FXUS61 KCTP 270552
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1252 AM EST FRI NOV 27 2009
.SYNOPSIS...
A STRONG COLD FRONT WILL CROSS THE REGION THIS EVENING...ACCOMPANIED
BY NUMEROUS RAIN SHOWERS. MUCH COLDER AIR WILL PUSH INTO THE
REGION LATER TONIGHT PROVIDING BLUSTERY AND UNSETTLED CONDITIONS
WHICH WILL LAST INTO SATURDAY. A RIDGE OF HIGH PRESSURE WILL BRING
FAIR BUT CHILLY WEATHER FOR MUCH OF SUNDAY BEFORE ANOTHER COLD
FRONT BRINGS A CHANCE FOR RAIN AND SNOW SHOWERS EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
REGIONAL RADAR LOOP SHOWING DEVELOPING BAND OF LGT TO MOD RAIN OVR
CENTRAL PA THIS EVENING IN VICINITY OF SLOW MOVING COLD FRONT.
ASCENDING BRANCH OF INDIRECT JET CIRC APPEARS TO BE COLLOCATED WITH
ASCENDING BRANCH OF FRONTAL CIRC PRODUCING THE DEEPER LIFT/INCREASE
IN PRECIP. 850-700MB FGEN FIELDS OF 18Z NAM...WHICH LINE UP WELL
WITH RAIN...SUGGEST PRECIP WILL TAPER OFF OVR THE CENTRAL MTNS AND
PUSH INTO EASTERN PA LATE TONIGHT.
CHALLENGE FOR THE OVERNIGHT FCST CENTERS ON POTENTIAL CHANGEOVER
TO SNOW ON BACK EDGE OF PRECIP SHIELD. ALREADY HAVE RPTS OF SLEET
MIXING WITH THE HEAVIER BURSTS OF RAIN IN STATE COLLEGE AND MODEL
SOUNDINGS SUGGEST A BRIEF CHANGE TO SNOW IS LIKELY LATER TONIGHT
OVR THE HIGH TERRAIN OF CENTRAL AND EASTERN PA. HOWEVER...SFC
TEMPS PROBABLY TOO WARM AND QPF TOO LIGHT FOR MORE THAN A COATING.
THE LAUREL HIGHLANDS APPEAR TO STAND THE BEST CHC OF A LIGHT SNOW
ACCUM OF AN INCH OR LESS LATE TONIGHT...AS LAKE EFFECT/OROGRAPHIC
SNOW COMMENCES. REGIONAL RADAR CURRENTLY SHOWS A BREAK IN THE
PRECIP OVR EASTERN OHIO/WESTERN PA ALONG WEAK SFC RIDGE.
HOWEVER...SECONDARY COLD FRONT OVR CENTRAL OHIO WILL PUSH INTO PA
TOWARDS DAWN...ACCOMPANIED BY A WIND SHIFT TO THE NW. MODELS
INDICATING A NEARLY SATURATED LYR FROM SFC-700MB ASCENDING THE
LAURELS BY 12Z...SUGGESTING SNOW SHWRS WILL BE UNDERWAY.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SATURDAY/...
THE FIRST SHOT OF TRUE (THOUGH QUITE ELEVATION DEPENDENT) LAKE
EFFECT/OROGRAPHIC SNOW ACROSS THE NORTHWEST MOUNTAINS AND LAUREL
HIGHLANDS WILL BE ONGOING FRIDAY AS A SHARP AND SLIGHTLY NEG TILT
UPPER TROUGH MOVES ACROSS PENN AND HELPS TO RAPIDLY INTENSIFY LOW
PRESSURE OFF THE MID ATLANTIC/SRN NEW ENGLAND COAST.
AS THE LOW DEEPENS RAPIDLY MOVING INTO THE GULF OF MAINE LATER
FRIDAY...WEST TO NORTHWEST WINDS WILL INCREASE TO 15 TO 20 MPH
WITH GUSTS OF 30 TO 35 MPH TWD EVENING.
