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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WATCHES ARE NO LONGER IN EFFECT AS AREAS S OF THE PA BORDER...EVEN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.

&&

$$








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.

&&

$$







000
FXUS61 KPBZ 312038
AFDPBZ

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

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

&&

.NEAR TERM /THROUGH TONIGHT/...
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. OVRNGT LOWS WERE ADJUSTED TO NR THE LATEST SREF NMBRS.

&&

.SHORT TERM /SUNDAY 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 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 /20Z SATURDAY THROUGH THURSDAY/...
GENERAL VFR UNTIL THE PRE-DAWN HOURS SUNDAY WHEN CONDITIONS WILL
DETERIORATE TO IFR CIGS AND SNOW AS LOW PRESSURE ADVANCES EAST.
EXPECT IFR FROM AROUND 09Z SUNDAY AT KZZV TO QUICKLY SPREAD TO KLBE
AND KDUJ 12-14Z AND REMAIN THROUGHOUT THE END OF THE TAF PERIOD..

.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.

&&

$$

07/10






000
FXUS61 KPBZ 312038
AFDPBZ

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

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

&&

.NEAR TERM /THROUGH TONIGHT/...
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. OVRNGT LOWS WERE ADJUSTED TO NR THE LATEST SREF NMBRS.

&&

.SHORT TERM /SUNDAY 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 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 /20Z SATURDAY THROUGH THURSDAY/...
GENERAL VFR UNTIL THE PRE-DAWN HOURS SUNDAY WHEN CONDITIONS WILL
DETERIORATE TO IFR CIGS AND SNOW AS LOW PRESSURE ADVANCES EAST.
EXPECT IFR FROM AROUND 09Z SUNDAY AT KZZV TO QUICKLY SPREAD TO KLBE
AND KDUJ 12-14Z AND REMAIN THROUGHOUT THE END OF THE TAF PERIOD..

.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.

&&

$$

07/10







000
FXUS61 KPBZ 311555
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1055 AM EST SAT JAN 31 2015

.SYNOPSIS...
HIGH PRESSURE WILL BUILD IN THROUGH THIS EVENING. LOW PRESSURE
WILL BRING WINTRY WEATHER SUNDAY INTO MONDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
LINGERING STRATOCU FM DUJ TO LBE SHOULD CLEAR BY ERLY AFTN AS HIGH
PRES CONTS TO BLD IN. OTRW...MAINLY CLEAR SKIES AND DRY WEA ARE
EXPD THRU THE DAY WITH BELOW AVG TEMPS CONTG.

PREVIOUS...
TONIGHT...FRONTAL BOUNDARY BRIDGING FROM WEAK LOW DROPPING ACROSS
EASTERN GREAT LAKES...TO THE MORE SIGNIFICANT SURFACE SYSTEM
MOVING INTO MISSOURI... DROPS TOWARD THE NORTHERN CWA. AS THIS
OCCURS...MOISTURE BEGINS TO STREAK IN FROM THE WEST ESPECIALLY
AFTER 06Z. BEGINNINGS OF DEEP LIFT DRIVEN VIA ISENTROPIC ASCENT
AND RRQ OF H250 JET TO THE NORTH WILL START TO SPREAD SNOW ACROSS
THE CWA. SLOWED POPS SLIGHTLY FROM PREVIOUS FORECAST BUT STILL
BRING LIKELY POPS TO PIT/HLG BY 12Z. SNOW COULD START EARLY ENOUGH
TO GET A FRESH INCH ON THE GROUND NEAR ZZV BY 12Z...WITH LESSER
AMOUNTS TO THE NORTH AND EAST.

TEMPERATURES MODIFIED SLIGHTLY FROM PREVIOUS FORECAST...MAINLY BY
BLENDING IN NAM/MET. CL

&&

.SHORT TERM /SUNDAY THROUGH MONDAY/...
PRECIPITATION WILL START OVERSPREADING THE AREA WEST TO EAST ACROSS
THE SFC COLD FRONT SUNDAY AHEAD OF THE VIGOROUS LOW MOVING OUT OF
THE PLAINS. SNOW WILL BE THE PRIMARY PRECIPITATION TYPE AS THE EVENT
BEGINS EARLY SUN. LATER SUN AFTERNOON SNOW WILL REMAIN NORTH OF
I-70...BUT A MIX OR PLAIN RAIN CAN BE EXPECTED SOUTH OF I-70 AS
TEMPERATURES WARM.

THE LOW INTENSIFIES AS IT ENTERS THE OHIO RIVER VALLEY...BOLSTERED
ALOFT AS TWO JET STREAKS TEMPORARILY PHASE TO MAXIMIZE UPPER LEVEL
DIVERGENCE. INTENSIFICATION OF THE LOW WILL AMPLIFY THE LLVL WIND
FIELD RESULTING IN A STRONG 50+ KT H85 JET NOSING INTO SWPA.
NAM/SREF/GFS ALL SHOW THE TRACK OF THE H85 LOW A LITTLE FURTHER
NORTH THAN THAT OF THE ECMWF AND NORTH OF PREVIOUS RUNS. AS THE
CLOSED H85 LOW TRACKS THROUGH NCENTRAL OHIO...THIS MEANS THAT WAA
WILL BRING POSITIVE H85 ISOTHERMS INTO NRN WV AND SWPA THROUGH EARLY
MON MORNING. THIS KEEPS RAIN OR A RAIN/SNOW MIX SOUTH OF I-70 BEFORE
THE COLD AIR PUSHES IN ON THE BACKSIDE OF THE LOW MON MORNING. THIS
SLIGHTLY WARMER SOLN MARKS THE LARGEST CHANGE MADE TO THE PREVIOUS
FORECAST.

LARGELY KEPT THE QPF PLACEMENT AND NUMBERS THE SAME...BLENDING THE
LATEST WPC GUIDANCE WITH THE PREVIOUS NUMBERS. THE WARMER AIR
INVADING UP THE WRN SLOPES OF THE RIDGES WILL WORK TO KEEP OUR SERN
ZONES RAIN LONGER AND ULTIMATELY CUT INTO SNOW TOTALS FOR THE
DURATION OF THE EVENT. HOW FAR NORTH THAT WARM AIR IS ABLE TO INVADE
IS ANOTHER QUESTION. IF THE H85 LOW FOLLOWS THE CURRENT ECMWF
TRACK...THE PGH METRO WILL STAY NEARLY ALL SNOW. IF IT FOLLOWS THE
MORE NORTHERN TRACK...SEVERAL HOURS OF RAIN DURING THE TIME OF BEST
PRECIPITATION COULD CUT INTO THE PGH METRO TOTALS AS WELL.

ALL TOLD...A GENERAL 8-10" NORTH ALONG THE I-80
CORRIDOR...BUT TIGHTENED THE ACCUMULATION GRADIENT NEAR THE PGH
METRO WITH NRN ALLEGHENY COUNTY IN THE 5-7" RANGE AND SRN PORTIONS
OF THE COUNTY IN THE 3-5" RANGE. TRIMMED BACK TOTALS ACROSS THE SRN
EXTENT OF THE CWA AS WELL WITH MANY LOCATIONS IN THE 1-3" RANGE. IF
THE WARMER SOLNS WIN OUT...NUMBERS ACROSS THE SOUTH COULD BE CLOSER
TO THE 1" SIDE OF THAT RANGE. WITH QUESTIONS SURROUNDING THE TRACK
AND EXTENT OF WARM AIR...A WELL COLLABORATED DECISION WAS MADE TO
HOLD WITH THE WINTER STORM WATCH IN PLACE.
TAX

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
LLVL MOISTURE WILL LINGER IN THE HIGH ACROSS THE HIGH TERRAIN
THROUGH THE PRE-DAWN HOURS TUES...BUT ANY CHC OF PRECIPITATION WILL
BE FLEETING AS SFC HIGH PRESSURE WILL BUILD IN FROM THE WEST. NRN
AXIS OF THE SFC RIDGE WILL QUICKLY SHIFT EAST OF THE AREA TUES UNDER
ZONAL FLOW ALOFT. SERN EXTENT OF THE HIGH WILL HOLD BACK TO THE
WEST...AND WILL TRY TO HOLD THE NEXT SYSTEM OFF TO OUR NORTH. A WEAK
SFC LOW PASSES NORTH WEDS...BUT WILL WORK TO AMPLIFY THE UPPER TROF.
THE TRAILING COLD FRONT SWINGS THROUGH WEDS NIGHT/THURS
MORNING...BRINGING THE BEST CHANCE OF POPS IN THE EXTENDED PERIOD.
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 7 DAY PERIOD.
TAX

&&

.AVIATION /16Z SATURDAY THROUGH WEDNESDAY/...
FINGERS OF STRATOCU ARE STARTING TO STREAM IN FROM ACROSS LAKE
ERIE. EXPECT THIS VARIABLE AND BORDERLINE MVFR CIG TO IMPACT
SEVERAL TERMINALS DURING THE MORNING AND EARLY AFTERNOON AS A WEAK
WARM FRONT LIFTS THROUGH. VFR CONDITIONS SHOULD RETURN BY MID TO
LATE AFTERNOON...BUT MID/HI CLOUDS WILL BE ON THE INCREASE AHEAD
OF OUR SIGNIFICANT SUNDAY STORM. SNOW WILL START ARRIVING FROM THE
WEST AFTER MIDNIGHT AND SPREAD EASTWARD WITH TIME...WITH MVFR
CIG/VIS DROPPING TO IFR WITHIN AN HOUR OR TWO AFTER SNOW
COMMENCES. AREAS EAST OF PIT/MGW MAY AVOID IFR UNTIL AFTER 12Z.
WINDS WILL GENERALLY BE 10 KNOTS OR LESS FROM THE SOUTHWEST
THROUGH MUCH OF THE TAF PERIOD. CL


.OUTLOOK.../SATURDAY NIGHT THROUGH WEDNESDAY/...
WIDESPREAD RESTRICTIONS CAN BE EXPECTED INTO MONDAY AS A LOW
PRESSURE SYSTEM CROSSES THE REGION.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR MDZ001.
OH...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR OHZ039>041-048>050-057>059.
PA...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR PAZ007>009-013>016-020>023-029-073>076.
WV...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR WVZ001>003-023-041.

&&

$$








000
FXUS61 KPBZ 311555
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1055 AM EST SAT JAN 31 2015

.SYNOPSIS...
HIGH PRESSURE WILL BUILD IN THROUGH THIS EVENING. LOW PRESSURE
WILL BRING WINTRY WEATHER SUNDAY INTO MONDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
LINGERING STRATOCU FM DUJ TO LBE SHOULD CLEAR BY ERLY AFTN AS HIGH
PRES CONTS TO BLD IN. OTRW...MAINLY CLEAR SKIES AND DRY WEA ARE
EXPD THRU THE DAY WITH BELOW AVG TEMPS CONTG.

PREVIOUS...
TONIGHT...FRONTAL BOUNDARY BRIDGING FROM WEAK LOW DROPPING ACROSS
EASTERN GREAT LAKES...TO THE MORE SIGNIFICANT SURFACE SYSTEM
MOVING INTO MISSOURI... DROPS TOWARD THE NORTHERN CWA. AS THIS
OCCURS...MOISTURE BEGINS TO STREAK IN FROM THE WEST ESPECIALLY
AFTER 06Z. BEGINNINGS OF DEEP LIFT DRIVEN VIA ISENTROPIC ASCENT
AND RRQ OF H250 JET TO THE NORTH WILL START TO SPREAD SNOW ACROSS
THE CWA. SLOWED POPS SLIGHTLY FROM PREVIOUS FORECAST BUT STILL
BRING LIKELY POPS TO PIT/HLG BY 12Z. SNOW COULD START EARLY ENOUGH
TO GET A FRESH INCH ON THE GROUND NEAR ZZV BY 12Z...WITH LESSER
AMOUNTS TO THE NORTH AND EAST.

TEMPERATURES MODIFIED SLIGHTLY FROM PREVIOUS FORECAST...MAINLY BY
BLENDING IN NAM/MET. CL

&&

.SHORT TERM /SUNDAY THROUGH MONDAY/...
PRECIPITATION WILL START OVERSPREADING THE AREA WEST TO EAST ACROSS
THE SFC COLD FRONT SUNDAY AHEAD OF THE VIGOROUS LOW MOVING OUT OF
THE PLAINS. SNOW WILL BE THE PRIMARY PRECIPITATION TYPE AS THE EVENT
BEGINS EARLY SUN. LATER SUN AFTERNOON SNOW WILL REMAIN NORTH OF
I-70...BUT A MIX OR PLAIN RAIN CAN BE EXPECTED SOUTH OF I-70 AS
TEMPERATURES WARM.

THE LOW INTENSIFIES AS IT ENTERS THE OHIO RIVER VALLEY...BOLSTERED
ALOFT AS TWO JET STREAKS TEMPORARILY PHASE TO MAXIMIZE UPPER LEVEL
DIVERGENCE. INTENSIFICATION OF THE LOW WILL AMPLIFY THE LLVL WIND
FIELD RESULTING IN A STRONG 50+ KT H85 JET NOSING INTO SWPA.
NAM/SREF/GFS ALL SHOW THE TRACK OF THE H85 LOW A LITTLE FURTHER
NORTH THAN THAT OF THE ECMWF AND NORTH OF PREVIOUS RUNS. AS THE
CLOSED H85 LOW TRACKS THROUGH NCENTRAL OHIO...THIS MEANS THAT WAA
WILL BRING POSITIVE H85 ISOTHERMS INTO NRN WV AND SWPA THROUGH EARLY
MON MORNING. THIS KEEPS RAIN OR A RAIN/SNOW MIX SOUTH OF I-70 BEFORE
THE COLD AIR PUSHES IN ON THE BACKSIDE OF THE LOW MON MORNING. THIS
SLIGHTLY WARMER SOLN MARKS THE LARGEST CHANGE MADE TO THE PREVIOUS
FORECAST.

LARGELY KEPT THE QPF PLACEMENT AND NUMBERS THE SAME...BLENDING THE
LATEST WPC GUIDANCE WITH THE PREVIOUS NUMBERS. THE WARMER AIR
INVADING UP THE WRN SLOPES OF THE RIDGES WILL WORK TO KEEP OUR SERN
ZONES RAIN LONGER AND ULTIMATELY CUT INTO SNOW TOTALS FOR THE
DURATION OF THE EVENT. HOW FAR NORTH THAT WARM AIR IS ABLE TO INVADE
IS ANOTHER QUESTION. IF THE H85 LOW FOLLOWS THE CURRENT ECMWF
TRACK...THE PGH METRO WILL STAY NEARLY ALL SNOW. IF IT FOLLOWS THE
MORE NORTHERN TRACK...SEVERAL HOURS OF RAIN DURING THE TIME OF BEST
PRECIPITATION COULD CUT INTO THE PGH METRO TOTALS AS WELL.

ALL TOLD...A GENERAL 8-10" NORTH ALONG THE I-80
CORRIDOR...BUT TIGHTENED THE ACCUMULATION GRADIENT NEAR THE PGH
METRO WITH NRN ALLEGHENY COUNTY IN THE 5-7" RANGE AND SRN PORTIONS
OF THE COUNTY IN THE 3-5" RANGE. TRIMMED BACK TOTALS ACROSS THE SRN
EXTENT OF THE CWA AS WELL WITH MANY LOCATIONS IN THE 1-3" RANGE. IF
THE WARMER SOLNS WIN OUT...NUMBERS ACROSS THE SOUTH COULD BE CLOSER
TO THE 1" SIDE OF THAT RANGE. WITH QUESTIONS SURROUNDING THE TRACK
AND EXTENT OF WARM AIR...A WELL COLLABORATED DECISION WAS MADE TO
HOLD WITH THE WINTER STORM WATCH IN PLACE.
TAX

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
LLVL MOISTURE WILL LINGER IN THE HIGH ACROSS THE HIGH TERRAIN
THROUGH THE PRE-DAWN HOURS TUES...BUT ANY CHC OF PRECIPITATION WILL
BE FLEETING AS SFC HIGH PRESSURE WILL BUILD IN FROM THE WEST. NRN
AXIS OF THE SFC RIDGE WILL QUICKLY SHIFT EAST OF THE AREA TUES UNDER
ZONAL FLOW ALOFT. SERN EXTENT OF THE HIGH WILL HOLD BACK TO THE
WEST...AND WILL TRY TO HOLD THE NEXT SYSTEM OFF TO OUR NORTH. A WEAK
SFC LOW PASSES NORTH WEDS...BUT WILL WORK TO AMPLIFY THE UPPER TROF.
THE TRAILING COLD FRONT SWINGS THROUGH WEDS NIGHT/THURS
MORNING...BRINGING THE BEST CHANCE OF POPS IN THE EXTENDED PERIOD.
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 7 DAY PERIOD.
TAX

&&

.AVIATION /16Z SATURDAY THROUGH WEDNESDAY/...
FINGERS OF STRATOCU ARE STARTING TO STREAM IN FROM ACROSS LAKE
ERIE. EXPECT THIS VARIABLE AND BORDERLINE MVFR CIG TO IMPACT
SEVERAL TERMINALS DURING THE MORNING AND EARLY AFTERNOON AS A WEAK
WARM FRONT LIFTS THROUGH. VFR CONDITIONS SHOULD RETURN BY MID TO
LATE AFTERNOON...BUT MID/HI CLOUDS WILL BE ON THE INCREASE AHEAD
OF OUR SIGNIFICANT SUNDAY STORM. SNOW WILL START ARRIVING FROM THE
WEST AFTER MIDNIGHT AND SPREAD EASTWARD WITH TIME...WITH MVFR
CIG/VIS DROPPING TO IFR WITHIN AN HOUR OR TWO AFTER SNOW
COMMENCES. AREAS EAST OF PIT/MGW MAY AVOID IFR UNTIL AFTER 12Z.
WINDS WILL GENERALLY BE 10 KNOTS OR LESS FROM THE SOUTHWEST
THROUGH MUCH OF THE TAF PERIOD. CL


.OUTLOOK.../SATURDAY NIGHT THROUGH WEDNESDAY/...
WIDESPREAD RESTRICTIONS CAN BE EXPECTED INTO MONDAY AS A LOW
PRESSURE SYSTEM CROSSES THE REGION.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR MDZ001.
OH...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR OHZ039>041-048>050-057>059.
PA...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR PAZ007>009-013>016-020>023-029-073>076.
WV...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR WVZ001>003-023-041.

&&

$$







000
FXUS61 KPBZ 311330
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
830 AM EST SAT JAN 31 2015

.SYNOPSIS...
HIGH PRESSURE WILL BUILD IN THROUGH THIS EVENING. LOW PRESSURE
WILL BRING WINTRY WEATHER SUNDAY INTO MONDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
UPDT TO CANCEL WIND CHILL ADVY AS WNDS HAVE DMNSHD. ASLO ADJUSTED
SKY COVER BASED ON RECENT SATELLITE AND NR TERM MDLS.

PREVIOUS...STRATOCU DECK CONTINUES TO ERODE SLOWLY...WITH ONLY
THE FAR NORTHEASTERN CWA STILL UNDER THEIR INFLUENCE. THESE WILL
CONTINUE TO DISSIPATE...LEAVING MOSTLY CLEAR SKIES AND VERY COLD
TEMPERATURES. CONTINUED MINOR PUFF OF WIND HAS KEPT TEMPS FROM
REALLY BOTTOMING OUT SO FAR...BUT STILL EXPECT SOME BELOW ZERO
VALUES TO BE REALIZED THIS MORNING.

HIGH PRESSURE WILL KEEP CWA DRY TODAY. WEAK WARM FRONTAL PASSAGE
WILL ALLOW FOR SOME CU/SC CLOUDS LATER THIS MORNING AND THIS
AFTERNOON...WITH WARMER H925/H850 AIR ARRIVING ON THE HEELS OF
W/WNW WINDS JUST OFF THE SURFACE. LOWER CLOUDS WILL MOVE OFF LATER
IN THE DAY...TO BE REPLACED BY INCREASING MID/HI CLOUDS AHEAD OF
OUR WELL-ADVERTISED SUNDAY STORM.

TONIGHT...FRONTAL BOUNDARY BRIDGING FROM WEAK LOW DROPPING ACROSS
EASTERN GREAT LAKES...TO THE MORE SIGNIFICANT SURFACE SYSTEM
MOVING INTO MISSOURI... DROPS TOWARD THE NORTHERN CWA. AS THIS
OCCURS...MOISTURE BEGINS TO STREAK IN FROM THE WEST ESPECIALLY
AFTER 06Z. BEGINNINGS OF DEEP LIFT DRIVEN VIA ISENTROPIC ASCENT
AND RRQ OF H250 JET TO THE NORTH WILL START TO SPREAD SNOW ACROSS
THE CWA. SLOWED POPS SLIGHTLY FROM PREVIOUS FORECAST BUT STILL
BRING LIKELY POPS TO PIT/HLG BY 12Z. SNOW COULD START EARLY ENOUGH
TO GET A FRESH INCH ON THE GROUND NEAR ZZV BY 12Z...WITH LESSER
AMOUNTS TO THE NORTH AND EAST.

TEMPERATURES MODIFIED SLIGHTLY FROM PREVIOUS FORECAST...MAINLY BY
BLENDING IN NAM/MET. CL

&&

.SHORT TERM /SUNDAY THROUGH MONDAY/...
PRECIPITATION WILL START OVERSPREADING THE AREA WEST TO EAST ACROSS
THE SFC COLD FRONT SUNDAY AHEAD OF THE VIGOROUS LOW MOVING OUT OF
THE PLAINS. SNOW WILL BE THE PRIMARY PRECIPITATION TYPE AS THE EVENT
BEGINS EARLY SUN. LATER SUN AFTERNOON SNOW WILL REMAIN NORTH OF
I-70...BUT A MIX OR PLAIN RAIN CAN BE EXPECTED SOUTH OF I-70 AS
TEMPERATURES WARM.

THE LOW INTENSIFIES AS IT ENTERS THE OHIO RIVER VALLEY...BOLSTERED
ALOFT AS TWO JET STREAKS TEMPORARILY PHASE TO MAXIMIZE UPPER LEVEL
DIVERGENCE. INTENSIFICATION OF THE LOW WILL AMPLIFY THE LLVL WIND
FIELD RESULTING IN A STRONG 50+ KT H85 JET NOSING INTO SWPA.
NAM/SREF/GFS ALL SHOW THE TRACK OF THE H85 LOW A LITTLE FURTHER
NORTH THAN THAT OF THE ECMWF AND NORTH OF PREVIOUS RUNS. AS THE
CLOSED H85 LOW TRACKS THROUGH NCENTRAL OHIO...THIS MEANS THAT WAA
WILL BRING POSITIVE H85 ISOTHERMS INTO NRN WV AND SWPA THROUGH EARLY
MON MORNING. THIS KEEPS RAIN OR A RAIN/SNOW MIX SOUTH OF I-70 BEFORE
THE COLD AIR PUSHES IN ON THE BACKSIDE OF THE LOW MON MORNING. THIS
SLIGHTLY WARMER SOLN MARKS THE LARGEST CHANGE MADE TO THE PREVIOUS
FORECAST.

