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Area Forecast Discussion
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000
FXUS61 KPHI 052302
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
602 PM EST THU MAR 5 2015

.SYNOPSIS...
A STORM SYSTEM WILL EXIT TO OUR EAST THIS EVENING, THEN ARCTIC HIGH 
PRESSURE BUILDS IN OVERNIGHT AND FRIDAY. THE HIGH WILL THEN SETTLE 
TO OUR SOUTH ON SATURDAY. A WEAK LOW PRESSURE SYSTEM WILL TRACK TO 
OUR NORTH LATE SUNDAY INTO MONDAY, PULLING A COLD FRONT ACROSS OUR 
REGION ON MONDAY. HIGH PRESSURE SHOULD THEN BUILD INTO THE AREA  
TUESDAY INTO WEDNESDAY, WITH THE NEXT COLD FRONT SCHEDULED TO ARRIVE 
LATER WEDNESDAY INTO THURSDAY.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
630PM ESTF SENT AROUND 550 PM WITH WARNING CANCELLATION. NEXT
EXPIRE WILL OCCUR AT 650 PM. STORM IS WINDING DOWN. WE MODIFIED
THE CALL TO ACTION FOR MORE SAFETY ON SNOW REMOVAL. WE ENDED THE
SNOW PER THE LATEST VERSIONS OF THE HRRR.


FOR CENTRAL NEW JERSEY AND THE PHILADELPHIA METRO REGION, STORM
ENDS BY 7 PM. 

IN THE DELMARVA AND SOUTHEAST NEW JERSEY, THE CHANGEOVER WAS SLOW
THIS AFTERNOON AND THIS WILL CUT INTO THE ACCUMULATIONS OF SNOW
AND SLEET. FAVORABLE ISENTROPIC LIFT AND 700MB FRONTOGENETICAL
FORCING ARE TAKING PLACE RESULTING IN HEAVIER BANDING, SO NOT A
DRASTIC REDUCTION IN TOTALS. SUSSEX AND CAPE MAY COUNTIES MAY HAVE
THE HARDEST TIME REACHING WARNING CRITERIA (4-6 OR SO) WITH AREAS
FURTHER NORTH ENDING UP WITH 6 INCHES OR SO.

TEMPERATURES WILL TUMBLE ONCE SKIES CLEAR. THIS SHOULD TAKE PLACE
FAIRLY QUICKLY AFTER THE SNOW ENDS GIVEN A STEEP DROP IN DEW
POINTS AND CONSIDERABLE DRY AIR ADVECTION. RECORD LOWS ARE
POSSIBLE, PLEASE SEE CLIMATE SECTION BELOW. LOW TEMPERATURES
TONIGHT ARE COMPOSED OF MET/MAV AND THE MODELED TWO METER
TEMPERATURES FROM THE GFS WHICH HAS DONE WELL AT NIGHT WITH SNOW
COVER.

WIND CHILLS ARE LIKELY TO FALL BELOW ZERO ACROSS MOST OF THE REGION, 
WITH THE POCONOS SEEING WIND CHILLS WHICH MAY GET CLOSE TO ADVISORY 
THRESHOLD FOR A FEW HOURS. GIVEN THE LIMITED WINDOW AND MARGINAL 
VALUES IN TERMS OF AND ADVISORY, WILL JUST CONTINUE MENTION IN THE 
HWO.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
SUNNY DAY WITH HIGH PRESSURE BUILDING IN ON FRIDAY BUT STILL 
COLD. DID GO A TOUCH WARMER THAN MAV/MET GIVEN THE COOL DAYTIME BIAS 
WITH SNOW COVER. OTHER ELEMENTS STRAIGHT MAV/MET. CONTINUED 
NORTHWESTERLY WINDS UNDER 10 MPH OR SO.

&&

.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
THE OVERALL SYNOPTIC SETUP IS COMPRISED OF AN UPPER-LEVEL TROUGH 
FROM THE MIDWEST TO THE NORTHEAST AND MID ATLANTIC. AS SHORT WAVE 
ENERGY MOVES THROUGH THE FLOW, THIS FEATURE SHOULD AMPLIFY A LITTLE 
FOR A TIME OR TWO. THIS SHOULD EVENTUALLY WEAKEN AS ENERGY EJECTS 
ACROSS THE SOUTHERN PLAINS LATE IN THE WEEKEND AND EARLY NEXT WEEK, 
WITH A RIDGE POTENTIALLY BUILDING OFF THE SOUTHEASTERN U.S. COAST. 
THIS RESULTS IN THE UPPER-LEVEL FLOW TURNING MORE ZONAL NEXT WEEK. 
WE USED A MODEL BLEND FOR FRIDAY NIGHT THROUGH SUNDAY, THEN WENT 
WITH THE 12Z WPC GUIDANCE THEREAFTER. WE THEN MADE SOME ADJUSTMENTS 
AFTER ADDITIONAL COLLABORATION WITH OUR NEIGHBORING OFFICES.

