Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000
FXUS61 KPHI 231307
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
907 AM EDT SAT MAY 23 2015

.SYNOPSIS...
STRONG HIGH PRESSURE OVER PENNSYLVANIA WILL MOVE OFF THE MID ATLANTIC
COAST TONIGHT AND REMAIN CENTERED IN THE CENTRAL ATLANTIC OCEAN THIS
COMING WEEK. A WARM FRONT WILL PASS NORTHWARD THROUGH OUR REGION ON
MONDAY. A VERY WEAK COOL FRONT WILL DRIFT EAST INTO THE MID ATLANTIC
STATES LATE THIS COMING WEEK AND DISSIPATE BY NEXT WEEKEND.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
FROST ADVISORY HAS BEEN ALLOWED TO EXPIRE. NO OTHER CHANGES AT
THIS TIME.

A TRANQUIL DAY IS IN STORE FOR THE REGION WITH MASSIVE AMOUNTS OF
SUBSIDENCE TAKING PLACE. LOOKING AT FORECAST SOUNDINGS FOR THIS
AFTERNOON, OUR PWATS MAY REACH DAILY MINIMUMS IN A LOT PLACES
BASED OFF OF SPC`S SOUNDING CLIMATOLOGY FOR OKX/LWX...DRY BEGETS
DRY. DEWPOINTS SHOULD BOTTOM OUT IN THE MID TO UPPER-20S THIS
AFTERNOON EVEN THOUGH MIXING WILL NOT BE NEARLY AS STRONG/HIGH AS
IT WAS ON FRIDAY...NOT EXPECTING MUCH IN THE WAY OF GUSTS.

THERMALLY BOTH THE NAM AND GFS WERE A TOUCH TOO COLD AT 850/925MB
FOR THEIR 23/00Z INITIALIZATION. THE LOWERING SUBSIDENCE INVERSION
WILL LIMIT THE AMOUNT OF VERTICAL MIXING, AS STATED ABOVE, BUT WITH
MORE THAN ENOUGH SUNSHINE AND THE SURFACE FLOW BACKING TOWARDS THE
WEST, WE WENT A COUPLE DEGREES ABOVE GUIDANCE...STILL KEEPS US BELOW
NORMAL FOR THE DAY.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
THE SURFACE RIDGING SLIDES A BIT FARTHER TO OUR SOUTH AND EAST AS
THE SURFACE FLOW BACKS FARTHER TOWARDS THE SOUTHWEST. DO NOT THINK
WE COMPLETELY LOSE THE WINDS TONIGHT AND THERE COULD BE SOME HIGH
BASED CLOUDS STREAMING IN FROM THE SOUTHWEST SO HAVE KEPT CLOSE TO
GUIDANCE TONIGHT BUT WENT SLIGHTLY COOLER IN THE PINE BARRENS...NOT
THINKING FROST WILL BE AN ISSUE. AN INCREASE IN DEWPOINT
TEMPERATURES WILL ALSO KEEP TEMPERATURES FROM FALLING OFF THE TABLE
TONIGHT, THOUGH THEY MAY DROP QUICKLY AFTER SUNSET, ONCE WE LOSE THE
BETTER MIXING.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
**FIRST HEAT WAVE OF THE SEASON MAY DEVELOP FOR THE I-95 CORRIDOR THIS
 COMING WEEK**

500 MB: A STRONG RIDGE SUMMERTIME RIDGE DEVELOPS ALONG THE EAST
COAST IN THIS FORECAST PERIOD.

TEMPERATURES: THE FIRST 22 DAYS OF MAY HAS AVERAGED 5 TO 6 DEGREES
ABOVE NORMAL IN OUR FORECAST AREA AND DESPITE TODAYS COLD SHOT THE
MONTH AS A WHOLE SHOULD AVERAGE 6 TO 7 DEGREES ABOVE NORMAL, PLACING
IT EASILY IN THE TOP 10 WARMEST MONTHS OF MAY ON RECORD, AGAIN IN
OUR AREA. IT MOST LIKELY WILL BE A TOP 3 FINISHER AT LEAST IN PHILADELPHIA
AND ALLENTOWN. THE DAILY AVERAGE ON SUNDAY WILL STILL BE SEVERAL
DEGREES BELOW NORMAL BECAUSE OF THE CHILLY START, THEN IT WARMS TO
AROUND 5 DEGREES ABOVE NORMAL ON MEMORIAL DAY AND CALENDAR DAY
AVERAGES THEREAFTER THE REST OF THE COMING WEEK WILL BE 6 TO 12
DEGREES ABOVE NORMAL, EVERY DAY.

