000
FXUS61 KCTP 201534
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1034 AM EST THU NOV 20 2008
.SYNOPSIS...
A DEEP UPPER LEVEL TROUGH WILL DOMINATE OUR WEATHER THROUGH
SATURDAY...KEEPING CENTRAL PENNSYLVANIA UNSEASONABLY COLD WITH
SEVERAL BOUTS OF LAKE EFFECT AND OROGRAPHICALLY ENHANCED SNOW
SHOWERS. HIGH PRESSURE WILL BUILD OVER THE REGION LATE SATURDAY
AND SUNDAY. A COLD FRONT WILL PASS THROUGH THE STATE EARLY NEXT
WEEK.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
THE WEAK CLIPPER IS GONE NOW AND THE LAKE EFFECT IS KICKING IN.
THROUGH THE DAYLIGHT HOURS...MOST OF THE REGION WILL SEE LITTLE
ACCUMULATIONS THANKS TO THE FLUFFINESS OF THE SNOW AND THE
SUNLIGHT BREAKING THROUGH THE CLOUDS. TEMPS WILL RISE INTO THE 40S
IN THE FAR SE...BUT HOLD IN THE 20S ACROSS THE NW. THE BANDS ARE
BREAKING UP INTO JUST FLURRIES AS THEY DESCEND SOUTH AND EAST FROM
THE ALLEGHENY PLATEAU. BUT A FEW OF THE BANDS COULD...OF
COURSE...LAY DOWN A QUICK HALF INCH TO AN INCH ACROSS THE NW.
LATEST MESO MDLS CONTINUE TO INDICATE SOME REALLY LONG FETCH BANDS
RUNNING THROUGH WRN PA AND INTO THE MTS ALL DAY AND INTO THE
NIGHT. VEERING FLOW SHOULD SHIFTS LAKE EFFECT FOCUS SOUTHWARD
THIS EVENING.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH 6 PM FRIDAY/...
HAVE LEANED TOWARD THE HIGHER SREF POPS...WHICH INDICATE CAT POPS
ACROSS THE LAUREL HIGHLANDS AND APPEAR MORE REALISTIC THAN MOS
NUMBERS BASED ON DEEP/MOIST FLOW ASCENDING THE ALLEGHENIES. MAX
OMEGA FALLS BLW DGZ...INDICATING SOME RIMING AND LESS THAN IDEAL
S:W RATIOS. HOWEVER...WINDS REMAIN WELL ALIGNED /WITH LK HURON
CONNECTION/ FOR THE LAURELS TO GET SIG SNOW TONIGHT AND
FRIDAY...THEN WE SHOULD SEE A GRADUAL SHIFT TO THE NORTH...AND
INTO THE NW LAKE EFFECT BELT BY LATE FRIDAY. MODEL QPF SUGGESTS A
GENERAL 4-8 INCH SNOWFALL OVR CAMBRIA/SOMERSET TONIGHT AND FRIDAY.
WILL COVER WITH A WINT STORM WARNING...GIVEN THIS IS THE FIRST SIG
SNOWFALL OF THE SEASON.
PASSAGE OF UPPER LVL SHORTWAVE LATE TONIGHT AND EARLY FRIDAY WILL
BRING THE POTENTIAL OF LIGHT ACCUMS WELL EAST OF THE MTNS. WILL
HAVE TO WATCH FOR POTENTIAL AFFECT ON THE MORNING COMMUTE ACROSS
THE SUSQ VALLEY...WHERE TEMPS ABV THE FREEZING MARK UPON ARRIVAL
OF SHSN COULD PRODUCE BLACK ICE CONDS FRIDAY AM.
BACKING FLOW EXPECTED LATE FRIDAY IN WAKE OF SHORTWAVE...SHIFTING
FOCUS OF LAKE EFFECT NORTHWRD INTO THE NW MTNS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
NAEFS SHOWING -15C 850 TEMPS CROSSING LK ERIE FRI NITE/EARLY
SAT...WHICH SHOULD PRODUCE SIG LAKE EFFECT SNOW OVR THE NW MTNS
FRI NITE INTO SATURDAY. CROSS HAIR OMEGA/DGZ SIGNATURE INDICATING
HIGH SNOW/WATER RATIOS...LIKELY RESULTING IN LOCALLY HVY ACCUMS.
LAKE EFFECT SHOULD FINALLY DIMINISH SAT NIGHT AS SFC HIGH BUILDS
INTO THE REGION. THE COMBINATION OF SNOW COVER...LIGHT WIND AND
CLEARING SKIES COULD RESULT IN THE COLDEST NIGHT SO FAR THIS
SEASON WITH SINGLE DIGIT LOWS POSS OVR THE ALLEGHENIES BASED ON
GEFS PLUMES.
NEXT SHORTWAVE WILL BRING ANOTHER FAIRLY SIGNIFICANT TROUGH FOR
EARLY NEXT WEEK. DETAILS REMAIN DIFFICULT TO NAIL DOWN AT THIS
TIME FRAME...BUT DETERIORATING WEATHER MON-WED WITH A PERIOD OF
LIGHT PRECIP /PROBABLY SHSN/. TEMPS REMAIN BLW NORMAL THRU AT
LEAST THE MIDDLE OF NEXT WEEK.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
RADAR RETURNS SHOWING PURE LAKE EFFECT REGIME WITH MULTIPLE BANDS
NOW COMING OFF OF LAKE HURON AND CROSSING LAKE ERIE...WITH
ADDITIONAL BANDS OFF LAKE ERIE ALONE. BFD/JST WILL CONTINUE TO BE
IMPACTED ALL DAY WITH IFR CONDS THRU THE MUCH OF THE DAY.
AOO/UNV/IPT WILL GENERALLY STAY MVFR WITH CIGS BUT VSBYS WILL BE
IN AND OUT OF VFR TO MVFR FOR ANOTHER FEW HRS...THEN IMPROVE TO
VFR THIS AFTN...BUT -SHSN WILL REMAIN IN THE VICINITY. SE WILL
STAY VFR FROM HERE OUT WITH JUST A FLURRY POSSIBLE. SFC WNDS WILL
BE OUT OF THE WNW AT 8-12KTS WITH HIGHER GUSTS.
LAKE EFFECT/CYCLONIC FLOW REGIME APPEARS TO REMAIN IN TACT THROUGH
FRIDAY/EARLY SAT WITH SOME IMPROVEMENT ANTICIPATED FOR THE LATER
IN THE WEEKEND. ATTM...THE PD FM LATE SAT INTO SUNDAY LOOKS LIKE
THE BEST CHC FOR WDSPRD VFR AS A HIGH PRESSURE SYS BRIEFLY VISITS
THE REGION. HOWEVER...THE MDLS SHOW ANOTHER SYS APPROACHING FOR
EARLY NEXT WEEK.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
LAKE EFFECT SNOW WARNING UNTIL 6 PM EST SATURDAY FOR PAZ004-
005.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM EST FRIDAY
FOR PAZ024-033.
WINTER WEATHER ADVISORY UNTIL 7 AM EST FRIDAY FOR PAZ010-011-
017.
&&
$$
SYNOPSIS...FITZGERALD
NEAR TERM...DANGELO/FITZGERALD
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD/RXR
AVIATION...DANGELO/STEINBUGL
