Area Forecast Discussion
Issued by NWS State College, PA

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381
FXUS61 KCTP 142052
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
352 PM EST SUN FEB 14 2016

.SYNOPSIS...
THE DEEP TROUGH WITH THE ARCTIC AIR HAS MOVED TO OUR EAST. A
STRONG WAVE TO OUR WEST WILL ALLOW FOR A RAPID RETURN OF WARM AIR
INTO PENNSYLVANIA MONDAY INTO TUESDAY. THE SURFACE CYCLONE WITH
THIS WAVE WILL TRACK FROM SOUTH-TO-NORTH OVER THE STATE MONDAY
NIGHT AND TUESDAY. THIS WILL BRING SNOW TO A MIX AND THEN RAIN
OVER MOST OF THE REGION. COLD AIR RETURNS TUESDAY-WEDNESDAY
BEFORE A SIGNIFICANT LATE WEEK WARM UP.

&&

.NEAR TERM /UNTIL 11 PM THIS EVENING/...
MOSTLY SUNNY AND COLD FOR THE REMAINDER OF THE DAY. TEMPERATURES
HOLDING GENERALLY IN THE TEENS TO AROUND 20 IN THE SOUTH.

HIGH CLOUDS WILL MOVE OVER THE SOUTHWESTERN AREAS LATER THIS
AFTERNOON AND EVENING AHEAD OF A POTENTIALLY SIGNIFICANT WEATHER
EVENT MONDAY AND TUESDAY.

TEMPERATURES MAY FALL BACK A FEW DEGREES AFTER SUNSET.
AGAIN...HIGH CLOUDS JSUT TO THE SW...SHOULD HELP TAPER THE
DROP IN TEMPERATURES ACROSS THE FAR SW LATER THIS EVENING.

&&

.SHORT TERM /11 PM THIS EVENING THROUGH 6 PM MONDAY/...
TEMPERATURES WILL FALL A FEW DEGREES BEFORE MIDNIGHT WITH THE
OVERNIGHT LOW IN MANY CENTRAL AND SOUTHERN LOCATIONS OCCURRING A
FEW HOURS EITHER SIDE OF MIDNIGHT. TEMPERATURES SHOULD SLOWLY
BEGIN TO RISE AFTER MIDNIGHT AS CLOUDS THICKEN AND RETURN FLOW OF
WARM AIR INCREASES.

MOST OF THE GUIDANCE IMPLIES LIGHT SNOW ARRIVES IN SOUTHWEST
MOUNTAINS BEFORE SUNRISE. VERY LIGHT SNOW IS EXPECTED. BASED ON
THE NCEP ENSEMBLES AND BLENDS...THE SNOW WILL BE SLOW TO SPREAD
NORTH IN THE MORNING AND THEN WILL ACCELERATE NORTH IN THE
AFTERNOON. ALL AREAS SHOULD START AS SNOW.

TIMING OF TRANSITIONS VARY SLIGHTLY BY MODEL AND EFS. USED BLEND
GEFS AND 15Z SREF AS REFERENCE TIMES HERE. GEFS AND SREF IMPLY ICE
PELLETS WILL DEVELOP A FEW HOURS EITHER SIDE OF 4 PM MONDAY ALONG
THE SOUTHERN TIER COUNTIES FREEZING RAIN WILL RAPIDLY MIX IN.
TIMED ADVISORY FOR FREEZING RAIN BASED ON THIS LOGIC.

THE 0C 850 LINE AND PTYPE ISSUES IN GEFS/SREF MOVE NORTH QUICKLY.
THIS WOULD LEAD TO A CHANGE FROM SNOW TO ICE PELLETS IN STATE
COLLEGE BY 10 PM AND FREEZING RAIN AFTER MIDNIGHT AS RAIN/SNOW
LINE MOVES NORTHWARD.

A TRANSITION TO ALL RAIN IS LIKELY BETWEEN 7 AND 10 PM IN THE
SOUTHEASTERN COUNTIES LIMITING SNOWFALL AND ICE ACCUMUATIONS.

&&

.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
STILL SOME VARIATION IN SPEED AND TRACK OF LOW MOVING NE LATER
MONDAY INTO TUESDAY. FINAL OUTCOME DEPENDS ON HOW 3 SEPERATE
SYSTEMS PHASE. AS NOTED ABOVE...FIRST BATCH OF SNOW FROM THE
IOWA AREA MOVES LATER TONIGHT.

THEN WARM ADVECTION LATER MONDAY AFTERNOON RESULTS IN MORE SNOW.

