Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000
FXUS61 KPHI 270246
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
946 PM EST WED NOV 26 2014


.SYNOPSIS...
A COASTAL LOW WILL QUICKLY MOVE TO THE NORTHEAST OVERNIGHT. HIGH
PRESSURE IS FORECAST TO BUILD ACROSS THE EAST COAST FRIDAY INTO
EARLY SATURDAY, BEFORE SQUEEZING TO THE SOUTH SATURDAY NIGHT. A
COLD FRONT IS EXPECTED TO SAG DOWN ACROSS THE AREA SUNDAY NIGHT,
BEFORE SLOWLY MOVING THROUGH THE AREA MONDAY INTO MONDAY NIGHT.
HIGH PRESSURE WILL THEN RETURN TO THE NORTHEAST FOR TUESDAY,
FOLLOWED BY ANOTHER POTENTIAL FRONTAL SYSTEM WEDNESDAY.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
MANY THANKS FOR THE REPORTS TODAY. IT WAS A BUSY TRAVEL DAY FOR
MANY AND WE APPRECIATE THE SKYWARN NETS, THE SPECIAL COCORAHS REPORTS
AS WELL AS ALL THE INFORMATION ON SOCIAL MEDIA. HAVE A MUCH
QUIETER AND HAPPY THANKSGIVING TOMORROW!

WITHOUT MUCH TO BLOCK IT, THE SURFACE LOW PRESSURE SYSTEM HAS
QUICKLY REACHED THE WATERS SOUTH OF NANTUCKET. FRONTOGENETIC
FORCING IS NOW NORTHEAST OF OUR CWA AND WHAT PRECIPITATION IS LEFT
IS BECOMING VERY LIGHT. THE BANDED PRECIPITATION MOVING THROUGH
NEW JERSEY HAS HAD THE OPPOSITE OF EXPECTED AFFECTS AS
TEMPERATURES HAVE RISEN AND VSBYS IMPROVED AS IT MOVED THROUGH. AS
IT PASSED OUR OFFICE IT WAS AS IF THE RAIN DROPS WERE TRYING TO
FREEZE, BUT COULDNT.

WITH VSBYS THREE MILES OR GREATER WHERE SNOW IS STILL FALLING,
WE WILL LET ALL WINTER RELATED HEADLINES EXPIRE AT 10 PM.
TEMPERATURES ARE EXPECTED TO FALL BELOW FREEZING BY MORNING IN MANY
AREAS, SO ANY TRAVEL OVERNIGHT BE WARY ABOUT THE POTENTIAL FOR
ICY SPOTS DEVELOPING ON UNTREATED ROADWAYS, PARKING LOTS AND
SIDEWALKS. TO THE NORTHWEST THE SNOW AND SLUSH SHOULD FREEZE, TO THE
SOUTHEAST NOT AS CONFIDENT ABOUT AOB FREEZING MINS, BUT THERE IS
PLENTY OF STANDING WATER AROUND.

PROPS TO THE ECMWF THAT HAD THIS GULF OF MEXICO SYSTEM AFFECTING
US THE LONGEST INTO THE LONG TERM, IT ALSO HAD A WARMER SOLUTION
THAT THE GFS AND WRF-NMMB TRENDED TOWARD. PTYPE A BLEND OF THE WRF
AND GFS WORKED BEST AS WE CLOSED IN WITHIN OUR CWA. WE SAW SNOW AT
SOME MIGHTY HIGH 1000-500MB THICKNESSES (AT LEAST 549DM), MOST OF
THE ACCUMULATING SNOW OCCURRED AT THICKNESSES LESS THAN 546DM. AS
MY PREDECESSOR INDICATED, THE SOUNDING AROUND PHL WAS NEARLY
ISOTHERMAL FROM 700MB DOWNWARD, A RARE THERMAL EVENT INDEED.


