO PREVENT MUCH DAMAGE. STILL, CANT BE ABSOLUTELY
SURE AND SO PATCHY FROST IS IN THE FCST AND POSSIBLE SPS MATERIAL
LATER TODAY FOR THOSE LOCATED IN SUCH PLACES AS WALPACK, PEQUEST,
THE TYPICALLY COLDEST LOW LYING AREAS IN THE NW FRINGE OF OUR
FORECAST AREA.

A BIT OF HIGH THIN CIRRUS POSSIBLE TOWARD SUNRISE SATURDAY?

FCST GENERALLY FROM A 5050 BLEND OF 00Z/22 NCEP MOS GUIDANCE
(GFS/NAM).

CONFIDENCE: ABOVE AVERAGE.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
THE SYNOPTIC SETUP IS COMPRISED OF A CLOSED LOW MOVING FROM NORTHERN
NEW ENGLAND TO THE CANADIAN MARITIMES SATURDAY. THIS IS DUE TO
ENERGY STARTING TO EJECT INTO THE CENTRAL AND SOUTHERN PLAINS, WHICH
WILL ALSO BUILD A RIDGE FROM FLORIDA NORTHWESTWARD INTO THE MIDWEST
SATURDAY INTO MONDAY. THE RIDGE STRENGTHENS SOME AS IT SHIFTS
EASTWARD MONDAY AND TUESDAY, HOWEVER IT SHOULD THEN START TO FLATTEN
SOME ON ITS NORTHERN SIDE FROM ABOUT TUESDAY ONWARD. THE MAIN
FEATURE IS A FRONTAL BOUNDARY THAT SLIDES ACROSS THE NORTHEAST BUT
THIS THEN LIFTS BACK NORTHWARD AS A WARM FRONT MONDAY. IT LOOKS TO
TURN RATHER WARM TO EVEN HOT NEXT WEEK AS THE UPPER-LEVEL RIDGE IS
IN PLACE DESPITE IT GRADUALLY SHIFTING MORE OFFSHORE WITH TIME. WE
USED A MODEL BLEND FOR SATURDAY THROUGH MONDAY, THEN THE 00Z WPC
GUIDANCE WITH CONTINUITY THEREAFTER. SOME TWEAKS WERE THEN MADE
FOLLOWING ADDITIONAL COLLABORATION WITH OUR NEIGHBORING OFFICES.

FOR SATURDAY...A CHILLY START /PATCHY FROST UP NORTH/, OTHERWISE
HIGH PRESSURE STARTS TO SHIFT OFFSHORE AT NIGHT AS RIDGING BUILDS TO
OUR WEST. THE AIRMASS WILL BE COOL, THEREFORE HIGHS SHOULD BE IN THE
60S TO ABOUT 70 DEGREES ACROSS THE REGION. DUE TO HIGH PRESSURE IN
PLACE, LESS WIND IS EXPECTED COMPARED TO FRIDAY.

FOR SUNDAY AND MONDAY...A RIDGE TO OUR WEST WILL GRADUALLY BUILD
EASTWARD. SOME ENERGY SLIDING SOUTHEASTWARD ACROSS NORTHERN NEW
ENGLAND WILL DROP A FRONTAL BOUNDARY INTO OUR AREA SUNDAY NIGHT.
THIS BOUNDARY GENERALLY LOOKS TO BE ON THE WEAK SIDE, HOWEVER IT
COULD BE ACTIVATED MONDAY AS IT LIFTS NORTHWARD AS A WARM FRONT. AS
THE RIDGE BUILDS, OUR AREA IS STILL WITHIN THE NORTHWESTERLY FLOW
ALOFT. THE LOW-LEVEL FLOW IS FORECAST TO BE SOUTHWESTERLY, AND THE
COMBINATION OF WAA AND SOME FRONTAL LIFT AIDED BY SOME SHORT WAVE
ENERGY ALONG THE FRONT SHOULD PRODUCE SOME CONVECTION ON MONDAY. IT
APPEARS THAT THE BULK OF THE WAA/LIFT IS AIMED UP THE OHIO VALLEY
AND ACROSS THE GREAT LAKES. WE WILL NEED TO WATCH THIS THOUGH AS
SOME CONVECTION COULD SLIP INTO OUR AREA FROM THE WEST/NORTHWEST,
ESPECIALLY THE NORTHERN HALF, DURING MONDAY BEFORE THE RIDGE AXIS
REACHES OUR CWA. THE AMOUNT OF INSTABILITY WILL BE KEY AS WE
CONTINUE TO RECOVER FROM A RATHER DRY AIRMASS THAT IS IN PLACE PRIOR
TO MONDAY. OVERALL, CONVECTION MAY PRODUCE AT LEAST LOCALLY HEAVY
DOWNPOURS MONDAY. A MUCH WARMER AIRMASS IS EXPECTED TO 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 ARE EXPECTED TO 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 WELL TO OUR NORTH AND WEST,
SOME CONVECTION CANNOT BE RULED OUT. THIS APPEARS TO BE MAINLY
FOCUSED NEAR A LEE SIDE TROUGH IN THE PRESENCE OF A WARM/HOT AND
INCREASINGLY HUMID AIRMASS. GIVEN THE PRESENCE OF THE RIDGE AND THE
NORTHWESTERLY FLOW ALOFT BREAKING DOWN ACROSS OUR AREA, ANY
CONVECTION COULD BE SLOW MOVING WHICH WOULD RESULT IN LOCALLY HEAVY
RAIN. AS OF NOW, THE WESTERN ZONES HAVE A HIGHER CHC OF CONVECTION
GIVEN THE FORECAST PLACEMENT OF THE RIDGE AND ALSO A LEE SIDE
TROUGH. SOME PLACES ARE FORECAST TO REACH 90 DEGREES EACH AFTERNOON.
THE AFTERNOON HEAT INDICES ARE FORECAST TO BE CLOSE TO 95 DEGREES
ESPECIALLY WEDNESDAY AFTERNOON FOR THE URBANIZED AREAS OF THE
PHILADELPHIA METRO. IT SHOULD BE COOLER ALONG THE COAST DUE TO A
SOUTHERLY FLOW.