STRONG WARM ADVECTION AFTER THIS WOULD SUPPORT SLEET...RAIN...AND
FREEZING RAIN AT TIMES LATER MONDAY NIGHT INTO TUE MORNING...AS
WARMER AIR ALOFT MOVES IN. MAV NUMBERS HAVE MOST IF NOT ALL THE
AREA ABOVE 32 DEGREES BY 12Z TUE. NOT SURE THINGS WILL WARM THIS
FAST...ESPECIALLY ACROSS THE WEST AND NORTH.

EVEN WITH THE WARM UP ON TUE...EC AND SOME OTHER MODELS SHOW
TRANSFER OF ENERGY TO THE COAST TUE AFT...THUS ONE WOULD HAVE TO
WATCH FOR RAIN TO GO BACK TO SNOW ON THE BACK SIDE OF THE SYSTEM.

MAIN CHANGE WAS TO EDGE SNOW AMTS UP ACROSS THE NW MONDAY NIGHT.
WEIGHTED AMTS TO WPC GRAPHICS.

WPC STILL SHOW ICE ACROSS MUCH OF THE AREA. NEW WPC GRAPHIC
CLOSE TO WHAT WE HAVE.

LEFT TEMPS AS IS FOR MONDAY NIGHT. TEMPS SHOULD RISE LATE.

WILL ALSO HAVE TO WATCH FOR THE POSSIBILITY OF FLOODING ACROSS
SOUTHEAST PA...GIVEN RAINFALL AND SNOWMELT POTENTIAL. LATEST MDL
ENSEMBLE RIVER FORECASTS SUGGESTS MINOR FLOODING IS A POSSIBILITY
ACROSS THE LOWER SUSQ VALLEY BY TUES.

FOR WED...SOME SNOW SHOWERS WITH COLD FRONT. MOISTURE IS LIMITED.

MAINLY DRY FOR THU INTO FRIDAY. A WARMING TREND. NEAR TO ABOVE
NORMAL TEMPS APPEAR LIKELY...AS HEIGHTS ARE FORECAST TO RISE AND
A LOW PRESSURE SYSTEM LIFTS THROUGH THE GREAT LAKES TO THE WEST
OF PA.

SOME RAIN SHOWERS POSSIBLE LATE FRIDAY INTO SAT.

SOME HINTS OF ANOTHER WEAK...FAST MOVING SYSTEM FOR SUNDAY. DID
NOT GO REAL HIGH ON POPS.

&&

.AVIATION /21Z SUNDAY THROUGH FRIDAY/...
MOST OF THE AREA WILL HAVE VFR CONDITIONS THROUGH AT LEAST 5 AM
MONDAY. LIGHT SNOW WILL MOVE INTO THE SOUTHWEST AROUND THAT TIME
AND WE WILL SEE A SLOW DEGRADATION OF FLYING CONDITIONS MONDAY AS
SNOW MOVES FROM NORTH TO SOUTH ACROSS THE REGION.

MOST OF THE SNOW WILL BE IN THE SOUTHWEST THEN SOUTHEAST. BEFORE
15Z-18Z MONDAY THEN IT SPREADS NORTH. FREEZING RAIN WILL MOVE IN
AND SPREAD NORTHWARD.

WIDESPREAD IFR/LIFR LIKELY MONDAY NIGHT AND TUESDAY IN
RAIN...MIXED PRECIPITATION AND SOME HEAVIER SNOW IN EXTREME
NORTHWESTERN AREAS.

OUTLOOK...

MON...WIDESPREAD RESTRICTIONS DEVELOP WITH SNOW DEVELOPING.

MON NIGHT AND TUE...SNOW LIKELY WRN HALF OF PENN...WITH RAIN
AND/OR SNOW IN THE SE. WIDESPREAD RESTRICTIONS SET IN. LLWS POSS
SE.

WED...ANOTHER WAVE SLIDES THROUGH KEEPING RESTRICTIONS IN
PLACE ALONG WITH POTENTIAL FOR LIGHT SNOW...ESP OVER THE WEST.

THU...MAINLY VFR.

FRI...MAINLY VFR. PERHAPS A RAIN SHOWER...MAINLY LATE.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 5 PM MONDAY TO 7 AM EST TUESDAY
FOR PAZ006-010>012-017>019-024>028-033-034-037-041-042-045-046-
049>053.
WINTER WEATHER ADVISORY FROM 2 PM MONDAY TO 1 AM EST TUESDAY
FOR PAZ035-036-056>059-063>066.
WINTER STORM WATCH FROM MONDAY EVENING THROUGH TUESDAY MORNING
FOR PAZ004-005.

&&

$$
SYNOPSIS...GRUMM/MARTIN
NEAR TERM...GRUMM/MARTIN
SHORT TERM...GRUMM/MARTIN
LONG TERM...MARTIN
AVIATION...GRUMM/MARTIN



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