FXUS61 KCTP 100017
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
717 PM EST WED DEC 9 2009
.SYNOPSIS...
A SHARP COLD FRONT WILL CROSS THE STATE TONIGHT...BRINGING GUSTY
WEST WINDS AND MUCH COLDER AIR BY THURSDAY MORNING. AN UNSETTLED
PATTERN WILL PERSIST OVER THE REGION INTO EARLY NEXT WEEK...
WITH STORM SYSTEMS BRINGING A CHANCE OF MIXED PRECIPITATION ON
SUNDAY...AND AGAIN ON TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
VIGOROUS SHORTWAVE AND ASSOCIATED SHARP COLD FRONT PUSHING THRU THE
AREA LATE THIS AFTERNOON AND EVENING. INSTABILITY WEST OF THE
ALLEGHENIES IN PARTIAL TO FULL SUNSHINE EARLIER THIS AFTERNOON
HELPED TO SPROUT SOME LOW TOPPED CONVECTION WHICH TAPPED SOME
HIGHER MOMENTUM 850 MB WINDS...CAUSING WIND DAMAGE AND SOME 1 INCH
HAIL REPORTS OVER VENANGO AND WARREN COUNTIES. AREAS EAST OF THE
ALLEGHENIES HAVE BEEN COLD AIR DAMMED...AND THESE STORMS ARE
WEAKENING BUT COULD STILL SURVIVE INTO THE CENTRAL MOUNTAINS TO
PRODUCE SOME STRONG WIND GUSTS THIS EVENING.
WIND ADVISORY HEADLINES BEING CARRIED FOR ALL AREAS...WITH CENTRAL
MTNS BEGINNING AT 20Z AND THE EAST AT 22Z...THROUGH 11Z THU.
BUFKIT PROFILES SHOW THE INCREASINGLY DEEP MIXED LAYER TAPPING
50-60 KT WINDS FROM JUST A FEW THOUSAND FEET ABOVE THE SURFACE.
LAKE EFFECT TRAJECTORIES NOT LIKELY TO BRING BANDING FAR ENOUGH
SOUTH AND EAST TO IMPACT WARREN AND MCKEAN COUNTIES...BUT A SLIGHT
SHIFT WOULD BRING SOME ACCUMULATING BANDS INTO THOSE AREAS LATE
TONIGHT AND THURSDAY ESPECIALLY.
WINDS WILL BE THE MAIN STORY OVERNIGHT AND THURSDAY AS 850 MB 50KT
WINDS WILL PARTIALLY MIX TO THE SURFACE EVEN BEHIND THE CONVECTION
PRODUCING LOCAL GUSTS ABOVE 40 MPH OVERNIGHT INTO THU MORNING.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
SFC HIGH PRESSURE BUILDING SOUTH OF PA INTO THE MID ATLANTIC
REGION WILL KEEP A STRONG WESTERLY BOUNDARY LAYER FLOW OVER THE
AREA. THE COLDEST AIR MASS OF THE SEASON THUS FAR WILL COMBINE
WITH THESE WINDS TO PRODUCT SINGLE DIGIT AND TEEN WIND CHILLS
THURSDAY MORNING THROUGHOUT THE REGION.
BLYR FLOW FROM THE WSW SHOULD KEEP FOCUS OF LAKE EFFECT SNOW
NORTH OF THE BORDER...WHERE AN INTENSE SINGLE LES BAND SHOULD
AFFECT WESTERN NY STATE. FURTHER SOUTH...OROGRAPHIC EFFECTS WILL
PRODUCE A CHC OF -SHSN ACROSS THE ALLEGHENIES OF PA WITH LIGHT
ACCUMS OF LESS THAN AN INCH MOST LIKELY.
MAINLY DRY/COLD PATTERN SHOULD HOLD THROUGH THURS...AS LAKE EFFECT
REMAINS FOCUSED NORTH OF BORDER. ENS MEAN 850 TEMPS ARND -14C
SUGGEST HIGHS FROM THE 20S MTNS...TO L30S SUSQ VALLEY. A GUSTY
WEST WIND WILL CONTINUE TO MAKE IT FEEL EVEN COLDER WITH WIND
CHILLS IN THE TEENS/20S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
W/NW FLOW REGIME WILL PERSIST THRU FIRST HALF OF WEEKEND AS MID-LVL
TROUGH BEGINS TO RELAX. THUR NGT TEMPS COULD FALL INTO THE SINGLE
DIGITS/MID TEENS...HOWEVER IT HINGES ON CLOUD COVER. POTENT 850MB
THERMAL TROUGH DIGS ACROSS PA THUR NGT WITH -18 TO -20 DEG C
AIR...WHICH IS ARND 2 TO 3 STD DEV BLO NRM. EXPECT DOWNSLOPING TO
PROVIDE THIN CLOUD SHIELD FOR PORTIONS OF THE SUSQ-VALLEY AND
PROVIDE AFTN TEMPS FRI PSBLY IN THE L20S/M20S NW MTNS...U20S/L30S.
SHORTWAVE SLIDES NE FROM GULF OF MEXICO STATES AND COULD POTENTIALLY
BRING SOME LIGHT SNOW TO SOUTHERN PA SUN/MON. ALTHOUGH LATEST
NAEFS/OPER EC SUGGEST THIS IS AN INCREASINGLY UNLIKELY EVENT.
SHORTWAVE APPROACHING FROM THE N PLAINS WILL BRING NEXT CHC OF
WIDESPREAD PRECIP ARND TUESDAY OF NEXT WEEK. CURRENT GEFS/OPER EC
TRACK SFC LOW WEST OF PA...INDICATING A BRIEF WARM UP...FOLLOWED
BY SHRASN WITH FROPA.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
MOST AREAS WILL BE VFR OVERNIGHT AND THU. MVFR AND EVEN IFR
AT TIMES AT BFD AND JST.
THE MAIN THING WILL BE GUSTY WINDS INTO THU.
THINGS SLOWLY IMPROVE ON FRIDAY...AS HEIGHTS COME UP AND
LAKE EFFECT SNOW SHOWERS BECOME LESS OF A PROBLEM...AND THE
WINDS SLOWLY DIE DOWN.
MORE STORMY WEATHER WILL BE POSSIBLE ON SUNDAY...BUT THAT
IS A WAYS OUT.
OUTLOOK...
FRI/FRI NIGHT...MVFR (AND LOCALIZED IFR) WEST WITH SCATTERED SNOW
SHOWERS IN MTNS OF NORTHERN AND WESTERN PA. VFR MOST OF CENTRAL
AND EAST. STILL WINDY.
SAT/SUN...MVFR TO IFR WITH MIXED PRECIPITATION POSSIBLE.
MON...MVFR TO VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 6 AM EST THURSDAY FOR PAZ004>006-010>012-
017>019-024>028-033>037-041-042-045-046-049>053-056>059-
063>066.
&&
$$
SYNOPSIS...FITZGERALD
NEAR TERM...DEVOIR
SHORT TERM...DEVOIR
LONG TERM...FITZGERALD/BEACHLER
AVIATION...DEVOIR/GARTNER/MARTIN
