Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 122048
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
348 PM EST FRI FEB 12 2016

.SYNOPSIS...
AN ARCTIC COLD FRONT WILL MOVE THROUGH NORTHWESTERN PENN EARLY THIS
EVENING...AND PUSH ACROSS THE SUSQ VALLEY SHORTLY AROUND OR
SHORTLY AFTER MIDNIGHT. THIS FRONT WILL BE FOLLOWED BY THE
COLDEST AIR OF THE SEASON JUST IN TIME FOR VALENTINES WEEKEND WITH
STRONG/GUSTY NORTHWEST WINDS...DANGEROUSLY COLD WIND CHILLS...AND
AREAS OF SIGNIFICANT LAKE EFFECT AND UPSLOPE SNOW ACROSS THE
NORTHWEST MOUNTAINS AND LAUREL HIGHLANDS. HIGH PRESSURE WILL
SETTLE ACROSS THE STATE LATE IN THE WEEKEND...THEN A STRENGTHENING
STORM WILL LIFT UP THE EAST COAST EARLY NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
LOWERING AND THICKENING ALTOSTRATUS AND NS DECK IS NOW PRODUCING
STEADY LIGHT SNOW ACROSS THE WESTERN HALF OF PENN WITH VSBYS
GENERALLY IN THE 1-3SM RANGE AS WAA. THE LIGHT PRECIP IS THE
RESULT OF WEAK WAA OVERSPREADING THE AREA IN ADVANCE OF UPPER LOW
/POLAR VORTEX/ PLUNGING SOUTH FROM JAMES BAY.

NEAR TERM...HIGH RES MODELS REMAIN PRETTY CONSISTENT ON THE
TIMING OF THE ARCTIC FROPA /ACROSS THE FAR NW IN THE 23-01Z
WINDOW...AND NEAR THE I-99/RT 22 CORRIDOR IN SW AND CENTRAL PENN
BETWEEN 03-05Z...WITH THE SUSQ VALLEY TO BE IMPACTED BY SCATTERED
SHSN/BRIEF ISOLATED SQUALLS MAINLY AFTER MIDNIGHT.

THE LIGHT WARM ADVECTION SNOWS LATE TODAY AND EARLY TONIGHT WILL
BRING A GENERAL COATING TO ONE INCH WITH SOME SLICK TRAVEL ON AREA
ROADS.

THE SQUALLS LATER TONIGHT WILL BRING AN ADDITIONAL COATING TO 2
INCHES OF FLUFFY...WIND WHIPPED SNOW...THOUGH SOME LOCALIZED 3
INCH AMOUNTS AREN/T OUT OF THE QUESTION WHERE THE INITIAL NE/SW
BAND OR TWO OF SQUALLS IS FOLLOWED-UP BY MORE BOUNDARY LAYER WIND
PARALLEL...NARROW SQUALLS LATER TONIGHT/SAT MORNING.

WILL HIGHLIGHT/TRACK THE TIMING OF THIS SQUALL BAND VIA SPECIAL
WEATHER STATEMENTS AS NEEDED THIS EVENING AND OVERNIGHT.

WE PEPPERED THE FCST AREA WITH A HOST OF WARNINGS AND ADVISORIES
FOR SNOW/LES...WIND CHILLS...AND STRONG WIND GUSTS SATURDAY. THESE
FLAGS ARE STAGGERED IN TIME TONIGHT...RIGHT THROUGH SUNDAY
MORNING. SEE PHLWSWCTP AND PHLNPWCTP /OR OUR VARIOUS SOCIAL MEDIA
OUTLETS - FB AND TWITTER - FOR DETAILS.

