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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KCTP 040449
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1149 PM EST TUE MAR 3 2015

.SYNOPSIS...
LOW PRESSURE WILL TRACK NORTH OF PENNSYLVANIA TONIGHT...AS ITS
TRAILING COLD FRONT SAGS SOUTH THROUGH THE REGION. A WAVE OF LOW
PRESSURE WILL TRACK SOUTH OF PENNSYLVANIA WEDNESDAY NIGHT AND
EARLY THURSDAY. HIGH PRESSURE WILL BUILD SOUTHEAST INTO THE STATE
FRIDAY AND SATURDAY.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
LL JET AND ASSOC PUSH OF WARM AIR ALOFT HAS CHANGED PRECIP TO
PLAIN RAIN OVR MUCH OF THE ALLEGHENY PLATEAU AS OF 04Z.
MEANWHILE...FZRA CONTINUES TO FALL ACROSS MOST OF THE REST OF
CENTRAL PA. MDL SOUNDINGS...AS WELL AS LATEST HRRR OUTPUT...CONTINUE
TO INDICATE THE LOW LVL COLD AIR WILL ERODE FROM WEST TO EAST
OVERNIGHT WITH THE LAST OF THE FZRA ENDING ACROSS THE HIGH TERRAIN
NE OF KIPT BTWN 06Z-09Z.

BASED ON ASOS ICE ACCRETIONS THRU 02Z AND UPSTREAM RADAR
TRENDS...HAVE DOWNGRADED ICE STORM WARNING TO A WINT WX ADV ACROSS
THE N MTNS. DESPITE WARMING TEMPS...WILL MAINTAIN WINT WX ADV
THRU 06Z ACROSS MUCH OF THE ALLEGHENY PLATEAU...DUE TO POTENTIAL
OF RESIDUAL ICY SPOTS ON UNTREATED ROADS. SPOTTER FROM WARREN CO
CONFIRMED THE ICY ROADS WITH TEMPS ABV 32F AT 01Z. LOW LVL COLD
AIR WILL BE MORE PERSISTENT EAST OF THE MTNS...SO HAVE KEPT ADV IN
PLACE THRU 12Z...BUT MID SHIFT MAY NEED TO CANCEL EARLY.

REGIONAL RADAR LOOP AT 04Z ALREADY SHOWING PRECIP TAPERING OFF
ACROSS THE NORTHERN COUNTIES...AND NR TERM MDL DATA INDICATES THE
FOCUS OF ADDITIONAL PRECIP TONIGHT /IN THE FORM OF RAIN/ WILL BE
OVR THE LAUREL HIGHLANDS...WHERE SWRLY LL JET AND PLUME OF HIGHER
PWATS INTERSECT THE HIGHER TERRAIN OF SW PA. MAY HAVE TO BE
CONCERNED ABOUT LOCALIZED FLOODING FROM KJST SOUTHWARD...WHERE
RAINFALL AND TEMPS APPROACHING 50F COULD WILL PRODUCE SIG
SNOWMELT.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
SFC FRONTAL BOUNDARY WILL SAG SOUTH OF PA EARLY WEDNESDAY.
HOWEVER...LINGERING PRECIP REMAINS LIKELY ACROSS SOUTHERN PA IN
REGION OF 8-7H FGEN FORCING. MDL BLYR TEMPS INDICATE PRECIP WILL
FALL AS LGT RAIN ACROSS THE SOUTHEAST COUNTIES. HOWEVER...MDL
SOUNDINGS JUST COLD ENOUGH TO SUPPORT A RAIN/SNOW MIX ACROSS THE
LAUREL HIGHLANDS...WHERE A LIGHT ACCUM OF UP TO AN INCH APPEARS
POSSIBLE BY WED EVENING. DRIER AIR ACROSS NORTHERN PA SHOULD
TRANSLATE TO A MAINLY DRY DAY THERE WITH JUST A CHC OF -SHSN.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
AN ACTIVE LATE-WINTER PRECIPITATION PATTERN WILL IMPACT CENTRAL
PA THROUGH MIDWEEK FOLLOWED BY WHAT IS HOPEFULLY THE LAST SHOT OF
ARCTIC AIR FOR THE SEASON THURSDAY INTO FRIDAY. THE PATTERN SHOULD
DRY OUT LATE IN THE WEEK THROUGH THE UPCOMING WEEKEND WITH HIGH
PRESSURE IN CONTROL MOST OF THE TIME. THE GENERAL MODEL AND ENSEMBLE
CONSENSUS IS TO MAINTAIN A RIDGE IN THE WEST AND TROUGH IN THE
EAST THROUGH THE WEEKEND WITH SOME SIGNS OF A PATTERN SHIFT BY THE
MIDDLE OF NEXT WEEK WITH TROUGHING FCST TO DEVELOP ALONG THE WEST
COAST. BELOW NORMAL TEMPS SHOULD MODERATE CLOSER TO NORMAL EARLY
NEXT WEEK WITH SOME HINTS AT EVEN WARMER TEMPS LATER NEXT WEEK.

