Area Forecast Discussion
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FXUS61 KPBZ 280000 AAB
AFDPBZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PITTSBURGH PA
700 PM EST SAT DEC 27 2014

.SYNOPSIS...
A COLD FRONT WILL BE ACCOMPANIED BY SHOWERS TONIGHT AND SUNDAY
MORNING. A RETURN TO NORMAL AND BELOW-NORMAL TEMPERATURES WILL
START TUESDAY.

&&

.NEAR TERM /THROUGH SUNDAY NIGHT/...
TRENDS AS XPCD IN PREV DISCUSSION CONT ON SCHEDULE. NO CHGS MADE
IN NEAR-TERM. PREV DISCUSSION FOLLOWS...

SHWRS ARE DVLPG IN SWRN OH ATTM AND WILL INCR IN CVRG EARLY THIS
EVE AHEAD OF SURGING CDFNT. THESE SHWRS WILL IMPACT ALL OF FCST
AREA OVNGT...SO POPS WERE INCRD TO MATCH CURRENT MOS NUMBERS AS
PCPN IS XPCD.

CDFNT XPCD TO CROSS FCST AREA LATE TNGT AND EARLY SUN MRNG...
WHICH WILL PROVIDE A RAPID END FROM N TO S AS DRY AIR INVADES.
FOCUS BY AFTN WILL BE FAR SERN ZONES...WHERE TERRAIN MAY SUSTAIN
SHWRS LATE IN THE DAY.

IT APPEARS THAT ONLY LMTD COLD AIR WILL ARRIVE WHILE PCPN IS
ONGOING...SO A BRIEF PD OF RAIN/SNOW WILL BE PSBL AT BACK END OF
PCPN AND IN THE RDGS SUN AFTN/EVE. VERY LMTD ACCUMS PSBL IN THE
RDGS...AS WARM GROUND ELSEWHERE WILL BE SLOW TO FEEL THE EFFECTS
OF COLD AIR ARRIVAL.

MAXIMA ON SUN LKLY WILL OCCUR EARLY IN THE DAY AS COLD AIR
ARRIVES AND CLDS/PCPN SUPPRESS INSOLATION MUCH OF THE DAY. MINIMA
TNGT WILL RMN ELEVATED FOR THE SAME REASON...BUT WILL DROP INTO
THE MID 20S-LWR 30S SUN NGT AMID COLD AIR ADVCTN.

&&

.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
SFC HIPRES IN THE NRN PLNS WILL RDG EWD INTO THE GRTLKS RGN MON-
MON NGT. LGT NWLY-NLY LOW-LVL WINDS WILL PERSIST BENEATH STOUT
MID-LVL FLOW. DRY AIR SHOULD PRECLUDE PCPN MOST ZONES THIS PD...
BUT A DVLPG COASTAL LOW MAY SPREAD LGT PCPN WWD INTO RDGS MON
AFTN-EVE.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
THE EXTENDED WILL LARGELY BE DRY WITH A DECREASING TREND IN
TEMPERATURES AS A BROAD TROUGH IN THE LONGWAVE PATTERN SLOWLY SAGS
SOUTH ACROSS THE EASTERN CONUS.

POTENT SHRTWV TROF XPCD TO IMPACT FCST AREA FRI NGT AND SAT. BOTH
GFS AND ECMWF SHOW TEMPORAL CONSISTENCY...ALTHOUGH THE EXACT
TRACK OF THE SYSTEM DIFFERS. REGARDLESS...THE SFC FEATURE PASSES
TO THE NW OF THE FCST AREA...LEADING TO STRONG WARM AIR ADVCTN
THAT SHOULD KEEP PCPN LIQUID. ONLY CAVEAT WILL BE SUB-FREEZING
TEMPS AT ONSET...WHICH COULD SPELL A FRZG RAIN SCENARIO FOR AREAS
THAT TYPICALLY RETAIN COLD AIR...SPCLY SHELTERED VLLYS IN RDG
CNTYS AND NRN ZONES. POPS WERE INCRD DAY 7 GIVEN XPCD MEASURABLE
PCPN...BUT UNCERTAINTY RMNS IN PCPN TYPE.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
RAPID DETERIOTATION TO MVFR SHOULD OCCUR THIS EVENING AS LOWERING
CIGS MOVE IN AHEAD OF AN INCOMING FRONT. SHIELD OF SHOWERS SHOULD
MOVE ACROSS THE ENTIRE AREA BY 06Z...WITH ALL AREAS FALLING DEEP
INTO MVFR OR NEAR IFR CONDITIONS. BEYOND 06Z...MOST AREAS WILL
LIKELY GO IFR WITH CIGS LIKELY TO REMAIN IFR THROUGH SUNDAY
MORNING BEFORE MVFR CONDITIONS RETURN BY AFTERNOON. FRIES


OUTLOOK.../SATURDAY NIGHT THROUGH WEDNESDAY/...
PERIODIC MVFR RESTRICTIONS CAN BE EXPECTED FOR THE FIRST HALF OF
THE WEEK

&&

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

&&

$$

UPDATE...KRAMAR




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