LOW TEMPS AT DAYBREAK SAT WILL VARY FROM SLIGHTLY UNDER ZERO
F ACROSS THE NW MTNS...TO THE LOWER AND MID TEENS IN THE SUSQ
VALLEY.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
ARCTIC AIR MASS WILL POUR INTO THE REGION EARLY SATURDAY...ACCOMPANIED
BY GUSTY NW WINDS...WHICH WILL PRODUCE DANGEROUS WIND CHILLS
ACROSS AT LEAST THE NORTHERN AND WESTERN MTNS. ISSUED A WIND
ADVISORY OUTSIDE OF THE PREVIOUS WIND CHILL FLAGGED AREAS WHERE
CHILLS WON/T MEET CRITERIA...BUT WINDS WILL GUSTS AROUND 40KT AT
TIMES THROUGHOUT THE DAY.

WE`LL SEE THE COLDEST DAYTIME TEMPS SINCE LAST WINTER
TOMORROW. GEFS MEAN 8H TEMPS BTWN -22F AND -25F SHOULD SUPPORT
HIGH TEMPS SATURDAY ONLY AROUND ZERO ACROSS THE NW MTNS...TO THE
LOWER AND MID TEENS IN THE SE.

LK HURON CONNECTION SHOULD SHOULD FOCUS THE MOST PERSISTENT SNOW
SHOWERS ACROSS THE NW WARREN CO AND THE LAUREL HIGHLANDS...WHERE
AN ADDITIONAL INCH OR SO SEEMS LIKELY BASED ON NCAR MESOSCALE
ENSEMBLE.

AN ADDITIONAL FEW...TO SVRL INCHES OF LES AND UPSLOPE SNOW LIKELY
SAT ACROSS THE NW SNOWBELT AND LAURELS...AND ADVISORIES/WARNINGS
FOR SNOW/LES ARE IN EFFECT UNTIL 03Z SUNDAY.

ELSEWHERE...DRY ARCTIC AIR MASS SHOULD PRECLUDE SIG LAKE EFFECT
SNOW ACROSS CENTRAL PA SATURDAY.

&&

.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
*IMPACT WEATHER HIGHLIGHTS: FRIGID TEMPERATURES AND DANGEROUS WIND
 CHILLS FOR VALENTINES WEEKEND. POTENTIAL WINTER STORM EARLY NEXT
 WEEK.

POLAR VORTEX DIVING INTO NORTHERN NEW ENGLAND WILL DELIVER THE
COLDEST AIR OF THE SEASON WITH ARCTIC BLAST INTO CENTRAL PA
LATE SAT-SUN. THE GLOBAL MODELS AND ENSEMBLES KEEP A MEAN TROUGH
IN PLACE OVER THE EASTERN US INTO THE MIDDLE OF NEXT WEEK
WITH SEVERAL REINFORCING SHOTS OF COLD AIR MOVING THROUGH THE MEAN
TROF POSITION.

THE MOST NOTABLE FEATURE DURING THE PERIOD WILL BE A LOW PRESSURE
SYSTEM TRACKING UP THE EAST COAST ON TUESDAY. THE LATEST MODEL
GUIDANCE HAS TRENDED WEST WITH THE LOW TRACK...BUT THERE IS STILL
A DECENT SPREAD. AT THIS TIME PRECIPITATION WITH THIS SYSTEM
APPEARS LIKELY MON-TUE BUT THE TRACK WILL ULTIMATELY DETERMINE
PRECIPITATION TYPE. NEXT WEEK SHOULD END ON A MILDER NOTE.

THE COLDEST TEMPS/WCHILLS EXPECTED SAT NIGHT OVR THE AREA...AS
8H TEMP ANOMALIES OF NEAR 3SD BLW CLIMO GRAZE THE AREA. MINIMUM
TEMPERATURES SATURDAY NIGHT INTO EARLY SUNDAY MORNING EXPECTED TO
RANGE FROM ARND ZERO IN THE LOWER SUSQ VALLEY TO -10F IN THE
NORTHWEST MTNS. THE FRIGID TEMPERATURES COMBINED WITH DANGEROUS
WIND CHILLS /-10 TO -25 BELOW ZERO/ WILL RESULT IN AN INCREASED
RISK FOR FROSTBITE AND HYPOTHERMIA.

