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Area Forecast Discussion
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000
FXUS61 KPHI 271759
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1259 PM EST TUE JAN 27 2015

.SYNOPSIS...
THE STRONG STORM SYSTEM RESPONSIBLE FOR OUR RECENT SNOW WILL MOVE
TOWARD THE GULF OF MAINE THIS AFTERNOON AND TONIGHT BEFORE
REACHING THE CANADIAN MARITIMES ON WEDNESDAY. HIGH PRESSURE
BUILDING IN FROM THE OHIO VALLEY WEDNESDAY WILL SETTLE OVERHEAD
WEDNESDAY NIGHT. A CLIPPER SYSTEM WILL MOVE THROUGH THE REGION
THURSDAY NIGHT AND FRIDAY MORNING. HIGH PRESSURE RETURNS SATURDAY
BEFORE ANOTHER LOW PRESSURE SYSTEM MOVES INTO THE EASTERN UNITED
STATES SUNDAY INTO MONDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LIGHT SNOW CONTINUES OVER A GOOD PORTION OF OUR FORECAST AREA
NORTH OF PHILA. ANY ADDITIONAL ACCUMULATION IS EXPECTED TO BE
GENERALLY AN INCH OR LESS...SO SOME ADVISORIES AND WARNINGS HAVE
BEEN CANCELLED OR ADJUSTED. SKIES WILL REMAIN CLOUDY THROUGHOUT
MOST OF THE DAY...BUT THERE COULD BE SOME BRIGHTER SPOTS TOWARD
BERKS COUNTY. HIGH TEMPS AROUND 20 FAR NORTH, UPPER 20S TO AROUND
30 IN THE PHL METRO AREA...AND MID 30S FAR SOUTH.

WE CONTINUE TO ISSUE UPDATED PUBLIC INFORMATION STATEMENT
CONTAINING THE LATEST SNOWFALL REPORTS. WE THANK ALL THOSE WHO
HAVE GONE OUT AND MEASURED THEIR SNOW AND REPORTED TO US. IT
REALLY HELPS OUR FORECAST PROCESS.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
DEEP LOW PRESSURE WILL CONTINUE TO PULL AWAY TO THE NORTHEAST AS 
HIGH PRESSURE BEGINS TO BUILD OVER THE AREA. THE ONLY MENTION OF 
PRECIP WILL BE SOME LEFTOVER SNOW SHOWERS THIS EVENING ACROSS THE 
SRN POCONOS AND CLOSER TO NYC AREA. SKIES WILL BECOME PARTLY CLOUDY 
TO CLR FROM THE SW TO NE AS THE NIGHT PROGRESSES. LOWS TONIGHT WILL 
BE IN THE TEENS AND LOW 20S OVER MOST AREAS WITH A FEW SINGLE DIGIT 
READINGS OVER THE SRN POCONOS.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
THE COASTAL LOW WILL STEADILY WEAKEN ON WEDNESDAY AS IT LIFTS 
NORTHEASTWARD THROUGH THE CANADIAN MARITIMES. NORTH-NORTHWESTERLY 
FLOW ON THE BACKSIDE OF THE TROUGH WILL GRADUALLY WEAKEN THROUGHOUT 
THE DAY AS HIGH PRESSURE BUILDS IN FROM THE OHIO VALLEY. WEDNESDAY 
WILL BE 5-10F DEGREES BELOW NORMAL. HOWEVER, DID LEAN ON THE WARMER 
SIDE OF GUIDANCE FOR MAX TEMPS UNDER FULL SUNSHINE AND  ADIABATIC 
WARMING FROM A DOWNSLOPING COMPONENT TO THE WINDS AS WELL AS LARGE 
SCALE SUBSIDENCE IN WAKE OF THE EXITING TROUGH. 

RADIATIONAL COOLING SHOULD BE STRONG WITH CLEAR SKIES AND CALM WINDS 
OVERNIGHT AS THE CENTER OF HIGH PRESSURE SHIFTS DIRECTLY OVERHEAD. 
GIVEN HOW DRY THE AIRMASS IS, THERE IS THE POTENTIAL FOR TEMPS TO 
BOTTOM OUT IN THE TEENS FOR THE I-95 URBAN CORRIDOR, ALONG THE COAST 
AND IN THE DELMARVA AND SINGLE DIGITS ELSEWHERE. MIN TEMP FORECAST 
WAS A BLEND BETWEEN PREVIOUS FORECAST (WHICH WAS THE COLDER THAN ANY 
00Z GUIDANCE) AND THE 00Z NAM.