LARGELY KEPT THE QPF PLACEMENT AND NUMBERS THE SAME...BLENDING THE
LATEST WPC GUIDANCE WITH THE PREVIOUS NUMBERS. THE WARMER AIR
INVADING UP THE WRN SLOPES OF THE RIDGES WILL WORK TO KEEP OUR SERN
ZONES RAIN LONGER AND ULTIMATELY CUT INTO SNOW TOTALS FOR THE
DURATION OF THE EVENT. HOW FAR NORTH THAT WARM AIR IS ABLE TO INVADE
IS ANOTHER QUESTION. IF THE H85 LOW FOLLOWS THE CURRENT ECMWF
TRACK...THE PGH METRO WILL STAY NEARLY ALL SNOW. IF IT FOLLOWS THE
MORE NORTHERN TRACK...SEVERAL HOURS OF RAIN DURING THE TIME OF BEST
PRECIPITATION COULD CUT INTO THE PGH METRO TOTALS AS WELL.

ALL TOLD...A GENERAL 8-10" NORTH ALONG THE I-80
CORRIDOR...BUT TIGHTENED THE ACCUMULATION GRADIENT NEAR THE PGH
METRO WITH NRN ALLEGHENY COUNTY IN THE 5-7" RANGE AND SRN PORTIONS
OF THE COUNTY IN THE 3-5" RANGE. TRIMMED BACK TOTALS ACROSS THE SRN
EXTENT OF THE CWA AS WELL WITH MANY LOCATIONS IN THE 1-3" RANGE. IF
THE WARMER SOLNS WIN OUT...NUMBERS ACROSS THE SOUTH COULD BE CLOSER
TO THE 1" SIDE OF THAT RANGE. WITH QUESTIONS SURROUNDING THE TRACK
AND EXTENT OF WARM AIR...A WELL COLLABORATED DECISION WAS MADE TO
HOLD WITH THE WINTER STORM WATCH IN PLACE.
TAX

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
LLVL MOISTURE WILL LINGER IN THE HIGH ACROSS THE HIGH TERRAIN
THROUGH THE PRE-DAWN HOURS TUES...BUT ANY CHC OF PRECIPITATION WILL
BE FLEETING AS SFC HIGH PRESSURE WILL BUILD IN FROM THE WEST. NRN
AXIS OF THE SFC RIDGE WILL QUICKLY SHIFT EAST OF THE AREA TUES UNDER
ZONAL FLOW ALOFT. SERN EXTENT OF THE HIGH WILL HOLD BACK TO THE
WEST...AND WILL TRY TO HOLD THE NEXT SYSTEM OFF TO OUR NORTH. A WEAK
SFC LOW PASSES NORTH WEDS...BUT WILL WORK TO AMPLIFY THE UPPER TROF.
THE TRAILING COLD FRONT SWINGS THROUGH WEDS NIGHT/THURS
MORNING...BRINGING THE BEST CHANCE OF POPS IN THE EXTENDED PERIOD.
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 7 DAY PERIOD.
TAX

&&

.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
FINGERS OF STRATOCU ARE STARTING TO STREAM IN FROM ACROSS LAKE
ERIE. EXPECT THIS VARIABLE AND BORDERLINE MVFR CIG TO IMPACT
SEVERAL TERMINALS DURING THE MORNING AND EARLY AFTERNOON AS A WEAK
WARM FRONT LIFTS THROUGH. VFR CONDITIONS SHOULD RETURN BY MID TO
LATE AFTERNOON...BUT MID/HI CLOUDS WILL BE ON THE INCREASE AHEAD
OF OUR SIGNIFICANT SUNDAY STORM. SNOW WILL START ARRIVING FROM THE
WEST AFTER MIDNIGHT AND SPREAD EASTWARD WITH TIME...WITH MVFR
CIG/VIS DROPPING TO IFR WITHIN AN HOUR OR TWO AFTER SNOW
COMMENCES. AREAS EAST OF PIT/MGW MAY AVOID IFR UNTIL AFTER 12Z.
WINDS WILL GENERALLY BE 10 KNOTS OR LESS FROM THE SOUTHWEST
THROUGH MUCH OF THE TAF PERIOD. CL


.OUTLOOK.../SATURDAY NIGHT THROUGH WEDNESDAY/...
WIDESPREAD RESTRICTIONS CAN BE EXPECTED INTO MONDAY AS A LOW
PRESSURE SYSTEM CROSSES THE REGION.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR MDZ001.
OH...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR OHZ039>041-048>050-057>059.
PA...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR PAZ007>009-013>016-020>023-029-073>076.
WV...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR WVZ001>003-023-041.

&&

$$







000
FXUS61 KPBZ 311330
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
830 AM EST SAT JAN 31 2015

.SYNOPSIS...
HIGH PRESSURE WILL BUILD IN THROUGH THIS EVENING. LOW PRESSURE
WILL BRING WINTRY WEATHER SUNDAY INTO MONDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
UPDT TO CANCEL WIND CHILL ADVY AS WNDS HAVE DMNSHD. ASLO ADJUSTED
SKY COVER BASED ON RECENT SATELLITE AND NR TERM MDLS.

PREVIOUS...STRATOCU DECK CONTINUES TO ERODE SLOWLY...WITH ONLY
THE FAR NORTHEASTERN CWA STILL UNDER THEIR INFLUENCE. THESE WILL
CONTINUE TO DISSIPATE...LEAVING MOSTLY CLEAR SKIES AND VERY COLD
TEMPERATURES. CONTINUED MINOR PUFF OF WIND HAS KEPT TEMPS FROM
REALLY BOTTOMING OUT SO FAR...BUT STILL EXPECT SOME BELOW ZERO
VALUES TO BE REALIZED THIS MORNING.

HIGH PRESSURE WILL KEEP CWA DRY TODAY. WEAK WARM FRONTAL PASSAGE
WILL ALLOW FOR SOME CU/SC CLOUDS LATER THIS MORNING AND THIS
AFTERNOON...WITH WARMER H925/H850 AIR ARRIVING ON THE HEELS OF
W/WNW WINDS JUST OFF THE SURFACE. LOWER CLOUDS WILL MOVE OFF LATER
IN THE DAY...TO BE REPLACED BY INCREASING MID/HI CLOUDS AHEAD OF
OUR WELL-ADVERTISED SUNDAY STORM.

TONIGHT...FRONTAL BOUNDARY BRIDGING FROM WEAK LOW DROPPING ACROSS
EASTERN GREAT LAKES...TO THE MORE SIGNIFICANT SURFACE SYSTEM
MOVING INTO MISSOURI... DROPS TOWARD THE NORTHERN CWA. AS THIS
OCCURS...MOISTURE BEGINS TO STREAK IN FROM THE WEST ESPECIALLY
AFTER 06Z. BEGINNINGS OF DEEP LIFT DRIVEN VIA ISENTROPIC ASCENT
AND RRQ OF H250 JET TO THE NORTH WILL START TO SPREAD SNOW ACROSS
THE CWA. SLOWED POPS SLIGHTLY FROM PREVIOUS FORECAST BUT STILL
BRING LIKELY POPS TO PIT/HLG BY 12Z. SNOW COULD START EARLY ENOUGH
TO GET A FRESH INCH ON THE GROUND NEAR ZZV BY 12Z...WITH LESSER
AMOUNTS TO THE NORTH AND EAST.

TEMPERATURES MODIFIED SLIGHTLY FROM PREVIOUS FORECAST...MAINLY BY
BLENDING IN NAM/MET. CL

&&

.SHORT TERM /SUNDAY THROUGH MONDAY/...
PRECIPITATION WILL START OVERSPREADING THE AREA WEST TO EAST ACROSS
THE SFC COLD FRONT SUNDAY AHEAD OF THE VIGOROUS LOW MOVING OUT OF
THE PLAINS. SNOW WILL BE THE PRIMARY PRECIPITATION TYPE AS THE EVENT
BEGINS EARLY SUN. LATER SUN AFTERNOON SNOW WILL REMAIN NORTH OF
I-70...BUT A MIX OR PLAIN RAIN CAN BE EXPECTED SOUTH OF I-70 AS
TEMPERATURES WARM.

THE LOW INTENSIFIES AS IT ENTERS THE OHIO RIVER VALLEY...BOLSTERED
ALOFT AS TWO JET STREAKS TEMPORARILY PHASE TO MAXIMIZE UPPER LEVEL
DIVERGENCE. INTENSIFICATION OF THE LOW WILL AMPLIFY THE LLVL WIND
FIELD RESULTING IN A STRONG 50+ KT H85 JET NOSING INTO SWPA.
NAM/SREF/GFS ALL SHOW THE TRACK OF THE H85 LOW A LITTLE FURTHER
NORTH THAN THAT OF THE ECMWF AND NORTH OF PREVIOUS RUNS. AS THE
CLOSED H85 LOW TRACKS THROUGH NCENTRAL OHIO...THIS MEANS THAT WAA
WILL BRING POSITIVE H85 ISOTHERMS INTO NRN WV AND SWPA THROUGH EARLY
MON MORNING. THIS KEEPS RAIN OR A RAIN/SNOW MIX SOUTH OF I-70 BEFORE
THE COLD AIR PUSHES IN ON THE BACKSIDE OF THE LOW MON MORNING. THIS
SLIGHTLY WARMER SOLN MARKS THE LARGEST CHANGE MADE TO THE PREVIOUS
FORECAST.

LARGELY KEPT THE QPF PLACEMENT AND NUMBERS THE SAME...BLENDING THE
LATEST WPC GUIDANCE WITH THE PREVIOUS NUMBERS. THE WARMER AIR
INVADING UP THE WRN SLOPES OF THE RIDGES WILL WORK TO KEEP OUR SERN
ZONES RAIN LONGER AND ULTIMATELY CUT INTO SNOW TOTALS FOR THE
DURATION OF THE EVENT. HOW FAR NORTH THAT WARM AIR IS ABLE TO INVADE
IS ANOTHER QUESTION. IF THE H85 LOW FOLLOWS THE CURRENT ECMWF
TRACK...THE PGH METRO WILL STAY NEARLY ALL SNOW. IF IT FOLLOWS THE
MORE NORTHERN TRACK...SEVERAL HOURS OF RAIN DURING THE TIME OF BEST
PRECIPITATION COULD CUT INTO THE PGH METRO TOTALS AS WELL.

ALL TOLD...A GENERAL 8-10" NORTH ALONG THE I-80
CORRIDOR...BUT TIGHTENED THE ACCUMULATION GRADIENT NEAR THE PGH
METRO WITH NRN ALLEGHENY COUNTY IN THE 5-7" RANGE AND SRN PORTIONS
OF THE COUNTY IN THE 3-5" RANGE. TRIMMED BACK TOTALS ACROSS THE SRN
EXTENT OF THE CWA AS WELL WITH MANY LOCATIONS IN THE 1-3" RANGE. IF
THE WARMER SOLNS WIN OUT...NUMBERS ACROSS THE SOUTH COULD BE CLOSER
TO THE 1" SIDE OF THAT RANGE. WITH QUESTIONS SURROUNDING THE TRACK
AND EXTENT OF WARM AIR...A WELL COLLABORATED DECISION WAS MADE TO
HOLD WITH THE WINTER STORM WATCH IN PLACE.
TAX

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
LLVL MOISTURE WILL LINGER IN THE HIGH ACROSS THE HIGH TERRAIN
THROUGH THE PRE-DAWN HOURS TUES...BUT ANY CHC OF PRECIPITATION WILL
BE FLEETING AS SFC HIGH PRESSURE WILL BUILD IN FROM THE WEST. NRN
AXIS OF THE SFC RIDGE WILL QUICKLY SHIFT EAST OF THE AREA TUES UNDER
ZONAL FLOW ALOFT. SERN EXTENT OF THE HIGH WILL HOLD BACK TO THE
WEST...AND WILL TRY TO HOLD THE NEXT SYSTEM OFF TO OUR NORTH. A WEAK
SFC LOW PASSES NORTH WEDS...BUT WILL WORK TO AMPLIFY THE UPPER TROF.
THE TRAILING COLD FRONT SWINGS THROUGH WEDS NIGHT/THURS
MORNING...BRINGING THE BEST CHANCE OF POPS IN THE EXTENDED PERIOD.
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 7 DAY PERIOD.
TAX

&&

.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
FINGERS OF STRATOCU ARE STARTING TO STREAM IN FROM ACROSS LAKE
ERIE. EXPECT THIS VARIABLE AND BORDERLINE MVFR CIG TO IMPACT
SEVERAL TERMINALS DURING THE MORNING AND EARLY AFTERNOON AS A WEAK
WARM FRONT LIFTS THROUGH. VFR CONDITIONS SHOULD RETURN BY MID TO
LATE AFTERNOON...BUT MID/HI CLOUDS WILL BE ON THE INCREASE AHEAD
OF OUR SIGNIFICANT SUNDAY STORM. SNOW WILL START ARRIVING FROM THE
WEST AFTER MIDNIGHT AND SPREAD EASTWARD WITH TIME...WITH MVFR
CIG/VIS DROPPING TO IFR WITHIN AN HOUR OR TWO AFTER SNOW
COMMENCES. AREAS EAST OF PIT/MGW MAY AVOID IFR UNTIL AFTER 12Z.
WINDS WILL GENERALLY BE 10 KNOTS OR LESS FROM THE SOUTHWEST
THROUGH MUCH OF THE TAF PERIOD. CL


.OUTLOOK.../SATURDAY NIGHT THROUGH WEDNESDAY/...
WIDESPREAD RESTRICTIONS CAN BE EXPECTED INTO MONDAY AS A LOW
PRESSURE SYSTEM CROSSES THE REGION.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR MDZ001.
OH...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR OHZ039>041-048>050-057>059.
PA...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR PAZ007>009-013>016-020>023-029-073>076.
WV...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR WVZ001>003-023-041.

&&

$$








000
FXUS61 KPBZ 311055
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
555 AM EST SAT JAN 31 2015

.SYNOPSIS...
HIGH PRESSURE WILL BUILD IN THROUGH SATURDAY. LOW PRESSURE WILL
BRING WINTRY WEATHER SUNDAY INTO MONDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
STRATOCU DECK CONTINUES TO ERODE SLOWLY...WITH ONLY THE FAR
NORTHEASTERN CWA STILL UNDER THEIR INFLUENCE. THESE WILL CONTINUE
TO DISSIPATE...LEAVING MOSTLY CLEAR SKIES AND VERY COLD
TEMPERATURES. CONTINUED MINOR PUFF OF WIND HAS KEPT TEMPS FROM
REALLY BOTTOMING OUT SO FAR...BUT STILL EXPECT SOME BELOW ZERO
VALUES TO BE REALIZED THIS MORNING.

HIGH PRESSURE WILL KEEP CWA DRY TODAY. WEAK WARM FRONTAL PASSAGE
WILL ALLOW FOR SOME CU/SC CLOUDS LATER THIS MORNING AND THIS
AFTERNOON...WITH WARMER H925/H850 AIR ARRIVING ON THE HEELS OF
W/WNW WINDS JUST OFF THE SURFACE. LOWER CLOUDS WILL MOVE OFF LATER
IN THE DAY...TO BE REPLACED BY INCREASING MID/HI CLOUDS AHEAD OF
OUR WELL-ADVERTISED SUNDAY STORM.

TONIGHT...FRONTAL BOUNDARY BRIDGING FROM WEAK LOW DROPPING ACROSS
EASTERN GREAT LAKES...TO THE MORE SIGNIFICANT SURFACE SYSTEM
MOVING INTO MISSOURI... DROPS TOWARD THE NORTHERN CWA. AS THIS
OCCURS...MOISTURE BEGINS TO STREAK IN FROM THE WEST ESPECIALLY
AFTER 06Z. BEGINNINGS OF DEEP LIFT DRIVEN VIA ISENTROPIC ASCENT
AND RRQ OF H250 JET TO THE NORTH WILL START TO SPREAD SNOW ACROSS
THE CWA. SLOWED POPS SLIGHTLY FROM PREVIOUS FORECAST BUT STILL
BRING LIKELY POPS TO PIT/HLG BY 12Z. SNOW COULD START EARLY ENOUGH
TO GET A FRESH INCH ON THE GROUND NEAR ZZV BY 12Z...WITH LESSER
AMOUNTS TO THE NORTH AND EAST.

TEMPERATURES MODIFIED SLIGHTLY FROM PREVIOUS FORECAST...MAINLY BY
BLENDING IN NAM/MET. CL

&&

.SHORT TERM /SUNDAY THROUGH MONDAY/...
PRECIPITATION WILL START OVERSPREADING THE AREA WEST TO EAST ACROSS
THE SFC COLD FRONT SUNDAY AHEAD OF THE VIGOROUS LOW MOVING OUT OF
THE PLAINS. SNOW WILL BE THE PRIMARY PRECIPITATION TYPE AS THE EVENT
BEGINS EARLY SUN. LATER SUN AFTERNOON SNOW WILL REMAIN NORTH OF
I-70...BUT A MIX OR PLAIN RAIN CAN BE EXPECTED SOUTH OF I-70 AS
TEMPERATURES WARM.

THE LOW INTENSIFIES AS IT ENTERS THE OHIO RIVER VALLEY...BOLSTERED
ALOFT AS TWO JET STREAKS TEMPORARILY PHASE TO MAXIMIZE UPPER LEVEL
DIVERGENCE. INTENSIFICATION OF THE LOW WILL AMPLIFY THE LLVL WIND
FIELD RESULTING IN A STRONG 50+ KT H85 JET NOSING INTO SWPA.
NAM/SREF/GFS ALL SHOW THE TRACK OF THE H85 LOW A LITTLE FURTHER
NORTH THAN THAT OF THE ECMWF AND NORTH OF PREVIOUS RUNS. AS THE
CLOSED H85 LOW TRACKS THROUGH NCENTRAL OHIO...THIS MEANS THAT WAA
WILL BRING POSITIVE H85 ISOTHERMS INTO NRN WV AND SWPA THROUGH EARLY
MON MORNING. THIS KEEPS RAIN OR A RAIN/SNOW MIX SOUTH OF I-70 BEFORE
THE COLD AIR PUSHES IN ON THE BACKSIDE OF THE LOW MON MORNING. THIS
SLIGHTLY WARMER SOLN MARKS THE LARGEST CHANGE MADE TO THE PREVIOUS
FORECAST.

LARGELY KEPT THE QPF PLACEMENT AND NUMBERS THE SAME...BLENDING THE
LATEST WPC GUIDANCE WITH THE PREVIOUS NUMBERS. THE WARMER AIR
INVADING UP THE WRN SLOPES OF THE RIDGES WILL WORK TO KEEP OUR SERN
ZONES RAIN LONGER AND ULTIMATELY CUT INTO SNOW TOTALS FOR THE
DURATION OF THE EVENT. HOW FAR NORTH THAT WARM AIR IS ABLE TO INVADE
IS ANOTHER QUESTION. IF THE H85 LOW FOLLOWS THE CURRENT ECMWF
TRACK...THE PGH METRO WILL STAY NEARLY ALL SNOW. IF IT FOLLOWS THE
MORE NORTHERN TRACK...SEVERAL HOURS OF RAIN DURING THE TIME OF BEST
PRECIPITATION COULD CUT INTO THE PGH METRO TOTALS AS WELL.

ALL TOLD...A GENERAL 8-10" NORTH ALONG THE I-80
CORRIDOR...BUT TIGHTENED THE ACCUMULATION GRADIENT NEAR THE PGH
METRO WITH NRN ALLEGHENY COUNTY IN THE 5-7" RANGE AND SRN PORTIONS
OF THE COUNTY IN THE 3-5" RANGE. TRIMMED BACK TOTALS ACROSS THE SRN
EXTENT OF THE CWA AS WELL WITH MANY LOCATIONS IN THE 1-3" RANGE. IF
THE WARMER SOLNS WIN OUT...NUMBERS ACROSS THE SOUTH COULD BE CLOSER
TO THE 1" SIDE OF THAT RANGE. WITH QUESTIONS SURROUNDING THE TRACK
AND EXTENT OF WARM AIR...A WELL COLLABORATED DECISION WAS MADE TO
HOLD WITH THE WINTER STORM WATCH IN PLACE.
TAX

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
LLVL MOISTURE WILL LINGER IN THE HIGH ACROSS THE HIGH TERRAIN
THROUGH THE PRE-DAWN HOURS TUES...BUT ANY CHC OF PRECIPITATION WILL
BE FLEETING AS SFC HIGH PRESSURE WILL BUILD IN FROM THE WEST. NRN
AXIS OF THE SFC RIDGE WILL QUICKLY SHIFT EAST OF THE AREA TUES UNDER
ZONAL FLOW ALOFT. SERN EXTENT OF THE HIGH WILL HOLD BACK TO THE
WEST...AND WILL TRY TO HOLD THE NEXT SYSTEM OFF TO OUR NORTH. A WEAK
SFC LOW PASSES NORTH WEDS...BUT WILL WORK TO AMPLIFY THE UPPER TROF.
THE TRAILING COLD FRONT SWINGS THROUGH WEDS NIGHT/THURS
MORNING...BRINGING THE BEST CHANCE OF POPS IN THE EXTENDED PERIOD.
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 7 DAY PERIOD.
TAX

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
FINGERS OF STRATOCU ARE STARTING TO STREAM IN FROM ACROSS LAKE
ERIE. EXPECT THIS VARIABLE AND BORDERLINE MVFR CIG TO IMPACT
SEVERAL TERMINALS DURING THE MORNING AND EARLY AFTERNOON AS A WEAK
WARM FRONT LIFTS THROUGH. VFR CONDITIONS SHOULD RETURN BY MID TO
LATE AFTERNOON...BUT MID/HI CLOUDS WILL BE ON THE INCREASE AHEAD
OF OUR SIGNIFICANT SUNDAY STORM. SNOW WILL START ARRIVING FROM THE
WEST AFTER MIDNIGHT AND SPREAD EASTWARD WITH TIME...WITH MVFR
CIG/VIS DROPPING TO IFR WITHIN AN HOUR OR TWO AFTER SNOW
COMMENCES. AREAS EAST OF PIT/MGW MAY AVOID IFR UNTIL AFTER 12Z.
WINDS WILL GENERALLY BE 10 KNOTS OR LESS FROM THE SOUTHWEST
THROUGH MUCH OF THE TAF PERIOD. CL


.OUTLOOK.../SATURDAY NIGHT THROUGH WEDNESDAY/...
WIDESPREAD RESTRICTIONS CAN BE EXPECTED INTO MONDAY AS A LOW
PRESSURE SYSTEM CROSSES THE REGION.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR MDZ001.
     WIND CHILL ADVISORY UNTIL 10 AM EST THIS MORNING FOR MDZ001.
OH...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR OHZ039>041-048>050-057>059.
PA...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR PAZ007>009-013>016-020>023-029-073>076.
     WIND CHILL ADVISORY UNTIL 10 AM EST THIS MORNING FOR PAZ008-
     009-015-016-023-074-076.
WV...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR WVZ001>003-023-041.
     WIND CHILL ADVISORY UNTIL 10 AM EST THIS MORNING FOR WVZ023-
     041.

