Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 041559
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1059 AM EST WED MAR 4 2015

.SYNOPSIS...

A WAVE OF LOW PRESSURE WILL TRACK SOUTH OF PENNSYLVANIA LATER
TODAY INTO THURSDAY. HIGH PRESSURE WILL BUILD SOUTHEAST INTO THE
STATE FRIDAY AND SATURDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...

10 AM UPDATE:

HAVE ISSUED AN ADVISORY FOR THE STRIPE OF COUNTIES ON THE NORTHERN
EDGE OF THE WARNING TONIGHT AND THURSDAY.

TEMPERATURES HAVE RECOVERED ABOVE FREEZING OVER ALL BUT THE FAR
NORTH. TEMPS FOR MUCH OF TODAY WILL REMAIN STEADY OR SLOWLY RISE
BEFORE COLDER AIR BEGINS WORKING IN LATER TODAY AND TONIGHT.

SOUTHERN AREAS WILL REMAIN UNDER THE BEST THREAT FOR PERIODS OF
RAIN INTO THE AFTERNOON. COLDER AIR ARRIVING LATER TODAY AND THIS
EVENING WILL BRING A CHANGE BACK TO SNOW. LATEST BUFKIT SOUNDINGS
SHOW SNOW IN JOHNSTOWN BY 20-22Z...ALTOONA/STATE COLLEGE
22-00Z...AND NOT UNTIL 02-4Z IN THE HARRISBURG-YORK-LANCASTER
AREAS.

A STRONG JET ENTRANCE REGION ALOFT WILL SLIDE BY JUST NORTH OF
THE REGION TONIGHT AND THURSDAY...SUPPORTING AN AREA OF POTENT
LOW-MID LEVEL FRONTOGENETIC FORCING. MODELS RESPOND BY BRINGING A
PROLONGED PERIOD OF PRECIP TO MY FAR SOUTHERN ZONES. SREF AND GEFS
THREAT PAGES PAINT MY FAR SERN ZONES AS HAVING THE HIGHEST RISK
FOR HEAVY SNOW THROUGH MID DAY THURSDAY...WITH A RATHER SHARP CUT
OFF ON THE BACK SIDE UP INTO THE CENTRAL MOUNTAINS.

09Z SREF SHOWS HIGHEST PROB OF AT LEAST .50 QPF FROM SOUTHERN
FRANKLIN COUNTY ENE THROUGH NRN LANCASTER COUNTY.

OTHER THAN MINOR TWEAKS BASED ON LATEST CHANGE-OVER
TIMES...OVERALL FORECAST LOOKS ON TRACK.

&&

.SHORT TERM /THURSDAY/...

LATEST SREF SHOWS PRECIP ENDING FROM NW TO SE AS THE DAY WEARS ON
WITH MUCH OF THE DAY ENDING UP DRY OVER MY NORTHERN TIER...AND
MAINLY DRY AFTER 18Z NORTH OF I-80.

STILL YET ANOTHER VERY COLD DAY IS IN STORE WITH MAX TEMPS SOME
20-30 DEG BELOW NORMAL.

&&

.LONG TERM /THURSDAY 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.

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 /16Z WEDNESDAY THROUGH SUNDAY/...
A COLD FRONT /TRAVERSING NORTHERN AND WESTERN HIGHER TERRAIN AT
12Z/ WILL CONTINUE TO SAG SOUTHEAST ACROSS THE REGION TODAY.
WESTERLY WINDS WILL PICK UP TO 10-20 MPH IN THE WESTERN HIGHER
TERRAIN...WITH WINDS ELSEWHERE TURNING TO THE W/NW AND INCREASING
TO 5-10 MPH. WIDESPREAD CIG RESTRICTIONS TO MAINLY IFR CONDITIONS
WILL PERSIST ACROSS THE WEST TODAY...WITH CENTRAL AND EASTERN
SECTIONS SETTLING INTO GENERALLY PERSISTENT MVFR CONDITIONS. LIGHT
RAIN WILL OVERSPREAD THE SOUTHERN PORTION OF CWA EARLY IN THE
DAY...BUT AS COLDER AIR WORKS IN FROM THE NORTH AND ANOTHER WAVE
OF LOW PRESSURE SLIDES ALONG THE FRONTAL BOUNDARY...PRECIP
INTENSITY WILL INCREASE HEADING INTO TONIGHT WITH PRECIP TYPE
CHANGING BACK OVER TO SNOW. BIGGEST IMPACTS WILL BE FROM KJST TO
KMDT/KLNS AS WIDESPREAD IFR/LIFR CONDITIONS DEVELOP WED NIGHT INTO
THU.

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...
FLOOD WATCH UNTIL 7 PM EST THIS EVENING FOR PAZ017-024-025-033-
034.
WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 7 PM EST
THURSDAY FOR PAZ017>019-049>053.
WINTER STORM WARNING FROM 7 PM THIS EVENING TO 7 PM EST
THURSDAY FOR PAZ024>028-033>036-056>059-063>066.

&&

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


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