&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
THE COASTAL LOW THAT IS IMPACTING THE AREA TODAY WILL TRACK
NORTHEASTWARD INTO THE CANADIAN MARITIMES ON THURSDAY. THE TRAILING
SURFACE TROUGH/COLD FRONT IS FORECAST TO MOVE OFF THE NJ COAST AND
THROUGH THE DELMARVA. THE 12Z GFS AND ECMWF HINT AT A WEAK WAVE OF
LOW PRESSURE DEVELOPING ON THE LEE SIDE OF THE BLUE RIDGE MOUNTAINS
BY 12Z THURSDAY. THIS LOW WOULD THEN MOVE EAST-NORTHEAST OFF THE NC
COAST DURING THE AFTERNOON. A FEW SHOWERS NORTH OF THIS LOW MAY
BRUSH THE DELMARVA DURING THE DAY. BOUNDARY LAYER THERMAL PROFILES
MARGINALLY SUPPORTIVE OF A SNOW PERHAPS MIXING IN WITH THE RAIN BUT
NO ACCUMULATIONS EXPECTED WITH SURFACE TEMPERATURES NEAR 40F.

OTHERWISE, CLOUDS WILL LINGER ACROSS THE AREA FOR MOST OF THE DAY
WITH THE UPPER TROUGH PROGRESSING EASTWARD ACROSS THE MID ATLANTIC
AND NORTHEAST STATES. USED A BLEND OF THE MAV/MET GUIDANCE FOR
TEMPS, GIVING US HIGHS IN THE 30S FROM I-95 WEST AND LOWER 40S TO
THE EAST.

&&

.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
THURSDAY NIGHT IS EXPECTED TO BE DRY, WITH THE EXCEPTION OF A FEW
LAKE EFFECT SNOW SHOWERS THAT MAY MAKE THEIR WAY ACROSS OUR NORTHERN
AREAS. THEY WOULD BE QUITE ISOLATED, SO WE ONLY CARRY 20 POPS.

ON FRIDAY, HIGH PRESSURE BEGINS TO BUILD ACROSS THE EAST COAST,
BEFORE SQUEEZING TO OUR SOUTH AND EAST BY SATURDAY NIGHT. MODEL
GUIDANCE IS INDICATING A COUPLE OF SHORT WAVE/VORTICITY IMPULSES
SLIDING ACROSS THE AREA, ALONG WITH AN INCREASE IN MOISTURE ALOFT
ACROSS THE NORTHERN AREAS. THERE IS SOME TIMING DIFFERENCES, BUT WE
WILL KEEP A SLIGHT CHANCE OF SHOWERS ACROSS OUR NORTHWESTERN ZONES
WHERE THEY HAVE A BETTER CHANCE OF SQUEEZING OUT SOME MOISTURE.
ANYTHING THAT WOULD FALL IS EXPECTED TO BE LIGHT.

ON SUNDAY, WE WILL BE IN BETWEEN THE HIGH TO OUR EAST AND AN
APPROACHING COLD FRONT. ANOTHER WEAK SHORT WAVE/VORTICITY IMPULSE
AND MOISTURE PLUME ALOFT SPREAD ACROSS THE NORTHERN HALF OF THE AREA
SUNDAY, SO THERE REMAINS A SLIGHT CHANCE OF SHOWERS SUNDAY.

A FRONTAL BOUNDARY IS EXPECTED TO APPROACH THE AREA SUNDAY NIGHT
INTO MONDAY. THERE IS SOME DIFFERENCES WITH THIS BOUNDARY AS THE GFS
IS FAST THAN THE ECMWF AND CANADIAN, AND DRIES THE PRECIP OUT
SIMILAR TO THE CANADIAN, BUT UNLIKE THE ECMWF WHICH KEEPS SOME LIGHT
PRECIP ACROSS THE AREA. WE WILL CONTINUE WITH CHANCE/SLIGHT CHANCE
POPS, WITH THE HIGHEST ACROSS THE NORTHERN AND WESTERN AREAS WHERE
THE PRECIP WOULD IMPACT FIRST BEFORE DRYING OUT.

