FXUS61 KCTP 281906
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
206 PM EST SAT NOV 28 2009
.SYNOPSIS...
HIGH PRESSURE BUILDS INTO THE CAROLINAS TONIGHT. CLOUDS WILL
INCREASE ON SUNDAY IN ADVANCE OF A COLD FRONT WHICH WILL MOVE
THROUGH MONDAY MORNING AND CREATESCATTERED SHOWERS. IT WILL THEN
TURN BLUSTERY AS LAKE EFFECT SNOW SHOWERS START UP BY LATE MONDAY
AND LAST INTO TUESDAY. HIGH PRESSURE WILL BUILD IN FOR A SHORT
TIME DURING MID-WEEK BEFORE A STORM SYSTEM IS EXPECTED TO AFFECT
THE REGION THURSDAY. COLDER AIR WILL SETTLE OVER THE STATE FOR THE
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
STRATUS HANGING TOUGH OVER THE USUAL SUSPECTS...BUT EVEN KJST IS
CLEARING OUT ATTM. THIS SHOULD BODE WELL FOR THE EVENING...AND
WILL MAKE ALMOST EVERYONE MOSTLY CLEAR BY LATE THIS EVENING. THE
MINS TONIGHT ARE A CHALLENGE WITH FLOW QUICKLY RETURNING TO THE
SOUTHEAST...BUT CLEAR/ING SKIES AND STRATIFICATION/DIMINISHING
WIND WILL WORK OPPOSE THIS. ADD TO THIS MIX THE HIGH RH/S AND
CLOUDS THAT THE GUIDANCE WANTS TO DEVELOP OVER THE ALLEGHENIES
LATER TONIGHT AND SUN MORNING. IT IS TOUGH TO SEE HOW WITH LITTLE
UPSTREAM MOISTURE IN THE OBS HOW THIS WILL HAPPEN. BUT...THE
UPSLOPE/LIFT COMBINED WITH THE INVERSION AND FURTHER WARMING ALOFT
COULD TRAP ENOUGH MOISTURE TO CREATE LOW STRATUS. MOS POINTS TO
EVEN IFR CONDITIONS EARLY IN THE MORNING FOR NW PA. WILL THEREFORE
TWEAK THE CLOUDS INTO THE 70-80PCT RANGE BY SUNRISE IN THE NW THIRD
OF THE CWA. THIS WOULD ALSO HELP TO KEEP TEMPS MILDER IN THAT
AREA. MINS WILL THEREFORE HOLD WITH CONTINUITY WHICH PUTS MINS
ONLY A FEW DEGS FROM CURRENTS IN THE NW. WITHOUT CLOUDS AND NIL
WIND WILL TAKE THE E/SE INTO THE L30S AS WELL. THIS MAKES FOR A
RATHER UNIFORM MIN T GRID MAP.
&&
.SHORT TERM /SUNDAY/...
SUNDAY HOLDS LOTS OF SUN FOR THE SE HALF...BUT THOSE IN THE NW MAY
START THE DAY MOSTLY CLOUDY...AGAIN. THIS TIME...THERE IS ONLY A
TINY LIGHT AT THE END OF THE TUNNEL FOR THEM. THIS IS BECAUSE WARM
ADVECTION KICKS IN BEFORE A SFC LOW WHICH WILL SHOULD TAKE A TRACK
THROUGH WRN NY STATE. THIS WILL CREATE MID/HIGH CLOUDS OVER THE NW
BY THE END OF THE DAY. THE REST OF THE STATE WILL BE SUNNY/MSUNNY.
THE 8H TEMPS APPCH +8C IN THE SRN TIER DURING THE AFTN. THIS WOULD
ORDINARILY MAKE ME THINK OF MAXES IN THE L60S...BUT THE LOW SUN
ANGLE AND LACK OF STRONG DOWNSLOPING FLOW WILL TEMPER MY FCST OF
MAXES IN THE S TO AROUND 60F. THESE ARE STILL 12F ABOVE SEASONAL
NORMS. WILL KEEP PRECIP OUT OF THE FCST FOR ALL DAY - BUT A
SPRINKLE IS POSSIBLE IN THE NW BY SUNSET.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
A RATHER CHANGEABLE WEEK IS IN STORE WITH TWO PERIODS OF DISTURBED
WEATHER EXPECTED TO AFFECT CENTRAL PA AND CORRESPONDING
TEMPERATURE FLUCTUATIONS.
