FXUS61 KCTP 110053
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
753 PM EST THU DEC 10 2009
.SYNOPSIS...
STRONG NORTHWEST FLOW AROUND A DEPARTING SOUTHEAST CANADIAN STORM
WILL RELAX BY SATURDAY AS HIGH PRESSURE BUILDS OVER THE MID
ATLANTIC STATES. A WARM FRONT WILL PUSH THROUGH THE AREA
SUNDAY BRINGING SOME LIGHT MIXED PRECIPITATION TO THE AREA...
FOLLOWED BY A COLD FRONT AROUND TUESDAY OF NEXT WEEK.
&&
.NEAR TERM /THROUGH FRIDAY/...
MAIN LAKE ERIE SNOW BAND PROPOGATED SLOWLY NORTHWARD AND SLIGHTLY
WESTWARD THIS MORNING...AND HAS MAINTAINED THIS ALIGNMENT THROUGH
THE EARLY TO MID AFTERNOON HOURS...RUNNING ALONG AND NEARLY
PARALLEL TO THE LAKE ERIE SHORELINE WELL NORTH OF WARREN COUNTY.
4KM SPC WRF AND NAM12 SOLUTIONS CAPTURED THIS WELL...AND DO NOT
BRING AN APPRECIABLE SOUTHWARD DRIFT UNTIL LATE TONIGHT AND FRIDAY
MORNING. SO WHILE THE TRADITIONAL LAKE EFFECT SNOW AREA OF WARREN
AND MCKEAN COUNTIES WILL SEE SOME ACCUMULATIONS ON THE SOUTHERN
PERIPHERY OF THIS BAND...DO NOT ANTICIPATE ADVISORY CRITERIA TO BE
REACHED IN THE NEXT 12 TO 24 HOURS AT THIS TIME.
ELSEWHERE...SYNOPTIC LIFT PROVIDED BY ELONGATED UPPER TROF
APPROACHING FROM THE OHIO VALLEY IS KEEPING SCATTERED FLURRIES
GOING ACROSS MUCH OF WESTERN AND CENTRAL PA...WITH LITTLE IF ANY
ACCUMULATION IS EXPECTED FROM THESE.
HEADING OVERNIGHT...THE MAIN QUESTION WAS HOW LOW WIND CHILLS
WOULD DROP GIVEN FALLING TEMPS AND SUSTAINED WINDS OF 15 TO 25
MPH. WITH OUR LOCAL CRITERIA OF -15F WIND CHILLS NEEDED FOR
ADVISORY ISSUANCES...IT APPEARS WE'LL REMAIN JUST ABOVE CRITERIA
WITH MINIMUM WIND CHILLS BOTTOMING OUT AROUND -10F ACROSS THE
NORTHWEST MOUNTAINS OVERNIGHT AND FRIDAY MORNING.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH 6 PM FRIDAY/...
THE BRISK WEST TO SOUTHWEST LOW LEVEL FLOW WILL KEEP FOCUS OF
MOST INTENSE LAKE EFFECT SNOW NORTH OF THE BORDER FRIDAY...WHERE
THE MOST INTENSE SINGLE LES BAND SHOULD BE AFFECTING WESTERN NY
STATE. WILL NEED TO CONTINUE TO MONITOR ITS EVOLUTION OVERNIGHT
INTO FRIDAY FOR POTENTIAL ADVISORY ISSUANCES OVER WARREN AND
MCKEAN COUNTIES SHOULD IT SNEAK FURTHER SOUTH.
FRIDAY STILL EXPECTED TO BE THE COLDEST DAY YET THIS SEASON...AS
GEFS SHOWING CORE OF COLD PASSING OVR PA WITH -2SD T0 -3SD ENS
MEAN 850 TEMPS OF ARND -18C. EVEN MIXING TO 850MB ONLY RESULTS IN
HIGH TEMPS FROM THE UTEENS NW MTNS...TO NR 30F LOWER SUSQ VALLEY.
