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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KCTP 241716
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1216 PM EST SAT JAN 24 2015

.SYNOPSIS...
LOW PRESSURE NEAR THE DELMARVA PENINSULA THIS MORNING WILL TRACK
QUICKLY NORTHEAST TODAY. AN ALBERTA CLIPPER WILL TRACK JUST SOUTH
OF PENNSYLVANIA SUNDAY NIGHT WITH ANOTHER WEAKER CLIPPER TAKING
THE SAME PATH MONDAY NIGHT AND EARLY TUESDAY. HIGH PRESSURE WILL
BUILD OVER THE REGION MID WEEK...FOLLOWED BY ANOTHER CLIPPER LATE
THURSDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
WEAK DEFORMATION PRECIPITATION HAS LARGELY FIZZLED...ALLOWING
EARLY CANCELLATION OF HEADLINES. 850 MB LOW CURRENTLY MOVING
OFFSHORE...AND COLDER AIR IS FILLING IN BEHIND OVER THE LOWER
SUSQ...WHERE TEMPS BRIEFLY ROSE THROUGH THE MIDDLE 30S. TEMPS ARE
STEADY OR FALLING FROM THERE NORTHWESTWARD NOW. FARTHER WEST...
A FAST MOVING AND WEAK CLIPPER TYPE SHORTWAVE WILL BE DIVING INTO
THE REGION FROM THE GRT LKS TOWARD EVENING...LIKELY SPREADING
-SHSN ACROSS THE ALLEGHENY PLATEAU TOWARDS DUSK.

THE AIR MASS BEHIND TONIGHT/S LOW IS NOT PARTICULARLY COLD AND
ENS MEAN 925 TEMPS SUPPORT HIGHS TODAY IN THE M/U30S OVR MUCH OF
THE AREA...WHICH SHOULD RESULT IN MUCH IMPROVED ROAD CONDS BY AFTN.
ACROSS THE ALLEGHENY PLATEAU...UPSLOPING FLOW AND RESIDUAL LOW LVL
MOISTURE WILL LIKELY RESULT IN PERSISTENT STRATOCU ALL DAY...HOLDING
TEMPS JUST BLW FREEZING.
-- End Changed Discussion --

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
PASSAGE OF SHORTWAVE THIS EVENING SHOULD PRODUCE -SHSN ACROSS THE
ALLEGHENY PLATEAU WITH A SMALL ACCUM OF AN INCH OR LESS. LATE
TONIGHT...SHORTWAVE PASSES EAST OF THE STATE...CAUSING -SHSN TO
TAPER OFF OVR THE NW MTNS. HOWEVER...RESIDUAL UPSLOPE FLOW INTO
THE LAURELS WILL KEEP THE -SHSN GOING DOWN THERE. A DOWNSLOPING
WEST WIND SHOULD RESULT IN NOTHING MORE THAN FLURRIES EAST OF THE
MTNS TONIGHT. WIDESPREAD STRATOCU SHOULD HOLD READINGS UP TONIGHT
WITH LOWS IN THE 20S.

SOME LIGHT OROGRAPHIC SNOW MAY BE ONGOING SUNDAY MORNING ACROSS
THE LAUREL HIGHLANDS. HOWEVER...MAIN FOCUS WILL BE ON POTENT
ALBERTA CLIPPER DIVING INTO THE OHIO VALLEY. BLEND OF MED RANGE
GUIDANCE SUPPORTS A GOOD CHANCE OF SNOW OVERSPREADING AT LEAST THE
SOUTHWEST QUARTER OF THE STATE BY EVENING. A BIT OF SUN APPEARS
POSSIBLE ACROSS NE PA ON SUNDAY. OTHERWISE...PLENTY OF MID LVL
CLOUDINESS INDICATED BY MDLS IN ADVANCE OF CLIPPER. CONSALL MAX
TEMPS RANGE FROM THE L20S NW MTNS...TO THE U30S S OF HARRISBURG.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
MDL SPREAD DECREASING/CONFIDENCE INCREASING WITH RESPECT TO
TIMING/TRACK OF CLIPPER SUNDAY NIGHT. HAVE THEREFORE RAMPED UP THE
CHANCE OF SNOW ACROSS THE ENTIRE REGION...WITH CATEGORICAL POPS
ACROSS THE LAURELS/SC MTNS. PLENTY OF COLD AIR AVAILABLE AND
EXPECT NO PRECIP TYPE ISSUES WITH THIS EVENT. ADDITIONAL SHORTWAVE
AND ASSOC WEAKER CLIPPER IS PROGGED TO TAKE A SIMILAR PATH SOUTH
OF PA MON NIGHT/EARLY TUESDAY...LIKELY CAUSING OCNL LIGHT SNOW TO
LINGER INTO TUESDAY. BLEND OF ENSEMBLE AND OPER MDL QPF IS
POINTING TOWARD AN ADVISORY TYPE SNOWFALL ATTM ACROSS THE
LAUREL/SC MTNS SUN NITE/MON AM...WITH LIGHTER ADDITIONAL ACCUMS
LIKELY FROM SECOND CLIPPER MON NITE/TUE AM.