AN ALBERTA CLIPPER IS FORECAST TO TRACK EASTWARD ACROSS THE UPPER 
MIDWEST/GREAT LAKES ON THURSDAY BEFORE MOVING THROUGH THE NORTHEAST 
STATES ON FRIDAY. ISENTROPIC LIFT AHEAD OF THE ATTENDANT COLD FRONT 
AND DPVA WITH THE UPPER SHORTWAVE TROUGH WILL SPREAD INTO 
NORTHEASTERN PA LATE IN DAY THURSDAY AND THE REMAINDER OF THE CWA 
THURSDAY NIGHT. A PERIOD OF LIGHT SNOW IS LIKELY DURING THIS TIME 
WITH THE HIGHEST POPS OVER EASTERN PA AND NORTHERN NJ. THIS SYSTEM 
WILL HAVE A BIT MORE MOISTURE (PWAT APPROACH 0.6 INCHES) TO WORK 
WITH THAN WHAT TYPICALLY ACCOMPANIES CLIPPERS AS IT IS ABLE TO TAP 
INTO LIMITED GULF OF MEXICO MOISTURE. GIVEN THE PROGRESSIVE NATURE 
OF THE LOW IS AND THE FACT THAT IT IS NOT FORECAST TO STRENGTHEN 
UNTIL IT REACHES THE GULF OF MAINE, SNOWFALL AMOUNTS SHOULD BE 
LIGHT: 1-3 INCHES IN THE POCONOS AND EXTREME NW NJ, LESS THAN AN 
INCH FARTHER SOUTH AND EAST.

STRONG CAA BEHIND THE COLD FRONT ON FRIDAY. MAX TEMPS IN THE 30S ARE 
FORECAST TO OCCUR IN THE AM WITH TEMPS FALLING THROUGHOUT THE 
AFTERNOON. BRISK NW WINDS HAVE THE POTENTIAL TO GUST 30-40 MPH 
ASSUMING DEEP MIXING IS REALIZED ON LAND. ADDITIONAL SNOW SHOWERS 
ARE POSSIBLE IN THE POCONOS.

DAYS 4.5-7 OF THE FORECAST WAS BASED ON THE 05Z/27 WPC ELEMENTS
OF TT/TD/WIND/SKY/POP. WE ADJUSTED THE WPC TEMPS MUCH HIGHER SUN
NIGHT AND A BIT HIGHER MONDAY PER NEW 00Z/27 MODE GUIDANCE
SUGGESTING LOW PRESSURE AND PRECIPITATION IN THIS TIME FRAME.

FRI NIGHT...VERY COLD WITH WIND CHILL ADVISORY POTENTIAL. NW FLOW 
BEHIND THE DEPARTING AREA OF LOW PRESSURE SHOULD STILL HAVE GUSTY 
WINDS WITH IT THROUGH THE NIGHT.  

SATURDAY...FAIR AND VERY COLD. AVERAGE TEMPS ABOUT 15 DEGREES BELOW 
NORMAL. 

SUNDAY...MODERATING WITH INCREASING CLOUDS DURING THE DAY AND PCPN 
OF SOME SORT EXPECTED AT NIGHT. HIGHLY VARIABLE SET OF SOLUTIONS AND 
CONFIDENCE ON TEMPS/PTYPE IS WELL BELOW AVERAGE. 

MONDAY...MAYBE SOME LEFT OVER PCPN, ESPECIALLY DURING THE MORNING 
THEN DRYING OUT AND TURNING COLDER.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, 
KMIV, KACY AND SURROUNDING AREAS.

