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Area Forecast Discussion
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000
FXUS61 KPHI 060843
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
343 AM EST FRI MAR 6 2015

.SYNOPSIS...
AN ARCTIC HIGH PRESSURE SYSTEM WILL MOVE ACROSS THE FORECAST AREA 
TODAY AND THEN SINK SOUTH ON SATURDAY. A WEAK LOW PRESSURE SYSTEM   
WILL TRACK TO OUR NORTH LATE SATURDAY INTO SUNDAY. A WEAK COLD FRONT
SHOULD PASS ACROSS OUR REGION MONDAY. A LOW PRESSURE SYSTEM IS
PREDICTED TO FORM ON THIS FRONTAL BOUNDARY OFF THE NORTH CAROLINA
COAST TUESDAY AND THEN MOVE FARTHER OFFSHORE. A HIGH PRESSURE
SYSTEM SHOULD THEN BUILD INTO THE EASTERN UNITED STATES ON
WEDNESDAY AND THURSDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
FAIR WEATHER AND COLD TEMPERATURES TODAY WITH HIGH PRESSURE BUILDING 
IN FROM THE OHIO VALLEY. SKIES WILL BE CLR THIS MORNING...AND THEN 
THERE WILL BE SOME HIGH CLOUDS THIS AFTERNOON. HIGH TEMPERATURES 
TODAY WILL BE WELL BELOW NORMAL...WITH LOW/MID 20S NORTH AND MID 20S 
TO LOW 30S OVER METRO PHILADELPHIA AND OVER THE DELMARVA. WINDS WILL 
BE NORTH OR NORTHWEST AT 5 TO 10 MPH THIS MORNING AND THEN BECOME 
WEST OR SOUTHWEST AROUND 5 MPH BY DUSK. 

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
SHORT TERM... HIGH PRESSURE WILL CONTINUE TO REMAIN OVER THE AREA 
TONIGHT. WINDS WILL BE LIGHTER THAN THU NIGHT AND WITH THE AMPLE 
SNOW COVER ACROSS THE REGION...LOW TEMPERATURES COULD BE AS COLD (OR 
PERHAPS COLDER) THAN THU NIGHTS READINGS. PRESENTLY WE HAVE SINGLE 
DIGITS ACROSS MOST AREAS WITH TEENS ALONG THE SHORE AND 12 FOR PHL. 
WINDS WILL BE LIGHT TONIGHT. 
 
&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
THE 500MB INITIALIZATION LOOKED BETTER OFF THE WRF VS THE GFS, OVERALL 
THEY WERE SPLIT AT 850MB AND BOTH ABOUT 1C TOO COLD AT 925MB ON
AVERAGE. AFTER HAVING THREE WINTRY PCPN EVENTS IN THE FIRST FIVE DAYS
OF MARCH, THE LONG TERM REMAINS RELATIVELY MORE SUBDUED WITH A MUCH
ANTICIPATED RETURN (EVEN IF ITS JUST FOR A COUPLE OF DAYS) OF NEAR
NORMAL TEMPERATURES. THE ONE CHANGE TONIGHT VS LAST NIGHT IS THE 
INCREASING CHANCE THAT A SOUTHERN STREAM SYSTEM MIGHT BRING SOME RAIN 
INTO THE REGION ON TUESDAY.

THE MODERATING TREND WILL START ON SATURDAY AFTER A COLD COLD COLD
MORNING. MID LEVEL WAA ASSOCIATED WITH A CLIPPER LOW PRESSURE
SHOULD BRING MID AND HIGH LEVEL CLOUDS INTO OUR CWA, ESPECIALLY
NORTH. IN SPITE OF THIS, WE WENT TOWARD THE HIGHER SET OF STAT
GUIDANCE. TODAY (FRIDAY) WILL BE A GOOD LITMUS TEST IF STAT
GUIDANCE COLD BIAS IN SPITE OF AMPLE SNOW COVER CONTINUES. AS FAR
AS SNOW SHOWERS, THERE HAS NOT BEEN MUCH OF A CHANGE TO THE
GEOGRAPHICAL EXTENT OF MEASURABLE PCPN REACHING DEEPER INTO OUR
CWA. ONLY CHANGE WE MADE, WAS TO START THE LOW CHANCE OF SNOW
SHOWERS FAR NORTH ON SATURDAY AFTERNOON.

THE WEAK COLD FRONT ASSOCIATED WITH THE CLIPPER SHOULD PASS THROUGH 
OUR CWA ON SATURDAY NIGHT. NOT MUCH DEEP MOISTURE TO GENERATE 
SHOWERS. LOW CHANCE FOR SNOW SHOWERS WAS KEPT FAR NORTH. MODELS ARE 
INDICATING MORE LOW LEVEL CLOUDS (POSSIBLY TRAPPED UNDER AN
INVERSION NORTH) AROUND AND THIS IS REASON FOR MUCH HIGHER MINS.