A CONTINUED GUSTY WEST WIND WILL MAKE IT FEEL EVEN COLDER...WITH
AFTN WIND CHILLS HOLDING IN THE SINGLE DIGITS AND TEENS. BUFKIT
SOUNDINGS INDICATE FREQUENT GUSTS BTWN 30-35MPH ARE LIKELY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
LAKE EFFECT BAND WILL WEAKEN FRIDAY NIGHT...FINALLY. HIGH
CONFIDENCE THE FIRST HALF OF THE WEEKEND SHOULD REMAIN QUIET WITH
A BUILDING SFC RIDGE PROVIDING ANTI- CYCLONIC FLOW FROM THE TENN
VALLEY NORTH INTO CENTRAL PA THRU SAT. W/NW FLOW WILL
PERSIST...COUPLED WITH A MODERATING THERMAL TROUGH TO -10 DEG C AT
850MB AND EXPECT FLURRIES/LGT SN ACROSS NW MTNS AND WEAK UPSLOPE
CONDS FOR PORTIONS OF THE LAURELS.
TEMPS BEGIN TO MODERATE SAT. ATTM THE FOCUS IS ON DEVELOPMENT OF A
COASTAL LOW BEING ADVERTISED BY SEVERAL GUIDANCE MEMBERS FOR SUN
NGT/MON. SFC RIDGE SHUD PUSH EAST OFF THE COAST AND STEADILY SLIDE
OUT TO SEA...ALLOWING SFC LOW TO FOLLOW IN IT/S WAKE. THE WILDCARD
IS THAT IF THE SFC RIDGE STRENGTHENS...THE SFC LOW MAY TRACK FURTHER
NW ACROSS THE LOWER SUSQ-VALLEY LATE SUN/EARLY MON. IT DOES APPEAR
CONFIDENCE IS HIGH THAT ELEVATED MOISTURE POOLS NORTH ALONG ARRIVAL
OF BNDRY SUN SO HAVE MAINTAINED INCREASING CLOUD COVER. OVERALL THE
EVENT WILL BE LIMITED ON MOISTURE. 0 DEG 850MB ISOTHERM SHUD LIFT
NORTH SUN NGT...WHICH WOULD SUPPORT ONSET OF MOISTURE BEING A BRIEF
PERIOD OF SN/FZRA THEN ALL RA. ACROSS NW MTNS COLD AIR MAY
PERSIST...WITH LGT SN.
CONFIDENCE IS WAINING A BIT IN REGARDS TO MID-WEEK SHORTWAVE
INTENSITY ACROSS THE PLAINS. SEVERAL MODELS STILL HINT AT A CHC FOR
PRECIP ARRIVING TUE/WED AHEAD OF A MID-LVL TROUGH AXIS...AS
COOLER/DRIER AIR RETURNS FOR THE END OF THE WEEK. ATTM FEEL MOISTURE
FROM MID-WEEK SYSTEM WILL BE FOCUSED FURTHER SOUTH ACROSS THE
GULF/SOUTHERN ATLANTIC STATES.
&&
.AVIATION /01Z FRIDAY THROUGH TUESDAY/...
PERSISTENT CYC OVER-LAKE BLYR FLOW WILL KEEP MVFR/IFR RESTRICTIONS
AT BFD/JST THRU MOST OF THE OVERNIGHT AND FRIDAY. MVFR CIGS AND
BRIEF SNOW SHOWERS WILL BE COMMON OVER THE CENTRAL MOUNTAINS.
VFR CONDITIONS WILL PREVAIL AT MDT.
PRES GRAD BTWN DEPARTING LOW AND SFC HIGH BUILDING EWD FM THE LWR
MS VLY WILL RESULT IN GUSTY WLY SFC WNDS 25-35KTS INTO FRIDAY. WINDS
WILL RELAX BY SATURDAY AS HIGH BUILDS OVER MID ATLANTIC REGION.
WARM AIR WILL TRY TO RETURN ON SUNDAY BRINGING SOME MIXED
PRECIPITATION TO THE REGION...FOLLOWED BY A FEW DRY DAYS AHEAD OF
A COLD FRONT LATER TUESDAY...FOLLOWED BY QUITE COLD CONDITIONS FOR
THE MIDDLE AND END OF NEXT WEEK.
OUTLOOK...
SAT...BCMG VFR.
SUN/MON...MVFR TO IFR IN LIGHT MIXED PRECIPITATION.
TUE...VFR TO MVFR WITH SHSN/RASN ARRIVING AHEAD OF ARCTIC FRONT.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DEVOIR
NEAR TERM...DEVOIR
SHORT TERM...DEVOIR
LONG TERM...FITZGERALD/BEACHLER
AVIATION...DEVOIR/MARTIN/STEINBUGL
