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Area Forecast Discussion
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000
FXUS61 KCTP 251310
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
810 AM EST SUN JAN 25 2015

.SYNOPSIS...
AN ALBERTA CLIPPER WILL TRACK JUST SOUTH OF PENNSYLVANIA TONIGHT
AND EARLY MONDAY...THEN REDEVELOP AND EXPLOSIVELY INTENSIFY OFF
THE MID ATLANTIC COAST MONDAY NIGHT AND TUESDAY. HIGH PRESSURE
WILL BUILD OVER THE REGION MID WEEK...FOLLOWED BY ANOTHER CLIPPER
LATE THURSDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
COLD FRONT WORKING ITS WAY SOUTH ACROSS THE NORTHWEST AND NORTH
CENTRAL MOUNTAINS. REGIONAL RADAR MOSAIC DETECTING A BAND OF
-SHSN/FLURRIES. MUCH DRIER AIR WORKING IN BEHIND THIS BOUNDARY
WILL SHUT OFF THE SNOW SHOWERS ACROSS THE NW MTNS LATER THIS
MORNING AND COULD EVEN BRING SOME PARTIAL CLEARING TO THE N TIER
COUNTIES TODAY. FURTHER SOUTH...DEEPENING LYR OF MOISTURE
ASCENDING THE LAURELS COULD PRODUCE SOME LIGHT OROGRAPHIC SNOW
ACROSS THE LAUREL HIGHLANDS THRU EARLY AFTN. HOWEVER...FOCUS
REMAINS ON THE APPROACHING POTENT CLIPPER DIVING INTO THE
OHIO...WHICH PROMISES TO SPREAD A STEADIER...MORE SIGNIFICANT SNOW
INTO SOUTHWEST PA TOWARD EVENING.

OVERCAST SKIES...COMBINED WITH LOW LVL CAA...SHOULD BALANCE THE
DIURNAL TREND AND RESULT IN NEARLY STEADY TEMPS TODAY WITH HIGHS
FROM THE M20S ACROSS THE N MTNS...TO THE U30S ACROSS THE LOWER
SUSQ VALLEY.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
BLEND OF MDL QPF SUPPORTS SEVERAL INCHES OF ACCUM...MEETING
ADVISORY CRITERIA...ACROSS MUCH OF SOUTH CENTRAL PA TONIGHT AND
MONDAY. SNOW/WATER RATIOS BTWN 12/1 AND 15/1 USED BASED ON WPC
GUIDANCE AND MDL CROSS SECTIONS OF OMEGA AND TEMP...WHICH SHOW
GREATEST UPWARD MOTION OCCURRING ARND -12C...BUT WARMER TEMPS IN
THE LOWER CLOUDS...IMPLYING RIMING AND A SLIGHTLY DIMINISHED
SLR. 

WEAKENING SFC LOW OVR THE CENTRAL APPALACHIANS EXPECTED
MONDAY...WITH SECONDARY COASTAL DEVELOPMENT TAKING SHAPE E OF THE
DELMARVA. ALTHOUGH LG SCALE FORCING MAY NOT BE VERY IMPRESSIVE IN
BTWN SYSTEMS ACROSS CENTRAL PA...EASTERLY WIND ANOMALIES BTWN LOW
TO THE SOUTH AND HIGH PRES OVR S QUEBEC WILL TRANSPORT ABUNDANT MOISTURE
INTO CENTRAL PA...LIKELY SUPPORTING OCNL LIGHT SNOW THRU THE DAY.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
MAIN FOCUS IN THE EXTENDED FCST WILL BE EVOLUTION OF RAPIDLY
DEVELOPING COASTAL LOW EAST OF PA MON NITE AND TUESDAY. MDL DATA
SHOWING A FAIRLY TIGHT RANGE OF SOLUTIONS...NEARLY ALL OF WHICH
PLACE OUR EXTREME EASTERN COUNTIES FROM LANCASTER NORTH THRU
SCHUYLKILL CO ON THE WESTERN PERIPHERY OF THE SIGNIFICANT DEFORMATION
BAND SNOW. MDL 7H FGEN FIELDS SEEM TO IMPLY THE HEAVY SNOW WILL
REMAIN JUST EAST OF THE CWA. HOWEVER...GIVEN COMPLEXITY OF
CRITERIA DIFFERENCES ACROSS OUR BORDERS...AND 40% CONFIDENCE OF AN
ADDITIONAL 6 INCHES OR MORE OVER LEBANON/LANCASTER/E YORK COUNTIES
WITH THE SECONDARY LOW...OPTED TO ISSUE WINTER STORM WATCH FOR
THESE THREE COUNTIES FOR MONDAY AFTERNOON THROUGH TUESDAY MORNING.