&&

$$







000
FXUS61 KPBZ 311055
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
555 AM EST SAT JAN 31 2015

.SYNOPSIS...
HIGH PRESSURE WILL BUILD IN THROUGH SATURDAY. LOW PRESSURE WILL
BRING WINTRY WEATHER SUNDAY INTO MONDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
STRATOCU DECK CONTINUES TO ERODE SLOWLY...WITH ONLY THE FAR
NORTHEASTERN CWA STILL UNDER THEIR INFLUENCE. THESE WILL CONTINUE
TO DISSIPATE...LEAVING MOSTLY CLEAR SKIES AND VERY COLD
TEMPERATURES. CONTINUED MINOR PUFF OF WIND HAS KEPT TEMPS FROM
REALLY BOTTOMING OUT SO FAR...BUT STILL EXPECT SOME BELOW ZERO
VALUES TO BE REALIZED THIS MORNING.

HIGH PRESSURE WILL KEEP CWA DRY TODAY. WEAK WARM FRONTAL PASSAGE
WILL ALLOW FOR SOME CU/SC CLOUDS LATER THIS MORNING AND THIS
AFTERNOON...WITH WARMER H925/H850 AIR ARRIVING ON THE HEELS OF
W/WNW WINDS JUST OFF THE SURFACE. LOWER CLOUDS WILL MOVE OFF LATER
IN THE DAY...TO BE REPLACED BY INCREASING MID/HI CLOUDS AHEAD OF
OUR WELL-ADVERTISED SUNDAY STORM.

TONIGHT...FRONTAL BOUNDARY BRIDGING FROM WEAK LOW DROPPING ACROSS
EASTERN GREAT LAKES...TO THE MORE SIGNIFICANT SURFACE SYSTEM
MOVING INTO MISSOURI... DROPS TOWARD THE NORTHERN CWA. AS THIS
OCCURS...MOISTURE BEGINS TO STREAK IN FROM THE WEST ESPECIALLY
AFTER 06Z. BEGINNINGS OF DEEP LIFT DRIVEN VIA ISENTROPIC ASCENT
AND RRQ OF H250 JET TO THE NORTH WILL START TO SPREAD SNOW ACROSS
THE CWA. SLOWED POPS SLIGHTLY FROM PREVIOUS FORECAST BUT STILL
BRING LIKELY POPS TO PIT/HLG BY 12Z. SNOW COULD START EARLY ENOUGH
TO GET A FRESH INCH ON THE GROUND NEAR ZZV BY 12Z...WITH LESSER
AMOUNTS TO THE NORTH AND EAST.

TEMPERATURES MODIFIED SLIGHTLY FROM PREVIOUS FORECAST...MAINLY BY
BLENDING IN NAM/MET. CL

&&

.SHORT TERM /SUNDAY THROUGH MONDAY/...
PRECIPITATION WILL START OVERSPREADING THE AREA WEST TO EAST ACROSS
THE SFC COLD FRONT SUNDAY AHEAD OF THE VIGOROUS LOW MOVING OUT OF
THE PLAINS. SNOW WILL BE THE PRIMARY PRECIPITATION TYPE AS THE EVENT
BEGINS EARLY SUN. LATER SUN AFTERNOON SNOW WILL REMAIN NORTH OF
I-70...BUT A MIX OR PLAIN RAIN CAN BE EXPECTED SOUTH OF I-70 AS
TEMPERATURES WARM.

THE LOW INTENSIFIES AS IT ENTERS THE OHIO RIVER VALLEY...BOLSTERED
ALOFT AS TWO JET STREAKS TEMPORARILY PHASE TO MAXIMIZE UPPER LEVEL
DIVERGENCE. INTENSIFICATION OF THE LOW WILL AMPLIFY THE LLVL WIND
FIELD RESULTING IN A STRONG 50+ KT H85 JET NOSING INTO SWPA.
NAM/SREF/GFS ALL SHOW THE TRACK OF THE H85 LOW A LITTLE FURTHER
NORTH THAN THAT OF THE ECMWF AND NORTH OF PREVIOUS RUNS. AS THE
CLOSED H85 LOW TRACKS THROUGH NCENTRAL OHIO...THIS MEANS THAT WAA
WILL BRING POSITIVE H85 ISOTHERMS INTO NRN WV AND SWPA THROUGH EARLY
MON MORNING. THIS KEEPS RAIN OR A RAIN/SNOW MIX SOUTH OF I-70 BEFORE
THE COLD AIR PUSHES IN ON THE BACKSIDE OF THE LOW MON MORNING. THIS
SLIGHTLY WARMER SOLN MARKS THE LARGEST CHANGE MADE TO THE PREVIOUS
FORECAST.

LARGELY KEPT THE QPF PLACEMENT AND NUMBERS THE SAME...BLENDING THE
LATEST WPC GUIDANCE WITH THE PREVIOUS NUMBERS. THE WARMER AIR
INVADING UP THE WRN SLOPES OF THE RIDGES WILL WORK TO KEEP OUR SERN
ZONES RAIN LONGER AND ULTIMATELY CUT INTO SNOW TOTALS FOR THE
DURATION OF THE EVENT. HOW FAR NORTH THAT WARM AIR IS ABLE TO INVADE
IS ANOTHER QUESTION. IF THE H85 LOW FOLLOWS THE CURRENT ECMWF
TRACK...THE PGH METRO WILL STAY NEARLY ALL SNOW. IF IT FOLLOWS THE
MORE NORTHERN TRACK...SEVERAL HOURS OF RAIN DURING THE TIME OF BEST
PRECIPITATION COULD CUT INTO THE PGH METRO TOTALS AS WELL.

ALL TOLD...A GENERAL 8-10" NORTH ALONG THE I-80
CORRIDOR...BUT TIGHTENED THE ACCUMULATION GRADIENT NEAR THE PGH
METRO WITH NRN ALLEGHENY COUNTY IN THE 5-7" RANGE AND SRN PORTIONS
OF THE COUNTY IN THE 3-5" RANGE. TRIMMED BACK TOTALS ACROSS THE SRN
EXTENT OF THE CWA AS WELL WITH MANY LOCATIONS IN THE 1-3" RANGE. IF
THE WARMER SOLNS WIN OUT...NUMBERS ACROSS THE SOUTH COULD BE CLOSER
TO THE 1" SIDE OF THAT RANGE. WITH QUESTIONS SURROUNDING THE TRACK
AND EXTENT OF WARM AIR...A WELL COLLABORATED DECISION WAS MADE TO
HOLD WITH THE WINTER STORM WATCH IN PLACE.
TAX

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
LLVL MOISTURE WILL LINGER IN THE HIGH ACROSS THE HIGH TERRAIN
THROUGH THE PRE-DAWN HOURS TUES...BUT ANY CHC OF PRECIPITATION WILL
BE FLEETING AS SFC HIGH PRESSURE WILL BUILD IN FROM THE WEST. NRN
AXIS OF THE SFC RIDGE WILL QUICKLY SHIFT EAST OF THE AREA TUES UNDER
ZONAL FLOW ALOFT. SERN EXTENT OF THE HIGH WILL HOLD BACK TO THE
WEST...AND WILL TRY TO HOLD THE NEXT SYSTEM OFF TO OUR NORTH. A WEAK
SFC LOW PASSES NORTH WEDS...BUT WILL WORK TO AMPLIFY THE UPPER TROF.
THE TRAILING COLD FRONT SWINGS THROUGH WEDS NIGHT/THURS
MORNING...BRINGING THE BEST CHANCE OF POPS IN THE EXTENDED PERIOD.
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 7 DAY PERIOD.
TAX

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
FINGERS OF STRATOCU ARE STARTING TO STREAM IN FROM ACROSS LAKE
ERIE. EXPECT THIS VARIABLE AND BORDERLINE MVFR CIG TO IMPACT
SEVERAL TERMINALS DURING THE MORNING AND EARLY AFTERNOON AS A WEAK
WARM FRONT LIFTS THROUGH. VFR CONDITIONS SHOULD RETURN BY MID TO
LATE AFTERNOON...BUT MID/HI CLOUDS WILL BE ON THE INCREASE AHEAD
OF OUR SIGNIFICANT SUNDAY STORM. SNOW WILL START ARRIVING FROM THE
WEST AFTER MIDNIGHT AND SPREAD EASTWARD WITH TIME...WITH MVFR
CIG/VIS DROPPING TO IFR WITHIN AN HOUR OR TWO AFTER SNOW
COMMENCES. AREAS EAST OF PIT/MGW MAY AVOID IFR UNTIL AFTER 12Z.
WINDS WILL GENERALLY BE 10 KNOTS OR LESS FROM THE SOUTHWEST
THROUGH MUCH OF THE TAF PERIOD. CL


.OUTLOOK.../SATURDAY NIGHT THROUGH WEDNESDAY/...
WIDESPREAD RESTRICTIONS CAN BE EXPECTED INTO MONDAY AS A LOW
PRESSURE SYSTEM CROSSES THE REGION.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR MDZ001.
     WIND CHILL ADVISORY UNTIL 10 AM EST THIS MORNING FOR MDZ001.
OH...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR OHZ039>041-048>050-057>059.
PA...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR PAZ007>009-013>016-020>023-029-073>076.
     WIND CHILL ADVISORY UNTIL 10 AM EST THIS MORNING FOR PAZ008-
     009-015-016-023-074-076.
WV...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR WVZ001>003-023-041.
     WIND CHILL ADVISORY UNTIL 10 AM EST THIS MORNING FOR WVZ023-
     041.

&&

$$








000
FXUS61 KPBZ 311013
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
401 AM EST SAT JAN 31 2015

.SYNOPSIS...
HIGH PRESSURE WILL BUILD IN THROUGH SATURDAY. LOW PRESSURE WILL
BRING WINTRY WEATHER SUNDAY INTO MONDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
STRATOCU DECK CONTINUES TO ERODE SLOWLY...WITH ONLY THE FAR
NORTHEASTERN CWA STILL UNDER THEIR INFLUENCE. THESE WILL CONTINUE
TO DISSIPATE...LEAVING MOSTLY CLEAR SKIES AND VERY COLD
TEMPERATURES. CONTINUED MINOR PUFF OF WIND HAS KEPT TEMPS FROM
REALLY BOTTOMING OUT SO FAR...BUT STILL EXPECT SOME BELOW ZERO
VALUES TO BE REALIZED THIS MORNING.

HIGH PRESSURE WILL KEEP CWA DRY TODAY. WEAK WARM FRONTAL PASSAGE
WILL ALLOW FOR SOME CU/SC CLOUDS LATER THIS MORNING AND THIS
AFTERNOON...WITH WARMER H925/H850 AIR ARRIVING ON THE HEELS OF
W/WNW WINDS JUST OFF THE SURFACE. LOWER CLOUDS WILL MOVE OFF LATER
IN THE DAY...TO BE REPLACED BY INCREASING MID/HI CLOUDS AHEAD OF
OUR WELL-ADVERTISED SUNDAY STORM.

TONIGHT...FRONTAL BOUNDARY BRIDGING FROM WEAK LOW DROPPING ACROSS
EASTERN GREAT LAKES...TO THE MORE SIGNIFICANT SURFACE SYSTEM
MOVING INTO MISSOURI... DROPS TOWARD THE NORTHERN CWA. AS THIS
OCCURS...MOISTURE BEGINS TO STREAK IN FROM THE WEST ESPECIALLY
AFTER 06Z. BEGINNINGS OF DEEP LIFT DRIVEN VIA ISENTROPIC ASCENT
AND RRQ OF H250 JET TO THE NORTH WILL START TO SPREAD SNOW ACROSS
THE CWA. SLOWED POPS SLIGHTLY FROM PREVIOUS FORECAST BUT STILL
BRING LIKELY POPS TO PIT/HLG BY 12Z. SNOW COULD START EARLY ENOUGH
TO GET A FRESH INCH ON THE GROUND NEAR ZZV BY 12Z...WITH LESSER
AMOUNTS TO THE NORTH AND EAST.

TEMPERATURES MODIFIED SLIGHTLY FROM PREVIOUS FORECAST...MAINLY BY
BLENDING IN NAM/MET.



&&

.SHORT TERM /SUNDAY THROUGH MONDAY/...
PRECIPITATION WILL START OVERSPREADING THE AREA WEST TO EAST ACROSS
THE SFC COLD FRONT SUNDAY AHEAD OF THE VIGOROUS LOW MOVING OUT OF
THE PLAINS. SNOW WILL BE THE PRIMARY PRECIPITATION TYPE AS THE EVENT
BEGINS EARLY SUN. LATER SUN AFTERNOON SNOW WILL REMAIN NORTH OF
I-70...BUT A MIX OR PLAIN RAIN CAN BE EXPECTED SOUTH OF I-70 AS
TEMPERATURES WARM.

THE LOW INTENSIFIES AS IT ENTERS THE OHIO RIVER VALLEY...BOLSTERED
ALOFT AS TWO JET STREAKS TEMPORARILY PHASE TO MAXIMIZE UPPER LEVEL
DIVERGENCE. INTENSIFICATION OF THE LOW WILL AMPLIFY THE LLVL WIND
FIELD RESULTING IN A STRONG 50+ KT H85 JET NOSING INTO SWPA.
NAM/SREF/GFS ALL SHOW THE TRACK OF THE H85 LOW A LITTLE FURTHER
NORTH THAN THAT OF THE ECMWF AND NORTH OF PREVIOUS RUNS. AS THE
CLOSED H85 LOW TRACKS THROUGH NCENTRAL OHIO...THIS MEANS THAT WAA
WILL BRING POSITIVE H85 ISOTHERMS INTO NRN WV AND SWPA THROUGH EARLY
MON MORNING. THIS KEEPS RAIN OR A RAIN/SNOW MIX SOUTH OF I-70 BEFORE
THE COLD AIR PUSHES IN ON THE BACKSIDE OF THE LOW MON MORNING. THIS
SLIGHTLY WARMER SOLN MARKS THE LARGEST CHANGE MADE TO THE PREVIOUS
FORECAST.

LARGELY KEPT THE QPF PLACEMENT AND NUMBERS THE SAME...BLENDING THE
LATEST WPC GUIDANCE WITH THE PREVIOUS NUMBERS. THE WARMER AIR
INVADING UP THE WRN SLOPES OF THE RIDGES WILL WORK TO KEEP OUR SERN
ZONES RAIN LONGER AND ULTIMATELY CUT INTO SNOW TOTALS FOR THE
DURATION OF THE EVENT. HOW FAR NORTH THAT WARM AIR IS ABLE TO INVADE
IS ANOTHER QUESTION. IF THE H85 LOW FOLLOWS THE CURRENT ECMWF
TRACK...THE PGH METRO WILL STAY NEARLY ALL SNOW. IF IT FOLLOWS THE
MORE NORTHERN TRACK...SEVERAL HOURS OF RAIN DURING THE TIME OF BEST
PRECIPITATION COULD CUT INTO THE PGH METRO TOTALS AS WELL.

ALL TOLD...A GENERAL 8-10" NORTH ALONG THE I-80
CORRIDOR...BUT TIGHTENED THE ACCUMULATION GRADIENT NEAR THE PGH
METRO WITH NRN ALLEGHENY COUNTY IN THE 5-7" RANGE AND SRN PORTIONS
OF THE COUNTY IN THE 3-5" RANGE. TRIMMED BACK TOTALS ACROSS THE SRN
EXTENT OF THE CWA AS WELL WITH MANY LOCATIONS IN THE 1-3" RANGE. IF
THE WARMER SOLNS WIN OUT...NUMBERS ACROSS THE SOUTH COULD BE CLOSER
TO THE 1" SIDE OF THAT RANGE. WITH QUESTIONS SURROUNDING THE TRACK
AND EXTENT OF WARM AIR...A WELL COLLABORATED DECISION WAS MADE TO
HOLD WITH THE WINTER STORM WATCH IN PLACE.
TAX

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
LLVL MOISTURE WILL LINGER IN THE HIGH ACROSS THE HIGH TERRAIN
THROUGH THE PRE-DAWN HOURS TUES...BUT ANY CHC OF PRECIPITATION WILL
BE FLEETING AS SFC HIGH PRESSURE WILL BUILD IN FROM THE WEST. NRN
AXIS OF THE SFC RIDGE WILL QUICKLY SHIFT EAST OF THE AREA TUES UNDER
ZONAL FLOW ALOFT. SERN EXTENT OF THE HIGH WILL HOLD BACK TO THE
WEST...AND WILL TRY TO HOLD THE NEXT SYSTEM OFF TO OUR NORTH. A WEAK
SFC LOW PASSES NORTH WEDS...BUT WILL WORK TO AMPLIFY THE UPPER TROF.
THE TRAILING COLD FRONT SWINGS THROUGH WEDS NIGHT/THURS
MORNING...BRINGING THE BEST CHANCE OF POPS IN THE EXTENDED PERIOD.
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 7 DAY PERIOD.
TAX

&&

.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
MVFR STRATOCU CONTINUE TO ERODE SLOWLY FROM THE WEST...WITH ONLY A
FEW SHSN/FLURRIES REMAINING...AS LAKE HURON CONNECTION GETS CUT
OFF WITH WINDS BACKING TO WEST. ONCE THESE BREAK UP...VFR WITH
ONLY SCT AC EXPECTED OVERNIGHT THROUGH SUNRISE SATURDAY. SOME
BORDERLINE MVFR CIGS SATURDAY AFTERNOON WITH WARM FRONTAL ACTION.
VFR THEN EXPECTED TO RETURN FOR THE EVENING...BUT MID/HI CLOUDS
WILL BE ON THE INCREASE. HINT AT FIRST -SN AT PIT AROUND 09Z
SUNDAY WITH NEXT STORM SYSTEM.  CL


.OUTLOOK.../SATURDAY NIGHT THROUGH WEDNESDAY/...
WIDESPREAD RESTRICTIONS CAN BE EXPECTED SUNDAY AND MONDAY AS A LOW
PRESSURE SYSTEM CROSSES THE REGION.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR MDZ001.
     WIND CHILL ADVISORY UNTIL 10 AM EST THIS MORNING FOR MDZ001.
OH...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR OHZ039>041-048>050-057>059.
PA...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR PAZ007>009-013>016-020>023-029-073>076.
     WIND CHILL ADVISORY UNTIL 10 AM EST THIS MORNING FOR PAZ008-
     009-015-016-023-074-076.
WV...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR WVZ001>003-023-041.
     WIND CHILL ADVISORY UNTIL 10 AM EST THIS MORNING FOR WVZ023-
     041.

&&

$$










000
FXUS61 KPBZ 311013
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
401 AM EST SAT JAN 31 2015

.SYNOPSIS...
HIGH PRESSURE WILL BUILD IN THROUGH SATURDAY. LOW PRESSURE WILL
BRING WINTRY WEATHER SUNDAY INTO MONDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
STRATOCU DECK CONTINUES TO ERODE SLOWLY...WITH ONLY THE FAR
NORTHEASTERN CWA STILL UNDER THEIR INFLUENCE. THESE WILL CONTINUE
TO DISSIPATE...LEAVING MOSTLY CLEAR SKIES AND VERY COLD
TEMPERATURES. CONTINUED MINOR PUFF OF WIND HAS KEPT TEMPS FROM
REALLY BOTTOMING OUT SO FAR...BUT STILL EXPECT SOME BELOW ZERO
VALUES TO BE REALIZED THIS MORNING.

HIGH PRESSURE WILL KEEP CWA DRY TODAY. WEAK WARM FRONTAL PASSAGE
WILL ALLOW FOR SOME CU/SC CLOUDS LATER THIS MORNING AND THIS
AFTERNOON...WITH WARMER H925/H850 AIR ARRIVING ON THE HEELS OF
W/WNW WINDS JUST OFF THE SURFACE. LOWER CLOUDS WILL MOVE OFF LATER
IN THE DAY...TO BE REPLACED BY INCREASING MID/HI CLOUDS AHEAD OF
OUR WELL-ADVERTISED SUNDAY STORM.

TONIGHT...FRONTAL BOUNDARY BRIDGING FROM WEAK LOW DROPPING ACROSS
EASTERN GREAT LAKES...TO THE MORE SIGNIFICANT SURFACE SYSTEM
MOVING INTO MISSOURI... DROPS TOWARD THE NORTHERN CWA. AS THIS
OCCURS...MOISTURE BEGINS TO STREAK IN FROM THE WEST ESPECIALLY
AFTER 06Z. BEGINNINGS OF DEEP LIFT DRIVEN VIA ISENTROPIC ASCENT
AND RRQ OF H250 JET TO THE NORTH WILL START TO SPREAD SNOW ACROSS
THE CWA. SLOWED POPS SLIGHTLY FROM PREVIOUS FORECAST BUT STILL
BRING LIKELY POPS TO PIT/HLG BY 12Z. SNOW COULD START EARLY ENOUGH
TO GET A FRESH INCH ON THE GROUND NEAR ZZV BY 12Z...WITH LESSER
AMOUNTS TO THE NORTH AND EAST.

TEMPERATURES MODIFIED SLIGHTLY FROM PREVIOUS FORECAST...MAINLY BY
BLENDING IN NAM/MET.



&&

.SHORT TERM /SUNDAY THROUGH MONDAY/...
PRECIPITATION WILL START OVERSPREADING THE AREA WEST TO EAST ACROSS
THE SFC COLD FRONT SUNDAY AHEAD OF THE VIGOROUS LOW MOVING OUT OF
THE PLAINS. SNOW WILL BE THE PRIMARY PRECIPITATION TYPE AS THE EVENT
BEGINS EARLY SUN. LATER SUN AFTERNOON SNOW WILL REMAIN NORTH OF
I-70...BUT A MIX OR PLAIN RAIN CAN BE EXPECTED SOUTH OF I-70 AS
TEMPERATURES WARM.

