FXUS61 KCTP 291151
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
651 AM EST SUN NOV 29 2009
.SYNOPSIS...
HIGH PRESSURE WILL BEGIN TO WEAKEN AS A MILD AND DRY END TO THE
WEEKEND IS IN STORE. AN AREA OF LOW PRESSURE PASSES TO THE NORTH
MONDAY AS A COLD FRONT APPROACHES THE REGION OVERSPREADING
SCATTERED RAIN SHOWERS EARLY MONDAY. MUCH COOLER AIR ARRIVES
TUESDAY BEHIND FRONTAL PASSAGE WITH RAIN CHANGING TO SNOW
SHOWERS. HIGH PRESSURE BRIEFLY RETURNS FOR THE MIDDLE OF THE WEEK
AHEAD OF ANOTHER STORM SYSTEM LATE IN THE WEEK. COLDER AIR WILL
SETTLE OVER THE STATE FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CHALLENGES FOR TODAY RESIDE AROUND MAX TEMPS. SFC RIDGE RELAXES AS
FLOW TURNS SWSTRLY THIS AFTN AND ADVECTS A 925MB THERMAL RIDGE OF 6
TO 8 DEG C AIR INTO CENTRAL PA. A FEW ENSEMBLE MEMBERS PROG 10 DEG C
AIR PUSHING INTO SOUTHERN SUSQ-VALLEY. ATMOS OVER CENTRAL PA WILL
REMAIN PARCHED THRU MIDDAY...WITH MOISTURE POOLING INTO THE MID-LVLS
LATE THIS AFTN. MIXED LYR SHUD INCREASE TO 1500FT AGL...FILTERING TO
THE SFC A POCKET OF 25KT WINDS AND SHUD RESULT IN 15 TO 20MPH WINDS
THIS AFTN. HEAT CAPACITY WILL BE MINIMIZED TODAY AS A RESULT OF THE
AFOREMENTIONED ELEMENTS AND NEAR CLOUDLESS SKIES THRU
MIDDAY...HOWEVER DEW PTS WILL SLOWLY RISE INTO THE MID 30S BY 21Z AS
MOISTURE INCREASES. THUS EXPECT AFTN TEMPS TO WARM STEADILY INTO THE
50S...POSSIBLY 60 ALONG AND SOUTH OF THE TURNPIKE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/...
SEVERAL MESOSCALE SOLUTIONS PROG A WEAK VORT MAX LIFTING INTO
SOUTHERN ONTARIO EARLY THIS EVE LAYING A FRONTAL BNDRY SW THRU
CENTRAL OH. VORT MAX BRIEFLY AMPLIFIES AFT 00Z AHEAD OF 500MB
TROUGH AXIS. ENSEMBLES HAVE HIGH CONFIDENCE OF 30-40KT NOCTURNAL
LLVL JET DEVELOPING...ALONG WITH INCREASED LIFT AND MOISTURE
INTRUSION INTO THE BNDRY LYR. THUS HAVE INCREASED POPS TO
CATEGORICAL ACROSS THE NW MTNS BTWN 6-12Z. PRECIP TIMING/TOTALS
REMAINS A CHALLENGE FURTHER DOWNSTREAM ACROSS CENTRAL PORTIONS OF
MY CWFA AS BEST FORCING PASSES TO THE NORTH AND SOUTH. QPF TOTALS
FROM ENSEMBLES IS PROGGED ARND .05 TO .10 INCHES...SLIGHTLY
HIGHER ACROSS THE NW MTNS. OVERNIGHT TEMPS WILL REMAIN MILD ACROSS
CENTRAL/SOUTHERN PA ARND 40...AND MID-UPPER 30S ACROSS THE NW
CWFA.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
LEFT PACKAGE CLOSE TO WHAT WE HAD.
STILL LOOKING AT SOME SHOWERS SUNDAY NIGHT INTO MONDAY. EXPECT SOME
LAKE EFFECT SNOW SHOWERS MONDAY NIGHT INTO TUE...BUT BEST CHC WILL
BE AROUND SUNRISE TUESDAY...WHEN DIRECTIONAL SHEAR IS AT A MINIMUM.
BY TUE AFTERNOON...WINDS BACK TO THE SW...AND TEMPS START TO
WARM.
