FXUS61 KCTP 251741
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1241 PM EST FRI DEC 25 2009
.SYNOPSIS...
A COMPLEX LOW AND FRONTAL SYSTEM WILL BRING A WINTRY MIX OF
PRECIPITATION TODAY...CHANGING TO RAIN TONIGHT INTO SATURDAY.
COLDER AIR WILL RETURN SUNDAY...LASTING THROUGH AT LEAST THE
MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
RADAR SHOWS PRECIP SURGING NORTHEAST INTO THE AREA AT THIS
HOUR...WITH DISTINCT BANDS VISIBLE IN THE ORGANIZATION...EVIDENCE
OF GRAVITY WAVES PERHAPS. ENOUGH WARM AIR EXISTS ALOFT TO PRECLUDE
MUCH SNOW ACCORDING TO OBSERVATIONS...WITH SLEET AND FREEZING RAIN
BEING THE PREDOM TYPES AT THE ONSET.
WATER VAPOR IMAGERY SHOWING UPPER LOW LIFTING NORTH INTO THE
WESTERN LAKES...WITH DEEP...MOIST SOUTHERLY FLOW ORIGINATING OVR
GULF OF MEX AND EXTENDING NORTHWARD INTO THE NERN US.
BIG PROBLEM FOR THE REMAINDER OF THE DAY WILL BE SLOW PAINFUL
REBOUND IN TEMPS THAT WILL EVENTUALLY ALLEVIATE THE ICING
SITUATION. AS OF 11AM TEMPS RANGE FROM THE MID 20S OVER THE NY
BORDER COUNTIES TO AROUND FREEZING OVER THE MD BORDER COUNTIES.
RUC SHOWS 925 TEMPS REMAINING BELOW FREEZING THRU 18Z...WITH SLOW
RETREAT OF COLD AIR CONTINUING THRU 00Z. WHILE PRECIP AMOUNTS ARE
NOT EXPECTED TO BE HEAVY...TRAVEL PROBLEMS WILL CONTINUE ON
UNTREATED ROADS UNTIL THESE TEMPS REBOUND.
OF OTHER CONCERN IS POTENTIAL OF STRONG WIND GUSTS OVR THE
ALLEGHENY MTNS WITH PASSAGE OF LL JET. WIND GUSTS OVR 40KT
CURRENTLY NOTED OVR PARTS OF WEST VIRGINIA...AND SIMILAR GUST SEEM
POSSIBLE OVR THE LAUREL HIGHLANDS LATER TDY AS 60-70KT LL JET
SHIFTS NORTH. WILL HOLD OFF ON A WIND ADVISORY FOR NOW BASED ON
LATEST BUFKIT DATA. HOWEVER...ONE MAY BE NEEDED LATER TDY OVR
SOMERSET/CAMBRIA COUNTIES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
SECONDARY LOW DEVELOPMENT SOUTH OF PA...AND ASSOCIATED EASTERLY
LLJ...WILL KEEP THE RAIN GOING INTO SAT. HOWEVER...RAIN SHOULD
TAPER OFF LATE IN THE DAY ACROSS THE WEST...AS OCCLD FNTL BNDRY
PIVOTS NEWD. TEMPERATURES OVR SERN PENN MAY APPROACH 50F IN THE
WARM SECTOR SAT...BEFORE TEMPS DROP BEHIND THE OCCLD FNTL PASSAGE.
MANUAL 36HR GRIDDED QPF SHOWS MUCH OF THE AREA PICKING UP
1.00-1.50 INCH RNFL AMNTS THRU 00Z SUNDAY. THIS...ALONG WITH SNOW
MELT WILL CAUSE MINOR TO MODERATE RISES IN THE WEST BRANCH AND
LOWER SUSQ BASINS...AND MAY PUSH SOME SMALLER TRIBS TO CAUTIONS
STAGE. HYDRO FCSTS FROM THE MARFC DO NOT INDICATE ANY FLOODING
ATTM AND GIVEN THAT ANY PROBLEMS WOULD LKLY NOT OCCUR FOR ANOTHER
36HRS...DECIDED AGAINST A FLOOD WATCH...BUT WL MENTION SOME
SPECIFICS IN HWO AND HYDRO SECTION BELOW.
COLDER AIR WILL BEGIN TO MIX WITH/CHANGE ANY LINGERING RAIN
SHOWERS TO SNOW SHOWERS LATE SAT AND SAT NGT WITH LITTLE OR NO
ACCUMS XPCD.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
COLD MID LVL VORT WILL WOBBLE E ACROSS THE OH VLY AND INTO THE
MID ATLC REGION SUN/MON. BRISK/WINDY CONDS AND LES SHWRS WILL
ACCOMPANY A REINFORCING SURGE OF COLDER AIR MON NGT/TUE. HIGH PRES
SHOULD BRING SOME IMPROVEMENT BY THE MIDDLE OF NEXT WEEK.
STRONG NEG AO/NAO...+ PNA AND A SRN STREAM EL NINO CONNECTION
WL CONT TO OFFER A SET UP FAVORABLE FOR EAST COAST WINTER STORMS.
GFS/ECMWF MEAN SHOW A STORM SYSTEM ORGANIZED ALONG THE ECOAST
AROUND THE NEW YEAR...STAY TUNED.
&&
.AVIATION /17Z FRIDAY THROUGH TUESDAY/...
COMPLEX FRONT IS SPREADING A MAINLY LIGHT WINTRY MIX INTO CENTRAL
PA TERMINALS AT MID DAY. TEMPS SHUD REBOUND IN ALL AREAS BY
NIGHTFALL ALLEVIATING THE ICING THREAT...BUT LOW CEILINGS AND VIZ
WILL REMAIN A PROBLEM RIGHT INTO SATURDAY. IN ADDITION WINDS ARE
VERY STRONG JUST OFF THE SURFACE CREATING THE POTENTIAL FOR LOW
LEVEL WIND SHEAR.
MOST VALLEY LOCATIONS REMAIN COOL AIR DAMMED SO SFC WINDS ARE MAINLY
LIGHT AND OUT OF THE EAST OR SE. EXCEPTIONS ARE OVER HIGHER
WESTERN TERRAIN FROM JST-BFD WHERE GUSTS 20-30KT WILL REMAIN
COMMON.
OUTLOOK...
SAT...IFR CONDITIONS IMPROVING TO MVFR CENTRAL/EAST BY AFTERNOON.
SUN-TUE...MVFR/IFR WEST WITH FREQ LAKE EFFECTING AND OROGRAPHIC
SNOW SHOWERS IN THE WEST. CNTRL/EAST VFR/MVFR WITH SCATTERED SNOW
SHOWERS.
&&
.HYDROLOGY...
GENERALLY MINOR CHANGES IN RIVER LEVELS ARE EXPECTED OVER THE
NEXT 24 HOURS...WITH A RISE OF UP TO SEVERAL FEET EXPECTED LATER
IN THE PERIOD.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ037-
041-042.
WINTER WEATHER ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR
PAZ004>006-010>012-017>019-024>028-033>036-045-046-049>053-
056>059-063>066.
&&
$$
SYNOPSIS...LA CORTE/FITZGERALD
NEAR TERM...LA CORTE/FITZGERALD
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD/STEINBUGL
AVIATION...LA CORTE
HYDROLOGY...LA CORTE