FOR THURSDAY...IT LOOKS TO BE A REPEAT OF THE PREVIOUS TWO DAYS AS
WE REMAIN IN THE WARM SECTOR, MEANWHILE A COLD FRONT SLOWLY SAGS
SOUTHEASTWARD ACROSS THE GREAT LAKES. SOME OF THE GUIDANCE IS FASTER
WITH THIS FRONT, HOWEVER WE WENT WITH THE WPC TIMING. ONCE AGAIN A
WARM TO EVEN HOT DAY IS ANTICIPATED, ALTHOUGH IT MAY BE A LITTLE
COOLER AS THE RIDGE WEAKENS SOME. SINCE A SOUTHERLY FLOW IS
FORECAST, IT SHOULD BE COOLER ALONG THE COAST. SOME MAINLY AFTERNOON
AND EVENING CONVECTION IS POSSIBLE ESPECIALLY INLAND, PROBABLY
FOCUSED ALONG A LEE SIDE TROUGH.

&&

.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.

TODAY...VFR CLEAR BECOMING SCT-BKN AOA 6000 FT THIS AFTN WITH THE
SLIGHT CHC OF A WLY 38KT GUSTY SPRINKLE OR LIGHT SHOWER AHEAD OF A
COLD FRONT. GENERALLY GRADIENT WLY GUSTS 20 KT THIS MORNING
INCREASE TO 25-33 KT THIS AFTN.

TONIGHT...VFR CLEAR. THIN CIRRUS POSSIBLE TOWARD SUNRISE SATURDAY.
WSHIFT TO 20-25KT GUSTY NNW THIS EVENING FROM NORTH TO SOUTH, FIRST
NEAR I-80 AROUND 00Z REACHING KPHL/KACY AROUND 03-05Z.

CONFIDENCE: ABOVE AVERAGE.

OUTLOOK...
SATURDAY...VFR. NORTHWEST WINDS AROUND 10 KNOTS, BECOMING WEST-
SOUTHWEST DURING THE AFTERNOON.

SUNDAY...VFR. SOUTHWEST WINDS 10 TO 15 KNOTS, THEN DIMINISHING SOME
AT NIGHT.

MONDAY AND TUESDAY...MAINLY VFR. SOME SHOWERS AND THUNDERSTORMS ARE
POSSIBLE ESPECIALLY DURING MONDAY. SOUTHWEST WINDS MAINLY AROUND
10 KNOTS.

&&

.MARINE...
SAFE BOATING WEEK CONCLUDES TODAY. OUR FINAL PUBLIC INFORMATION
STATEMENT FOR THIS SEASON POSTED AT 408 AM WITH THE SOCIAL MEDIA
POST AROUND 8AM. I DID GO AHEAD AND ADD THE NEW USCG SAFETY APP TO
MY SMART PHONE, JUST IN CASE IT COMES IN HANDY VIA MARINE RELATED
TALKS/INTERVIEWS.

THE FORECAST...

STARTED SCA IMMEDIATELY ON DE BAY. 26 KT SHIP JOHN AND 30 KT CAPE
MAY MESONET AS OF ABOUT 620 AM.

SCA VCNTY 44009 EARLY TODAY WITH SEAS NOW RESPONDING.

OTRW...SCA ALL OTHER WATERS WITH THE PRIMARY THREAT PERIOD OF 2P-
MIDNIGHT. WLY WIND GST 25-30 KT THIS AFTN AHEAD OF A COLD FRONT
THEN JUST AFT OF THE COLD FRONTAL PASSAGE WIND SHIFT TO NNW THIS
EVENING. STRONGEST WIND NEAR THE SHORE WHERE ITS WARMER AND BETTER
MIXING-MOMENTUM TRANSFER.