THE FRONT SHOULD PUSH TO OUR SOUTH AS HIGH PRESSURE BUILDS ACROSS
THE NORTHEAST TUESDAY, BUT THERE COULD BE SOME LIGHT PRECIP THAT
LINGERS ACROSS THE SOUTHERN AREAS IF THE FRONT STALLS CLOSER TO THE
AREA.

ANOTHER FRONTAL BOUNDARY IS EXPECTED TO AFFECT THE AREA AROUND NEXT
WEDNESDAY. HOWEVER, THERE IS A QUESTION OF WHETHER THE FRONT SURGES
THROUGH LIKE THE ECMWF, OR GETTING HUNG UP TO OUR NORTH LIKE THE
GFS. WE WILL INTRODUCE A CHANCE/SLIGHT CHANCE OF POPS ACROSS THE
AREA AS BOTH ARE SHOWING THE POTENTIAL FOR PRECIP.

&&

.AVIATION /03Z THURSDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.

TONIGHT...MVFR TRENDING TO VFR. LATER THIS EVENING WE SHOULD SEE
THE PRECIPITATION BEGIN TO SLOW DOWN AS THE SURFACE LOW MOVES TO
OUR NORTHEAST. THERE IS A CHANCE THAT WE COULD SEE ANOTHER CHANGE
OVER TO A LIGHT RAIN/DRIZZLE AS WELL WHICH SHOULD HELP TO IMPROVE
CONDITIONS A BIT...WINDS BACK TOWARDS THE NORTHWEST LATE.

TOMORROW...VFR CONDITIONS EXPECTED. WINDS TURN MORE WESTERLY WITH MOSTLY
DRY CONDITIONS EXPECTED. COULD BE SOME ISOLATED SHOWERS AT ILG/MIV/ACY
DURING THE AFTERNOON HOURS.

OUTLOOK...
THURSDAY NIGHT...MOSTLY VFR.

FRIDAY-MONDAY...MOSTLY VFR. WIND GUSTS 15-20 KNOTS EACH DAY; NW
FRIDAY, SW SATURDAY & SUNDAY, AND NW ON MONDAY.

&&

.MARINE...
GALE WARNINGS WILL BE CHANGED TO SMALL CRAFT ADVISORY ON THE OCEAN
AND LOWER DELAWARE BAY. THE DELAWARE SMALL CRAFT ADVISORY WILL BE
CARRIED FOR A COUPLE MORE HOURS. ON THE OCEAN, IT WILL BECOME THE SEAS
THAT WILL BE DRIVER FOR SMALL CRAFT ADVISORY CONDITIONS TO
PERSIST INTO THANKSGIVING DAY.

OUTLOOK...
THURSDAY NIGHT...WINDS ARE EXPECTED TO BE BELOW SMALL CRAFT ADVISORY
LEVELS, BUT SEAS MAY REMAIN ELEVATED INTO THURSDAY NIGHT.

FRIDAY-FRIDAY NIGHT...SUB-SMALL CRAFT ADVISORY CONDITIONS EXPECTED
AS HIGH PRESSURE BUILDS OVER THE AREA.

SATURDAY-SUNDAY...NEAR SMALL CRAFT ADVISORY CONDITIONS POSSIBLE AS
HIGH PRESSURE PUSHES TO OUR SOUTH AND COLD FRONT APPROACHES LATE ON
SUNDAY NIGHT.

&&

.CLIMATE...
HERE ARE THE DAILY SNOWFALL RECORDS FOR OUR 4 SNOW CLIMATE SITES
FOR NOVEMBER 26.

ACY - TRACE IN 1977, 1957, 1955

PHL - 6.0 INCHES IN 1898

ILG - 0.1 INCHES IN 1950

ABE - 1.7 INCHES IN 1925.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THURSDAY FOR ANZ450>455.
     SMALL CRAFT ADVISORY UNTIL 1 AM EST THURSDAY FOR ANZ430-431.

&&

$$
SYNOPSIS...ROBERTSON
NEAR TERM...GIGI
SHORT TERM...KLEIN
LONG TERM...ROBERTSON
AVIATION...HEAVENER/ROBERTSON
MARINE...KLEIN/ROBERTSON
CLIMATE...





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