COLDEST AIR OF THE WEEK DIVES IN BEHIND THE DEPARTING SYSTEM ON
TUESDAY WITH STATEWIDE HIGHS A FEW DEGREES EITHER SIDE OF 20F.
AS SFC HIGH BUILDS OVR THE AREA TUE NIGHT...CLEARING SKIES...A
CALM WIND AND FRESH SNOW COVER COULD RESULT IN AN IDEAL
RADIATIONAL COOLING SCENARIO WITH SUB-ZERO LOWS POSSIBLE IN MANY
LOCATIONS.

MODERATING CHILL IS IN STORE FOR THE MID TO LATE WEEK...AS
RIDGING AT THE SURFACE AND ALOFT MOVES IN AHEAD OF NEXT IN SERIES
OF ALBERTA CLIPPERS. DECENT AGREEMENT AMONG MED RANGE GUIDANCE
WITH TIMING OF THIS NEXT CLIPPER...SO HAVE INCREASED CHC OF LGT SNOW
LATE THU/THU NIGHT.

LONGER RANGE OUTLOOK FEATURES NO RESPITE FROM THE COLD WX...WITH
ECENS INDICATING A DEEPENING TROUGH OVR THE EASTERN CONUS.

&&

.AVIATION /17Z SATURDAY THROUGH WEDNESDAY/...
LOW PRESSURE NEAR THE DELMARVA PENINSULA THIS MORNING WILL TRACK
QUICKLY NORTHEAST TODAY. AN ALBERTA CLIPPER WILL TRACK JUST SOUTH
OF PENNSYLVANIA SUNDAY NIGHT WITH ANOTHER WEAKER CLIPPER TAKING
THE SAME PATH MONDAY NIGHT AND EARLY TUESDAY.

LIGHT SNOW IS ENDING FROM WEST TO EAST MID TO LATE MORNING ACROSS
CENTRAL PA. IMPROVEMENTS TO CIGS WILL BEGIN LATE THIS MORNING AND
EARLY AFTERNOON FOR THE CENTRAL AND EASTERN SECTIONS AS CIGS RISE
TO MVFR AND EVENTUALLY TO VFR. IN THE WESTERN HIGHER
TERRAIN...IMPROVEMENT WILL NOT BE QUITE AS ROBUST WITH CIGS LIKELY
ONLY LIFTING TO MVFR AND MAYBE A SHORT PERIOD OF VFR. WINDS WILL
SHIFT TO THE WEST AND PICK UP A BIT LATE IN THE DAY AS LOW LEVEL
FLOW INCREASES...PUSHING WINDS TO AROUND 10-15 MPH IN THE WEST.

STRONGER LOW LEVEL WESTERLY FLOW WILL KEEP WINDS UP AROUND 10-15
MPH IN THE WESTERN HIGHER TERRAIN TONIGHT...WITH 850MB WINDS
INCREASING TO 35-45 KTS OVER THE SW HALF OF CWA...SO ADDED MENTION
OF LLWS THERE. THIS IS ASSOCIATED WITH A WEAK SHORTWAVE THAT WILL
ALSO SPAWN LIGHT SNOW SHOWERS WITH VSBY REDUCTIONS TONIGHT IN SAME
AREA. COULD BE AN OCCASIONAL ENCROACHMENT INTO THE CENTRAL MTNS OF
MVFR CIGS...WHILE SOUTHEAST REMAINS VFR.

A PROLONGED PERIOD OF RESTRICTIONS LIKELY SUNDAY NIGHT INTO MON
NIGHT AS ANOTHER CLIPPER LOW MOVES THROUGH.

OUTLOOK...

SUN...VFR INTO THE AFTERNOON...THEN SNOW DEVELOPING ACROSS THE
WEST IN THE AFTERNOON OR EVENING...AND OVERSPREADING ALL OF
CENTRAL PENN AND THE SUSQ VALLEY AT NIGHT.

MON...AM SNOW WITH WIDESPREAD MVFR TO IFR LIKELY.

TUE-WED...NO SIG WEATHER EXPECTED.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
NONE.
-- End Changed Discussion --

&&

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