Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 222049
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
349 PM EST MON DEC 22 2014

.SYNOPSIS...
A WEAK LOW PRESSURE SYSTEM WILL BRING LIGHT RAIN AND FREEZING RAIN
TO CENTRAL AND EASTERN PA TONIGHT AS IT LIFTS UP THE MID ATLANTIC
COAST. AN INTENSIFYING STORM SYSTEM WILL TRACK WEST OF PENNSYLVANIA
WEDNESDAY NIGHT...PUSHING A COLD FRONT THROUGH THE STATE. ANOTHER
LESS POTENT COLD FRONT IS LIKELY TO IMPACT THE REGION BY NEXT
WEEKEND.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
MOISTURE SLOWLY INCREASING ACROSS THE LAUREL HIGHLANDS...CENTRAL
MOUNTAINS AND LOWER SUSQ AT MID AFTERNOON. PRECIP HAS BROKEN OUT
OVER THE SOUTH CENTRAL MOUNTAINS WHERE SFC TEMPS ARE HOVERING
AROUND 32F AND SFC TD IS IN THE MID 20S. FZRA ADVISORY IN PLACE
THROUGH 05Z TONIGHT FOR LIGHT AMOUNTS OF ICE. LOWER SUSQ SHOULD
REMAIN ALL RAIN...BUT WESTERN PORTIONS OF YORK COUNTY IN THE
HIGHER TERRAIN IS ALSO EXPECTED TO SEE SOME ICE.

HI RES MODELS INDICATE A PROLONGED PERIOD OF FREEZING AND EVEN
SOME FROZEN (IP) HYDROMETEORS AS THE LIGHT SHIELD OF PRECIP LIFTS
NORTHWARD TONIGHT. BLEND OF TRENDS AND HI RES MODELS KEEP AREAS OF
FZDZ AND LCL SLEET OVER THE WESTERN...CENTRAL AND EVENTUALLY INTO
THE NORTH CENTRAL MOUNTAINS LATE TONIGHT. ADVISORIES MAY BE NEEDED
FOR THOSE NORTHERN AREAS LATER ON...BUT PRECIP MAY REMAIN FROZEN
(SLEET/SNOW MIXTURE THERE) SO HELD OFF FOR NOW.

EXPECT THE SOUTHERN TIER TO WARM SUFFICIENTLY TO CHANGE TO RAIN BY
OR AFTER 05Z. IT WILL TAKE MUCH LONGER FROM THE WEST CENTRAL
MOUNTAINS NORTHWARD. MINS WILL RANGE FROM THE UPPER 20S NORTH TO
THE LOWER 30S SOUTH.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
LOOKING AT MAINLY A CLOUDY DAY ON TUE...WITH SOME PATCHY
LIGHT RAIN. TEMPERATURES WILL BE ABOVE NORMAL...BUT MAINLY
IN THE 40S...AS THE MAIN LOW IS TOO FAR WEST FOR CENTRAL
PA TO BE IN MUCH OF A SOUTHERLY GRADIENT.

BETTER CHANCE OF RAIN LATER TUESDAY NIGHT INTO WED...AS
COLD FRONT MOVES TO THE EAST.

TEMPERATURES WILL CLIMB INTO THE 50S ON WED...AS STRONGER
SOUTHERLY WINDS DEVELOP.

WENT WITH A CHANCE OF THUNDER WED EVENING...GIVEN DEWPOINTS
IN THE UPPER 40S TO LOWER 50S. ALSO FAIRLY STRONG DYNAMICS
AND WIND FIELDS. LIMITING FACTOR FOR SEVERE STORMS WILL BE
TIME OF DAY AND THERMAL RIDGE WELL TO THE EAST OF THE FRONT.

WIND GUST COULD BE IN THE ADVISORY RANGE LATE.

DID NOT BUY INTO THE NAM SOLUTION AT THIS POINT.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
CLOUDS SHOULD BREAK BEHIND THE COLD FRONT ON THU. A FEW SNOW
AND RAIN SHOWERS WILL BE POSSIBLE WITH THE UPPER LEVEL TROUGH.
MUCH OF THE DAY WILL BE DRY. NOT REAL COLD BEHIND THE FRONT.