SUNDAY STARTS TRANQUIL WITH WEAK SURFACE RIDGE GIVING WAY TO AN
INTENSIFYING COLD FRONT PUSHING EASTWARD FROM THE OHIO VALLEY.
THIS SHOULD SPREAD RAIN THEN SNOW SHOWERS ACROSS THE AREA LATE
SUNDAY FOLLOWED BY ANOTHER SHORT LIVED LAKE EFFECT SNOW SHOWER
REGIME MONDAY INTO TUESDAY.
UNCERTAINTY REGARDING THE STRENGTH AND TIMING OF POTENTIAL MID TO
LATE WEEK STORMINESS PERSISTS AS PER LATEST MEDIUM RANGE MODELS
AND ENSEMBLES. SOUTHWESTERN U.S. CUTOFF IS EXPECTED TO EJECT INTO
THE SOUTHERN PLAINS AND LOWER MISSISSIPPI RIVER VALLEY ON TUESDAY
WHILE A POLAR DISTURBANCE TRACKS THROUGH THE UPPER MIDWEST AND
INTO THE WESTERN GREAT LAKES. DETERMINISTIC SOLUTIONS DEVELOP A
RATHER FAST MOVING AND INTENSIFYING SFC LOW WITH CONSENSUS TRACK
FROM THE GULF COAST REGION NEWD THROUGH THE MID ATLANTIC REGION
WEDNESDAY REACHING NEWFOUNDLAND ON THURSDAY...WITH A FAIRLY
HOMOGENEOUS COLD AIR MASS COVERING THE EASTERN THIRD OF THE
COUNTRY IN ITS WAKE FOR FRIDAY INTO EARLY SATURDAY.
NOTED UNCERTAINTY IN TIMING OF PRECIPITATION ON WEDNESDAY AND
PTYPE WED NIGHT AND THURSDAY AND WILL CONTINUE TO BROADBRUSH
RAIN/SNOW CHANCES UNTIL CONFIDENCE IMPROVES OVER THE NEXT FEW
DAYS.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
GUSTY WINDS DIMINISHING ALREADY AND SUNSET STILL A FEW HRS AWAY.
ANY LINGERING MVFR CIGS IN KUNV/KBFD SHUD IMPROVE TO VFR THIS
EVENING AS AN AREA OF HIGH PRESSURE STEADILY BUILDS IN FROM THE
WEST AND COLD POOL ALOFT SLIDES E. LLVL MSTR THEN INCREASES FROM
THE W AS THE INVERSION HOLDS AND DEWPOINTS RISE. 925MB MSTR GOES
INTO THE 90+PCT RANGE FOR MOST OF NW PA BEFORE 09Z. WILL THEREFORE
DROP CIGS AT KBFD TONIGHT AND HINT AT THOS CONDITIONS AT KJST AND
KUNV. SOME BR ALSO PSBL IN THE CENT/ERN AIRFIEDS...ESP IN THE
VALLEYS. BUT WITH GUID VERY OPTIMISTIC WITH THE VISBYS...WILL JUST
MENTION TEMPOS FOR FOG ATTM. VFR SHOULD LAST THRU ALL OF SUN FOR
THE E...BUT LOWERING CIGS IN THE W WILL EVENTUALLY LEAD TO SCT
SHRA AS A FAST MOVING AND DRY FRONT PUSHES THRU MON AM.
OUTLOOK...
TUE...IFR/MVFR W IN POST FRONTAL SHSN. VFR E.
WED...VFR.
WED PM/THUR...MVFR DROPPING TO IFR IN SN NW/RA SE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...DEVOIR/MARTIN
AVIATION...DANGELO