QPF: A BASICALLY RAINFREE 6 DAY PERIOD IS EXPECTED ALONG THE COAST
WITH I-95 NWWD RAINFALL CONTINGENT ON A WEAKENING COLD FRONT
MOVING TO NEAR I-95 LATE THIS COMING WEEK. IF THE RIDGE ALOFT
PREVENTS IT FROM DRIFTING THIS FAR EAST, THE ENTIRE CWA WOULD BE
BASICALLY RAINFREE THIS ENTIRE 6 DAY EXTENDED FORECAST PERIOD.
FOR NOW, WE ACCEPTED THE ECMWF POTENTIAL FOR THURSDAY-FRIDAY
HOWEVER CONFIDENCE ON EASTWARD EXTENT INTO OUR FORECAST AREA IS
BELOW AVERAGE AS OF THIS WRITING.

FORECAST BASIS: UNLESS OTHERWISE NOTED, A 50 50 BLEND 00Z/23 GFS/NAM
MOS GUIDANCE SUNDAY - MONDAY,  00Z/23 MEX MOS MONDAY NIGHT AND
TUESDAY, THEN THE 0541Z/23 WPC GRIDDED ELEMENTS OF MAX/MIN TEMP, 12
HOUR POP, 6 HOUR DEWPOINT-SKY-WIND FROM TUESDAY NIGHT THROUGH NEXT
SATURDAY?

HAZARDS: CONTINUING THE MOUNT HOLLY PHILOSOPHY FROM YESTERDAY...
THIS FORECAST IS WEIGHED MORE ON THE ECMWF OPERATIONAL RUNS AND
IT`S SOMEWHAT WARMER RESPECTIVE ENSEMBLE MEAN. THERE IS A CHANCE
THAT AN EARLY SEASON LOWER CRITERIA (96F HEAT INDEX) HEAT
ADVISORY WILL NEED TO BE ISSUED WEDNESDAY FOR THE WILMINGTON-
PHILADELPHIA- TRENTON CORRIDOR.


THE DAILIES...

CONFIDENCE ON THE GENERAL FORECAST THIS ENTIRE 6 DAY PERIOD IS ABOVE
AVERAGE EXCEPT WHERE EXPRESSLY NOTED BELOW.

SUNDAY...M/S.   SW WIND WITH GUSTS TO 15 MPH DURING THE AFTERNOON.

SUNDAY NIGHT...FAIR. MID DECK WAA CLOUDS TOWARD DAWN. LIGHT SW WIND.

MONDAY...AFTER CONSIDERABLE WAA MORNING CLOUDINESS IT BECOMES P TO
M/SUNNY. SW WIND GUSTS 15-20 MPH DURING THE AFTERNOON.

TUESDAY...P-M/S. SW WIND GUSTS TO 25 MPH DURING THE AFTERNOON.
MINIMAL SHOWER RISK LATE IN THE POCONOS.

WEDNESDAY...P-M/S. SW WIND GUSTS TO 25 MPH DURING THE AFTERNOON. A
SOMEWHAT BETTER CHANCE OF TSTMS IN A HOTTER-MORE UNSTABLE
ENVIRONMENT OVER E PA AND NW NJ BUT CONFIDENCE IS BELOW AVG.