MODELS CONTINUE TO SHOW AN AMPLIFIED AND MOIST SW FLOW ALOFT AND
JET ENTRANCE REGION DYNAMICS SUPPORTING A BROAD STRIPE OF PCPN
ALONG A WELL DEFINED BAROCLINIC ZONE AHEAD OF PHASING UPPER LEVEL
ENERGY OVER THE DSW/ROCKIES ON WED AND MOVING EWD THROUGH THE OH
VLY AND MID ATLC ON THURSDAY. SEVERAL WAVES OF LOW PRESSURE ARE
FCST TO DEVELOP AND MOVE ENEWD ALONG A SW-NE ORIENTED COLD FRONT
WHICH SHOULD PROGRESS AND SETTLE SEWD THROUGH THE MID ATLC REGION
BY EARLY THURS...AS ARCTIC HIGH PRESSURE BUILDS INTO THE UPPER
PLAINS. AMPLE MOISTURE IS FCST BY THE MODELS TO MOVE INTO A
DEEPENING COLD SECTOR ALONG/NORTH OF THE SEWD-ADVANCING COLD
FRONTAL BOUNDARY WHICH COULD RESULT IN A LATE SEASON HEAVY SNOW
EVENT FOR SOUTH CENTRAL PA WED NGT INTO THURS. THERE ARE MODEL
DIFFERENCES WITH THE TIMING OF THE FRONT WHICH IS LKLY TIED TO THE
CONSOLIDATION OF SHORTWAVE ENERGY UPSTREAM. THAT SAID...THE
CONSENSUS FCST AXIS OF MAX QPF /0.50 INCH OR GREATER/ HAS BEEN
FAIRLY CONSISTENT PAINTED OVER THE SRN 1/3 OF THE CWA. SIMILAR TO
YESTERDAY...USED A MULTI MODEL BLEND WITH PSEUDO BIAS CORRECTION
FACTOR TO DERIVE GRIDDED QPF AMTS WHICH GENERALLY RANGE FROM 0.25
TO 0.75 INCHES ACROSS THE SRN 1/2 OF THE CWA. THE COLUMN WILL BE
IN A STATE OF TRANSITION AND COOLING DOWN FROM NW TO SE WED-WED
NGT AS THE COLD FRONT PUSHES SOUTHEAST ACROSS THE AREA. THIS
SHOULD SUPPORT A TRANSITION FROM RAIN TO SNOW. A PERIOD OF SLEET
MAY IMPACT FCST SNOW ACCUMULATIONS WITH THE DURATION A KEY FACTOR
IN THIS FCST. WITH INCREASING CONFIDENCE AND GREATEST RISK IN THE
POTENTIAL FOR HEAVY SNOW/6+ INCHES...WHICH IS SUPPORTED BY ROBUST
WPC ENSEMBLE AS WELL AS THE GEFS MEAN...HAVE ISSUED A WINTER STORM
WATCH FOR THE SOUTH-CENTRAL COUNTIES FROM WEDNESDAY EVENING
THROUGH THURSDAY EVENING.

WHAT IS HOPEFULLY THE LAST SHOT OF ARCTIC AIR THIS SEASON SHOULD
ARRIVE BEHIND THE COLD FRONT. FRIDAY MORNING LOWS ARE LKLY TO BE
20-30F BELOW NORMAL WITH SINGLE DIGIT LOWS +/- ZERO DEGREES. SUCH
READINGS MAY BREAK DAILY RECORDS.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
03Z TAFS SENT.

MAINLY RAIN NOW IN MOST AREAS.

EARLIER DISCUSSION BELOW.

A WARM FRONT LIFTING NE FROM THE OH VLY WILL KEEP A LARGE
AREA OF FREEZING RAIN AND SLEET ACROSS MOST OF THE AREA THIS
EVENING. JST WARM ENOUGH FOR JUST RAIN...BUT GROUND AND OBJECT
TEMPS LIKELY STILL COLD. THE OTHER FACTOR OVERNIGHT WILL BE LLWS.

THE PRECIPITATION WILL LIKELY GO OVER TO JUST RAIN LATE TONIGHT
FOR A SHORT TIME. MANY AREAS MAY JUST SEE NOTHING ONCE THE
STRONGER WARM ADVECTION SHUTS OFF.

FOR WED...RAIN WILL GO BACK TO SNOW FROM NW TO SE. HARD TO SEE
CONDITIONS BEING VERY GOOD.

VERY COLD LOW LEVEL AIR WILL BE ADVECTED BACK TO THE SOUTH LATE
WED INTO THU. A SERIES OF WEAK LOW PRESSURE SYSTEMS WILL TRACK
ALONG THE COLD FRONT FROM LATE WED INTO THU...LIKELY GIVING
AT LEAST SOUTHERN PA SOME SNOW. THE COMBINATION OF INCREASING
WINDS...SNOW...AND FALLING TEMPERATURES WILL LIKELY RESULT IN
POOR CONDITIONS FOR AVIATION.

IMPROVING CONDITIONS WILL SET IN FOR FRIDAY INTO MONDAY...AS COLD
HIGH PRESSURE BUILDS INTO THE AREA.

OUTLOOK...

WED NIGHT...SIG REDUCTIONS IN SNOW DEVELOPING MAINLY ACROSS THE
SOUTH.

THU...SLOWLY IMPROVING CONDITIONS...LINGERING MVFR NW AND SE.

FRI-SAT...MAINLY VFR.

SUN...MVFR WITH CHC -SHSN MAINLY NORTH AND WEST. VFR SE.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM EST WEDNESDAY FOR PAZ012-
018-019-025>028-034>037-041-042-045-046-049>053-056>059-
063>066.
WINTER WEATHER ADVISORY UNTIL 1 AM EST WEDNESDAY FOR
PAZ004>006-010-011-017-024.
WINTER STORM WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY
EVENING FOR PAZ024>028-033>036-056>059-063>066.

&&

$$
SYNOPSIS...FITZGERALD
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD/STEINBUGL
LONG TERM...STEINBUGL
AVIATION...MARTIN