CONDITIONS HAVE GRADUALLY IMPROVED TO VFR AND SKIES WILL
TRANSITION TO BROKEN AND SCATTERED THROUGHOUT THE REMAINDER OF THE
AFTERNOON. ANY REMAINING MVFR CEILINGS WILL TRANSITION TO VFR BY 20Z. NORTHWEST
WIND GUSTS AROUND 20 KNOTS WILL CONTINUE AT ALL TAF SITES. FOR
TONIGHT THERE IS POTENTIAL FOR SOME LOW CLOUDS AROUND 2,000 FEET
TO FORM. HOWEVER WITH CONTINUED NORTHWEST WINDS OVER 10 KNOTS
THERE IS LITTLE TO MODERATE CONFIDENCE THIS WILL OCCUR.

WEDNESDAY WILL BE A VFR DAY WITH NORTHWEST GUSTS AGAIN AROUND 20
KNOTS. SOME HIGHER GUSTS ARE POSSIBLE IN THE AFTERNOON. GUSTS
WILL AGAIN DECREASE AFTER SUNSET. 

OUTLOOK...
WEDNESDAY AND WEDNESDAY NIGHT...PRIMARILY VFR. NW WINDS 10-15 KT IN 
THE DAY, BECOMING CALM AT NIGHT.

THURSDAY INTO FRIDAY MORNING...VFR TO FOR MUCH OF THURSDAY. LIGHT 
SNOW WILL LIKELY SPREAD INTO THE AREA FROM WEST TO EAST THURSDAY 
NIGHT BUT MAY REACH ABE/RDG BY LATE AFTERNOON. MVFR/IFR RESTRICTIONS 
POSSIBLE WITH THE SNOW. HIGHEST CONFIDENCE IS AT NORTHERN TERMINALS.
 
FRIDAY AFTERNOON...VFR WITH BLUSTERY NW WIND GUSTING TO 30 KT.

FRI NIGHT...VFR.  GUSTY NW WINDS.

SATURDAY...VFR.

&&

.MARINE...
STORM WARNINGS CHANGED TO GALE WARNINGS FOR NJ WATERS. 

DEEP LOW PRESSURE EAST OF THE WATERS WILL CONTINUE TO MOVE NORTHEAST 
TODAY. STRONG WINDS WILL CONTINUE TODAY WITH GALE GUSTS EXPECTED AT 
LEAST THE FIRST PART OF TODAY. WINDS WILL PROBABLY DROP BACK BELOW 
GALE STRENGTH LATER...BUT THE DAY SHIFT CAN MAKE THAT CALL LATER. 
SIGNIFICANT SEAS WILL CONTINUE TODAY THEN SUBSIDE TONIGHT. 

OUTLOOK...
WEDNESDAY...SCA LIKELY WITH FREEZING SPRAY.

WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...NO MARINE HEADLINES ARE 
ANTICIPATED. SOME FREEZING SPRAY POSSIBLE WEDNESDAY NIGHT.

FRIDAY- NEAR GALE-FORCE GUSTS BEHIND A CLIPPER SYSTEM.

FRI NIGHT: POSSIBLE LEFTOVER NW GALE FORCE WIND GUSTS.

SATURDAY...SCA CONDITIONS POSSIBLE.

&&

.TIDES/COASTAL FLOODING...
THE OVERNIGHT HIGH TIDE ALONG THE NJ/DEL SHORE AND DEL BAY PRODUCED
MINOR TIDAL FLOODING, BUT NOTHING TOO SERIOUS. WITH A WELL-
ESTABLISHED NORTHWEST FLOW OVER THE REGION, NO ADDITIONAL TIDAL
ISSUES ARE EXPECTED WITH SUBSEQUENT HIGH TIDE CYCLES.


&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR 
     NJZ001-007>010-015.
     WINTER STORM WARNING UNTIL 3 PM EST THIS AFTERNOON FOR 
     NJZ012>014-020-025-026.
DE...NONE.
MD...NONE.
MARINE...GALE WARNING UNTIL 6 PM EST THIS EVENING FOR ANZ430-431-
     450>455.

&&

$$
SYNOPSIS...KLEIN
NEAR TERM...MIKETTA
SHORT TERM...O'HARA
LONG TERM...DRAG/KLEIN
AVIATION...DRAG/FRANCK/GAINES/KLEIN
MARINE...DRAG/KLEIN
TIDES/COASTAL FLOODING...STAFF







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