THE MODEL SPREAD HAS NARROWED A BIT CONCERNING A POTENTIAL WINTER
STORM SYSTEM IMPACTING THE MID ATLC/NORTHEAST NEXT MON-TUE. LATEST
GEFS AND ECENS INDICATING A SFC LOW TRACK ACROSS EASTERN PA IS
MOST LIKELY...WHICH WOULD FAVOR RAIN ACROSS ALL BUT PERHAPS THE W
MTNS. CONFIDENCE REMAINS LOW ON PTYPES ACROSS WESTERN PA...BUT NOW
DEFINITELY FAVORS RAIN ACROSS THE EAST. ALL THE MODELS ARE
SIGNALING A SIGNIFICANT QPF EVENT...AND THEREFORE HAVE INCREASED
POPS IN THE LKLY RANGE FOR MON NIGHT THROUGH TUESDAY.

A MODERATING TREND IS EXPECTED 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 /21Z FRIDAY THROUGH WEDNESDAY/...
MOST OF CENTRAL PA WILL CONTINUE TO BE VFR INTO THE MID
AFTERNOON. W/SW WINDS WILL BE 10 MPH OR LESS MUCH OF THE DAY.

UPPER TROUGH AND WEAK WARM ADVECTION LIGHT SNOW MOVES THROUGH THE
REGION LATE THIS AFTERNOON AND EVENING...ACCOMPANIED BY 1-3SM
VSBYS AND MVFR TO LOW END VFR CIGS SPREADING NE TO COVER THE SUSQ
VALLEY BY DARK.

THIS SYNOPTIC LIGHT SNOW WILL BE FOLLOWED BY A BLAST OF ARCTIC
AIR. AS ARCTIC AIR ARRIVES /REACHING NW MTNS BY 00Z/... MORE SIG
SNOW SHOWERS/SQUALLS WILL BRING PERIODS OF LIFR/VLIFR IN THIS
EVENING INTO SATURDAY MORNING - ESP OVER THE NW HALF OF CWA. THESE
WILL BE ACCOMPANIED BY GUSTY NORTHWESTERLY WINDS...AND THESE BRISK
WINDS WILL CONTINUE INTO SATURDAY.

DOWNSLOPE FLOW KICKS IN LATE TONIGHT...BRINGING IMPROVEMENT TO VFR
IN MOST PLACES THROUGHOUT THE CENTRAL RIDGE AND VALLEY REGION.
THE WESTERN HIGHER TERRAIN WILL CONTINUE TO SEE RESTRICTIONS IN
SNOW SHOWERS/BLOWING SNOW/UPSLOPE FLOW INTO THE WEEKEND.

OUTLOOK...

SAT...WINDY. SHSN/REDUCED VIS POSS W MTNS...MAINLY AM.

SUN...NO SIG WX EXPECTED.

MON...PM SNOW POSSIBLE.

MON NIGHT AND TUE...SNOW LIKELY NW HALF OF PENN...WITH RAIN OR
SNOW IN THE SE.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
WIND CHILL WARNING FROM 4 AM SATURDAY TO 11 AM EST SUNDAY FOR
PAZ004>006-037-041-042.
WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 10 PM EST
SATURDAY FOR PAZ010-017-024-033.
WIND CHILL ADVISORY FROM 4 AM SATURDAY TO 11 AM EST SUNDAY FOR
PAZ010>012-017-018-024-033.
WIND ADVISORY FROM 4 AM TO 5 PM EST SATURDAY FOR PAZ019-
025>028-034>036-045-046-049>053-056>059-063>066.
WIND CHILL ADVISORY FROM 5 PM SATURDAY TO 11 AM EST SUNDAY FOR
PAZ019-025>028-034>036-045-046-049>053-056>059-063>066.
LAKE EFFECT SNOW ADVISORY FROM 7 PM THIS EVENING TO 10 PM EST
SATURDAY FOR PAZ005.
LAKE EFFECT SNOW WARNING FROM 7 PM THIS EVENING TO 10 PM EST
SATURDAY FOR PAZ004.

&&

$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT
LONG TERM...FITZGERALD/GARTNER
AVIATION...LAMBERT


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