THE LOW INTENSIFIES AS IT ENTERS THE OHIO RIVER VALLEY...BOLSTERED
ALOFT AS TWO JET STREAKS TEMPORARILY PHASE TO MAXIMIZE UPPER LEVEL
DIVERGENCE. INTENSIFICATION OF THE LOW WILL AMPLIFY THE LLVL WIND
FIELD RESULTING IN A STRONG 50+ KT H85 JET NOSING INTO SWPA.
NAM/SREF/GFS ALL SHOW THE TRACK OF THE H85 LOW A LITTLE FURTHER
NORTH THAN THAT OF THE ECMWF AND NORTH OF PREVIOUS RUNS. AS THE
CLOSED H85 LOW TRACKS THROUGH NCENTRAL OHIO...THIS MEANS THAT WAA
WILL BRING POSITIVE H85 ISOTHERMS INTO NRN WV AND SWPA THROUGH EARLY
MON MORNING. THIS KEEPS RAIN OR A RAIN/SNOW MIX SOUTH OF I-70 BEFORE
THE COLD AIR PUSHES IN ON THE BACKSIDE OF THE LOW MON MORNING. THIS
SLIGHTLY WARMER SOLN MARKS THE LARGEST CHANGE MADE TO THE PREVIOUS
FORECAST.

LARGELY KEPT THE QPF PLACEMENT AND NUMBERS THE SAME...BLENDING THE
LATEST WPC GUIDANCE WITH THE PREVIOUS NUMBERS. THE WARMER AIR
INVADING UP THE WRN SLOPES OF THE RIDGES WILL WORK TO KEEP OUR SERN
ZONES RAIN LONGER AND ULTIMATELY CUT INTO SNOW TOTALS FOR THE
DURATION OF THE EVENT. HOW FAR NORTH THAT WARM AIR IS ABLE TO INVADE
IS ANOTHER QUESTION. IF THE H85 LOW FOLLOWS THE CURRENT ECMWF
TRACK...THE PGH METRO WILL STAY NEARLY ALL SNOW. IF IT FOLLOWS THE
MORE NORTHERN TRACK...SEVERAL HOURS OF RAIN DURING THE TIME OF BEST
PRECIPITATION COULD CUT INTO THE PGH METRO TOTALS AS WELL.

ALL TOLD...A GENERAL 8-10" NORTH ALONG THE I-80
CORRIDOR...BUT TIGHTENED THE ACCUMULATION GRADIENT NEAR THE PGH
METRO WITH NRN ALLEGHENY COUNTY IN THE 5-7" RANGE AND SRN PORTIONS
OF THE COUNTY IN THE 3-5" RANGE. TRIMMED BACK TOTALS ACROSS THE SRN
EXTENT OF THE CWA AS WELL WITH MANY LOCATIONS IN THE 1-3" RANGE. IF
THE WARMER SOLNS WIN OUT...NUMBERS ACROSS THE SOUTH COULD BE CLOSER
TO THE 1" SIDE OF THAT RANGE. WITH QUESTIONS SURROUNDING THE TRACK
AND EXTENT OF WARM AIR...A WELL COLLABORATED DECISION WAS MADE TO
HOLD WITH THE WINTER STORM WATCH IN PLACE.
TAX

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
LLVL MOISTURE WILL LINGER IN THE HIGH ACROSS THE HIGH TERRAIN
THROUGH THE PRE-DAWN HOURS TUES...BUT ANY CHC OF PRECIPITATION WILL
BE FLEETING AS SFC HIGH PRESSURE WILL BUILD IN FROM THE WEST. NRN
AXIS OF THE SFC RIDGE WILL QUICKLY SHIFT EAST OF THE AREA TUES UNDER
ZONAL FLOW ALOFT. SERN EXTENT OF THE HIGH WILL HOLD BACK TO THE
WEST...AND WILL TRY TO HOLD THE NEXT SYSTEM OFF TO OUR NORTH. A WEAK
SFC LOW PASSES NORTH WEDS...BUT WILL WORK TO AMPLIFY THE UPPER TROF.
THE TRAILING COLD FRONT SWINGS THROUGH WEDS NIGHT/THURS
MORNING...BRINGING THE BEST CHANCE OF POPS IN THE EXTENDED PERIOD.
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 7 DAY PERIOD.
TAX

&&

.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
MVFR STRATOCU CONTINUE TO ERODE SLOWLY FROM THE WEST...WITH ONLY A
FEW SHSN/FLURRIES REMAINING...AS LAKE HURON CONNECTION GETS CUT
OFF WITH WINDS BACKING TO WEST. ONCE THESE BREAK UP...VFR WITH
ONLY SCT AC EXPECTED OVERNIGHT THROUGH SUNRISE SATURDAY. SOME
BORDERLINE MVFR CIGS SATURDAY AFTERNOON WITH WARM FRONTAL ACTION.
VFR THEN EXPECTED TO RETURN FOR THE EVENING...BUT MID/HI CLOUDS
WILL BE ON THE INCREASE. HINT AT FIRST -SN AT PIT AROUND 09Z
SUNDAY WITH NEXT STORM SYSTEM.  CL


.OUTLOOK.../SATURDAY NIGHT THROUGH WEDNESDAY/...
WIDESPREAD RESTRICTIONS CAN BE EXPECTED SUNDAY AND MONDAY AS A LOW
PRESSURE SYSTEM CROSSES THE REGION.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR MDZ001.
     WIND CHILL ADVISORY UNTIL 10 AM EST THIS MORNING FOR MDZ001.
OH...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR OHZ039>041-048>050-057>059.
PA...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR PAZ007>009-013>016-020>023-029-073>076.
     WIND CHILL ADVISORY UNTIL 10 AM EST THIS MORNING FOR PAZ008-
     009-015-016-023-074-076.
WV...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR WVZ001>003-023-041.
     WIND CHILL ADVISORY UNTIL 10 AM EST THIS MORNING FOR WVZ023-
     041.

&&

$$











000
FXUS61 KPBZ 310546
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1246 AM EST SAT JAN 31 2015

.SYNOPSIS...
HIGH PRESSURE WILL BUILD IN THROUGH SATURDAY. LOW PRESSURE WILL
BRING WINTRY WEATHER SUNDAY INTO MONDAY.

&&

.NEAR TERM /THROUGH TODAY/...
THE FAA TERMINAL DOPPLER RADAR INDICATES ONLY A COUPLE OF
MICROSCALE SNOW BANDS REMAIN...ONE OVER MOSTLY WASHINGTON
COUNTY...AND ANOTHER MUCH WEAKER ONE OVER SOUTHWESTERN ALLEGHENY
COUNTY. MODEL SOUNDINGS FROM BOTH THE RAP AND HRRR SHOW A SCENARIO
WHEREBY INVERSION HEIGHTS ARE FALLING SIMULTANEOUSLY WITH BOUNDARY
LAYER MOISTURE DEPTH DECREASING AS WELL. LIKEWISE...UPSTREAM
ACTIVITY OFF OF LAKE HURON IS QUICKLY FALLING APART...AND THE
TREND TOWARD ANY ADDITIONAL INPUT FROM THE SLIVER OF LAKE ERIE
THAT IS OPEN WILL NOT BE PARTICULARLY HELPFUL TO REGENERATION OF
ANY OF THE BANDS. THAT SAID...ACTIVITY WILL LIKELY TAKE A FEW
HOURS TO WANE WITH THE UPSLOPE AREAS TAKING THE LONGEST TO FULLY
HALT THEIR SNOW SHOWER AND FLURRY ACTION.

NORTHWESTERLY FLOW CONTINUES THROUGH MUCH OF THE EVENING HOURS
BEFORE SLOWLY TURNING WEST OVERNIGHT AS A SURFACE HIGH BUILDS
GENERALLY JUST TO THE SOUTH OF THE REGION. WITH AT THE VERY LEAST
PARTIAL CLEARING...IF NOT FULL CLEARING AT TIMES...TEMPERATURES
SHOULD DROP RAPIDLY WITH NEW SNOW COVER. THIS COMBINED WITH
DECREASING YET STILL BRISK SURFACE FLOW WILL ALLOW FOR WIND CHILL
ADVISORY CRITERIA WIND CHILL INDEX VALUES BY MORNING OVER THE HIGHER
TERRAIN AND NORTHEASTERN CWA. THIS IS IN LINE WITH CURRENT
HEADLINES...AND NO ADDITIONAL EXPANSION OF THESE HEADLINES ARE
ANTICIPATED AT THIS TIME. HOWEVER...WITH RAPID CLEARING AND NEW
SNOW ON THE GROUND...ALL AREAS WILL LIKELY BE VERY COLD BY
MORNING...WITH MANY PORTIONS OF THE CWA CHALLENGING OR EVEN
DROPPING BELOW ZERO BY THAT JUNCTURE.

SOME WARMER AIR DOES START TO FLOW NORTHWARD ON SATURDAY AS THE
SURFACE HIGH AXIS MOVES TO THE EAST OF THE AREA AND SOUTHWESTERLY
FLOW PREVAILS FOR A TIME. EXPECTATIONS SHOULD BE
MUTED...THOUGH...AS SUCH A COLD START AND WEAK VERTICAL MIXING
WILL LIKELY KEEP MOST OF THE AREA IN THE 20S. FRIES

&&

.SHORT TERM /TONIGHT THROUGH MONDAY/...
HIGH PRES SHOULD CONT DRY WEA INTO SAT EVE. A DIGGING UPR TROF IS
PROGGED TO ADVN OUT OF THE PLAINS AND TRACK ACRS THE GT LKS AND
OH VLY RGN SUN INTO MON. ASSOCIATED SFC LOW PRES IS PROGGED TO
DEEPEN AS IT MOVES ACRS THE TN AND OH VLY RGNS ALSO. THIS WL
SPREAD SNW INTO THE RGN LT SAT NGT THRU MON MRNG WITH DEEP
AVAILABLE MSTR AND OMEGA.

WITH A CLOSED 850MB LOW...A MORE PROLONGED PCPN EVENT IS EXPD AS
OPPOSED TO THE OPEN SYSTEM EARLIER IN THE WK. WITH ENOUGH
POTENTIAL FOR HEAVY SNW OR A SNW/ICE MIX...ISSUED A WINTER STORM
WATCH FOR MUCH OF THE AREA. LEFT AREAS GENLY S OF I 70 OUT OF THE
WATCH...EXCEPT FOR THE WV/MD RIDGES...AS ENOUGH WRM AIR IS EXPD TO
WRAP IN AHD OF THE LOW TO ALLOW FOR A RAIN/SNW MIX OR EVEN A PD OF
ALL RAIN. AREAS BETWEEN I 70- AND I 80 COULD SEE ENOUGH WRM AIR
ALOFT FOR FRZG RAIN TO MIX IN AT TIMES AS WELL. GENLY FOLLOWED A
SREF/GFS/ECMWF MDL BLEND TO WORK OUT THE DETAILS...AND USED
CRITICAL THICKNESSES/MDL SOUNDING PROFILES FOR PCPN TYPE. BEST
POTENTIAL FOR GREATER THAN 6 INCHES OF SNW EXISTS N OF PIT BASED
ON LATEST MDL GUIDANCE...THOUGH THIS WL BE REFINED OVR THE NXT
COUPLE OF DAYS.

SNW SHOULD CONT MON UNTIL THE UPR TROF AXIS SHIFTS E IN THE AFTN.
NUDGED TEMPS TO THE LATEST COLDER THAN SEASONAL AVG SREF GUIDANCE.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
A COLD...WINTER PATTERN WILL CONTINUE FOR THE REST OF THE LONG
TERM. THE NEXT BEST CHANCE FOR SNOW SHOWERS WILL ARRIVE LATE IN
THE PERIOD.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
MVFR STRATOCU CONTINUE TO ERODE SLOWLY FROM THE WEST...WITH ONLY A
FEW SHSN/FLURRIES REMAINING...AS LAKE HURON CONNECTION GETS CUT
OFF WITH WINDS BACKING TO WEST. ONCE THESE BREAK UP...VFR WITH
ONLY SCT AC EXPECTED OVERNIGHT THROUGH SUNRISE SATURDAY. SOME
BORDERLINE MVFR CIGS SATURDAY AFTERNOON WITH WARM FRONTAL ACTION.
VFR THEN EXPECTED TO RETURN FOR THE EVENING...BUT MID/HI CLOUDS
WILL BE ON THE INCREASE. HINT AT FIRST -SN AT PIT AROUND 09Z
SUNDAY WITH NEXT STORM SYSTEM.  CL


.OUTLOOK.../SATURDAY NIGHT THROUGH WEDNESDAY/...
WIDESPREAD RESTRICTIONS CAN BE EXPECTED SUNDAY AND MONDAY AS A LOW
PRESSURE SYSTEM CROSSES THE REGION.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR MDZ001.
     WIND CHILL ADVISORY UNTIL 10 AM EST THIS MORNING FOR MDZ001.
OH...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR OHZ039>041-048>050-057>059.
PA...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR PAZ007>009-013>016-020>023-029-073>076.
     WIND CHILL ADVISORY UNTIL 10 AM EST THIS MORNING FOR PAZ008-
     009-015-016-023-074-076.
WV...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR WVZ001>003-023-041.
     WIND CHILL ADVISORY UNTIL 10 AM EST THIS MORNING FOR WVZ023-
     041.

&&

$$







000
FXUS61 KPBZ 310546
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1246 AM EST SAT JAN 31 2015

.SYNOPSIS...
HIGH PRESSURE WILL BUILD IN THROUGH SATURDAY. LOW PRESSURE WILL
BRING WINTRY WEATHER SUNDAY INTO MONDAY.

&&

.NEAR TERM /THROUGH TODAY/...
THE FAA TERMINAL DOPPLER RADAR INDICATES ONLY A COUPLE OF
MICROSCALE SNOW BANDS REMAIN...ONE OVER MOSTLY WASHINGTON
COUNTY...AND ANOTHER MUCH WEAKER ONE OVER SOUTHWESTERN ALLEGHENY
COUNTY. MODEL SOUNDINGS FROM BOTH THE RAP AND HRRR SHOW A SCENARIO
WHEREBY INVERSION HEIGHTS ARE FALLING SIMULTANEOUSLY WITH BOUNDARY
LAYER MOISTURE DEPTH DECREASING AS WELL. LIKEWISE...UPSTREAM
ACTIVITY OFF OF LAKE HURON IS QUICKLY FALLING APART...AND THE
TREND TOWARD ANY ADDITIONAL INPUT FROM THE SLIVER OF LAKE ERIE
THAT IS OPEN WILL NOT BE PARTICULARLY HELPFUL TO REGENERATION OF
ANY OF THE BANDS. THAT SAID...ACTIVITY WILL LIKELY TAKE A FEW
HOURS TO WANE WITH THE UPSLOPE AREAS TAKING THE LONGEST TO FULLY
HALT THEIR SNOW SHOWER AND FLURRY ACTION.

NORTHWESTERLY FLOW CONTINUES THROUGH MUCH OF THE EVENING HOURS
BEFORE SLOWLY TURNING WEST OVERNIGHT AS A SURFACE HIGH BUILDS
GENERALLY JUST TO THE SOUTH OF THE REGION. WITH AT THE VERY LEAST
PARTIAL CLEARING...IF NOT FULL CLEARING AT TIMES...TEMPERATURES
SHOULD DROP RAPIDLY WITH NEW SNOW COVER. THIS COMBINED WITH
DECREASING YET STILL BRISK SURFACE FLOW WILL ALLOW FOR WIND CHILL
ADVISORY CRITERIA WIND CHILL INDEX VALUES BY MORNING OVER THE HIGHER
TERRAIN AND NORTHEASTERN CWA. THIS IS IN LINE WITH CURRENT
HEADLINES...AND NO ADDITIONAL EXPANSION OF THESE HEADLINES ARE
ANTICIPATED AT THIS TIME. HOWEVER...WITH RAPID CLEARING AND NEW
SNOW ON THE GROUND...ALL AREAS WILL LIKELY BE VERY COLD BY
MORNING...WITH MANY PORTIONS OF THE CWA CHALLENGING OR EVEN
DROPPING BELOW ZERO BY THAT JUNCTURE.

SOME WARMER AIR DOES START TO FLOW NORTHWARD ON SATURDAY AS THE
SURFACE HIGH AXIS MOVES TO THE EAST OF THE AREA AND SOUTHWESTERLY
FLOW PREVAILS FOR A TIME. EXPECTATIONS SHOULD BE
MUTED...THOUGH...AS SUCH A COLD START AND WEAK VERTICAL MIXING
WILL LIKELY KEEP MOST OF THE AREA IN THE 20S. FRIES

&&

.SHORT TERM /TONIGHT THROUGH MONDAY/...
HIGH PRES SHOULD CONT DRY WEA INTO SAT EVE. A DIGGING UPR TROF IS
PROGGED TO ADVN OUT OF THE PLAINS AND TRACK ACRS THE GT LKS AND
OH VLY RGN SUN INTO MON. ASSOCIATED SFC LOW PRES IS PROGGED TO
DEEPEN AS IT MOVES ACRS THE TN AND OH VLY RGNS ALSO. THIS WL
SPREAD SNW INTO THE RGN LT SAT NGT THRU MON MRNG WITH DEEP
AVAILABLE MSTR AND OMEGA.

WITH A CLOSED 850MB LOW...A MORE PROLONGED PCPN EVENT IS EXPD AS
OPPOSED TO THE OPEN SYSTEM EARLIER IN THE WK. WITH ENOUGH
POTENTIAL FOR HEAVY SNW OR A SNW/ICE MIX...ISSUED A WINTER STORM
WATCH FOR MUCH OF THE AREA. LEFT AREAS GENLY S OF I 70 OUT OF THE
WATCH...EXCEPT FOR THE WV/MD RIDGES...AS ENOUGH WRM AIR IS EXPD TO
WRAP IN AHD OF THE LOW TO ALLOW FOR A RAIN/SNW MIX OR EVEN A PD OF
ALL RAIN. AREAS BETWEEN I 70- AND I 80 COULD SEE ENOUGH WRM AIR
ALOFT FOR FRZG RAIN TO MIX IN AT TIMES AS WELL. GENLY FOLLOWED A
SREF/GFS/ECMWF MDL BLEND TO WORK OUT THE DETAILS...AND USED
CRITICAL THICKNESSES/MDL SOUNDING PROFILES FOR PCPN TYPE. BEST
POTENTIAL FOR GREATER THAN 6 INCHES OF SNW EXISTS N OF PIT BASED
ON LATEST MDL GUIDANCE...THOUGH THIS WL BE REFINED OVR THE NXT
COUPLE OF DAYS.

SNW SHOULD CONT MON UNTIL THE UPR TROF AXIS SHIFTS E IN THE AFTN.
NUDGED TEMPS TO THE LATEST COLDER THAN SEASONAL AVG SREF GUIDANCE.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
A COLD...WINTER PATTERN WILL CONTINUE FOR THE REST OF THE LONG
TERM. THE NEXT BEST CHANCE FOR SNOW SHOWERS WILL ARRIVE LATE IN
THE PERIOD.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
MVFR STRATOCU CONTINUE TO ERODE SLOWLY FROM THE WEST...WITH ONLY A
FEW SHSN/FLURRIES REMAINING...AS LAKE HURON CONNECTION GETS CUT
OFF WITH WINDS BACKING TO WEST. ONCE THESE BREAK UP...VFR WITH
ONLY SCT AC EXPECTED OVERNIGHT THROUGH SUNRISE SATURDAY. SOME
BORDERLINE MVFR CIGS SATURDAY AFTERNOON WITH WARM FRONTAL ACTION.
VFR THEN EXPECTED TO RETURN FOR THE EVENING...BUT MID/HI CLOUDS
WILL BE ON THE INCREASE. HINT AT FIRST -SN AT PIT AROUND 09Z
SUNDAY WITH NEXT STORM SYSTEM.  CL


.OUTLOOK.../SATURDAY NIGHT THROUGH WEDNESDAY/...
WIDESPREAD RESTRICTIONS CAN BE EXPECTED SUNDAY AND MONDAY AS A LOW
PRESSURE SYSTEM CROSSES THE REGION.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR MDZ001.
     WIND CHILL ADVISORY UNTIL 10 AM EST THIS MORNING FOR MDZ001.
OH...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR OHZ039>041-048>050-057>059.
PA...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR PAZ007>009-013>016-020>023-029-073>076.
     WIND CHILL ADVISORY UNTIL 10 AM EST THIS MORNING FOR PAZ008-
     009-015-016-023-074-076.
WV...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING
     FOR WVZ001>003-023-041.
     WIND CHILL ADVISORY UNTIL 10 AM EST THIS MORNING FOR WVZ023-
     041.

&&

$$








000
FXUS61 KPBZ 310238
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
938 PM EST FRI JAN 30 2015

.SYNOPSIS...
HIGH PRESSURE WILL BUILD IN THROUGH SATURDAY. LOW PRESSURE WILL
BRING WINTRY WEATHER SUNDAY INTO MONDAY.

&&

.NEAR TERM /THROUGH SATURDAY/...
THE FAA TERMINAL DOPPLER RADAR INDICATES ONLY A COUPLE OF
MICROSCALE SNOW BANDS REMAIN...ONE OVER MOSTLY WASHINGTON
COUNTY...AND ANOTHER MUCH WEAKER ONE OVER SOUTHWESTERN ALLEGHENY
COUNTY. MODEL SOUNDINGS FROM BOTH THE RAP AND HRRR SHOW A SCENARIO
WHEREBY INVERSION HEIGHTS ARE FALLING SIMULTANEOUSLY WITH BOUNDARY
LAYER MOISTURE DEPTH DECREASING AS WELL. LIKEWISE...UPSTREAM
ACTIVITY OFF OF LAKE HURON IS QUICKLY FALLING APART...AND THE
TREND TOWARD ANY ADDITIONAL INPUT FROM THE SLIVER OF LAKE ERIE
THAT IS OPEN WILL NOT BE PARTICULARLY HELPFUL TO REGENERATION OF
ANY OF THE BANDS. THAT SAID...ACTIVITY WILL LIKELY TAKE A FEW
HOURS TO WANE WITH THE UPSLOPE AREAS TAKING THE LONGEST TO FULLY
HALT THEIR SNOW SHOWER AND FLURRY ACTION.

NORTHWESTERLY FLOW CONTINUES THROUGH MUCH OF THE EVENING HOURS
BEFORE SLOWLY TURNING WEST OVERNIGHT AS A SURFACE HIGH BUILDS
GENERALLY JUST TO THE SOUTH OF THE REGION. WITH AT THE VERY LEAST
PARTIAL CLEARING...IF NOT FULL CLEARING AT TIMES...TEMPERATURES
SHOULD DROP RAPIDLY WITH NEW SNOW COVER. THIS COMBINED WITH
DECREASING YET STILL BRISK SURFACE FLOW WILL ALLOW FOR WIND CHILL
ADVISORY CRITERIA WIND CHILL INDEX VALUES BY MORNING OVER THE HIGHER
TERRAIN AND NORTHEASTERN CWA. THIS IS IN LINE WITH CURRENT
HEADLINES...AND NO ADDITIONAL EXPANSION OF THESE HEADLINES ARE
ANTICIPATED AT THIS TIME. HOWEVER...WITH RAPID CLEARING AND NEW
SNOW ON THE GROUND...ALL AREAS WILL LIKELY BE VERY COLD BY
MORNING...WITH MANY PORTIONS OF THE CWA CHALLENGING OR EVEN
DROPPING BELOW ZERO BY THAT JUNCTURE.