THURSDAY AND FRIDAY...P-M/S. A LITTLE MORE SOUTHERLY COMPONENT TO
THE WIND AND MAX GUSTS UNDER 20 MPH. CHANCE OF SHOWERS AND TSTMS
WITH A SLOWLY WEAKENING COOL FRONT DRIFTING EAST INTO OUR AREA.
CONFIDENCE ON WHETHER THAT FRONT MAKES IT THIS FAR EAST IS BELOW
AVERAGE. PWAT NEAR 1.75 INCHES, IMPLYING IF THE LIFT MECHANISM
ARRIVES IN THIS SUMMERTIME AIRMASS, IT WILL RELEASE HEAVY RAINS.
WITH LIGHTER WINDS AND HIGHER HUMIDITY, PATCHY FOG PROBABLY
DEVELOPS LATE EACH NIGHT.

&&

.AVIATION /13Z SATURDAY THROUGH WEDNESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.

TODAY - TONIGHT...VFR. NORTHERLY WINDS TO START THE DAY WILL BACK
TOWARDS THE WEST BY THE EARLY AFTERNOON AS HIGH PRESSURE SETTLES
IN...LESS THAN 10 KNOTS. SEA BREEZE IS EXPECTED TO PUSH THROUGH ACY
BY MID-AFTERNOON. WINDS BACK FARTHER TOWARDS SOUTHWEST TONIGHT
BECOMING LIGHTER.

OUTLOOK...

SUNDAY: VFR, SOUTHWEST WINDS GUST 15 KT DURING THE AFTERNOON. WAA
MID DECK OVC MAY DEVELOP TOWARD SUNRISE MONDAY.

MONDAY THROUGH WEDNESDAY: VFR, WITH SOME LOWER RESTRICTIONS POSSIBLE
IN ANY LATE AFTERNOON SHOWERS OR TSTORMS TUESDAY AND WEDNESDAY VCNTY
KABE/KRDG ONLY. SOUTH TO SOUTHWEST WINDS WITH GUSTS AROUND 20 KNOTS
EACH AFTERNOON.

&&

.MARINE...
TODAY - TONIGHT...WE CANCELED THE SCA FOR THIS MORNING AS THE WINDS
SHOULD BE DECREASING AS THE MORNING WEARS ON. OTHERWISE, SUB-SCA
CONDITIONS EXPECTED TODAY AND TONIGHT WITH HIGH PRESSURE SITTING
OVERHEAD. NORTHERLY WINDS TO START WILL BACK TOWARDS THE WEST AND
THEN SOUTHWEST BY LATE TONIGHT AND BECOMING LIGHTER WITH THE HIGH
SHIFTING A BIT TOWARDS THE EAST.


OUTLOOK...
THROUGH WEDNESDAY...SEAS AND WINDS ARE EXPECTED TO REMAIN BELOW
SCA CRITERIA. WINDS WILL BE OUT OF THE SOUTH TO SOUTHWEST WITH
SOME WIND GUSTS AROUND 20 KNOTS.

&&

.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...
**A TOP 10 WARMEST MAY WILL OCCUR IN LARGE PORTIONS OF OUR FORECAST
 AREA AND LESSENING DOUBT FOR A TOP 3 WARMEST KABE/KPHL**

UPDATED AT 510 AM THIS SATURDAY MORNING:

THE FIRST 22 DAYS OF MAY IN OUR FORECAST AREA WERE AVERAGING
ABOUT 5 TO 6 DEGREES ABOVE NORMAL.

RUNNING THE NUMBERS FROM THIS MORNINGS 330AM FCST THROUGH THE END
OF THE MONTH 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
66.5 OR ABOUT 6.5 DEGREES ABOVE NORMAL WHICH WOULD BE 2ND OR 3RD
WARMEST ON RECORD. 1991 WAS THE WARMEST WITH 67.2, FOLLOWED BY
2012 66.1, THEN 1944 WHEN MAY AVERAGED 66.0.

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...NONE.

&&

$$
SYNOPSIS...DRAG
NEAR TERM...HEAVENER
SHORT TERM...HEAVENER
LONG TERM...DRAG
AVIATION...DRAG/HEAVENER
MARINE...DRAG/HEAVENER
RIP CURRENTS...
CLIMATE...



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