Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 221929
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
329 PM EDT FRI MAY 22 2015

.SYNOPSIS...
HIGH PRESSURE ACROSS THE GREAT LAKES WILL BUILD EASTWARD TONIGHT
REACHING OUR REGION TOMORROW. THIS AREA OF HIGH PRESSURE WILL SLIDE
OFF THE COAST SUNDAY. A WARM FRONTAL BOUNDARY WILL THEN PASS
NORTHWARD THROUGH OUR REGION ON MONDAY.  A TROUGH OF LOW PRESSURE
WILL MOVE IN BEHIND THE WARM FRONTAL PASSAGE FOR THE MIDDLE AND
LATER HALF OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...

ISOLATED-SCATTERED SHOWERS HAVE BEGUN TO DEVELOP AS SOME WEAK
CAPE DEVELOPED UNDERNEATH THE COLD POOL ALOFT AND AHEAD OF THE
APPROACHING COLD FRONT AND ASSOCIATED WEAK SHORT WAVE. THERE COULD
EVEN BE A FEW RUMBLES OF THUNDER, BUT WIDESPREAD THUNDERSTORMS ARE
NOT EXPECTED. PW VALUES ARE GENERALLY LESS THAT 3/4 OF AN INCH, SO
THE SHOWERS SHOULD NOT BE OVERLY HEAVY. A BRIEF PERIOD OF MODERATE
RAIN COULD OCCUR, BUT NOT MORE THAN A TENTH OR SO IS EXPECTED,
EVEN WITH THE HEAVIEST SHOWER. THE GREATEST THREAT FOR SHOWERS
WOULD BE ACROSS THE NORTHERN THIRD/HALF OF THE AREA BETWEEN NOW
AND SUNSET. AS DAYTIME INSTABILITY IS LOST, THE SHOWERS SHOULD
BEGIN TO DISSIPATE THROUGH SUNSET. WINDS WILL REMAIN GUSTY THROUGH
THE REMAINDER OF THE AFTERNOON AND INTO THE EARLY EVENING HOURS.
HOWEVER, AS THE SUN GOES DOWN AND DAYTIME MIXING IS LOST, THE
GUSTS SHOULD DROP OFF. THERE COULD BE ANOTHER BRIEF PERIOD OF
GUSTY WINDS RIGHT AS THE FRONT GOES THROUGH, BUT OVERALL WINDS
SHOULD DIMINISH OVERNIGHT.

TEMPERATURES WILL DROP OFF OVERNIGHT BEHIND THE COLD FRONT, WITH
EVERYONE DROPPING CLOSE TO 10 DEGREES BELOW NORMAL. THERE COULD EVEN
BE SOME PATCHY FROST ACROSS THE NORTHERN AREAS. PORTIONS OF THE
POCONOS HAVE THE BEST CHANCE OF BEING THE COLDEST WITH MORE
WIDESPREAD FROST, SO AN ADVISORY HAS BEEN ISSUED FOR CARBON/MONROE,
PENNSYLVANIA. WE DID INCLUDE PATCHY FROST FOR SUSSEX COUNTY, NEW
JERSEY, BUT ARE NOT SURE IT WILL BE AS WIDESPREAD AS THE POCONOS, SO
WE DID NOT ISSUE AN ADVISORY THERE.



&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...

OTHER THAN THE PATCHY MORNING FROST UP NORTH,SATURDAY WILL BE A
BEAUTIFUL DAY AS HIGH PRESSURE CRESTS OVER THE AREA AND TEMPERATURES
WILL REMAIN AROUND CLOSE TO 10 DEGREES BELOW NORMAL. PW VALUES WILL
DROP BELOW 1/4 OF AN INCH, AND ONLY CIRRUS CLOUDS ARE EXPECTED
THROUGH THE DAY.

&&

.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...

THIS FORECAST IS WEIGHED MORE ON THE ECMWF OPERATIONAL RUNS TODAY
AND IT`S RESPECTIVE ENSEMBLE MEAN. THIS RESULTS IN A DRIER AND HOT
PERIOD FOR MOST OF NEXT WEEK. THE GFS LOOKS TO HAVE TO MUCH
CONVECTION. THE MAIN REASON FOR THIS CONCLUSION IS THE LACK OF A
FOCUSED TRIGGERING MECHANISM PRESENT. THE FIRST HEAT WAVE OF THE
SEASON POSSIBLE TUE-THU NEXT WEEK, MAYBE PAST THU?, PARTICULARLY PHL
METRO AREA AND SW.

