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County Warning Area [CWA]: PBZ
Regional NWS Weather Office: Pittsburgh, PA

000
FXUS61 KPBZ 312339
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
639 PM EST SAT JAN 31 2015

.SYNOPSIS...
LOW PRESSURE WILL BRING WINTRY WEATHER SUNDAY INTO MONDAY.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
UPDT TO SKY COVER BASED ON SATELLITE AND NR TERM MDL DATA. WITH
CLRG ERLY LOWERED TEMPS TO THE COLDER GFS NMBRS. PREVIOUS...HIGH
PRES WL CONT TO BRING DRY WEA INTO THE EVE. A DIGGING UPR TROF AND
DVLPG SFC LOW PRES WL BEGIN TO SPREAD SNW INTO THE RGN LT TNGT.
MORE ON THIS IN THE SHORT TERM SECTION. ACCUMULATIONS BY MRNG
SHOULD BE GENLY LESS THAN AN INCH AS THE PCPN WL JUST BE STARTING.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY/...
THAT DIGGING UPR TROF AND SFC LOW WL CONT TO ADVN OUT OF THE
MIDWEST THRU OUR RGN SUNDAY MONDAY. MDLS HAVE SHIFTED THE TRACK OF
THE SFC AND CLOSED 850 MB LOWS FURTHER N...SHIFTING THE FOCUS FOR
HEAVIER SNW N OF PIT. A LLVL JET IS PROGGED TO DVLP ALG WITH DEEP
MSTR AND INCRG OMEGA WITH WRM ADVCTN LTR SUN INTO SUN NGT...WHEN
THE HEAVIEST PCPN IS EXPD. ALONG WITH THAT WRM ADVCTN...A
CHANGEOVER TO MAINLY RAIN IS EXPD S OF I 70...WITH A MIX OF
SNW...SLEET AND FRZG RAIN N TO ARND PIT. A BRF CHANGEOVER TO ALL
RAIN IS PSBL AS WELL. N OF I 80 SHOULD STAY COLD ENOUGH FOR ALL
SNW. GFS WAS FARTHEST N WITH THE SFC AND 850 MB LOWS...AND SEEMED
TOO AGGRESSIVE WITH THE WRM ADVCTN. OPTED FOR THE COLDER NAM/ECMWF
SOLNS WHICH ALLOWS FOR A LTL MORE GRADUAL OF A FCST SHIFT. RELIED
ON CRITICAL THICKNESSES AND MDL SOUNDING PROFILES FOR PCPN TYPE
FCST.

ISSUED A WINTER STORM WARNING FOR AREAS N OF PIT WHERE 5 TO 10
INCHES OF SNW ARE EXPD. FM NR PIT AND S TO I 70 ISSUED WINTER WEA
ADVYS FOR 2-5 INCHES OF SNW AND A POTENTIAL FOR A WINTRY MIX.
WATCHES ARE NO LONGER IN EFFECT AS AREAS S OF THE PA BORDER...EVEN
IN THE RIDGES...SHOULD CHG OVER TO MAINLY RAIN. FRZG PCPN IS PSBL
ESP IN GARRETT COUNTY BUT HELD OFF ON ANY ADDNL HEADLINES ATTM.

WRAP ARND SNW BEHIND THE EXITING LOW IS EXPD MON BUT ONLY ARND AN
INCH OR TWO OF ADDNL SNW IS EXPD.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
ONLY CHANGE TO EXTENDED WAS TO SPEED UP FRONTAL PASSAGE WEDNESDAY
AND BUMP UP POPS. NO OTHER CHANGES AS MUCH COLDER AIR POURS IN
BEHIND THE FRONT AS A STOUT HIGH PRESSURE CENTERS OVERHEAD.
TEMPERATURES EXPECTED TO BE WELL BELOW AVERAGE FROM MID-WEEK THROUGH
THE END OF THE PERIOD.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
VFR CONDITIONS WILL PREVAIL THROUGH MOST OF THE NIGHT AS THE NEXT
SYSTEM START TO INCREASE HIGH CLOUDS ACROSS THE AREA. SNOW WILL
ADVANCE FROM SW TO NE ACROSS ALL SITES DURING THE OVERNIGHT AND
PREDAWN HOURS. CONDITIONS WILL LIKELY RAPIDLY DETERIORATE TO IFR
AT MOST SITES. THE TRACK OF THE SYSTEM IS CONTINUE TO MOVE
FARTHER NORTHWEST ON THE LATEST FORECAST GUIDANCE SUCH THAT THE
MID-LEVEL DRY SLOT IS LIKELY TO GO OVER ALMOST ALL SITES BY
SATURDAY AFTERNOON OR EVENING. THIS SHOULD ALLOW FOR WARMER
SURFACE AIR ALONG WITH DRIER AIR ALOFT TO MAKE SNOW TAPER TO LIGHT
RAIN OR DRIZZLE. DEEPER MOSITURE WILL RETURN SUNDAY
NIGHT...BRINGING RAIN SHWOERS THEN SNOW SHOWERS BACK INTO THE
FORECAST ON MONDAY. FRIES

.OUTLOOK.../SUNDAY NIGHT THROUGH THURSDAY/...
WIDESPREAD RESTRICTIONS CAN BE EXPECTED INTO MONDAY AS A LOW
PRESSURE SYSTEM CROSSES THE REGION. NEXT CHANCE FOR WIDESPREAD
RESTRICTIONS WILL BE WITH A WEDNESDAY COLD FRONT.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...WINTER WEATHER ADVISORY FROM 4 AM SUNDAY TO NOON EST MONDAY
     FOR OHZ039-040-048>050-057>059.
     WINTER STORM WARNING FROM 4 AM SUNDAY TO NOON EST MONDAY FOR
     OHZ041.
PA...WINTER WEATHER ADVISORY FROM 4 AM SUNDAY TO NOON EST MONDAY
     FOR PAZ021-029-073-074.
     WINTER STORM WARNING FROM 4 AM SUNDAY TO NOON EST MONDAY FOR
     PAZ007>009-013>016-020-022-023.
WV...WINTER WEATHER ADVISORY FROM 4 AM SUNDAY TO NOON EST MONDAY
     FOR WVZ001>003.

&&

$$

Forecast Discussion from: NOAA-NWS Script developed by: El Dorado Weather