SOME WARMER AIR DOES START TO FLOW NORTHWARD ON SATURDAY AS THE
SURFACE HIGH AXIS MOVES TO THE EAST OF THE AREA AND SOUTHWESTERLY
FLOW PREVAILS FOR A TIME. EXPECTATIONS SHOULD BE
MUTED...THOUGH...AS SUCH A COLD START AND WEAK VERTICAL MIXING
WILL LIKELY KEEP MOST OF THE AREA IN THE 20S. FRIES

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
HIGH PRES SHOULD CONT DRY WEA INTO SAT EVE. A DIGGING UPR TROF IS
PROGGED TO ADVN OUT OF THE PLAINS AND TRACK ACRS THE GT LKS AND
OH VLY RGN SUN INTO MON. ASSOCIATED SFC LOW PRES IS PROGGED TO
DEEPEN AS IT MOVES ACRS THE TN AND OH VLY RGNS ALSO. THIS WL
SPREAD SNW INTO THE RGN LT SAT NGT THRU MON MRNG WITH DEEP
AVAILABLE MSTR AND OMEGA.

WITH A CLOSED 850MB LOW...A MORE PROLONGED PCPN EVENT IS EXPD AS
OPPOSED TO THE OPEN SYSTEM EARLIER IN THE WK. WITH ENOUGH
POTENTIAL FOR HEAVY SNW OR A SNW/ICE MIX...ISSUED A WINTER STORM
WATCH FOR MUCH OF THE AREA. LEFT AREAS GENLY S OF I 70 OUT OF THE
WATCH...EXCEPT FOR THE WV/MD RIDGES...AS ENOUGH WRM AIR IS EXPD TO
WRAP IN AHD OF THE LOW TO ALLOW FOR A RAIN/SNW MIX OR EVEN A PD OF
ALL RAIN. AREAS BETWEEN I 70- AND I 80 COULD SEE ENOUGH WRM AIR
ALOFT FOR FRZG RAIN TO MIX IN AT TIMES AS WELL. GENLY FOLLOWED A
SREF/GFS/ECMWF MDL BLEND TO WORK OUT THE DETAILS...AND USED
CRITICAL THICKNESSES/MDL SOUNDING PROFILES FOR PCPN TYPE. BEST
POTENTIAL FOR GREATER THAN 6 INCHES OF SNW EXISTS N OF PIT BASED
ON LATEST MDL GUIDANCE...THOUGH THIS WL BE REFINED OVR THE NXT
COUPLE OF DAYS.

SNW SHOULD CONT MON UNTIL THE UPR TROF AXIS SHIFTS E IN THE AFTN.
NUDGED TEMPS TO THE LATEST COLDER THAN SEASONAL AVG SREF GUIDANCE.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
A COLD...WINTER PATTERN WILL CONTINUE FOR THE REST OF THE LONG
TERM. THE NEXT BEST CHANCE FOR SNOW SHOWERS WILL ARRIVE LATE IN
THE PERIOD.

&&

.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
LINGERING MVFR STRATOCUMULUS AND SNOW SHOWERS CONTINUE TO PLAGUE
SEVERAL OF THE TAF SITES EARLY TONIGHT. THIS IS IN PART DUE TO
WHAT LOOKS TO BE AN UPSTREAM CONNECTION WITH MOISTURE FROM LAKE
HURON. SUBSIDENCE FROM THE BUILDING RIDGE AND A WESTERLY WIND
SHIFT WILL HELP TO DIMINISH THE CLOUD COVER AND IMPROVE CONDITIONS OVER
NEXT FEW HOURS...WITH THE HRRR AND RUC SUGGESTING VFR CONDITIONS
BY 03Z. IN ADDITION...WINDS WILL WEAKEN WITH THE BUILDING HIGH
PRESSURE....WITH NEARLY CALM WIND ANTICIPATED OVERNIGHT. VFR
CONDITIONS WILL REMAIN THROUGH THE REST OF THE TAF PERIOD...WITH
HIGH CLOUDS AND SOME DIURNAL CU DEVELOPING SATURDAY AFTERNOON
AHEAD OF THE SYSTEM PROGGED FOR SUNDAY.

.OUTLOOK.../SATURDAY NIGHT THROUGH WEDNESDAY/...
WIDESPREAD RESTRICTIONS CAN BE EXPECTED SUNDAY AND MONDAY AS A LOW
PRESSURE SYSTEM CROSSES THE REGION.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
     MORNING FOR MDZ001.
     WIND CHILL ADVISORY UNTIL 10 AM EST SATURDAY FOR MDZ001.
OH...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
     MORNING FOR OHZ039>041-048>050-057>059.
PA...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
     MORNING FOR PAZ007>009-013>016-020>023-029-073>076.
     WIND CHILL ADVISORY UNTIL 10 AM EST SATURDAY FOR PAZ008-009-
     015-016-023-074-076.
WV...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
     MORNING FOR WVZ001>003-023-041.
     WIND CHILL ADVISORY UNTIL 10 AM EST SATURDAY FOR WVZ023-041.

&&

$$








000
FXUS61 KPBZ 310120
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
820 PM EST FRI JAN 30 2015

.SYNOPSIS...
HIGH PRESSURE WILL BUILD IN THROUGH SATURDAY. LOW PRESSURE WILL
BRING WINTRY WEATHER SUNDAY INTO MONDAY.

&&

.NEAR TERM /THROUGH SATURDAY/...
THE REGIONAL RADAR MOSAIC INDICATES SNOW SHOWER ACTIVITY...WHILE
STILL FAIRLY PERVASIVE...IS DEFINITELY IN A DOWNWARD TREND ACROSS
THE CWA THIS EVENING. MODEL SOUNDINGS FROM BOTH THE RAP AND HRRR
SHOW A SCENARIO WHEREBY INVERSION HEIGHTS ARE FALLING
SIMULTANEOUSLY WITH BOUNDARY LAYER MOISTURE DEPTH DECREASING AS
WELL. LIKEWISE...UPSTREAM ACTIVITY OFF OF LAKE HURON IS QUICKLY
FALLING APART...AND THE TREND TOWARD ANY ADDITIONAL INPUT FROM THE
SLIVER OF LAKE ERIE THAT IS OPEN WILL NOT BE PARTICULARLY HELPFUL
TO REGENERATION OF ANY OF THE BANDS. THAT SAID...ACTIVITY WILL
LIKELY TAKE A FEW HOURS TO WANE WITH THE UPSLOPE AREAS TAKING THE
LONGEST TO FULLY HALT THEIR SNOW SHOWER AND FLURRY ACTION.
HOWEVER...GIVEN THE DOWNWARD TREND IN ACTIVITY AND MINIMAL
ACCUMULATION EXPECTATIONS THE REST OF THE EVENING...WINTER WEATHER
ADVISORIES FOR THE HIGHER TERRAIN HAVE BEEN ALLOWED TO EXPIRE AS
SCHEDULED AT 7 PM.

NORTHWESTERLY FLOW CONTINUES THROUGH MUCH OF THE EVENING HOURS
BEFORE SLOWLY TURNING WEST OVERNIGHT AS A SURFACE HIGH BUILDS
GENERALLY JUST TO THE SOUTH OF THE REGION. WITH AT THE VERY LEAST
PARTIAL CLEARING...IF NOT FULL CLEARING AT TIMES...TEMPERATURES
SHOULD DROP RAPIDLY WITH NEW SNOW COVER. THIS COMBINED WITH
DECREASING YET STILL BRISK SURFACE FLOW WILL ALLOW FOR WIND CHILL
ADVISORY CRITERIA WIND CHILL INDEX VALUES BY MORNING OVER THE HIGHER
TERRAIN AND NORTHEASTERN CWA. THIS IS IN LINE WITH CURRENT
HEADLINES...AND NO ADDITIONAL EXPANSION OF THESE HEADLINES ARE
ANTICIPATED AT THIS TIME. HOWEVER...WITH RAPID CLEARING AND NEW
SNOW ON THE GROUND...ALL AREA WILL LIKELY BE VERY COLD BY
MORNING...WITH MANY PORTIONS OF THE CWA CHALLENGING ZERO BY THAT
JUNCTURE.

SOME WARMER AIR DOES START TO FLOW NORTHWARD ON SATURDAY AS THE
SURFACE HIGH AXIS MOVES TO THE EAST OF THE AREA AND SOUTHWESTERLY
FLOW PREVAILS FOR A TIME. EXPECTATIONS SHOULD BE
MUTED...THOUGH...AS SUCH A COLD START AND WEAK VERTICAL MIXING
WILL LIKELY KEEP MOST OF THE AREA IN THE 20S. FRIES

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
HIGH PRES SHOULD CONT DRY WEA INTO SAT EVE. A DIGGING UPR TROF IS
PROGGED TO ADVN OUT OF THE PLAINS AND TRACK ACRS THE GT LKS AND
OH VLY RGN SUN INTO MON. ASSOCIATED SFC LOW PRES IS PROGGED TO
DEEPEN AS IT MOVES ACRS THE TN AND OH VLY RGNS ALSO. THIS WL
SPREAD SNW INTO THE RGN LT SAT NGT THRU MON MRNG WITH DEEP
AVAILABLE MSTR AND OMEGA.

WITH A CLOSED 850MB LOW...A MORE PROLONGED PCPN EVENT IS EXPD AS
OPPOSED TO THE OPEN SYSTEM EARLIER IN THE WK. WITH ENOUGH
POTENTIAL FOR HEAVY SNW OR A SNW/ICE MIX...ISSUED A WINTER STORM
WATCH FOR MUCH OF THE AREA. LEFT AREAS GENLY S OF I 70 OUT OF THE
WATCH...EXCEPT FOR THE WV/MD RIDGES...AS ENOUGH WRM AIR IS EXPD TO
WRAP IN AHD OF THE LOW TO ALLOW FOR A RAIN/SNW MIX OR EVEN A PD OF
ALL RAIN. AREAS BETWEEN I 70- AND I 80 COULD SEE ENOUGH WRM AIR
ALOFT FOR FRZG RAIN TO MIX IN AT TIMES AS WELL. GENLY FOLLOWED A
SREF/GFS/ECMWF MDL BLEND TO WORK OUT THE DETAILS...AND USED
CRITICAL THICKNESSES/MDL SOUNDING PROFILES FOR PCPN TYPE. BEST
POTENTIAL FOR GREATER THAN 6 INCHES OF SNW EXISTS N OF PIT BASED
ON LATEST MDL GUIDANCE...THOUGH THIS WL BE REFINED OVR THE NXT
COUPLE OF DAYS.

SNW SHOULD CONT MON UNTIL THE UPR TROF AXIS SHIFTS E IN THE AFTN.
NUDGED TEMPS TO THE LATEST COLDER THAN SEASONAL AVG SREF GUIDANCE.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
A COLD...WINTER PATTERN WILL CONTINUE FOR THE REST OF THE LONG
TERM. THE NEXT BEST CHANCE FOR SNOW SHOWERS WILL ARRIVE LATE IN
THE PERIOD.

&&

.AVIATION /01Z SATURDAY THROUGH WEDNESDAY/...
LINGERING MVFR STRATOCUMULUS AND SNOW SHOWERS CONTINUE TO PLAGUE
SEVERAL OF THE TAF SITES EARLY TONIGHT. THIS IS IN PART DUE TO
WHAT LOOKS TO BE AN UPSTREAM CONNECTION WITH MOISTURE FROM LAKE
HURON. SUBSIDENCE FROM THE BUILDING RIDGE AND A WESTERLY WIND
SHIFT WILL HELP TO DIMINISH THE CLOUD COVER AND IMPROVE CONDITIONS OVER
NEXT FEW HOURS...WITH THE HRRR AND RUC SUGGESTING VFR CONDITIONS
BY 03Z. IN ADDITION...WINDS WILL WEAKEN WITH THE BUILDING HIGH
PRESSURE....WITH NEARLY CALM WIND ANTICIPATED OVERNIGHT. VFR
CONDITIONS WILL REMAIN THROUGH THE REST OF THE TAF PERIOD...WITH
HIGH CLOUDS AND SOME DIURNAL CU DEVELOPING SATURDAY AFTERNOON
AHEAD OF THE SYSTEM PROGGED FOR SUNDAY.

.OUTLOOK.../SATURDAY NIGHT THROUGH WEDNESDAY/...
WIDESPREAD RESTRICTIONS CAN BE EXPECTED SUNDAY AND MONDAY AS A LOW
PRESSURE SYSTEM CROSSES THE REGION.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
     MORNING FOR MDZ001.
     WIND CHILL ADVISORY UNTIL 10 AM EST SATURDAY FOR MDZ001.
OH...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
     MORNING FOR OHZ039>041-048>050-057>059.
PA...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
     MORNING FOR PAZ007>009-013>016-020>023-029-073>076.
     WIND CHILL ADVISORY UNTIL 10 AM EST SATURDAY FOR PAZ008-009-
     015-016-023-074-076.
WV...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
     MORNING FOR WVZ001>003-023-041.
     WIND CHILL ADVISORY UNTIL 10 AM EST SATURDAY FOR WVZ023-041.

&&

$$














000
FXUS61 KPBZ 310120
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
820 PM EST FRI JAN 30 2015

.SYNOPSIS...
HIGH PRESSURE WILL BUILD IN THROUGH SATURDAY. LOW PRESSURE WILL
BRING WINTRY WEATHER SUNDAY INTO MONDAY.

&&

.NEAR TERM /THROUGH SATURDAY/...
THE REGIONAL RADAR MOSAIC INDICATES SNOW SHOWER ACTIVITY...WHILE
STILL FAIRLY PERVASIVE...IS DEFINITELY IN A DOWNWARD TREND ACROSS
THE CWA THIS EVENING. MODEL SOUNDINGS FROM BOTH THE RAP AND HRRR
SHOW A SCENARIO WHEREBY INVERSION HEIGHTS ARE FALLING
SIMULTANEOUSLY WITH BOUNDARY LAYER MOISTURE DEPTH DECREASING AS
WELL. LIKEWISE...UPSTREAM ACTIVITY OFF OF LAKE HURON IS QUICKLY
FALLING APART...AND THE TREND TOWARD ANY ADDITIONAL INPUT FROM THE
SLIVER OF LAKE ERIE THAT IS OPEN WILL NOT BE PARTICULARLY HELPFUL
TO REGENERATION OF ANY OF THE BANDS. THAT SAID...ACTIVITY WILL
LIKELY TAKE A FEW HOURS TO WANE WITH THE UPSLOPE AREAS TAKING THE
LONGEST TO FULLY HALT THEIR SNOW SHOWER AND FLURRY ACTION.
HOWEVER...GIVEN THE DOWNWARD TREND IN ACTIVITY AND MINIMAL
ACCUMULATION EXPECTATIONS THE REST OF THE EVENING...WINTER WEATHER
ADVISORIES FOR THE HIGHER TERRAIN HAVE BEEN ALLOWED TO EXPIRE AS
SCHEDULED AT 7 PM.

NORTHWESTERLY FLOW CONTINUES THROUGH MUCH OF THE EVENING HOURS
BEFORE SLOWLY TURNING WEST OVERNIGHT AS A SURFACE HIGH BUILDS
GENERALLY JUST TO THE SOUTH OF THE REGION. WITH AT THE VERY LEAST
PARTIAL CLEARING...IF NOT FULL CLEARING AT TIMES...TEMPERATURES
SHOULD DROP RAPIDLY WITH NEW SNOW COVER. THIS COMBINED WITH
DECREASING YET STILL BRISK SURFACE FLOW WILL ALLOW FOR WIND CHILL
ADVISORY CRITERIA WIND CHILL INDEX VALUES BY MORNING OVER THE HIGHER
TERRAIN AND NORTHEASTERN CWA. THIS IS IN LINE WITH CURRENT
HEADLINES...AND NO ADDITIONAL EXPANSION OF THESE HEADLINES ARE
ANTICIPATED AT THIS TIME. HOWEVER...WITH RAPID CLEARING AND NEW
SNOW ON THE GROUND...ALL AREA WILL LIKELY BE VERY COLD BY
MORNING...WITH MANY PORTIONS OF THE CWA CHALLENGING ZERO BY THAT
JUNCTURE.

SOME WARMER AIR DOES START TO FLOW NORTHWARD ON SATURDAY AS THE
SURFACE HIGH AXIS MOVES TO THE EAST OF THE AREA AND SOUTHWESTERLY
FLOW PREVAILS FOR A TIME. EXPECTATIONS SHOULD BE
MUTED...THOUGH...AS SUCH A COLD START AND WEAK VERTICAL MIXING
WILL LIKELY KEEP MOST OF THE AREA IN THE 20S. FRIES

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
HIGH PRES SHOULD CONT DRY WEA INTO SAT EVE. A DIGGING UPR TROF IS
PROGGED TO ADVN OUT OF THE PLAINS AND TRACK ACRS THE GT LKS AND
OH VLY RGN SUN INTO MON. ASSOCIATED SFC LOW PRES IS PROGGED TO
DEEPEN AS IT MOVES ACRS THE TN AND OH VLY RGNS ALSO. THIS WL
SPREAD SNW INTO THE RGN LT SAT NGT THRU MON MRNG WITH DEEP
AVAILABLE MSTR AND OMEGA.

WITH A CLOSED 850MB LOW...A MORE PROLONGED PCPN EVENT IS EXPD AS
OPPOSED TO THE OPEN SYSTEM EARLIER IN THE WK. WITH ENOUGH
POTENTIAL FOR HEAVY SNW OR A SNW/ICE MIX...ISSUED A WINTER STORM
WATCH FOR MUCH OF THE AREA. LEFT AREAS GENLY S OF I 70 OUT OF THE
WATCH...EXCEPT FOR THE WV/MD RIDGES...AS ENOUGH WRM AIR IS EXPD TO
WRAP IN AHD OF THE LOW TO ALLOW FOR A RAIN/SNW MIX OR EVEN A PD OF
ALL RAIN. AREAS BETWEEN I 70- AND I 80 COULD SEE ENOUGH WRM AIR
ALOFT FOR FRZG RAIN TO MIX IN AT TIMES AS WELL. GENLY FOLLOWED A
SREF/GFS/ECMWF MDL BLEND TO WORK OUT THE DETAILS...AND USED
CRITICAL THICKNESSES/MDL SOUNDING PROFILES FOR PCPN TYPE. BEST
POTENTIAL FOR GREATER THAN 6 INCHES OF SNW EXISTS N OF PIT BASED
ON LATEST MDL GUIDANCE...THOUGH THIS WL BE REFINED OVR THE NXT
COUPLE OF DAYS.

SNW SHOULD CONT MON UNTIL THE UPR TROF AXIS SHIFTS E IN THE AFTN.
NUDGED TEMPS TO THE LATEST COLDER THAN SEASONAL AVG SREF GUIDANCE.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
A COLD...WINTER PATTERN WILL CONTINUE FOR THE REST OF THE LONG
TERM. THE NEXT BEST CHANCE FOR SNOW SHOWERS WILL ARRIVE LATE IN
THE PERIOD.

&&

.AVIATION /01Z SATURDAY THROUGH WEDNESDAY/...
LINGERING MVFR STRATOCUMULUS AND SNOW SHOWERS CONTINUE TO PLAGUE
SEVERAL OF THE TAF SITES EARLY TONIGHT. THIS IS IN PART DUE TO
WHAT LOOKS TO BE AN UPSTREAM CONNECTION WITH MOISTURE FROM LAKE
HURON. SUBSIDENCE FROM THE BUILDING RIDGE AND A WESTERLY WIND
SHIFT WILL HELP TO DIMINISH THE CLOUD COVER AND IMPROVE CONDITIONS OVER
NEXT FEW HOURS...WITH THE HRRR AND RUC SUGGESTING VFR CONDITIONS
BY 03Z. IN ADDITION...WINDS WILL WEAKEN WITH THE BUILDING HIGH
PRESSURE....WITH NEARLY CALM WIND ANTICIPATED OVERNIGHT. VFR
CONDITIONS WILL REMAIN THROUGH THE REST OF THE TAF PERIOD...WITH
HIGH CLOUDS AND SOME DIURNAL CU DEVELOPING SATURDAY AFTERNOON
AHEAD OF THE SYSTEM PROGGED FOR SUNDAY.

.OUTLOOK.../SATURDAY NIGHT THROUGH WEDNESDAY/...
WIDESPREAD RESTRICTIONS CAN BE EXPECTED SUNDAY AND MONDAY AS A LOW
PRESSURE SYSTEM CROSSES THE REGION.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
     MORNING FOR MDZ001.
     WIND CHILL ADVISORY UNTIL 10 AM EST SATURDAY FOR MDZ001.
OH...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
     MORNING FOR OHZ039>041-048>050-057>059.
PA...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
     MORNING FOR PAZ007>009-013>016-020>023-029-073>076.
     WIND CHILL ADVISORY UNTIL 10 AM EST SATURDAY FOR PAZ008-009-
     015-016-023-074-076.
WV...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
     MORNING FOR WVZ001>003-023-041.
     WIND CHILL ADVISORY UNTIL 10 AM EST SATURDAY FOR WVZ023-041.

&&

$$













000
FXUS61 KPBZ 302359
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
659 PM EST FRI JAN 30 2015

.SYNOPSIS...
HIGH PRESSURE WILL BUILD IN THROUGH SATURDAY. LOW PRESSURE WILL
BRING WINTRY WEATHER SUNDAY INTO MONDAY.