FOR FRIDAY NIGHT AND SATURDAY...A SHORT WAVE TROUGH LOOKS TO SLIDE 
ACROSS THE AREA, HOWEVER A DRY AIRMASS RESULTS IN NO PRECIPITATION. 
AT THE SURFACE, HIGH PRESSURE BUILDS OVER THE AREA HOWEVER ITS 
CENTER SLIDES TO OUR SOUTH THROUGH SATURDAY. THIS WILL RESULT IN A 
GRADUAL RETURN FLOW BEING ESTABLISHED AND AFTER A VERY COLD START 
SATURDAY, SOME MODERATION IS EXPECTED IN THE AFTERNOON.

FOR SUNDAY AND MONDAY...A SHORT WAVE IS FORECAST TO TRACK NEAR THE 
MIDWEST AND GREAT LAKES SUNDAY, THEN WELL TO OUR NORTH MONDAY. THIS 
WILL DRIVE WEAK LOW PRESSURE WELL TO OUR NORTH, HOWEVER A COLD FRONT 
IS FORECAST TO MOVE THROUGH DURING MONDAY. IT APPEARS THAT THE 
MOISTURE WILL BE LACKING WITH THIS FEATURE AS MUCH OF THE LIFT 
OCCURS WELL TO OUR NORTH. THERE COULD BE A SNOW SHOWER THOUGH SUNDAY 
NIGHT INTO MONDAY ACROSS THE FAR NORTHWEST. OTHERWISE, THE AIRMASS 
IS FORECAST TO CONTINUE TO MODIFY AS THE FLOW COMES MORE FROM THE 
WEST AND NOT THE NORTH.

FOR TUESDAY AND WEDNESDAY...HIGH PRESSURE SHOULD SHIFT TO OUR EAST 
AS A COLD FRONT MOVES ACROSS THE MIDWEST AND THE GREAT LAKES. LOW 
PRESSURE APPEARS TO TRACK WELL TO OUR NORTH ONCE AGAIN, WITH A WARM 
FRONT LIFTING MOSTLY TO OUR NORTHWEST. WHILE THE FLOW LOOKS FAIRLY 
WEAK, ENOUGH WAA IS EXPECTED TO OCCUR TO ALLOW FOR FURTHER 
MODERATION OF THE AIRMASS WITH MANY AREAS GETTING INTO THE LOWER 50S 
WEDNESDAY AFTERNOON. THE COLD FRONT SHOULD BE ARRIVING LATE 
WEDNESDAY, HOWEVER GIVEN THE TRACK OF THE SURFACE LOW AND SHORT WAVE 
ALOFT IT ALSO LOOKS TO BE MOISTURE STARVED. 

FOR THURSDAY...A WEAK SURFACE HIGH IS ANTICIPATED TO MOVE ACROSS THE 
AREA, WHILE A FRONTAL BOUNDARY IS DRAPED FROM NEAR MAINE TO THE 
GREAT LAKES THEN INTO THE CENTRAL PLAINS. THE AIRMASS SHOULD BE MUCH 
MILDER WITH AFTERNOON HIGHS GETTING INTO THE 50S. THE OCEAN AND 
DELAWARE BAY ARE COLD AND IF THERE IS LIGHT ENOUGH FLOW, THEN A 
COOLING AFFECT CAN BE EXPECTED CLOSER TO THE COAST.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.

TONIGHT...IFR/LIFR SNOW AT KMIV AND KACY ENDS AROUND 00Z/6 FOLLOWED
BY VFR CIGS FOR A FEW HRS THEN THEN VFR CLEAR AFTER 04X. NORTH-
NORTHWEST WIND GUST 20 KT EARLY THEN DIMINISHES. FOR THE REMAINING
TAF SITES VFR CIGS WITH ANY REMAINING 4MI FLURRIES ENDING BY 00Z
AND THEN BECOMING VFR CLEAR 01Z-03Z. 

FRIDAY...VFR CLEAR WITH CIRRUS LATE IN THE DAY. LIGHT WIND.