SATURDAY NIGHT THROUGH SUNDAY NIGHT: HIGH PRESSURE WILL MOVE OFF THE
CAROLINA COASTLINE. THIS WILL LEAD TO A MORE DOMINANT SOUTH TO
SOUTHWEST WIND AND A WARM FRONTAL BOUNDARY MOVING NORTH INTO THE
REGION SUNDAY NIGHT. MOISTURE WILL BE ON THE INCREASE WITH THE
TEMPERATURE TRENDS ON BOTH HIGHS AND LOWS INCREASING. STILL PLEASANT
OVERALL WITH PLENTY OF SUNSHINE!


MONDAY: A WARM FRONTAL BOUNDARY WILL MOVE THROUGH EARLY IN THE DAY.
SOME CONVECTION MAY ATTEMPT TO FIRE UP OR MOVE ALONG THE BOUNDARY
WITH THE HIGHEST CHANCES ACROSS NORTHERN PARTS OF THE CWA. HOWEVER,
THE TREND OVER THE PAST FEW MODEL CYCLES IS FOR DECREASED CHANCES OF
SHOWER OR THUNDERSTORM ACTIVITY. ONLY WENT WITH SLIGHT CHANCE FOR
THE LEHIGH VALLEY AND POCONOS IN THIS PERIOD. SHEAR IS GOING TO BE
VERY WEAK THROUGH ALL PERIODS, SO THE MAIN THREATS FROM ANY
THUNDERSTORMS WILL BE FROM LOCALLY HEAVY DOWNPOURS AND FREQUENT
LIGHTNING, HIGH PW VALUES. CONTINUED WARMING TREND AND SOUTHERLY
FLOW AFTER THE WARM FRONTAL PASSAGE AS WELL. SOME WIND GUSTS FROM 15-
20 MPH POSSIBLE AS WELL BASED ON GFS SOUNDING ANALYSIS MONDAY
AFTERNOON.

MONDAY NIGHT THROUGH TUESDAY NIGHT: REGION FIRMLY IN WARM SECTOR.
WITH CONTINUED SOUTHERLY-SOUTHWESTERLY WINDS AND WAA. SOME GUSTS
CLOSE TO 20 MPH ARE ONCE AGAIN POSSIBLE TUESDAY AFTERNOON. SURGING
925 MB TEMPS FROM 20-25C MAY CONTRIBUTE TO THE FIRST WIDESPREAD 90
DEGREE DAY OF THE YEAR BY TUESDAY. A BROAD TROUGH TO OUR NORTHWEST
MAY BE ENOUGH OF A TRIGGER FOR A THUNDERSTORM OR TWO ACROSS THE
LEHIGH VALLEY NORTH AND WEST. OVERALL, TREND IN THE NEXT FEW
PERIODS, LIKE WITH MANY WEATHER SYSTEMS IN RECENT WEEKS IS TO LOWER
POPS AS WE GET CLOSER TO AN EVENT. HIGHEST CHANCES FOCUSED NW OF PHL.

WEDNESDAY THROUGH FRIDAY: WELL WE CONTINUE TO BE ON THE BACKSIDE OF
THE RIDGE WITH THE A SIMILAR PATTERN TO MON-TUE. AS STATED EARLIER,
THIS FORECAST LEANS IN THE DIRECTION OF THE ECMWF AND IT`S ENSEMBLE
MEAN. THAT LIMITS THE INFLUENCE OF THE INCOMING TROUGH ALLOWING FOR
A HOTTER PERIOD WITH LOWER RAIN CHANCES. 925 MB TEMPERATURES SUGGEST
THE HOTTEST DAY TO BE WEDNESDAY, IN THE LOW 90`S WITH HIGHS AROUND
90 FOR THURSDAY AND FRIDAY. MUGGY NIGHTS ARE LIKELY AS WELL WITH
LOWS IN THE UPPER 60`S TO 70 ON AVERAGE.  BY WEEKS END, THE
INFLUENCE OF ANY TROUGH MAY INCREASE. THIS WOULD LEAD TO MORE IN THE
WAY OF SCATTERED CLOUDS AND POPCORN THUNDERSTORM CHANCES.
TEMPERATURE FORECASTS ARE WARMER THAN THE ENSEMBLE GUIDANCE OUTPUT
AT THIS TIME FOR HIGHS, PARTICULARLY THE GFS WHICH LOOKS TO MUCH
DRIVEN BY QUESTIONABLE CONVECTION.