WINDS DIMINISH TOWARD SUNRISE SATURDAY.

OUTLOOK...
SATURDAY AND SUNDAY...NORTHWEST WINDS DIMINISHING SATURDAY AND THEN
BECOMING SOUTHWEST TOWARD EVENING. THE SOUTHWESTERLY FLOW CONTINUES
SUNDAY AND SHOULD INCREASE SOME, HOWEVER OVERALL THE CONDITIONS
SHOULD BE BELOW ADVISORY CRITERIA.

MONDAY AND TUESDAY...A SOUTHWESTERLY FLOW OF 10-20 KNOTS IS
ANTICIPATED WITHIN A WARM/HOT AIRMASS. THIS MAY RESULT IN THE HIGHER
WINDS CLOSER TO THE COAST. A FEW SHOWERS AND THUNDERSTORMS ARE
POSSIBLE ESPECIALLY MONDAY. SEAS AT OR BELOW 4 FEET, ALTHOUGH THESE
MAY NEAR 5 FEET TUESDAY ACROSS THE NORTHERN COASTAL WATERS.

&&

.FIRE WEATHER...
WIND GUSTS OF 25 TO 35 MPH ARE EXPECTED THIS AFTERNOON AND RELATIVE
HUMIDITY VALUES SHOULD FALL INTO THE 20 TO 30 PERCENT RANGE IN
MUCH OF OUR REGION AT THAT TIME. HOWEVER, YESTERDAYS RAINFALL IS
FORECAST TO KEEP FINE FUEL MOISTURE FROM FALLING BELOW CRITICAL
LEVELS AT THOSE LOCATIONS WHERE THE GREEN-UP IS NOT COMPLETE, MOST
NOTABLY THE PINE BARRENS. AS A RESULT, WE ARE NOT ANTICIPATING ANY
FIRE WEATHER ISSUES FOR FRIDAY.

&&

.RIP CURRENTS...
POTENTIAL HEAT WAVE NEXT WEEK. THIS PLUS WATER TEMPS CONTINUING ABOVE
NORMAL IS NOT GOOD FOR SAFETY.  ONCE IT TURNS HOT AND BEACHES ARE
UNGUARDED, SWIMMERS MAY TAKE CHANCES AT UNGUARDED LOCATIONS. BE SMART
ABOUT ANY SWIMMING EARLY THIS SEASON.

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!

PLEASE BROADCAST THIS MESSAGE: FOR ULTIMATE SAFETY, ALWAYS SWIM
IN THE PRESENCE OF LIFE GUARDS! THANK YOU!

&&

.CLIMATE...
**LITTLE DOUBT THAT A TOP 10 WARMEST MAY WILL OCCUR IN LARGE
 PORTIONS OF OUR FORECAST AREA**

THE FIRST 21 DAYS OF MAY IN OUR FORECAST AREA WERE AVERAGING
ABOUT 6 DEGREES ABOVE NORMAL.

RUNNING THE NUMBERS FROM THIS MORNINGS 330AM FCST THROUGH THE
28TH AND THE 00Z/22 FTPRHA (GFS MOS) FOR THE LAST 3 DAYS BEYOND
OUR WFO RESPONSIBILITY (29-31) WE FIND THE FOLLOWING.

FOR PHILADELPHIA...PERIOD OF RECORD (POR) BACK TO 1874.
PROJECTING A MONTHLY AVERAGE TEMPERATURE OF 69 TO 70, AT LEAST 5
TO 6 DEGREES ABOVE NORMAL. HEADING FOR SECOND OR THIRD WARMEST ON
RECORD. WARMEST WAS 70.8 IN 1991. THEN 69.2 2004.

FOR ALLENTOWN...PERIOD OF RECORD (POR) BACK TO 1922. PROJECTING
65.9 OR ABOUT 6 DEGREES ABOVE NORMAL WHICH WOULD BE 4TH-5TH
WARMEST ON RECORD. 1991 WAS THE WARMEST WITH 67.2, FOLLOWED BY
2012 66.1, THEN 1944 WHEN MAY AVERAGED 66.0 AND FINALLY THE 2004
65.9 DEGREE AVG. THE NEXT WARMEST WAS 65.3 IN 1939.

THE FOLLOWING WAS POSTED BECAUSE ITS LIKELY THAT WE WILL
EXPERIENCE OUR FIRST 90 IN PHILADELPHIA BY THE MIDDLE OF NEXT
WEEK, AND POSSIBLY A HEAT WAVE.

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 UNTIL 6 AM EDT SATURDAY FOR ANZ450>453.
     SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ454-
     455.
     SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR ANZ430-431.

&&

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



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