FOR THE MOST PART...WED STILL LOOKING DRY DURING THE DAY. MODELS
ONCE AGAIN A LITTLE FASTER WITH CLDS AND RAIN MOVING IN DURING THE
AFTERNOON ON WED...SO MADE MINOR ADJUSTMENTS TO THE ONSET OF THE
SHOWERS ACROSS THE SOUTH. REALLY JUST ADJUSTING IT BACK CLOSE TO
WHAT I HAD YESTERDAY.
THE NAM TODAY WANTS TO LIFT SYSTEM OUT OF THE SW ON WED...BUT
I STILL HAVE PROBLEMS WITH THE UPCOMING SYSTEM. PATTERN NOT REALLY
SET UP TO LOCK IN THE COLD AIR AND DRIVE A MAJOR COASTAL.
AT FIRST I TOOK OUT MENTION OF SNOW WED NIGHT ACROSS THE N AND W...
BASED ON SLIGHTLY WARMER TEMPS. HOWEVER...WITH TEMPS NEAR FREEZING
AND THE FURTHER EAST TRACK ON THE DGEX AND ECMWF...DECIDED TO LEAVE
IT IN.
THINK SYSTEM WILL BE WEAKER AND FASTER EAST THAN SOME MODELS HAVE
IT...LIKE THE GFS...BUT STILL MOST LIKELY AN INLAND TRACK. HPC AND
GFS TRACK IT TOWARD SYR. SPEED LOOKS FAIRLY GOOD. THUS COULD SEE
SOME HEAVY RAIN...AND EVEN SOME THUNDER ACROSS FAR EASTERN AREAS
ON THU...GIVEN LOW TRACK AND STRONG DYNAMICS...AS A STRONG WARM
FRONT SETS UP ACROSS THE FAR SE. SHOULD SYSTEM BE REAL STRONG...
THEN LEADING EDGE OF DRY AIR ALOFT ON THU COULD RESULT IN STRONG
WINDS AND A HEAVY RAIN THREAT. FOR NOW...DID UP QPF SOME AND ADD
THUNDER TO THE EAST ON THU.
LOOKS LIKE FLOW STAYS SW ALOFT ON THU NIGHT...THUS LAKE EFFECT
WILL BE MAINLY WEST OF THE MTS PRIOR TO LATER ON FRIDAY. WHILE
A DECENT SHOT OF COLD AIR WILL FOLLOW THE STORM...NOT SURE IF
IT WILL STAY AROUND VERY LONG. THINGS LOOKS LIKE THEY WOULD WARM
UP ON SUNDAY. WENT WITH AN INCREASE IN CLDS LATE SATURDAY.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
VFR CONDS WILL PERSIST THRU 18Z FOR MOST AIRFIELDS ACROSS CENTRAL
PA. WINDS WILL TURN SWSTRLY WITH OCCASIONAL GUSTS EXPECTED ARND 15
TO 20KTS AFT 18Z THRU 00Z. MOISTURE SLOWLY POOLS INTO NW MTNS
AIRFIELDS IN THE FORM OF CLOUDS...HOWEVER EXPECT VFR CONDS TO HOLD
UNTIL ARND 00-03Z. MVFR CIGS WILL EVENTUALLY OVERSPREAD THE
REGION...HOWEVER GUIDANCE APPEARS TO NOT FEATURE THIS UNTIL 04-08Z
FOR BFD/JST/AOO/UNV. FURTHER EAST CIGS SHUD HOLD UP ARND 10KFT
AGL. CONFIDENCE IS LOWERED WITH PRECIP TIMING...HAVE ADJUSTED IN
CURRENT TAF PKG. NOW IT APPEARS PRECIP WILL PUSH INTO CENTRAL PA
BTWN 06-12Z WITH MAINLY MVFR CONDS AND ISO IFR CIGS.
OUTLOOK...
MON...MVFR SCT IFR CIGS. SCT SHRA.
TUE...IFR/MVFR W IN POST FRONTAL SHSN. VFR E.
WED...VFR.
WED PM/THUR...MVFR TO IFR CIGS. LGT SHSN NW/SHRA SE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BEACHLER
NEAR TERM...BEACHLER
SHORT TERM...BEACHLER
LONG TERM...MARTIN
AVIATION...BEACHLER