THE MORE LKLY SCENARIO ATTM APPEARS TO BE ONCL LIGHT SNOW
CONTINUING ACROSS THE REST OF CENTRAL PA MONDAY NIGHT AND TUESDAY
ASSOC WITH NEXT SHORTWAVE DIVING INTO DEEPENING UPPER TROF AXIS
OVR PA. TIGHT PRES GRADIENT WEST OF COASTAL LOW SHOULD RESULT IN A
BLUSTERY DAY TUESDAY...BLOWING/DRIFTING SNOW A POSSIBILITY. BUFKIT
SOUNDINGS INDICATE GUSTS TO ARND 30KTS LIKELY.

FAIR AND CHILLY WED EXPECTED WED...AS HIGH PRES BUILDS OVR THE
AREA. MED RANGE GUIDANCE STILL INDICATES NEXT CHANCE OF SNOW
THURS/THU NIGHT WITH NEXT IN SERIES OF CLIPPERS. ECENS SHOWS A
DEEPENING UPPER LVL TROF OVR THE EASTERN CONUS BY NEXT
WEEKEND...OFFERING NO RESPITE FROM THE COLD WX.

&&

.AVIATION /13Z SUNDAY THROUGH THURSDAY/...
DECK OF LOWER STRATUS /ASSOCIATED WITH NOW EXITING SHORTWAVE TROF
AND COLD FRONT SAGGING SOUTHWARD ACROSS THE STATE/ PERSISTING
ACROSS MUCH OF THE REGION...BRINGING GENERALLY MVFR CONDITIONS TO
WESTERN AND CENTRAL TERMINALS...EXCEPT KJST WHERE LIFR PERSISTING
WITH SNOW /POSS STILL MIXING WITH LIGHT FREEZING DRIZZLE THROUGH
14Z/. DOWNSLOPING SHOULD BE ENOUGH TO KEEP EASTERN AIRFIELDS IN
VFR CONDITIONS. WINDS HAVE KICKED UP IN THE WEST AND CENTRAL MTNS
AS FLOW INCREASES...WITH SURFACE SPEEDS OF 10-15 MPH WITH GUSTS TO
25 MPH...BUT THESE WILL DIMINISH THROUGH THE LATE MORNING.

SOME IMPROVEMENT LIKELY STARTING MID/LATE MORNING FOR SEVERAL
HOURS...WITH CIGS RISING TO VFR IN THE NORTH. BUT RESTRICTIONS
WILL PERSIST AT KJST-KAOO THROUGH THE DAY.

AN ALBERTA CLIPPER WILL TRACK JUST SOUTH OF PENNSYLVANIA TONIGHT
INTO MONDAY...BRINGING ANOTHER ROUND OF SNOW WITH IFR CONDITIONS
TO THE REGION. THIS WILL IMPACT TERMINALS AFTER 00Z MONDAY...BUT
SOME AFFECTS POSSIBLE KJST AND KAOO BEFORE THIS TIME. EXPECT A
PROLONGED PERIOD OF RESTRICTIONS INTO MON NIGHT.

OUTLOOK...

SUN NIGHT...SNOW RAPIDLY OVERSPREADING FROM SW TO NE...BRINGING
IFR CONDITIONS TO THE ENTIRE REGION OVERNIGHT. 

MON...WIDESPREAD IFR/MVFR IN SNOW...GRADUAL IMPROVEMENT
OVERNIGHT. 

TUE...AREAS MVFR IN SHSN WEST...AND ANY LINGERING SNOW IN THE
EAST. 

WED...NO SIG WEATHER EXPECTED. 

THU...VFR TO START...WITH LATE DAY RESTRICTIONS SPREADING IN FROM
THE WEST.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 7 PM EST 
MONDAY FOR PAZ017>019-024>028-033>036-050-056-057-063-064.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 1 PM EST 
MONDAY FOR PAZ059-065-066.
WINTER STORM WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY 
MORNING FOR PAZ059-065-066.

&&

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



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