&&

.NEAR TERM /THROUGH SATURDAY/...
THE REGIONAL RADAR MOSAIC INDICATES SNOW SHOWER ACTIVITY...WHILE
STILL FAIRLY PERVASIVE...IS DEFINITELY IN A DOWNWARD TREND ACROSS
THE CWA THIS EVENING. MODEL SOUNDINGS FROM BOTH THE RAP AND HRRR
SHOW A SCENARIO WHEREBY INVERSION HEIGHTS ARE FALLING
SIMULTANEOUSLY WITH BOUNDARY LAYER MOISTURE DEPTH DECREASING AS
WELL. LIKEWISE...UPSTREAM ACTIVITY OFF OF LAKE HURON IS QUICKLY
FALLING APART...AND THE TREND TOWARD ANY ADDITIONAL INPUT FROM THE
SLIVER OF LAKE ERIE THAT IS OPEN WILL NOT BE PARTICULARLY HELPFUL
TO REGENERATION OF ANY OF THE BANDS. THAT SAID...ACTIVITY WILL
LIKELY TAKE A FEW HOURS TO WANE WITH THE UPSLOPE AREAS TAKING THE
LONGEST TO FULLY HALT THEIR SNOW SHOWER AND FLURRY ACTION.
HOWEVER...GIVEN THE DOWNWARD TREND IN ACTIVITY AND MINIMAL
ACCUMULATION EXPECTATIONS THE REST OF THE EVENING...WINTER WEATHER
ADVISORIES FOR THE HIGHER TERRAIN HAVE BEEN ALLOWED TO EXPIRE AS
SCHEDULED AT 7 PM.

NORTHWESTERLY FLOW CONTINUES THROUGH MUCH OF THE EVENING HOURS
BEFORE SLOWLY TURNING WEST OVERNIGHT AS A SURFACE HIGH BUILDS
GENERALLY JUST TO THE SOUTH OF THE REGION. WITH AT THE VERY LEAST
PARTIAL CLEARING...IF NOT FULL CLEARING AT TIMES...TEMPERATURES
SHOULD DROP RAPIDLY WITH NEW SNOW COVER. THIS COMBINED WITH
DECREASING YET STILL BRISK SURFACE FLOW WILL ALLOW FOR WIND CHILL
ADVISORY CRITERIA WIND CHILL INDEX VALUES BY MORNING OVER THE HIGHER
TERRAIN AND NORTHEASTERN CWA. THIS IS IN LINE WITH CURRENT
HEADLINES...AND NO ADDITIONAL EXPANSION OF THESE HEADLINES ARE
ANTICIPATED AT THIS TIME. HOWEVER...WITH RAPID CLEARING AND NEW
SNOW ON THE GROUND...ALL AREA WILL LIKELY BE VERY COLD BY
MORNING...WITH MANY PORTIONS OF THE CWA CHALLENGING ZERO BY THAT
JUNCTURE.

SOME WARMER AIR DOES START TO FLOW NORTHWARD ON SATURDAY AS THE
SURFACE HIGH AXIS MOVES TO THE EAST OF THE AREA AND SOUTHWESTERLY
FLOW PREVAILS FOR A TIME. EXPECTATIONS SHOULD BE
MUTED...THOUGH...AS SUCH A COLD START AND WEAK VERTICAL MIXING
WILL LIKELY KEEP MOST OF THE AREA IN THE 20S. FRIES

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
HIGH PRES SHOULD CONT DRY WEA INTO SAT EVE. A DIGGING UPR TROF IS
PROGGED TO ADVN OUT OF THE PLAINS AND TRACK ACRS THE GT LKS AND
OH VLY RGN SUN INTO MON. ASSOCIATED SFC LOW PRES IS PROGGED TO
DEEPEN AS IT MOVES ACRS THE TN AND OH VLY RGNS ALSO. THIS WL
SPREAD SNW INTO THE RGN LT SAT NGT THRU MON MRNG WITH DEEP
AVAILABLE MSTR AND OMEGA.

WITH A CLOSED 850MB LOW...A MORE PROLONGED PCPN EVENT IS EXPD AS
OPPOSED TO THE OPEN SYSTEM EARLIER IN THE WK. WITH ENOUGH
POTENTIAL FOR HEAVY SNW OR A SNW/ICE MIX...ISSUED A WINTER STORM
WATCH FOR MUCH OF THE AREA. LEFT AREAS GENLY S OF I 70 OUT OF THE
WATCH...EXCEPT FOR THE WV/MD RIDGES...AS ENOUGH WRM AIR IS EXPD TO
WRAP IN AHD OF THE LOW TO ALLOW FOR A RAIN/SNW MIX OR EVEN A PD OF
ALL RAIN. AREAS BETWEEN I 70- AND I 80 COULD SEE ENOUGH WRM AIR
ALOFT FOR FRZG RAIN TO MIX IN AT TIMES AS WELL. GENLY FOLLOWED A
SREF/GFS/ECMWF MDL BLEND TO WORK OUT THE DETAILS...AND USED
CRITICAL THICKNESSES/MDL SOUNDING PROFILES FOR PCPN TYPE. BEST
POTENTIAL FOR GREATER THAN 6 INCHES OF SNW EXISTS N OF PIT BASED
ON LATEST MDL GUIDANCE...THOUGH THIS WL BE REFINED OVR THE NXT
COUPLE OF DAYS.

SNW SHOULD CONT MON UNTIL THE UPR TROF AXIS SHIFTS E IN THE AFTN.
NUDGED TEMPS TO THE LATEST COLDER THAN SEASONAL AVG SREF GUIDANCE.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
A COLD...WINTER PATTERN WILL CONTINUE FOR THE REST OF THE LONG
TERM. THE NEXT BEST CHANCE FOR SNOW SHOWERS WILL ARRIVE LATE IN
THE PERIOD.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
MVFR CIGS WITH IFR VSBY IN SNOW SHWRS WL CONT THIS AFTN. GENL
IMPROVEMENT CAN BE ANTICIPATED THEREAFTER AS DRY ADVCTN AND SBSDNC
INCRS.  SFC WIND ARE EXPECTED TO CONTINUE TO GUST FROM THE W AND NW
AT 15 TO 25 KNOTS THROUGH THE DAY.  FURTHER IMPROVEMENTS CAN BE
EXPECTED AS HIGH PRES BLDS THROUGH SATURDAY MRNG.

.OUTLOOK.../SATURDAY NIGHT THROUGH WEDNESDAY/...
WIDESPREAD RESTRICTIONS CAN BE EXPECTED WITH SUNDAY LOW PRES AND
WITH A MONDAY CDFNT.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
     MORNING FOR MDZ001.
     WIND CHILL ADVISORY UNTIL 10 AM EST SATURDAY FOR MDZ001.
OH...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
     MORNING FOR OHZ039>041-048>050-057>059.
PA...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
     MORNING FOR PAZ007>009-013>016-020>023-029-073>076.
     WIND CHILL ADVISORY UNTIL 10 AM EST SATURDAY FOR PAZ008-009-
     015-016-023-074-076.
WV...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
     MORNING FOR WVZ001>003-023-041.
     WIND CHILL ADVISORY UNTIL 10 AM EST SATURDAY FOR WVZ023-041.

&&

$$







000
FXUS61 KPBZ 301947
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
247 PM EST FRI JAN 30 2015

.SYNOPSIS...
HIGH PRESSURE WILL BUILD IN THROUGH SATURDAY. LOW PRESSURE WILL
BRING WINTRY WEATHER SUNDAY INTO MONDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
SCT-NMRS SNW SHWRS WL CONT ACRS THE AREA INTO EARLY EVE...THOUGH
SHOULD RAPIDLY DMNSH AFT SUNSET AS HIGH PRES BLDS FURTHER INTO
THE RGN AND SBSDNC INCRS. COLD TEMPS ARE EXPD TNGT ALSO...WITH WND
CHILLS APCHG -10 TO -15 FOR AREAS NE-SE OF PIT WHERE WND CHILL
ADVYS WERE MAINTAINED.

&&

.SHORT TERM /SATURDAY THROUGH MONDAY/...
HIGH PRES SHOULD CONT DRY WEA INTO SAT EVE. A DIGGING UPR TROF IS
PROGGED TO ADVN OUT OF THE PLAINS AND TRACK ACRS THE GT LKS AND
OH VLY RGN SUN INTO MON. ASSOCIATED SFC LOW PRES IS PROGGED TO
DEEPEN AS IT MOVES ACRS THE TN AND OH VLY RGNS ALSO. THIS WL
SPREAD SNW INTO THE RGN LT SAT NGT THRU MON MRNG WITH DEEP
AVAILABLE MSTR AND OMEGA.

WITH A CLOSED 850MB LOW...A MORE PROLONGED PCPN EVENT IS EXPD AS
OPPOSED TO THE OPEN SYSTEM EARLIER IN THE WK. WITH ENOUGH
POTENTIAL FOR HEAVY SNW OR A SNW/ICE MIX...ISSUED A WINTER STORM
WATCH FOR MUCH OF THE AREA. LEFT AREAS GENLY S OF I 70 OUT OF THE
WATCH...EXCEPT FOR THE WV/MD RIDGES...AS ENOUGH WRM AIR IS EXPD TO
WRAP IN AHD OF THE LOW TO ALLOW FOR A RAIN/SNW MIX OR EVEN A PD OF
ALL RAIN. AREAS BETWEEN I 70- AND I 80 COULD SEE ENOUGH WRM AIR
ALOFT FOR FRZG RAIN TO MIX IN AT TIMES AS WELL. GENLY FOLLOWED A
SREF/GFS/ECMWF MDL BLEND TO WORK OUT THE DETAILS...AND USED
CRITICAL THICKNESSES/MDL SOUNDING PROFILES FOR PCPN TYPE. BEST
POTENTIAL FOR GREATER THAN 6 INCHES OF SNW EXISTS N OF PIT BASED
ON LATEST MDL GUIDANCE...THOUGH THIS WL BE REFINED OVR THE NXT
COUPLE OF DAYS.

SNW SHOULD CONT MON UNTIL THE UPR TROF AXIS SHIFTS E IN THE AFTN.
NUDGED TEMPS TO THE LATEST COLDER THAN SEASONAL AVG SREF GUIDANCE.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
A COLD...WINTER PATTERN WILL CONTINUE FOR THE REST OF THE LONG
TERM. THE NEXT BEST CHANCE FOR SNOW SHOWERS WILL ARRIVE LATE IN
THE PERIOD.

&&

.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
MVFR CIGS WITH IFR VSBY IN SNOW SHWRS WL CONT THIS AFTN. GENL
IMPROVEMENT CAN BE ANTICIPATED THEREAFTER AS DRY ADVCTN AND SBSDNC
INCRS.  SFC WIND ARE EXPECTED TO CONTINUE TO GUST FROM THE W AND NW
AT 15 TO 25 KNOTS THROUGH THE DAY.  FURTHER IMPROVEMENTS CAN BE
EXPECTED AS HIGH PRES BLDS THROUGH SATURDAY MRNG.

.OUTLOOK.../SATURDAY NIGHT THROUGH WEDNESDAY/...
WIDESPREAD RESTRICTIONS CAN BE EXPECTED WITH SUNDAY LOW PRES AND
WITH A MONDAY CDFNT.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
     MORNING FOR MDZ001.
     WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     SATURDAY FOR MDZ001.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MDZ001.
OH...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
     MORNING FOR OHZ039>041-048>050-057>059.
PA...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
     MORNING FOR PAZ007>009-013>016-020>023-029-073>076.
     WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     SATURDAY FOR PAZ008-009-015-016-023-074-076.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ074-
     076.
WV...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
     MORNING FOR WVZ001>003-023-041.
     WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     SATURDAY FOR WVZ023-041.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR WVZ023-
     041.

&&

$$

07/15






000
FXUS61 KPBZ 301947
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
247 PM EST FRI JAN 30 2015

.SYNOPSIS...
HIGH PRESSURE WILL BUILD IN THROUGH SATURDAY. LOW PRESSURE WILL
BRING WINTRY WEATHER SUNDAY INTO MONDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
SCT-NMRS SNW SHWRS WL CONT ACRS THE AREA INTO EARLY EVE...THOUGH
SHOULD RAPIDLY DMNSH AFT SUNSET AS HIGH PRES BLDS FURTHER INTO
THE RGN AND SBSDNC INCRS. COLD TEMPS ARE EXPD TNGT ALSO...WITH WND
CHILLS APCHG -10 TO -15 FOR AREAS NE-SE OF PIT WHERE WND CHILL
ADVYS WERE MAINTAINED.

&&

.SHORT TERM /SATURDAY THROUGH MONDAY/...
HIGH PRES SHOULD CONT DRY WEA INTO SAT EVE. A DIGGING UPR TROF IS
PROGGED TO ADVN OUT OF THE PLAINS AND TRACK ACRS THE GT LKS AND
OH VLY RGN SUN INTO MON. ASSOCIATED SFC LOW PRES IS PROGGED TO
DEEPEN AS IT MOVES ACRS THE TN AND OH VLY RGNS ALSO. THIS WL
SPREAD SNW INTO THE RGN LT SAT NGT THRU MON MRNG WITH DEEP
AVAILABLE MSTR AND OMEGA.

WITH A CLOSED 850MB LOW...A MORE PROLONGED PCPN EVENT IS EXPD AS
OPPOSED TO THE OPEN SYSTEM EARLIER IN THE WK. WITH ENOUGH
POTENTIAL FOR HEAVY SNW OR A SNW/ICE MIX...ISSUED A WINTER STORM
WATCH FOR MUCH OF THE AREA. LEFT AREAS GENLY S OF I 70 OUT OF THE
WATCH...EXCEPT FOR THE WV/MD RIDGES...AS ENOUGH WRM AIR IS EXPD TO
WRAP IN AHD OF THE LOW TO ALLOW FOR A RAIN/SNW MIX OR EVEN A PD OF
ALL RAIN. AREAS BETWEEN I 70- AND I 80 COULD SEE ENOUGH WRM AIR
ALOFT FOR FRZG RAIN TO MIX IN AT TIMES AS WELL. GENLY FOLLOWED A
SREF/GFS/ECMWF MDL BLEND TO WORK OUT THE DETAILS...AND USED
CRITICAL THICKNESSES/MDL SOUNDING PROFILES FOR PCPN TYPE. BEST
POTENTIAL FOR GREATER THAN 6 INCHES OF SNW EXISTS N OF PIT BASED
ON LATEST MDL GUIDANCE...THOUGH THIS WL BE REFINED OVR THE NXT
COUPLE OF DAYS.

SNW SHOULD CONT MON UNTIL THE UPR TROF AXIS SHIFTS E IN THE AFTN.
NUDGED TEMPS TO THE LATEST COLDER THAN SEASONAL AVG SREF GUIDANCE.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
A COLD...WINTER PATTERN WILL CONTINUE FOR THE REST OF THE LONG
TERM. THE NEXT BEST CHANCE FOR SNOW SHOWERS WILL ARRIVE LATE IN
THE PERIOD.

&&

.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
MVFR CIGS WITH IFR VSBY IN SNOW SHWRS WL CONT THIS AFTN. GENL
IMPROVEMENT CAN BE ANTICIPATED THEREAFTER AS DRY ADVCTN AND SBSDNC
INCRS.  SFC WIND ARE EXPECTED TO CONTINUE TO GUST FROM THE W AND NW
AT 15 TO 25 KNOTS THROUGH THE DAY.  FURTHER IMPROVEMENTS CAN BE
EXPECTED AS HIGH PRES BLDS THROUGH SATURDAY MRNG.

.OUTLOOK.../SATURDAY NIGHT THROUGH WEDNESDAY/...
WIDESPREAD RESTRICTIONS CAN BE EXPECTED WITH SUNDAY LOW PRES AND
WITH A MONDAY CDFNT.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
     MORNING FOR MDZ001.
     WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     SATURDAY FOR MDZ001.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MDZ001.
OH...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
     MORNING FOR OHZ039>041-048>050-057>059.
PA...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
     MORNING FOR PAZ007>009-013>016-020>023-029-073>076.
     WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     SATURDAY FOR PAZ008-009-015-016-023-074-076.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ074-
     076.
WV...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
     MORNING FOR WVZ001>003-023-041.
     WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     SATURDAY FOR WVZ023-041.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR WVZ023-
     041.

&&

$$

07/15







000
FXUS61 KPBZ 301714
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1214 PM EST FRI JAN 30 2015

.SYNOPSIS...
COLDER TEMPERATURES AND SNOW SHOWERS WILL PLAGUE THE UPPER OHIO
VALLEY REGION TODAY. HIGH PRESSURE WILL BUILD AND DIMINISH THE
SNOW SHOWERS THIS AFTERNOON AND PROVIDE A DRY SATURDAY BEFORE LOW
PRESSURE SPREADS MORE PRECIPITATION OVER THE AREA ON SUNDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
NO MAJOR CHGS FOR THE ERLY AFTN UPDT. A GRADUAL DCRS IN SNW SHWR
COVG IS EXPD THRU THE AFTN AS AN UPR TROF EXITS AND THE MOISTURE
DEPTH DCRS. THE EXCEPTION WL BE IN THE RIDGES SE OF PIT WHERE
UPSLOPE FLOW AND MOISTUR IN THE SNW GROWTH RGN WL CONT
ACCUMULATING SNW THRU THE AFTN. WITH COLD ADVCTN...FALLING TEMPS
ARE EXPD THRU THE DAY.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
UPDT TO ISSUE A WINTER STORM WATCH SUN/MON AFT REVIEW OF 12Z
GUIDANCE AND COORDINATION WITH SURROUNDING OFFICES.

PREVIOUS...SNOW SHOWERS WILL END IN THE RIDGES THIS EVENING AS
HIGH PRESSURE SPREADS ACROSS THE REGION. THE ARCTIC AIR MASS WILL
QUICKLY SHIFT TOWARD THE NORTHEAST IN RESPONSE TO THE MID-LEVEL
RIDGE THAT BUILDS INTO THE UPPER MIDWEST.

HIGH PRESSURE WILL KEEP THE AREA DRY SATURDAY.

MODELS ARE BEGINNING TO COME INTO AGREEMENT FOR ANOTHER SNOW
PRODUCING STORM SUNDAY. STILL LOTS OF UNCERTAINTY ON THE EXACT
TRACK OF THE SYSTEM...BUT IT DOES APPEAR THAT MOST IF NOT ALL OF
THE AREA WILL BE ON THE COLD SIDE OF THE SURFACE LOW. MODEL
DEPICTIONS OF THIS SYSTEM HAVE VARIED GREATLY OVER THE PAST FEW
DAYS...SO THERE STILL IS A LOT OF UNCERTAINTY OF WHAT WILL BE THE
FINAL SOLUTION. FOR NOW WILL LEAN CLOSE TO THE 21Z SREF SOLUTION
AS IT SEEMS TO BE A NICE MIX OF THE 00Z NAM AND GFS. IF THIS
SYSTEM AND ITS TRACK COMES TO FRUITION...HEADLINES WILL BE NEEDED.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
A COLD...WINTER PATTERN WILL CONTINUE FOR THE REST OF THE LONG
TERM. THE NEXT BEST CHANCE FOR SNOW SHOWERS WILL ARRIVE LATE IN
THE PERIOD.

&&

.AVIATION /17Z FRIDAY THROUGH TUESDAY/...
MVFR CIGS WITH IFR VSBY IN SNOW SHWRS WL CONT THIS AFTN. GENL
IMPROVEMENT CAN BE ANTICIPATED THEREAFTER AS DRY ADVCTN AND SBSDNC
INCRS.  SFC WIND ARE EXPECTED TO CONTINUE TO GUST FROM THE W AND NW
AT 15 TO 25 KNOTS THROUGH THE DAY.  FURTHER IMPROVEMENTS CAN BE
EXPECTED AS HIGH PRES BLDS THROUGH SATURDAY MRNG.

.OUTLOOK.../SATURDAY NIGHT THROUGH TUESDAY/...
WIDESPREAD RESTRICTIONS CAN BE EXPECTED WITH SUNDAY LOW PRES AND
WITH A MONDAY CDFNT.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
     MORNING FOR MDZ001.
     WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     SATURDAY FOR MDZ001.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MDZ001.
OH...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
     MORNING FOR OHZ039>041-048>050-057>059.
PA...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
     MORNING FOR PAZ007>009-013>016-020>023-029-073>076.
     WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     SATURDAY FOR PAZ008-009-015-016-023-074-076.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ074-
     076.
WV...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
     MORNING FOR WVZ001>003-023-041.
     WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     SATURDAY FOR WVZ023-041.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR WVZ023-
     041.

&&

$$

07/15








000
FXUS61 KPBZ 301714
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1214 PM EST FRI JAN 30 2015

.SYNOPSIS...
COLDER TEMPERATURES AND SNOW SHOWERS WILL PLAGUE THE UPPER OHIO
VALLEY REGION TODAY. HIGH PRESSURE WILL BUILD AND DIMINISH THE
SNOW SHOWERS THIS AFTERNOON AND PROVIDE A DRY SATURDAY BEFORE LOW
PRESSURE SPREADS MORE PRECIPITATION OVER THE AREA ON SUNDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
NO MAJOR CHGS FOR THE ERLY AFTN UPDT. A GRADUAL DCRS IN SNW SHWR
COVG IS EXPD THRU THE AFTN AS AN UPR TROF EXITS AND THE MOISTURE
DEPTH DCRS. THE EXCEPTION WL BE IN THE RIDGES SE OF PIT WHERE
UPSLOPE FLOW AND MOISTUR IN THE SNW GROWTH RGN WL CONT
ACCUMULATING SNW THRU THE AFTN. WITH COLD ADVCTN...FALLING TEMPS
ARE EXPD THRU THE DAY.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
UPDT TO ISSUE A WINTER STORM WATCH SUN/MON AFT REVIEW OF 12Z
GUIDANCE AND COORDINATION WITH SURROUNDING OFFICES.

PREVIOUS...SNOW SHOWERS WILL END IN THE RIDGES THIS EVENING AS
HIGH PRESSURE SPREADS ACROSS THE REGION. THE ARCTIC AIR MASS WILL
QUICKLY SHIFT TOWARD THE NORTHEAST IN RESPONSE TO THE MID-LEVEL
RIDGE THAT BUILDS INTO THE UPPER MIDWEST.

HIGH PRESSURE WILL KEEP THE AREA DRY SATURDAY.

MODELS ARE BEGINNING TO COME INTO AGREEMENT FOR ANOTHER SNOW
PRODUCING STORM SUNDAY. STILL LOTS OF UNCERTAINTY ON THE EXACT
TRACK OF THE SYSTEM...BUT IT DOES APPEAR THAT MOST IF NOT ALL OF
THE AREA WILL BE ON THE COLD SIDE OF THE SURFACE LOW. MODEL
DEPICTIONS OF THIS SYSTEM HAVE VARIED GREATLY OVER THE PAST FEW
DAYS...SO THERE STILL IS A LOT OF UNCERTAINTY OF WHAT WILL BE THE
FINAL SOLUTION. FOR NOW WILL LEAN CLOSE TO THE 21Z SREF SOLUTION
AS IT SEEMS TO BE A NICE MIX OF THE 00Z NAM AND GFS. IF THIS
SYSTEM AND ITS TRACK COMES TO FRUITION...HEADLINES WILL BE NEEDED.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
A COLD...WINTER PATTERN WILL CONTINUE FOR THE REST OF THE LONG
TERM. THE NEXT BEST CHANCE FOR SNOW SHOWERS WILL ARRIVE LATE IN
THE PERIOD.