QUESTION OF WHETHER OR NOT A MESOSCALE BAND OF DEFORMATION SNOW
CAN MANAGE TO FORM AND AFFECT NERN PA REMAINS. NEW GEM HUSTLES THE
BACKLASH PRECIP AWAY RAPIDLY INTO NEW ENGLAND LEAVING THE NAM AS
THE LONE WOLF WITH THE PRECIP THREAT. SO FOR NOW HAVE TO RIDE THE
CONSENSUS THAT INDICATES LITTLE MORE THAN NUISANCE AMOUNTS OVER MY
NERN ZONES.
AFTER MORE THAN 2 STRAIGHT WEEKS OF ABOVE NORMAL TEMPS...FRIDAY
WILL BE CHILLIER THAN NORMAL...THOUGH NOT TERRIBLY SO. THE CLOUDY
AND WINDY NW COUNTIES MAY BE IN THE 5-6 DEG BELOW NORMAL RANGE
WHILE THE REMAINDER OF THE REGION ENDS UP JUST SLIGHTLY BELOW
NORMAL.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
NOT A LOT OF CHANGE FROM YESTERDAY. COASTAL STORM LESS OF A THREAT
NOW...THEN WHEN I WORKED ON WED. ASIDE FROM SOME LINGERING LAKE
EFFECT FRIDAY NIGHT INTO EARLY SATURDAY...NOT A LOT GOING ON.
THE LAKE EFFECT WILL BE SOMEWHAT LIMITED AFTER 00Z SAT...AS
HEIGHTS RISE...AND THE AIRMASS IS NOT ALL THAT COLD ANYWAY.
SKIES SHOULD CLEAR NICELY LATER SATURDAY INTO THE FIRST PART OF
SUNDAY...AS WINDS SHIFT MORE THE THE WEST...AND VERY WARM AIR
MOVES TOWARD THE AREA FROM THE WEST. THIS WILL LIKELY BRING
SOME HIGH AND MID CLDS TO THE AREA LATER ON SUNDAY. PERHAPS A
SHOWER ACROSS WESTERN AREAS LATE.
TIMING OF NEXT FRONT NOT REAL CLEAR...BUT NOW APPEARS FASTER
THAN YESTERDAY...MOVING ACROSS MONDAY NIGHT INTO EARLY TUE...
PERHAPS A FEW SHOWERS.
HIGH PRESSURE BUILDS ACROSS THE NORTHERN STATES BY MIDWEEK.
IT MAY BE SOMEWHAT STORMY TO THE SOUTH...AND THIS SYSTEM MAY
BRUSH THE AREA LATE WED INTO THU. LIKE YESTERDAY...WENT WITH
A CHC OF RAIN SHOWERS AND SNOW SHOWERS...AS TEMPS WILL BE
BORDERLINE TO THE WEST AND NORTH. HARD TO SEE A LOT GOING
ON...DIFFICULT TO SEE WHY THE GFS DEVELOPS SUCH A STRONG
STORM LATE WED INTO THU.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
FRONTAL BNDRY CONTINUES TO PUSH EAST...HOWEVER SLOWING AS IT
SLIDES ACROSS THE SUSQ-VALLEY AIRFIELDS. POOR FLYING CONDS WILL
PERSIST THRU 10Z FOR IPT/MDT WITH BRIEF IMPROV CONDS. ACROSS THE
ALLEGHENIES FLOW HAS TURNED W/NWSTRLY AND WILL STEADILY INC.
JST/AOO/UNV WILL SEE BRIEFLY VFR CONDS...THEN TURN TO MVFR/IFR AS
PRECIP COVERAGE INCREASES. TEMPS HAVE COOLED BEHIND THE FRONT
ACROSS THE ALLEGHENIES AND LGT PRECIP HAS BECOME MIXED AT TIMES
WITH RASN AND PL. IN AND ANRD PRECIP VSBYS/CIGS WILL FLUCTUATE
BTWN MVFR/IFR CONDS TODAY.
OUTLOOK...
SAT...IFR/MVFR W/NW IN HIGH TERRAIN SHSN. VFR E OF THE
ALLEGHENIES IN SCT RASN.
SUN...VFR.
MON...IFR/MVFR SHRA.
TUE...IFR/MVFR W...MVFR/VFR E IN POST FRONTAL SHOWERS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...FITZGERALD
SHORT TERM...LA CORTE
LONG TERM...MARTIN
AVIATION...BEACHLER