OUTLOOK...
FRIDAY NIGHT THROUGH SUNDAY...VFR OVERALL. A WEAK SYSTEM MOVING BY 
LATER SATURDAY SHOULD RESULT IN MORE CLOUDS, HOWEVER ANY 
PRECIPITATION LOOKS TO STAY TO OUR NORTH AND WEST.
 
MONDAY AND TUESDAY...VFR OVERALL. A WEAK COLD FRONT MOVING THROUGH 
MONDAY SHOULD RESULT IN MORE CLOUDS, HOWEVER IT APPEARS THAT IT 
MOVES THROUGH DRY.

&&

.MARINE...
WAVES ALONG THE COASTAL WATERS WILL CONTINUE TO REMAIN NEAR OR ABOVE 
5 FT. IN ADDITION, WINDS ARE EXPECTED TO INCREASE SLIGHTLY THROUGH 
THE EVENING HOURS OUT OF THE NORTH NORTHWEST. THEREFORE THE SMALL 
CRAFT ADVISORY CONTINUES ON THE ATLANTIC COASTAL WATERS THROUGH THE 
OVERNIGHT HOURS. ON THE BAY, A FEW GUSTS ABOVE 20 KT ARE POSSIBLE, 
BUT CONDITIONS SHOULD GENERALLY STAY BELOW SMALL CRAFT ADVISORY 
CRITERIA. FOR FRIDAY, WINDS AND SEAS SHOULD REMAIN BELOW SCA
CRITERIA.

OUTLOOK...
FRIDAY NIGHT AND SATURDAY...THE CONDITIONS ARE EXPECTED TO BE
BELOW SMALL CRAFT ADVISORY CRITERIA, HOWEVER THE WINDS WILL
INCREASE SOME FROM THE WEST-SOUTHWEST DURING SATURDAY. THERE IS A
CHC FOR SOME LIGHT FREEZING SPRAY FRIDAY NIGHT AND SATURDAY
MORNING.
 
SUNDAY THROUGH TUESDAY...WE ARE ANTICIPATING SUB SMALL CRAFT 
ADVISORY CONDITIONS AS A WEAK FRONT MOVES THROUGH MAINLY DURING 
MONDAY.

&&

.CLIMATE...
WITH A SNOW COVER IN PLACE AND ANOTHER ARCTIC AIRMASS SETTLING
INTO THE REGION AND RADIATIONAL COOLING OCCURRING WE HAVE ANOTHER
CHANCE FOR MORE RECORD LOWS ACROSS THE REGION.

FRIDAY 3/6

RECORD LOWS    

ACY 10 1888  
PHL 10 1978 
ILG 11 1926 
ABE 7  1960 
TTN 7  1872 
GED 10 1978 
RDG 7  1978 
MPO -5 1909

THE CURRENT FORECAST CURRENTLY HAS MOST LOCATIONS BREAKING THERE 
RECORD LOW ON FRIDAY MORNING. THE ONE EXCEPTION WOULD BE MOUNT 
POCONO. 

SATURDAY 3/7

RECORD LOWS

ACY 10 1890 
PHL 9  1960 
ILG 11 1960 
ABE 1  1960 
TTN 7  1890 
GED 3  1960 
RDG 10 1989 
MPO -18 1911

IT APPEARS THAT READING AND ATLANTIC CITY HAVE THE BETTER CHANCE
OF GETTING TO THEIR RECORD LOW SATURDAY MORNING.

RECORD DAILY SNOWFALL FOR THURSDAY MARCH 5

RECORD EVENT REPORTS WILL UPDATE AROUND 730 PM KACY AND KILG. 
WE MAY NEED OTHERS AT THAT TIME.

KACY 0.3 - 1960 
KILG 3.7 - 1981
KABE 7.0 - 1917
KPHL 8.8 - 1981

FWIW...WATER EQUIVALENCE OF TOTAL SNOW DEPTH IN PORTIONS OF EASTERN
PA IS NOW WELL OVER 3 INCHES.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR PAZ070-
     071.
NJ...WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR NJZ013-
     014-016>027.
DE...WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR 
     DEZ001>004.
MD...WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR MDZ008-
     012-015-019-020.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST FRIDAY FOR ANZ450>455.

&&

$$
SYNOPSIS...GORSE
NEAR TERM...DRAG/GAINES 601
SHORT TERM...GAINES
LONG TERM...GORSE
AVIATION...GAINES/GORSE/O'HARA 601
MARINE...GORSE/JOHNSON/O'HARA 601
CLIMATE...601



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