SW FLOW ON FRIDAY WILL BRING IN MILD AIR.

A FEW MORE SHOWERS LATE FRIDAY INTO SUNDAY...AS THE NEXT COLD
FRONT MOVES ACROSS THE AREA. SHOWERS WILL BE MAINLY IN THE
FORM OF SNOW SHOWERS.

WENT WITH MAINLY DRY CONDITIONS FOR MONDAY. NOT REAL COLD FOR
LATE DEC. THERE COULD BE SOME SNOW SHOWERS LATE MONDAY
NIGHT...BUT WENT WITH A DRY FCST FOR NOW.

WITH SPLIT FLOW...THERE COULD BE SOME CHANCE FOR A SOUTHERN
WAVE TO BRING SOME RAIN OR SNOW SHOWERS TO THE AREA ANYTIME
FROM SUNDAY INTO MID WEEK...BUT AT THIS TIME...LOOKS LIKE
ANYTHING WOULD BE FAST MOVING...AND MAINLY TO THE SOUTH.

&&

.AVIATION /21Z MONDAY THROUGH SATURDAY/...
COMBINATION OF RETREATING HIGH PRES OVR THE CANADIAN MARITIMES AND
WEAK LOW LIFTING UP THE MID ATLANTIC COAST IS SPREADING AN
INCREASINGLY MOIST SERLY FLOW INTO CENTRAL PA THIS AFTERNOON.
LOWER CIGS PUSHING NORTHWARD IN RESPONSE TO DEEPENING LLVL
MOISTURE AND ONSHORE FLOW. THE INCREASING MOISTURE...COMBINED WITH
LG SCALE FORCING AHEAD OF SHORTWAVE LIFTING OUT THE SE
STATES...WILL SPREAD LIGHT RAIN AND FREEZING RAIN ACROSS ALL OF
CENTRAL AND SOUTHERN PA THIS AFTERNOON AND EVENING...WITH IP AND
ZR POSSIBLE ACROSS THE NORTH LATER TONIGHT.

MAIN CONCERN REMAINS POTENTIAL FOR LIGHT ICING...GIVEN COLD AIR
DAMMING SIGNATURE AND IMPLIED LOW-LEVEL AGEOSTROPHIC NORTHERLY
FLOW HOLDING LOW-LEVEL COLD AIR IN. OPER MDL SOUNDINGS AND ENS
PTYPES SUGGEST THE BEST CHC OF LATE -FZRA IS FROM THE LAUREL
HIGHLANDS AND HIGHER TERRAIN OF THE SC MTNS NORTHWARD THROUGH THE
WEST CENTRAL MOUNTAINS EARLY THIS EVENING...SPREADING NORTH LATE
TONIGHT. SOUTHERN AREAS WILL WARM ABOVE FREEZING AFT 05Z CHANGING
PRECIP TO RAIN...BUT AREAS NORTH OF A KJST TO KAOO TO KSEG LINE
WILL LIKELY KEEP PATCHY FZRA OVERNIGHT ALONG WITH IFR CIGS AND
VSBYS.

OUTLOOK...

TUE...LOW CIGS WITH DRIZZLE/LIGHT RAIN LIKELY. BECOMING BREEZY
MAINLY ACROSS HIGHER TERRAIN. LLWS POSS N/W.

WED...PERIODS OF RAIN ALONG WITH WIDESPREAD REDUCTIONS. BREEZY.
LLWS LIKELY.

THU...WINDY AND COLDER WITH SCT MVFR CIGS AND -SHSN. LLWS.

FRI...FAIR AND MOSTLY VFR.

SAT...FAIR AND MOSTLY VFR.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
FREEZING RAIN ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR
PAZ024>028-033>036-056-063-064.
FREEZING RAIN ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ065.

&&

$$
SYNOPSIS...DEVOIR
NEAR TERM...DEVOIR
SHORT TERM...MARTIN
LONG TERM...MARTIN
AVIATION...DEVOIR



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