Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 141456
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
956 AM EST SUN FEB 14 2016

.SYNOPSIS...
SURFACE HIGH WILL MOVE ACROSS THE TODAY...THEN OFF THE EAST COAST
TONIGHT. A DEEPENING UPPER LVL TROF OVER THE CENTRAL CONUS WILL
SPAWN A LOW PRES SYSTEM...WHICH WILL LIKELY TRACK NORTHWARD ACROSS
EASTERN PA ON TUESDAY. LATER IN THE WEEK...A RIDGE OF HIGH PRESSURE
MOVES IN ALOFT WITH MUCH WARMER AIR FOR LATE IN THE WEEK.

&&

.NEAR TERM /UNTIL 7 PM THIS EVENING/...

WITH THE EXCEPTION OF THE NORTHERN TIER COUNTIES....IN MOST AREAS
TEMPERATURES ARE IN THE SINGLE DIGITS TO LOW TEENS IN THE SOUTH
AND WITH LIGHT WINDS THE WINDCHILL ISSUES ARE NO LONGER
SIGNIFICANT. ALONG THE NEW YORK BORDER THERE ARE STILL MANY
LOCATIONS WITH TEMPERATURES BELOW ZERO AND WINDCHILLS IN THE -10
TO -20 RANGE.

THE TEMPERATURES SHOULD RISE TODAY AND WITH LIGHT WINDS ALL
WINDCHILL ISSUES WILL BE HISTORY. WE HAVE LET BOTH THE ADVISORY
AND WARNINGS EXPIRE AS OF 11 AM.

HIGH PRESSURE OVER THE REGION WILL MOVE OUT OVER THE WESTERN
ATLANTIC AND HIGH CLOUDS FROM THE APPROACHING STORM SYSTEM WILL
SPREAD CLOUDS FROM SOUTHWEST TO NORTHEAST OVER THE REGION THIS
AFTERNOON AND EVENING. LIGHT SNOW COULD ARRIVE IN EXTREME
SOUTHEASTERN AREAS LATER THIS EVENING.

&&

.SHORT TERM /7 PM THIS EVENING THROUGH 6 PM MONDAY/...

THE HRRR AND 12Z NAM SHOW LIGHT SNOW ARRIVING LATER EVENING IN
SOUTHWESTERN AREAS AND VERY SLOWY SPREADING NORTHWARD.

IT SHOULD BECOME CLOUDY OVERNIGHT OVER MUCH OF THE REGION WITH
TEMPERATURES FALLING EARLY THEN SLOWLY RISING OVERNIGHT. ANY SNOW
WILL BE VERY LIGHT AND MAINLY OVER THE SOUTHERN THIRD OF THE
REGION.

THE SREF IMPLIES MAINLY VERY LIGHT SNOW OVER SOUTHWESTERN AND
WESTERN AREAS THROUGH MID-MORNING MONDAY. THEN THE PROBABILITY OF
SNOW RAPIDLY SPREADS NORTHWARD IN THE AFTERNOON HOURS WITH SNOW OR
MIXED PRECIPITATION EVERYWHERE BY LATE AFTERNOON. BUT WARM AIR
WILL CAUSE A MIXING WITH ICE PELLETS AND FREEZING RAIN IN SOUTHERN
AREAS BY AFTERNOON.

THE SNOW WILL MIX WITH ICE PELLETS FARTHER NORTH LATER IN THE
EVENING AND OVERNIGHT WHICH IS THE NEXT PERIOD.

WE ARE GOING TO ISSUE A WINTER WEATHER ADVISORY AFTER ABOUT
MIDDAY AFTER WE SEE MORE 12Z MODELS AND ENSEMBLES.

PREVIOUS:
DEVELOPING WAA BTWN DEPARTING SFC HIGH AND WEAKENING SHORTWAVE
APPROACHING FROM THE MIDWEST WILL SPREAD INCREASING CLOUDINESS
ACROSS THE STATE OVERNIGHT. A BIT OF LGT SNOW COULD DEVELOP OVR
THE SOUTHERN AND WESTERN COUNTIES LATE SUN NIGHT.
HOWEVER...RESIDUAL LOW PWAT AIR ASSOC WITH DEPARTING ARCTIC AIR
MASS SHOULD LIMIT ANY ACCUMS TO A DUSTING.

