Area Forecast Discussion
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FXUS61 KPBZ 220509
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1209 AM EST MON DEC 22 2014

.SYNOPSIS...
MIDWESTERN LOW PRESSURE WILL BRING WARMER TEMPERATURES AND RAIN TO
THE REGION FOR THE FIRST HALF OF THE WEEK. SNOW SHOWER CHANCES WILL
COME WITH THE PASSAGE OF THAT SYSTEMS COLD FRONT ON CHRISTMAS.

&&

.NEAR TERM /THROUGH MONDAY/...
CLDS ARE EXPD TO GRDLY INCR LT TNGT INTO MON IN WRM ADVCTN. A WK
SFC LOW ADVNG UP THE E COAST COULD BRING SOME PCPN AS FAR W AS
GARRETT AND TUCKER COUNTIES THIS AFTN...THOUGH EVE UPR AIR CHARTS
AND MESO ANALYSIS INDICATE MUCH IF NOT ALL OF THIS PCPN SHOULD RMN
E OF OUR AREA. IF PCPN DOES RCH THESE LOCATIONS...A BRF PD OF
FRZG RAIN IS PSBL AS TEMPS THERE RMN BLO FRZG IN COLD AIR DAMMING.
OUTSIDE OF THE HIGHER TERRAIN...TEMPS SHOULD RCH JUST ABV SEASONAL
LVLS TDA.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
UPPER TROUGH WILL AMPLIFY AND SLOWLY PIVOT EASTWARD DURING THIS TIME
FRAME...BECOMING MORE NEGATIVELY TILTED WITH THE HELP OF A
STRENGTHENING UPPER LEVEL JET BY LATE WEDNESDAY. EARLY ON...THERE
STILL REMAINS SOME UNCERTAINTY IN REGARD TO THE AMOUNT OF PRECIP
THAT WE WILL SEE ON TUESDAY...AS WE WILL BE PARKED IN BETWEEN THE
BETTER MOISTURE FROM THE WEAK COASTAL SYSTEM...AND THE DEEPENING
MOISTURE ASSOCIATED WITH THE COLD FRONT TO OUR WEST. IN
ADDITION...S-SE WIND SHOULD HELP PROVIDE SOME DOWNSLOPING AND DRYING
JUST EAST OF THE RIDGES IN PA/WV. WITH THIS IN MIND...OPTED TO STAY
WITH THE CHANCE POPS FOR THE DAY TUESDAY. WILL INCREASE POPS
OVERNIGHT AS THE LOW LEVEL JET STRENGTHS AND HELPS TO PULL MOISTURE
FROM THE GULF NORTHWARD. WITH THE NEARLY NORTHWARD PROGRESSION OF
THE DEVELOPING SURFACE LOW...BOTH THE ECMWF AND GFS SUGGEST THE BULK
OF THE HEAVIEST RAIN WILL STAY JUST WEST OF THE FORECAST AREA...WITH
THE BEST CHANCE FOR MODERATE RAIN TO BE AS THE COLD FRONT CROSSES
WEDNESDAY NIGHT. THIS SHOULD LIMIT ANY FLOOD THREAT FOR THE PERIOD.

STRONG WARM ADVECTION WILL BE ONGOING THROUGH THE ENTIRE TIME
PERIOD. EVEN WITH CLOUD COVER...HIGH TEMPERATURES ON BOTH TUESDAY
AND WEDNESDAY SHOULD BE WELL ABOVE SEASONAL VALUES WITH HIGHS
LIKELY TO REACH THE MID 50`S.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
CDFNT PASSAGE WILL INITIATE SNOW SHOWER CHANCES ON CHRISTMAS...BUT
LACK OF DEPTH TO THE COLD LYR...DRY ADVCTN IN THE MID LVLS ON THE
SRN PERIMETER OF NWD DIGGING UPR LOW...AND RAPIDLY ENSUING WARM
ADVCTN WL ENSURE A LACK OF SNOW COVER FOR CHRISTMAS.

THE RMNDR OF THE LONG TERM PD IS PROGGED TO FEATURE SEASONAL TEMPS
WITH A LATE WEEK COOLING TREND AS MDLS PROG A REAMPLIFYING FLOW
PTN WITH ERN CONUS TROFFG.

&&

.AVIATION /05Z MONDAY THROUGH FRIDAY/...
GENL IMPROVEMENT TO VFR FOR ALL TAF SITES CAN BE EXPECTED FOR THE
TAF PD AS SLY FLOW ALOFT INTENSIFIES OVR LINGER SFC HIGH PRES.

OUTLOOK.../MONDAY NIGHT THROUGH FRIDAY/...
MIDWRN LOW PRES WL SPREAD RAIN AND RESTRICTIONS OVR AREA PORTS ON
TUESDAY AND WEDNESDAY. IMPROVEMENTS ARE EXPECTED TO BE INITIATED
LTR ON THURSDAY WITH DRY SHRTWV RIDGING.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.

&&

$$





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