&&

.AVIATION /17Z FRIDAY THROUGH TUESDAY/...
MVFR CIGS WITH IFR VSBY IN SNOW SHWRS WL CONT THIS AFTN. GENL
IMPROVEMENT CAN BE ANTICIPATED THEREAFTER AS DRY ADVCTN AND SBSDNC
INCRS.  SFC WIND ARE EXPECTED TO CONTINUE TO GUST FROM THE W AND NW
AT 15 TO 25 KNOTS THROUGH THE DAY.  FURTHER IMPROVEMENTS CAN BE
EXPECTED AS HIGH PRES BLDS THROUGH SATURDAY MRNG.

.OUTLOOK.../SATURDAY NIGHT THROUGH TUESDAY/...
WIDESPREAD RESTRICTIONS CAN BE EXPECTED WITH SUNDAY LOW PRES AND
WITH A MONDAY CDFNT.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
     MORNING FOR MDZ001.
     WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     SATURDAY FOR MDZ001.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MDZ001.
OH...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
     MORNING FOR OHZ039>041-048>050-057>059.
PA...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
     MORNING FOR PAZ007>009-013>016-020>023-029-073>076.
     WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     SATURDAY FOR PAZ008-009-015-016-023-074-076.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ074-
     076.
WV...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
     MORNING FOR WVZ001>003-023-041.
     WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     SATURDAY FOR WVZ023-041.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR WVZ023-
     041.

&&

$$

07/15







000
FXUS61 KPBZ 301458
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
958 AM EST FRI JAN 30 2015

.SYNOPSIS...
COLDER TEMPERATURES AND SNOW SHOWERS WILL PLAGUE THE UPPER OHIO
VALLEY REGION TODAY. HIGH PRESSURE WILL BUILD AND DIMINISH THE
SNOW SHOWERS THIS AFTERNOON AND PROVIDE A DRY SATURDAY BEFORE LOW
PRESSURE SPREADS MORE PRECIPITATION OVER THE AREA ON SUNDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A GRADUAL DCRS IN SNW SHWR COVG IS EXPD THRU THE AFTN AS AN UPR
TROF EXITS AND THE MOISTURE DEPTH DCRS. THE EXCEPTION WL BE IN THE
RIDGES SE OF PIT WHERE UPSLOPE FLOW AND MOISTUR IN THE SNW GROWTH
RGN WL CONT ACCUMULATING SNW THRU THE AFTN. WITH COLD
ADVCTN...FALLING TEMPS ARE EXPD THRU THE DAY.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
SNOW SHOWERS WILL END IN THE RIDGES THIS EVENING AS HIGH PRESSURE
SPREADS ACROSS THE REGION. THE ARCTIC AIR MASS WILL QUICKLY SHIFT
TOWARD THE NORTHEAST IN RESPONSE TO THE MID-LEVEL RIDGE THAT
BUILDS INTO THE UPPER MIDWEST.

HIGH PRESSURE WILL KEEP THE AREA DRY SATURDAY.

MODELS ARE BEGINNING TO COME INTO AGREEMENT FOR ANOTHER SNOW
PRODUCING STORM SUNDAY. STILL LOTS OF UNCERTAINTY ON THE EXACT
TRACK OF THE SYSTEM...BUT IT DOES APPEAR THAT MOST IF NOT ALL OF
THE AREA WILL BE ON THE COLD SIDE OF THE SURFACE LOW. MODEL
DEPICTIONS OF THIS SYSTEM HAVE VARIED GREATLY OVER THE PAST FEW
DAYS...SO THERE STILL IS A LOT OF UNCERTAINTY OF WHAT WILL BE THE
FINAL SOLUTION. FOR NOW WILL LEAN CLOSE TO THE 21Z SREF SOLUTION
AS IT SEEMS TO BE A NICE MIX OF THE 00Z NAM AND GFS. IF THIS
SYSTEM AND ITS TRACK COMES TO FRUITION...HEADLINES WILL BE NEEDED.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
A COLD...WINTER PATTERN WILL CONTINUE FOR THE REST OF THE LONG
TERM. THE NEXT BEST CHANCE FOR SNOW SHOWERS WILL ARRIVE LATE IN
THE PERIOD.

&&

.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
MVFR CIGS WITH IFR VSBY IN SNOW SHWRS WL CONT THIS MRNG. GENL
IMPROVEMENT CAN BE ANTICIPATED THIS AFTN WITH DIMINISHED SNOW SHWR
ACTIVITY...AND BY TNGT FOR THE MVFR STRATOCU AS DRY ADVCTN AND
SBSDNC INCRS.

SFC WIND ARE EXPECTED TO CONTINUE TO GUST FROM THE W AND NW AT 15
TO 25 KNOTS THROUGH THE DAY.

.OUTLOOK.../FRIDAY NIGHT THROUGH TUESDAY/...
IMPROVEMENTS CAN BE EXPECTED AS HIGH PRES BLDS ON SATURDAY.
HOWEVER...SNOW AND RESTRICTIONS ARE LIKELY WITH SUNDAY LOW PRES.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     SATURDAY FOR MDZ001.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MDZ001.
OH...NONE.
PA...WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     SATURDAY FOR PAZ008-009-015-016-023-074-076.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ074-
     076.
WV...WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     SATURDAY FOR WVZ023-041.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR WVZ023-
     041.

&&

$$








000
FXUS61 KPBZ 301458
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
958 AM EST FRI JAN 30 2015

.SYNOPSIS...
COLDER TEMPERATURES AND SNOW SHOWERS WILL PLAGUE THE UPPER OHIO
VALLEY REGION TODAY. HIGH PRESSURE WILL BUILD AND DIMINISH THE
SNOW SHOWERS THIS AFTERNOON AND PROVIDE A DRY SATURDAY BEFORE LOW
PRESSURE SPREADS MORE PRECIPITATION OVER THE AREA ON SUNDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A GRADUAL DCRS IN SNW SHWR COVG IS EXPD THRU THE AFTN AS AN UPR
TROF EXITS AND THE MOISTURE DEPTH DCRS. THE EXCEPTION WL BE IN THE
RIDGES SE OF PIT WHERE UPSLOPE FLOW AND MOISTUR IN THE SNW GROWTH
RGN WL CONT ACCUMULATING SNW THRU THE AFTN. WITH COLD
ADVCTN...FALLING TEMPS ARE EXPD THRU THE DAY.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
SNOW SHOWERS WILL END IN THE RIDGES THIS EVENING AS HIGH PRESSURE
SPREADS ACROSS THE REGION. THE ARCTIC AIR MASS WILL QUICKLY SHIFT
TOWARD THE NORTHEAST IN RESPONSE TO THE MID-LEVEL RIDGE THAT
BUILDS INTO THE UPPER MIDWEST.

HIGH PRESSURE WILL KEEP THE AREA DRY SATURDAY.

MODELS ARE BEGINNING TO COME INTO AGREEMENT FOR ANOTHER SNOW
PRODUCING STORM SUNDAY. STILL LOTS OF UNCERTAINTY ON THE EXACT
TRACK OF THE SYSTEM...BUT IT DOES APPEAR THAT MOST IF NOT ALL OF
THE AREA WILL BE ON THE COLD SIDE OF THE SURFACE LOW. MODEL
DEPICTIONS OF THIS SYSTEM HAVE VARIED GREATLY OVER THE PAST FEW
DAYS...SO THERE STILL IS A LOT OF UNCERTAINTY OF WHAT WILL BE THE
FINAL SOLUTION. FOR NOW WILL LEAN CLOSE TO THE 21Z SREF SOLUTION
AS IT SEEMS TO BE A NICE MIX OF THE 00Z NAM AND GFS. IF THIS
SYSTEM AND ITS TRACK COMES TO FRUITION...HEADLINES WILL BE NEEDED.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
A COLD...WINTER PATTERN WILL CONTINUE FOR THE REST OF THE LONG
TERM. THE NEXT BEST CHANCE FOR SNOW SHOWERS WILL ARRIVE LATE IN
THE PERIOD.

&&

.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
MVFR CIGS WITH IFR VSBY IN SNOW SHWRS WL CONT THIS MRNG. GENL
IMPROVEMENT CAN BE ANTICIPATED THIS AFTN WITH DIMINISHED SNOW SHWR
ACTIVITY...AND BY TNGT FOR THE MVFR STRATOCU AS DRY ADVCTN AND
SBSDNC INCRS.

SFC WIND ARE EXPECTED TO CONTINUE TO GUST FROM THE W AND NW AT 15
TO 25 KNOTS THROUGH THE DAY.

.OUTLOOK.../FRIDAY NIGHT THROUGH TUESDAY/...
IMPROVEMENTS CAN BE EXPECTED AS HIGH PRES BLDS ON SATURDAY.
HOWEVER...SNOW AND RESTRICTIONS ARE LIKELY WITH SUNDAY LOW PRES.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     SATURDAY FOR MDZ001.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MDZ001.
OH...NONE.
PA...WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     SATURDAY FOR PAZ008-009-015-016-023-074-076.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ074-
     076.
WV...WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     SATURDAY FOR WVZ023-041.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR WVZ023-
     041.

&&

$$







000
FXUS61 KPBZ 301242
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
742 AM EST FRI JAN 30 2015

.SYNOPSIS...
COLDER TEMPERATURES AND SNOW SHOWERS WILL PLAGUE THE UPPER OHIO
VALLEY REGION TODAY. HIGH PRESSURE WILL BUILD AND DIMINISH THE
SNOW SHOWERS THIS AFTERNOON AND PROVIDE A DRY SATURDAY BEFORE LOW
PRESSURE SPREADS MORE PRECIPITATION OVER THE AREA ON SUNDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
DAWN ADJUSTMENTS WERE MINOR...BUT DID INCLUDE INCRSD POPS FOR THE
EAST CNTRL OH CNTIES AS PER RADAR TRENDS UNDR CROSSING SHRTWV.
ACCUMULATIONS WL RMN RELATIVELY MINOR THOUGH FOR THAT AREA.

PREVIOUS...
ANOTHER SHORTWAVE TROUGH WILL CROSS THE AREA THIS MORNING...
PROVIDING ANOTHER PUSH OF ARCTIC AIR. THIS WILL SUSTAIN THE RISK
FOR SNOW SHOWERS THROUGHOUT MUCH OF THE MORNING WITH THE BEST
CHANCE ACROSS THE NORTH AND ESPECIALLY THE RIDGES. UPSLOPE SNOW
SHOWERS IN THE RIDGES WILL BE CRANKING THROUGH THE MORNING HOURS
AND THIS WILL BE THE LOCATIONS WERE SNOW ACCUMULATIONS WILL BE
OPTIMAL. WILL KEEP THE ADVISORY AS IS.

STEERING WINDS BEGIN TO SHOW A MORE NORTHERLY COMPONENT THIS
AFTERNOON BEHIND THE EXITING TROUGH. THESE STRONG WINDS WILL DRIVE
THE ARCTIC AIR SOUTHWARD ACROSS MY ENTIRE CWA. THE SNOW SHOWER
THREAT WILL WANE THROUGHOUT THE AFTERNOON DUE TO THE VEERING AND
SHEAR IN THE WINDS AND ALSO THE LOWERING OF INVERSIONS. THE RIDGES
WILL HOLD ONTO SNOW SHOWERS THE LONGEST THANKS TO THE ALWAYS
PERSISTENT OROGRAPHIC EFFECTS.

HIGHS WILL BE REACHED IN THE MORNING...WITH TEMPS SLOWLY FALLING
THROUGHOUT THE DAY.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
SNOW SHOWERS WILL END IN THE RIDGES THIS EVENING AS HIGH PRESSURE
SPREADS ACROSS THE REGION. THE ARCTIC AIR MASS WILL QUICKLY SHIFT
TOWARD THE NORTHEAST IN RESPONSE TO THE MID-LEVEL RIDGE THAT
BUILDS INTO THE UPPER MIDWEST.

HIGH PRESSURE WILL KEEP THE AREA DRY SATURDAY.

MODELS ARE BEGINNING TO COME INTO AGREEMENT FOR ANOTHER SNOW
PRODUCING STORM SUNDAY. STILL LOTS OF UNCERTAINTY ON THE EXACT
TRACK OF THE SYSTEM...BUT IT DOES APPEAR THAT MOST IF NOT ALL OF
THE AREA WILL BE ON THE COLD SIDE OF THE SURFACE LOW. MODEL
DEPICTIONS OF THIS SYSTEM HAVE VARIED GREATLY OVER THE PAST FEW
DAYS...SO THERE STILL IS A LOT OF UNCERTAINTY OF WHAT WILL BE THE
FINAL SOLUTION. FOR NOW WILL LEAN CLOSE TO THE 21Z SREF SOLUTION
AS IT SEEMS TO BE A NICE MIX OF THE 00Z NAM AND GFS. IF THIS
SYSTEM AND ITS TRACK COMES TO FRUITION...HEADLINES WILL BE NEEDED.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
A COLD...WINTER PATTERN WILL CONTINUE FOR THE REST OF THE LONG
TERM. THE NEXT BEST CHANCE FOR SNOW SHOWERS WILL ARRIVE LATE IN
THE PERIOD.

&&

.AVIATION /13Z FRIDAY THROUGH TUESDAY/...
MVFR CIGS WITH IFR VSBY IN SNOW SHWRS WL CONT THIS MRNG. GENL
IMPROVEMENT CAN BE ANTICIPATED THIS AFTN WITH DIMINISHED SNOW SHWR
ACTIVITY...AND BY TNGT FOR THE MVFR STRATOCU AS DRY ADVCTN AND
SBSDNC INCRS.

SFC WIND ARE EXPECTED TO CONTINUE TO GUST FROM THE W AND NW AT 15
TO 25 KNOTS THROUGH THE DAY.

.OUTLOOK.../FRIDAY NIGHT THROUGH TUESDAY/...
IMPROVEMENTS CAN BE EXPECTED AS HIGH PRES BLDS ON SATURDAY.
HOWEVER...SNOW AND RESTRICTIONS ARE LIKELY WITH SUNDAY LOW PRES.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     SATURDAY FOR MDZ001.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MDZ001.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
     PAZ007>009-015-016-023.
     WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     SATURDAY FOR PAZ008-009-015-016-023-074-076.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ074-
     076.
WV...WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     SATURDAY FOR WVZ023-041.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR WVZ023-
     041.

&&

$$

15






000
FXUS61 KPBZ 301242
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
742 AM EST FRI JAN 30 2015

.SYNOPSIS...
COLDER TEMPERATURES AND SNOW SHOWERS WILL PLAGUE THE UPPER OHIO
VALLEY REGION TODAY. HIGH PRESSURE WILL BUILD AND DIMINISH THE
SNOW SHOWERS THIS AFTERNOON AND PROVIDE A DRY SATURDAY BEFORE LOW
PRESSURE SPREADS MORE PRECIPITATION OVER THE AREA ON SUNDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
DAWN ADJUSTMENTS WERE MINOR...BUT DID INCLUDE INCRSD POPS FOR THE
EAST CNTRL OH CNTIES AS PER RADAR TRENDS UNDR CROSSING SHRTWV.
ACCUMULATIONS WL RMN RELATIVELY MINOR THOUGH FOR THAT AREA.

PREVIOUS...
ANOTHER SHORTWAVE TROUGH WILL CROSS THE AREA THIS MORNING...
PROVIDING ANOTHER PUSH OF ARCTIC AIR. THIS WILL SUSTAIN THE RISK
FOR SNOW SHOWERS THROUGHOUT MUCH OF THE MORNING WITH THE BEST
CHANCE ACROSS THE NORTH AND ESPECIALLY THE RIDGES. UPSLOPE SNOW
SHOWERS IN THE RIDGES WILL BE CRANKING THROUGH THE MORNING HOURS
AND THIS WILL BE THE LOCATIONS WERE SNOW ACCUMULATIONS WILL BE
OPTIMAL. WILL KEEP THE ADVISORY AS IS.

STEERING WINDS BEGIN TO SHOW A MORE NORTHERLY COMPONENT THIS
AFTERNOON BEHIND THE EXITING TROUGH. THESE STRONG WINDS WILL DRIVE
THE ARCTIC AIR SOUTHWARD ACROSS MY ENTIRE CWA. THE SNOW SHOWER
THREAT WILL WANE THROUGHOUT THE AFTERNOON DUE TO THE VEERING AND
SHEAR IN THE WINDS AND ALSO THE LOWERING OF INVERSIONS. THE RIDGES
WILL HOLD ONTO SNOW SHOWERS THE LONGEST THANKS TO THE ALWAYS
PERSISTENT OROGRAPHIC EFFECTS.

HIGHS WILL BE REACHED IN THE MORNING...WITH TEMPS SLOWLY FALLING
THROUGHOUT THE DAY.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
SNOW SHOWERS WILL END IN THE RIDGES THIS EVENING AS HIGH PRESSURE
SPREADS ACROSS THE REGION. THE ARCTIC AIR MASS WILL QUICKLY SHIFT
TOWARD THE NORTHEAST IN RESPONSE TO THE MID-LEVEL RIDGE THAT
BUILDS INTO THE UPPER MIDWEST.

HIGH PRESSURE WILL KEEP THE AREA DRY SATURDAY.

MODELS ARE BEGINNING TO COME INTO AGREEMENT FOR ANOTHER SNOW
PRODUCING STORM SUNDAY. STILL LOTS OF UNCERTAINTY ON THE EXACT
TRACK OF THE SYSTEM...BUT IT DOES APPEAR THAT MOST IF NOT ALL OF
THE AREA WILL BE ON THE COLD SIDE OF THE SURFACE LOW. MODEL
DEPICTIONS OF THIS SYSTEM HAVE VARIED GREATLY OVER THE PAST FEW
DAYS...SO THERE STILL IS A LOT OF UNCERTAINTY OF WHAT WILL BE THE
FINAL SOLUTION. FOR NOW WILL LEAN CLOSE TO THE 21Z SREF SOLUTION
AS IT SEEMS TO BE A NICE MIX OF THE 00Z NAM AND GFS. IF THIS
SYSTEM AND ITS TRACK COMES TO FRUITION...HEADLINES WILL BE NEEDED.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
A COLD...WINTER PATTERN WILL CONTINUE FOR THE REST OF THE LONG
TERM. THE NEXT BEST CHANCE FOR SNOW SHOWERS WILL ARRIVE LATE IN
THE PERIOD.

&&

.AVIATION /13Z FRIDAY THROUGH TUESDAY/...
MVFR CIGS WITH IFR VSBY IN SNOW SHWRS WL CONT THIS MRNG. GENL
IMPROVEMENT CAN BE ANTICIPATED THIS AFTN WITH DIMINISHED SNOW SHWR
ACTIVITY...AND BY TNGT FOR THE MVFR STRATOCU AS DRY ADVCTN AND
SBSDNC INCRS.

SFC WIND ARE EXPECTED TO CONTINUE TO GUST FROM THE W AND NW AT 15
TO 25 KNOTS THROUGH THE DAY.

.OUTLOOK.../FRIDAY NIGHT THROUGH TUESDAY/...
IMPROVEMENTS CAN BE EXPECTED AS HIGH PRES BLDS ON SATURDAY.
HOWEVER...SNOW AND RESTRICTIONS ARE LIKELY WITH SUNDAY LOW PRES.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     SATURDAY FOR MDZ001.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MDZ001.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
     PAZ007>009-015-016-023.
     WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     SATURDAY FOR PAZ008-009-015-016-023-074-076.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ074-
     076.
WV...WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     SATURDAY FOR WVZ023-041.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR WVZ023-
     041.

&&

$$

15





000
FXUS61 KPBZ 301033
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
533 AM EST FRI JAN 30 2015

.SYNOPSIS...
COLDER TEMPERATURES AND SNOW SHOWERS TODAY. HIGH PRESSURE WILL
BUILD IN FROM THE WEST LATE THIS AFTERNOON...DIMINISHING THE RISK
FOR SNOW SHOWERS. A DRY SATURDAY WITH ANOTHER STORM FOR SUNDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
ANOTHER SHORTWAVE TROUGH WILL CROSS THE AREA THIS MORNING...
PROVIDING ANOTHER PUSH OF ARCTIC AIR. THIS WILL SUSTAIN THE RISK
FOR SNOW SHOWERS THROUGHOUT MUCH OF THE MORNING WITH THE BEST
CHANCE ACROSS THE NORTH AND ESPECIALLY THE RIDGES. UPSLOPE SNOW
SHOWERS IN THE RIDGES WILL BE CRANKING THROUGH THE MORNING HOURS
AND THIS WILL BE THE LOCATIONS WERE SNOW ACCUMULATIONS WILL BE
OPTIMAL. WILL KEEP THE ADVISORY AS IS.

STEERING WINDS BEGIN TO SHOW A MORE NORTHERLY COMPONENT THIS
AFTERNOON BEHIND THE EXITING TROUGH. THESE STRONG WINDS WILL DRIVE
THE ARCTIC AIR SOUTHWARD ACROSS MY ENTIRE CWA. THE SNOW SHOWER
THREAT WILL WANE THROUGHOUT THE AFTERNOON DUE TO THE VEERING AND
SHEAR IN THE WINDS AND ALSO THE LOWERING OF INVERSIONS. THE RIDGES
WILL HOLD ONTO SNOW SHOWERS THE LONGEST THANKS TO THE ALWAYS
PERSISTENT OROGRAPHIC EFFECTS.

HIGHS WILL BE REACHED IN THE MORNING...WITH TEMPS SLOWLY FALLING
THROUGHOUT THE DAY.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
SNOW SHOWERS WILL END IN THE RIDGES THIS EVENING AS HIGH PRESSURE
SPREADS ACROSS THE REGION. THE ARCTIC AIR MASS WILL QUICKLY SHIFT
TOWARD THE NORTHEAST IN RESPONSE TO THE MID-LEVEL RIDGE THAT
BUILDS INTO THE UPPER MIDWEST.

HIGH PRESSURE WILL KEEP THE AREA DRY SATURDAY.

MODELS ARE BEGINNING TO COME INTO AGREEMENT FOR ANOTHER SNOW
PRODUCING STORM SUNDAY. STILL LOTS OF UNCERTAINTY ON THE EXACT
TRACK OF THE SYSTEM...BUT IT DOES APPEAR THAT MOST IF NOT ALL OF
THE AREA WILL BE ON THE COLD SIDE OF THE SURFACE LOW. MODEL
DEPICTIONS OF THIS SYSTEM HAVE VARIED GREATLY OVER THE PAST FEW
DAYS...SO THERE STILL IS A LOT OF UNCERTAINTY OF WHAT WILL BE THE
FINAL SOLUTION. FOR NOW WILL LEAN CLOSE TO THE 21Z SREF SOLUTION
AS IT SEEMS TO BE A NICE MIX OF THE 00Z NAM AND GFS. IF THIS
SYSTEM AND ITS TRACK COMES TO FRUITION...HEADLINES WILL BE NEEDED.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
A COLD...WINTER PATTERN WILL CONTINUE FOR THE REST OF THE LONG
TERM. THE NEXT BEST CHANCE FOR SNOW SHOWERS WILL ARRIVE LATE IN
THE PERIOD.