&&

.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.

VFR CONDITIONS WILL PERSIST THROUGH THE PERIOD. ISOLATED-SCATTERED
SHOWERS MAY TEMPORARILY AFFECT A FEW TAF SITES THIS AFTERNOON INTO
THE EARLY EVENING, BUT THEY SHOULD NOT CAUSE ANY RESTRICTIONS TO THE
CONDITIONS. AN ISOLATED LIGHTNING STRIKE MAY OCCUR ACROSS PORTIONS
OF NORTHEASTERN PENNSYLVANIA AND NORTHERN NEW JERSEY, BUT THEY
SHOULD BE ISOLATED ENOUGH TO NOT INCLUDE IN THE TAFS AT THIS TIME.
THE MAIN CONCERN TODAY IS THE WINDS WITH WINDS GUSTING 25-30 KNOTS
LATE THIS AFTERNOON. WIND GUSTS SHOULD SLOWLY DIMINISH AROUND AN
AFTER SUNSET. A COLD FRONT WILL MOVE THROUGH THE AREA AROUND/AFTER
SUNSET WHICH MAY HAVE A FEW GUSTS RIGHT BEHIND IT, BUT WINDS WILL
DROP OFF OVERNIGHT BEHIND THE FRONT AS HIGH PRESSURE BEGINS TO MOVE
INTO THE AREA.

VFR CONDITIONS AND LIGHTER WINDS WILL PERSIST FOR SATURDAY. THE
NORTHWEST WINDS SHOULD BECOME MORE WEST AND SOUTHWEST THROUGH THE
DAY.



OUTLOOK...

SATURDAY THROUGH SUNDAY NIGHT: VFR, SOUTHWEST WINDS AROUND 10 KNOTS.

MONDAY THROUGH WEDNESDAY: VFR, WITH SOME LOWER RESTRICTIONS
POSSIBLE IN ANY ISOLATED TO SCATTERED STORMS. BEST CHANCE FOR
STORMS ABE AND RDG TUESDAY AND WEDNESDAY IN THE LATE AFTERNOON
HOURS. SOUTH TO SOUTHWEST WINDS WITH SOME GUSTS FROM 15-20 KNOTS
POSSIBLE EACH AFTERNOON.

&&

.MARINE...

SMALL CRAFT ADVISORY REMAINS FOR ALL THE WATERS FOR THIS EVENING
AND OVERNIGHT UNCHANGED. THE SOUTHERN COASTAL WATERS DROPS OFF
FIRST AS THE PRESSURE GRADIENT WEAKENS THERE FIRST. THE DELAWARE
BAY DROPS OFF NEXT AS THEY COULD HAVE SOME GUSTS INTO THE EVENING
HOURS. THE NORTHERN COASTAL WASTERS LASTS THE LONGEST AS THE
PRESSURE GRADIENT MAY LAST LONGER THERE. HIGH PRESSURE BUILDS OVER
THE WATERS ON SATURDAY, LEADING TO SUB SMALL CRAFT ADVISORY
CONDITIONS EVERYWHERE.OUTLOOK... SEAS AND WINDS ARE EXPECTED TO
REMAIN BELOW SCA CRITERIA THROUGHOUT THE ENTIRE OUTLOOK PERIOD.
HOWEVER, ISOLATED TO SCATTERED THUNDERSTORMS ARE POSSIBLE MONDAY
THROUGH WEDNESDAY FOCUSED IN THE AFTERNOON AND EVENING. WINDS WILL
BE OUT OF THE SOUTH TO SOUTHWEST WITH SOME WIND GUSTS AROUND 20
KNOTS. HIGHEST SEAS AROUND FOUR FEET ACROSS THE NORTHERN WATERS ON
TUESDAY.

&&

.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...FROST ADVISORY FROM 3 AM TO 8 AM EDT SATURDAY FOR PAZ054-055.
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...GAINES
NEAR TERM...ROBERTSON
SHORT TERM...ROBERTSON
LONG TERM...GAINES
AVIATION...GAINES/ROBERTSON
MARINE...GAINES/ROBERTSON
RIP CURRENTS...DRAG
CLIMATE... DRAG


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