Area Forecast Discussion
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000
FXUS61 KPBZ 020042
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
742 PM EST SUN FEB 1 2015

.SYNOPSIS...
LOW PRESSURE WILL APPROACH AND CROSS THE REGION THROUGH MONDAY.
MUCH COLDER AIR IS EXPECTED EARLY IN THE WEEK.

&&

.NEAR TERM /THROUGH MONDAY/...
WITH 730PM UPDATE...HAVE ADDED FREEZING RAIN FOR THE NEXT COUPLE
OF HOURS AROUND THE PITTSBURGH METRO AREA. REPORTS OF FREEZING
RAIN HAVE COME IN FROM BEAVER AND BUTLER COUNTIES...AND FREEZING
RAIN IS ALSO BEING OBSERVED AT THE NWS OFFICE. ALTHOUGH AIR
TEMPERATURES ARE READING 32 TO 34 AROUND THESE LOCATIONS...THIS
APPEARS TO BE ANOTHER CASE WHERE AIR TEMPERATURES ARE WARMING UP
MORE QUICKLY THAN SURFACE TEMPERATURES. SO FAR ALL REPORTS HAVE
BEEN REPORTED INSIDE OF THE WINTER WEATHER ADVISORY AREA...SO NO
CHANGED TO HEADLINES ARE NEEDED AT THIS TIME. WILL CONTINUE TO
MONITOR EVOLUTION OF FREEZING RAIN.

WITH 6PM UPDATE...PRIMARY CHANGES WERE TO UPDATE HOURLY
TEMPERATURES AND SUBSEQUENT WEATHER TYPES ACROSS THE CENTRAL TIER
OF THE FORECAST AREA. NUDGED RAIN-SNOW LINE SLIGHTLY FARTHER NORTH
DURING THE EVENING HOURS...WHICH SHOULD ALLOW FOR MORE OF A MIX OF
RAIN AND SNOW ALONG THE PENNSYLVANIA TURNPIKE CORRIDOR. PARTIAL
THICKNESSES AND MODEL SOUNDINGS INDICATE THAT WHILE RAIN COULD
MAKE ITS WAY AS FAR NORTH AS INTERSTATE 80...STILL THINK LOCATIONS
NORTH OF THE INTERSTATE WILL REMAIN SNOW THE ENTIRE TIME. PREVIOUS
DISCUSSION FOLLOWS.

SFC LOW PRES WAS CENTERED OVER IL WL CONT TO ADVN ACRS THE RGN
TNGT TRACKING OVR WRN PA. THE 850 MB LOW IS PROGGED TO TRACK ACRS
NW PA AND LAKE ERIE...KEEPING THE HEAVIEST SNW AXIS ACRS NWRN PA.

ANOTHER AREA OF DEEP MSTR AND OMEGA IS EXPD TO MOVE ACRS THE AREA
AGAIN THIS EVE. CRITICAL THICKNESSES AND MDL SOUNDING PROFILES
SHOW WRM ADVCTN ACRS THE RGN THRU TNGT. THIS SHOULD ALLOW SNW TO
MIX WITH OR CHG TO RAIN WITH A PSBL BRIEF PD OF FRZG RAIN S OF I
80...REDUCING SNW TOTALS TNGT. FOR THIS REASON CHGD THE WINTER
STORM WRNG TO AN ADVY S OF I 80...BUT KEPT THE WRNG N AS PCPN
SHOULD STAY ALL SNW THERE. CANCELLED ADVYS IN OTHER AREAS WHERE
PCPN HAS TAPERED OFF AND WHERE NO SIGNIFICANT SNW/ICE ACCUMULATIONS
ARE EXPD. CONTD THE ADVY FOR ALLEGHENY COUNTY AND SURROUNDING
AREAS BUT THIS PORTION COULD BE CANCELLED ERLY IF TEMPS WRM
SUFFICIENTLY. GENLY FOLLOWED THE DETAILS OF THE NAM WHICH WAS
SLGTLY LESS AGGRESSIVE THAN THE GFS WITH WRM ADVCTN TNGT.

ADDNL SNW SHWRS ARE EXPD MON AS THE UPR TROF AXIS CROSSES AND
STRONG COLD ADVCTN SETS UP. UPSLOPE FLOW SHOULD SET UP AS
WELL...BUT MSTR THINS QUICKLY IN THE SNW GROWTH RGN WHICH SHOULD
HELP LIMIT ACCUMULATIONS TO ARND A COUPLE OF INCHES IN THE RIDGES.
USED A NAM/GFS BLEND FOR TEMPS.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
COLD HIGH PRESSURE WILL BRING AN END TO LINGERING SNOW SHOWERS
WITH CLOUDS BREAKING SOMEWHAT MONDAY NIGHT. LOWS WILL BE IN THE
SINGLE DIGITS WITH BELOW ZERO ACROSS THE NORTH. QUIET AND COLD
TUESDAY. NEXT COLD FRONT AND ASSOCIATED SHORTWAVE WILL APPROACH
LATER TUESDAY NIGHT AND WEDNESDAY WITH INCREASING CHANCES FOR SNOW
SHOWERS. TEMPERATURES AHEAD OF THE FRONT WEDNESDAY WILL MODERATE
TO NEAR THE SEASONAL AVERAGES.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
COLD AND DRY HIGH PRESSURE WILL DOMINATE INTO SATURDAY. LOW
PRESSURE WILL BRING THE CHANCE FOR SNOW SHOWERS LATER SATURDAY
NIGHT INTO SUNDAY.

&&

.AVIATION /01Z MONDAY THROUGH FRIDAY/...
CENTRAL AND SOUTHERN AIRPORTS HAVE IMPROVED TO MVFR. IFR TO LIFR
CIGS AND SNOW WILL REMAIN FOR KFKL AND KDUJ THROUGH THE
PERIOD...AND AS SURFACE LOW MOVES EAST ACROSS THE UPPER OHIO
VALLEY OVERNIGHT IFR CIGS AND VSBY IN RAIN WILL REDEVELOP. COLD
AIR WRAPS IN QUICKLY BEHIND SYSTEM MONDAY MORNING WITH A PERIOD OF
IFR SNOW SHOWERS AS WINDS SHIFT TO THE WEST AND NORTHWEST WITH
GUSTS TO 30 KTS.

OUTLOOK.../MONDAY NIGHT THROUGH FRIDAY/...
NEXT CHANCE FOR WIDESPREAD RESTRICTIONS WILL BE WITH A WEDNESDAY
COLD FRONT.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...WINTER WEATHER ADVISORY UNTIL NOON EST MONDAY FOR OHZ040-041.
PA...WINTER STORM WARNING UNTIL NOON EST MONDAY FOR PAZ007>009-015-
     016.
     WINTER WEATHER ADVISORY UNTIL NOON EST MONDAY FOR PAZ013-014-
     020>023-073-074.
WV...NONE.

&&

$$








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