EARLY RADIATIONAL COOLING SHOULD DROP TEMPERATURES OFF FAST THIS
EVENING...BUT RETURN FLOW AND INCREASING CLOUD COVER SHOULD CAUSE
TEMPERATURES TO BEGIN TO SLOWLY RISE LATE TONIGHT.

SPOTTY LGT SNOW ACROSS CENTRAL/SOUTHERN PA MON MORNING WILL
LIKELY GIVE WAY TO A STEADIER SNOW ACROSS SOUTHERN PA LATE IN THE
DAY...AS ISENTROPIC LIFT INCREASES AHEAD OF POTENT SHORTWAVE
APPROACHING FROM THE MISS VALLEY AND ASSOC SOUTHERLY LL JET.
GEFS/SREF PTYPE PROBS SUGGEST SOME MIXING MAY WORK INTO THE S TIER
COUNTIES BY EVENING.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
MDL SPREAD CONTINUES TO NARROW...WITH MOST RUNS TRACKING SFC LOW
ACROSS EASTERN PA TUESDAY...SUPPORTING RAISING POPS TO NEAR 100
PCT LATE MONDAY-EARLY TUESDAY. THIS TRACK WOULD CERTAINLY FAVOR
RAIN ACROSS EASTERN PA AND RAIN OR SNOW ACROSS WESTERN PA. BULK OF
MDL GUIDANCE SUPPORTS AN EVENTUAL TURNOVER TO RAIN ACROSS ALL BUT
PERHAPS THE NW MTNS BY EARLY TUES AM. ENSEMBLE PLUMES AND WPC
GUIDANCE SUPPORT A GENERAL 1-3 INCH SNOW ACCUM BEFORE CHANGEOVER.
SFC HIGH PROGGED EAST OF NJ IS IN A POSITION UNFAVORABLE TO HOLD
LL COLD AIR IN PLACE. HOWEVER...A TRANSITION PERIOD OF FZRA STILL
APPEARS QUITE POSSIBLE ACROSS CENTRAL PA MON EVENING. WPC GUIDANCE
SUPPORTS MARGINAL WARNING CRITERIA FOR ICE ACCRETION OVR THE SC
MTNS. HOWEVER...SREF/GEFS PLUMES INDICATE SUCH ICE AMTS ARE FAR
FROM CERTAIN. HAVE THEREFORE DECIDED TO HOLD OFF ON HEADLINES
ATTM. MAIN EVENT DOESN/T UNFOLD UNTIL LATE MONDAY...SO STILL TIME
TO HONE FCST WITH BENEFIT OF LATER GUIDANCE.

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. WPC ALSO HAS HIGHLIGHTED SE
PA FOR A SLIGHT RISK OF FLOODING TUESDAY.

NEAR TO ABOVE NORMAL TEMPS APPEAR LIKELY LATER NEXT WEEK...AS
HEIGHTS ARE FORECAST TO RISE AND A PSBL LOW PRESSURE SYSTEM LIFTS
THROUGH THE GREAT LAKES TO THE WEST OF PA.

&&

.AVIATION /15Z SUNDAY THROUGH THURSDAY/...

GENERALLY GOOD WEATHER TODAY BECOME VFR ALL LOCATIONS. COLD WITH
LIGHT WINDS. CLOUDS MOVE IN LATER THIS AFTERNOON AND EVENING AHEAD
OF APPROACHING WAVE.

PERIOD OF NICE WEATHER WILL BE SHORT-LIVED AS CIG RESTRICTIONS
SLIDE IN FROM THE SW AGAIN STARTING OVERNIGHT TONIGHT AHEAD OF
NEXT STORM SYSTEM. SNOW MONDAY WILL TRANSITION TO ASSORTED WINTRY
PRECIPITATION MONDAY NIGHT AND THEN AREAS OF RAIN IN THE SE HALF
ON TUE. EXPECT A LONG-DURATION IMPACT TO FLYING CONDITIONS MONDAY
INTO TUESDAY.

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.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
WIND CHILL WARNING UNTIL 11 AM EST THIS MORNING FOR PAZ004>006-
037-041-042.
WIND CHILL ADVISORY UNTIL 11 AM EST THIS MORNING FOR
PAZ010>012-017>019-024>028-033>036-045-046-049>053-056>059-
063>066.

&&

$$
SYNOPSIS...FITZGERALD
NEAR TERM...GRUMM
SHORT TERM...GRUMM/FITZGERALD
LONG TERM...FITZGERALD/GARTNER
AVIATION...GRUMM/RXR


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