ON SUNDAY, SOME WEAK PVA AND A JET STREAK ARE PREDICTED TO PASS 
ACROSS OUR CWA, LEANING NORTH. STILL TOO EARLY TO TELL IF WE HAVE 
THE GEOGRAPHY STRAIGHT, THE JET STREAK ITSELF LOOKS MORE CERTAIN. WE 
PUT IN A CHANCE OF FLURRIES NORTH AS A PROXY. WHILE SOUNDINGS 
SUGGEST LACK OF ICE COULD BE A PROBLEM (ESPECIALLY ON THE MOISTURE 
TRAPPED NAM SOUNDINGS), WESTERLY WINDS ARE NORMALLY NOT A FREEZING 
DRIZZLE DIRECTION IN OUR AREA. WHILE COLDER AIR (RELATIVE TO 
SATURDAY) IS PREDICTED TO MOVE INTO OUR AREA, IT WARMS BEYOND 
SATURDAY AT 925MB. THUS REASON FOR BUMP UP IN MAX TEMPS.

A HIGH PRESSURE SYSTEM BRIEFLY BUILDS INTO THE AREA ON MONDAY. BY 
THEN AIR MASS IS EVEN SLIGHTLY WARMER AND WE EXPECT THE SNOW COVER 
TO BE LOSING ITS EFFECTIVENESS ON SLOWING THE RISE OF MAX TEMPS.

CHANGE THEN COMES LATE MONDAY NIGHT AND MORE SO TUESDAY AS ALL THE 
RUNS HAVE TRENDED NORTH WITH A LOW FORMING OFF THE OLD STALLED 
FRONT. UNLESS PCPN FLIES IN ON MONDAY NIGHT, THERMALLY IT LOOKS WARM 
ENOUGH FOR RAIN, ESPECIALLY GIVEN SOUTH IS FAVORED OVER NORTH.
FASTER TIMING COUPLED WITH A MORE NORTHERN EXTENSION MIGHT BE
PROBLEMATIC FOR PTYPE. IN ITS WAKE, AN EVEN MILDER DAY IS
PREDICTED FOR WEDNESDAY BEFORE A CANADIAN HIGH PRESSURE SYSTEM
BRINGS COLDER AIR BACK INTO OUR CWA POSSIBLY AS SOON AS THURSDAY.
 
&&

.AVIATION /09Z FRIDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.

VFR CONDITIONS EXPECTED TODAY AND TONIGHT. HIGH PRESSURE WILL BUILD 
IN FROM THE WEST TODAY AND SKIES WILL BE MAINLY CLR THIS MORNING AND 
THEN SOME INCREASING HIGH CLOUDS FOR THE AFTERNOON. WINDS WILL BE 
NORTHERLY OR NORTHWEST AROUND 10 KTS EARLY TODAY THEN GO LIGHT 
WEST/SOUTHWEST TONIGHT. 

OUTLOOK...
SATURDAY...VFR OVERALL.

SATURDAY NIGHT THROUGH SUNDAY...SOME MVFR CONDITIONS DUE MAINLY
TO CIGS AS A WEAK SYSTEM MOVES BY LATER SATURDAY. HOWEVER,
ANY PRECIPITATION LOOKS TO REMAIN NORTH AND WEST OF THE 
TERMINALS.
 
SUNDAY NIGHT THROUGH MONDAY NIGHT...VFR OVERALL. 

TUESDAY...CHANCE OF MVFR CONDITIONS AT SOUTHERN AIRPORTS AND 
TERMINALS. PTYPE SHOULD BE RAIN. 

&&

.MARINE...
WE WILL CONTINUE WITH THE SCA FLAG FOR THE OCEAN WATERS AND SRN DEL 
BAY FOR THE MORNING. WINDS CONTINUE TO GUST 25 TO 30 KTS EARLY THIS 
MORNING...WITH A FEW 30 TO 35 KNT GUSTS AT THE (HIGHER) BRND1 
PLATFORM. WIND SPEEDS WILL DIMINISH  LATER THIS MORNING AS HIGH 
PRESSURE BEGINS TO BUILD OVERHEAD. SEAS 4 TO 6 FT ON THE OCEAN THIS 
MORNING...DIMINISHING THIS AFTERNOON. THERE IS A CHC FOR FREEZING 
SPRAY TODAY. 

OUTLOOK...
SATURDAY AND SATURDAY NIGHT...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 SATURDAY
MORNING.
 
SUNDAY THROUGH MONDAY NIGHT...WE ARE ANTICIPATING SUB SMALL CRAFT 
ADVISORY CONDITIONS AS A WEAK FRONT MOVES THROUGH.

TUESDAY...THERE IS A CHANCE OF SMALL CRAFT ADVISORY CONDITIONS 
PENDING THE PROXIMITY OF THE TRACK OF A LOW PRESSURE SYSTEM 
PREDICTED TO FORM OFF THE NORTH CAROLINA COAST.
 
&&

.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

 
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

RER'S POSTED FOR KILG AND KACY...BOTH 7.0 INCHES.

PHL HAD 7.5 AND ALLENTOWN 6.7.  

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...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EST THIS MORNING FOR ANZ431-
     450>455.

&&

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



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