&&

.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
SHSN WILL SLOWLY TAPER OFF WEST OF THE RIDGES THIS MORNING...ALTHOUGH
UPSLOPE WILL KEEP THEM GOING ALONG THE RIDGES THROUGH THE
AFTERNOON. MVFR WITH SPOTTY IFR WILL CONTINUE WITH THE
SNOW...WHILE CIGS WILL SLOWLY RISE ONCE SNOW ENDS...HLG IS ALREADY
VFR. FOR THE MOST PART THOUGH...THINK MVFR CIGS MAINTAIN THROUGH
THE DAY. SNOW MOSTLY SHUTS OFF BY 00Z...WITH CLOUDS BREAKING UP
SLOWLY OVERNIGHT. WINDS ARE EXPECTED TO CONTINUE TO GUST FROM THE
W AND NW AT 15 TO 25 KNOTS THROUGH THE DAY.

.OUTLOOK.../FRIDAY NIGHT THROUGH TUESDAY/...
IMPROVEMENTS CAN BE EXPECTED AS HIGH PRES BLDS ON SATURDAY.
HOWEVER...SNOW AND RESTRICTIONS ARE LIKELY WITH SUNDAY LOW PRES.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     SATURDAY FOR MDZ001.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MDZ001.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
     PAZ007>009-015-016-023.
     WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     SATURDAY FOR PAZ008-009-015-016-023-074-076.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ074-
     076.
WV...WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     SATURDAY FOR WVZ023-041.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR WVZ023-
     041.

&&

$$








000
FXUS61 KPBZ 301033
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
533 AM EST FRI JAN 30 2015

.SYNOPSIS...
COLDER TEMPERATURES AND SNOW SHOWERS TODAY. HIGH PRESSURE WILL
BUILD IN FROM THE WEST LATE THIS AFTERNOON...DIMINISHING THE RISK
FOR SNOW SHOWERS. A DRY SATURDAY WITH ANOTHER STORM FOR SUNDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
ANOTHER SHORTWAVE TROUGH WILL CROSS THE AREA THIS MORNING...
PROVIDING ANOTHER PUSH OF ARCTIC AIR. THIS WILL SUSTAIN THE RISK
FOR SNOW SHOWERS THROUGHOUT MUCH OF THE MORNING WITH THE BEST
CHANCE ACROSS THE NORTH AND ESPECIALLY THE RIDGES. UPSLOPE SNOW
SHOWERS IN THE RIDGES WILL BE CRANKING THROUGH THE MORNING HOURS
AND THIS WILL BE THE LOCATIONS WERE SNOW ACCUMULATIONS WILL BE
OPTIMAL. WILL KEEP THE ADVISORY AS IS.

STEERING WINDS BEGIN TO SHOW A MORE NORTHERLY COMPONENT THIS
AFTERNOON BEHIND THE EXITING TROUGH. THESE STRONG WINDS WILL DRIVE
THE ARCTIC AIR SOUTHWARD ACROSS MY ENTIRE CWA. THE SNOW SHOWER
THREAT WILL WANE THROUGHOUT THE AFTERNOON DUE TO THE VEERING AND
SHEAR IN THE WINDS AND ALSO THE LOWERING OF INVERSIONS. THE RIDGES
WILL HOLD ONTO SNOW SHOWERS THE LONGEST THANKS TO THE ALWAYS
PERSISTENT OROGRAPHIC EFFECTS.

HIGHS WILL BE REACHED IN THE MORNING...WITH TEMPS SLOWLY FALLING
THROUGHOUT THE DAY.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
SNOW SHOWERS WILL END IN THE RIDGES THIS EVENING AS HIGH PRESSURE
SPREADS ACROSS THE REGION. THE ARCTIC AIR MASS WILL QUICKLY SHIFT
TOWARD THE NORTHEAST IN RESPONSE TO THE MID-LEVEL RIDGE THAT
BUILDS INTO THE UPPER MIDWEST.

HIGH PRESSURE WILL KEEP THE AREA DRY SATURDAY.

MODELS ARE BEGINNING TO COME INTO AGREEMENT FOR ANOTHER SNOW
PRODUCING STORM SUNDAY. STILL LOTS OF UNCERTAINTY ON THE EXACT
TRACK OF THE SYSTEM...BUT IT DOES APPEAR THAT MOST IF NOT ALL OF
THE AREA WILL BE ON THE COLD SIDE OF THE SURFACE LOW. MODEL
DEPICTIONS OF THIS SYSTEM HAVE VARIED GREATLY OVER THE PAST FEW
DAYS...SO THERE STILL IS A LOT OF UNCERTAINTY OF WHAT WILL BE THE
FINAL SOLUTION. FOR NOW WILL LEAN CLOSE TO THE 21Z SREF SOLUTION
AS IT SEEMS TO BE A NICE MIX OF THE 00Z NAM AND GFS. IF THIS
SYSTEM AND ITS TRACK COMES TO FRUITION...HEADLINES WILL BE NEEDED.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
A COLD...WINTER PATTERN WILL CONTINUE FOR THE REST OF THE LONG
TERM. THE NEXT BEST CHANCE FOR SNOW SHOWERS WILL ARRIVE LATE IN
THE PERIOD.

&&

.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
SHSN WILL SLOWLY TAPER OFF WEST OF THE RIDGES THIS MORNING...ALTHOUGH
UPSLOPE WILL KEEP THEM GOING ALONG THE RIDGES THROUGH THE
AFTERNOON. MVFR WITH SPOTTY IFR WILL CONTINUE WITH THE
SNOW...WHILE CIGS WILL SLOWLY RISE ONCE SNOW ENDS...HLG IS ALREADY
VFR. FOR THE MOST PART THOUGH...THINK MVFR CIGS MAINTAIN THROUGH
THE DAY. SNOW MOSTLY SHUTS OFF BY 00Z...WITH CLOUDS BREAKING UP
SLOWLY OVERNIGHT. WINDS ARE EXPECTED TO CONTINUE TO GUST FROM THE
W AND NW AT 15 TO 25 KNOTS THROUGH THE DAY.

.OUTLOOK.../FRIDAY NIGHT THROUGH TUESDAY/...
IMPROVEMENTS CAN BE EXPECTED AS HIGH PRES BLDS ON SATURDAY.
HOWEVER...SNOW AND RESTRICTIONS ARE LIKELY WITH SUNDAY LOW PRES.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     SATURDAY FOR MDZ001.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MDZ001.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
     PAZ007>009-015-016-023.
     WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     SATURDAY FOR PAZ008-009-015-016-023-074-076.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ074-
     076.
WV...WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     SATURDAY FOR WVZ023-041.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR WVZ023-
     041.

&&

$$







000
FXUS61 KPBZ 300902
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
402 AM EST FRI JAN 30 2015

.SYNOPSIS...
COLDER TEMPERATURES AND SNOW SHOWERS TODAY. HIGH PRESSURE WILL
BUILD IN FROM THE WEST LATE THIS AFTERNOON...DIMINISHING THE RISK
FOR SNOW SHOWERS. A DRY SATURDAY WITH ANOTHER STORM FOR SUNDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
ANOTHER SHORTWAVE TROUGH WILL CROSS THE AREA THIS MORNING...
PROVIDING ANOTHER PUSH OF ARCTIC AIR. THIS WILL SUSTAIN THE RISK
FOR SNOW SHOWERS THROUGHOUT MUCH OF THE MORNING WITH THE BEST
CHANCE ACROSS THE NORTH AND ESPECIALLY THE RIDGES. UPSLOPE SNOW
SHOWERS IN THE RIDGES WILL BE CRANKING THROUGH THE MORNING HOURS
AND THIS WILL BE THE LOCATIONS WERE SNOW ACCUMULATIONS WILL BE
OPTIMAL. WILL KEEP THE ADVISORY AS IS.

STEERING WINDS BEGIN TO SHOW A MORE NORTHERLY COMPONENT THIS
AFTERNOON BEHIND THE EXITING TROUGH. THESE STRONG WINDS WILL DRIVE
THE ARCTIC AIR SOUTHWARD ACROSS MY ENTIRE CWA. THE SNOW SHOWER
THREAT WILL WANE THROUGHOUT THE AFTERNOON DUE TO THE VEERING AND
SHEAR IN THE WINDS AND ALSO THE LOWERING OF INVERSIONS. THE RIDGES
WILL HOLD ONTO SNOW SHOWERS THE LONGEST THANKS TO THE ALWAYS
PERSISTENT OROGRAPHIC EFFECTS.

HIGHS WILL BE REACHED IN THE MORNING...WITH TEMPS SLOWLY FALLING
THROUGHOUT THE DAY.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
SNOW SHOWERS WILL END IN THE RIDGES THIS EVENING AS HIGH PRESSURE
SPREADS ACROSS THE REGION. THE ARCTIC AIR MASS WILL QUICKLY SHIFT
TOWARD THE NORTHEAST IN RESPONSE TO THE MID-LEVEL RIDGE THAT
BUILDS INTO THE UPPER MIDWEST.

HIGH PRESSURE WILL KEEP THE AREA DRY SATURDAY.

MODELS ARE BEGINNING TO COME INTO AGREEMENT FOR ANOTHER SNOW
PRODUCING STORM SUNDAY. STILL LOTS OF UNCERTAINTY ON THE EXACT
TRACK OF THE SYSTEM...BUT IT DOES APPEAR THAT MOST IF NOT ALL OF
THE AREA WILL BE ON THE COLD SIDE OF THE SURFACE LOW. MODEL
DEPICTIONS OF THIS SYSTEM HAVE VARIED GREATLY OVER THE PAST FEW
DAYS...SO THERE STILL IS A LOT OF UNCERTAINTY OF WHAT WILL BE THE
FINAL SOLUTION. FOR NOW WILL LEAN CLOSE TO THE 21Z SREF SOLUTION
AS IT SEEMS TO BE A NICE MIX OF THE 00Z NAM AND GFS. IF THIS
SYSTEM AND ITS TRACK COMES TO FRUITION...HEADLINES WILL BE NEEDED.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
A COLD...WINTER PATTERN WILL CONTINUE FOR THE REST OF THE LONG
TERM. THE NEXT BEST CHANCE FOR SNOW SHOWERS WILL ARRIVE LATE IN
THE PERIOD.

&&

.AVIATION /09Z FRIDAY THROUGH TUESDAY/...
MVFR CONDITIONS WILL PERSIST THROUGH MUCH OF THE DAY TODAY. IFR
AND EVEN SPOTTY LIFR ARE POSSIBLE OVER THE NEXT FEW HOURS AS
INITIAL BATCH OF -SHSN MOVES THROUGH. UPSLOPE CONDITIONS WILL BE
SETTING UP THEREAFTER WITH GUSTY WNW WINDS...WITH DUJ AND LBE
SEEING THE MOST ACTIVITY. AFTER 18Z...SLOW IMPROVEMENT BEGINS AS
CIGS GRADUALLY BEGIN TO LIFT. SOME OF THE WESTERN TERMINALS MAY
SCATTER OUT TOWARDS THE END OF THE TAF PERIOD.

.OUTLOOK.../FRIDAY NIGHT THROUGH TUESDAY/...
IMPROVEMENTS CAN BE EXPECTED AS HIGH PRES BLDS ON SATURDAY.
HOWEVER...SNOW AND RESTRICTIONS ARE LIKELY WITH SUNDAY LOW PRES.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     SATURDAY FOR MDZ001.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MDZ001.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
     PAZ007>009-015-016-023.
     WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     SATURDAY FOR PAZ008-009-015-016-023-074-076.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ074-
     076.
WV...WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     SATURDAY FOR WVZ023-041.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR WVZ023-
     041.

&&

$$







000
FXUS61 KPBZ 300553
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1253 AM EST FRI JAN 30 2015

.SYNOPSIS...
COLDER TEMPERATURES AND SNOW SHOWERS TODAY. HIGH PRESSURE WILL
BUILD IN FROM THE WEST LATE THIS AFTERNOON...DIMINISHING THE RISK
FOR SNOW SHOWERS. A DRY SATURDAY WITH ANOTHER STORM FOR SUNDAY.

&&

.NEAR TERM /THROUGH TODAY/...
WIDESPREAD SNOW SHOWERS WITH EMBEDDED SQUALLS WILL CROSS THE AREA
LATE TONIGHT AHEAD OF A STRONG SHORTWAVE...WHICH WILL ALSO USHER
IN THE NEXT BLAST OF ARCTIC AIR. THIS SHORTWAVE IS RUSHING
EASTWARD AND WOULD EXPECT THE SNOW SHOWERS TO DISSIPATE ONCE IT
EXITS. UPSTREAM OBS AGREE WITH THIS ASSESSMENT AS MOST SITES ARE
NOW SNOW FREE. WILL NEED TO KEEP AN EYE ON THE POSSIBILITY FOR
PATCHY FREEZING DRIZZLE BEHIND THE SNOW AS MOISTURE ALOFT WILL
EXIT...PREVENTING THE INFUSION OF ICE CRYSTALS INTO THE LOWER CLOUD
DECK. HOWEVER...WITH SUCH STRONG CAA BEHIND THE AFOREMENTIONED
SHORTWAVE...SNOW GROWTH ZONES DROP QUICKLY AS WELL. IF FORECAST
SOUNDINGS ARE CORRECT...THE ATMOSPHERE SHOULD BE COLD ENOUGH TO
SUPPORT SCATTERED SNOW SHOWERS OR FLURRIES.

ANOTHER SHORTWAVE TROUGH WILL CROSS THE AREA THIS MORNING...
PROVIDING ANOTHER PUSH OF ARCTIC AIR. THIS WILL SUSTAIN THE RISK
FOR SNOW SHOWERS THROUGHOUT THE MORNING WITH THE BEST CHANCE
ACROSS THE NORTH AND ESPECIALLY THE RIDGES. UPSLOPE SNOW SHOWERS
IN THE RIDGES WILL BE CRANKING THROUGH THE MORNING HOURS AND THIS
WILL BE THE LOCATIONS WERE SNOW ACCUMULATIONS WILL BE OPTIMAL.
WILL KEEP THE ADVISORY AS IS.

STEERING WINDS BEGIN TO SHOW A MORE NORTHERLY COMPONENT THIS
AFTERNOON BEHIND THE EXITING TROUGH. THESE STRONG WINDS WILL DRIVE
THE ARCTIC AIR SOUTHWARD ACROSS MY ENTIRE CWA. THE SNOW SHOWER
THREAT WILL WANE THROUGHOUT THE AFTERNOON DUE TO THE VEERING AND
SHEAR IN THE WINDS AND ALSO THE LOWERING OF INVERSIONS. THE RIDGES
WILL HOLD ONTO SNOW SHOWERS THE LONGEST THANKS TO THE ALWAYS
PERSISTENT OROGRAPHIC EFFECTS.

HIGHS WILL BE REACHED IN THE MORNING...WITH TEMPS SLOWLY FALLING
THROUGHOUT THE DAY.

&&

.SHORT TERM /TONIGHT THROUGH SUNDAY/...
SNOW SHOWERS WILL END IN THE RIDGES THIS EVENING AS HIGH PRESSURE
SPREADS ACROSS THE REGION. THE ARCTIC AIR MASS WILL QUICKLY SHIFT
TOWARD THE NORTHEAST IN RESPONSE TO THE MID-LEVEL RIDGE THAT
BUILDS INTO THE UPPER MIDWEST.

HIGH PRESSURE WILL KEEP THE AREA DRY SATURDAY.

MODELS ARE BEGINNING TO COME INTO AGREEMENT FOR ANOTHER SNOW
PRODUCING STORM SUNDAY. STILL LOTS OF UNCERTAINTY ON THE EXACT
TRACK OF THE SYSTEM...BUT IT DOES APPEAR THAT MOST IF NOT ALL OF
THE AREA WILL BE ON THE COLD SIDE OF THE SURFACE LOW. MODEL
DEPICTIONS OF THIS SYSTEM HAVE VARIED GREATLY OVER THE PAST FEW
DAYS...SO THERE STILL IS A LOT OF UNCERTAINTY OF WHAT WILL BE THE
FINAL SOLUTION. FOR NOW WILL LEAN CLOSE TO THE 21Z SREF SOLUTION
AS IT SEEMS TO BE A NICE MIX OF THE 00Z NAM AND GFS. IF THIS
SYSTEM AND ITS TRACK COMES TO FRUITION...HEADLINES WILL BE NEEDED.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
A COLD...WINTER PATTERN WILL CONTINUE FOR THE REST OF THE LONG
TERM. THE NEXT BEST CHANCE FOR SNOW SHOWERS WILL ARRIVE LATE IN
THE PERIOD.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
MVFR CONDITIONS WILL PERSIST THROUGH MUCH OF THE DAY TODAY. IFR
AND EVEN SPOTTY LIFR ARE POSSIBLE OVER THE NEXT FEW HOURS AS
INITIAL BATCH OF -SHSN MOVES THROUGH. UPSLOPE CONDITIONS WILL BE
SETTING UP THEREAFTER WITH GUSTY WNW WINDS...WITH DUJ AND LBE
SEEING THE MOST ACTIVITY. AFTER 18Z...SLOW IMPROVEMENT BEGINS AS
CIGS GRADUALLY BEGIN TO LIFT. SOME OF THE WESTERN TERMINALS MAY
SCATTER OUT TOWARDS THE END OF THE TAF PERIOD.

.OUTLOOK.../FRIDAY NIGHT THROUGH TUESDAY/...
IMPROVEMENTS CAN BE EXPECTED AS HIGH PRES BLDS ON SATURDAY.
HOWEVER...SNOW AND RESTRICTIONS ARE LIKELY WITH SUNDAY LOW PRES.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MDZ001.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
     PAZ007>009-015-016-023.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ074-
     076.
WV...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR WVZ023-
     041.

&&

$$







000
FXUS61 KPBZ 300553
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1253 AM EST FRI JAN 30 2015

.SYNOPSIS...
COLDER TEMPERATURES AND SNOW SHOWERS TODAY. HIGH PRESSURE WILL
BUILD IN FROM THE WEST LATE THIS AFTERNOON...DIMINISHING THE RISK
FOR SNOW SHOWERS. A DRY SATURDAY WITH ANOTHER STORM FOR SUNDAY.

&&

.NEAR TERM /THROUGH TODAY/...
WIDESPREAD SNOW SHOWERS WITH EMBEDDED SQUALLS WILL CROSS THE AREA
LATE TONIGHT AHEAD OF A STRONG SHORTWAVE...WHICH WILL ALSO USHER
IN THE NEXT BLAST OF ARCTIC AIR. THIS SHORTWAVE IS RUSHING
EASTWARD AND WOULD EXPECT THE SNOW SHOWERS TO DISSIPATE ONCE IT
EXITS. UPSTREAM OBS AGREE WITH THIS ASSESSMENT AS MOST SITES ARE
NOW SNOW FREE. WILL NEED TO KEEP AN EYE ON THE POSSIBILITY FOR
PATCHY FREEZING DRIZZLE BEHIND THE SNOW AS MOISTURE ALOFT WILL
EXIT...PREVENTING THE INFUSION OF ICE CRYSTALS INTO THE LOWER CLOUD
DECK. HOWEVER...WITH SUCH STRONG CAA BEHIND THE AFOREMENTIONED
SHORTWAVE...SNOW GROWTH ZONES DROP QUICKLY AS WELL. IF FORECAST
SOUNDINGS ARE CORRECT...THE ATMOSPHERE SHOULD BE COLD ENOUGH TO
SUPPORT SCATTERED SNOW SHOWERS OR FLURRIES.

ANOTHER SHORTWAVE TROUGH WILL CROSS THE AREA THIS MORNING...
PROVIDING ANOTHER PUSH OF ARCTIC AIR. THIS WILL SUSTAIN THE RISK
FOR SNOW SHOWERS THROUGHOUT THE MORNING WITH THE BEST CHANCE
ACROSS THE NORTH AND ESPECIALLY THE RIDGES. UPSLOPE SNOW SHOWERS
IN THE RIDGES WILL BE CRANKING THROUGH THE MORNING HOURS AND THIS
WILL BE THE LOCATIONS WERE SNOW ACCUMULATIONS WILL BE OPTIMAL.
WILL KEEP THE ADVISORY AS IS.

STEERING WINDS BEGIN TO SHOW A MORE NORTHERLY COMPONENT THIS
AFTERNOON BEHIND THE EXITING TROUGH. THESE STRONG WINDS WILL DRIVE
THE ARCTIC AIR SOUTHWARD ACROSS MY ENTIRE CWA. THE SNOW SHOWER
THREAT WILL WANE THROUGHOUT THE AFTERNOON DUE TO THE VEERING AND
SHEAR IN THE WINDS AND ALSO THE LOWERING OF INVERSIONS. THE RIDGES
WILL HOLD ONTO SNOW SHOWERS THE LONGEST THANKS TO THE ALWAYS
PERSISTENT OROGRAPHIC EFFECTS.

HIGHS WILL BE REACHED IN THE MORNING...WITH TEMPS SLOWLY FALLING
THROUGHOUT THE DAY.

&&

.SHORT TERM /TONIGHT THROUGH SUNDAY/...
SNOW SHOWERS WILL END IN THE RIDGES THIS EVENING AS HIGH PRESSURE
SPREADS ACROSS THE REGION. THE ARCTIC AIR MASS WILL QUICKLY SHIFT
TOWARD THE NORTHEAST IN RESPONSE TO THE MID-LEVEL RIDGE THAT
BUILDS INTO THE UPPER MIDWEST.

HIGH PRESSURE WILL KEEP THE AREA DRY SATURDAY.

MODELS ARE BEGINNING TO COME INTO AGREEMENT FOR ANOTHER SNOW
PRODUCING STORM SUNDAY. STILL LOTS OF UNCERTAINTY ON THE EXACT
TRACK OF THE SYSTEM...BUT IT DOES APPEAR THAT MOST IF NOT ALL OF
THE AREA WILL BE ON THE COLD SIDE OF THE SURFACE LOW. MODEL
DEPICTIONS OF THIS SYSTEM HAVE VARIED GREATLY OVER THE PAST FEW
DAYS...SO THERE STILL IS A LOT OF UNCERTAINTY OF WHAT WILL BE THE
FINAL SOLUTION. FOR NOW WILL LEAN CLOSE TO THE 21Z SREF SOLUTION
AS IT SEEMS TO BE A NICE MIX OF THE 00Z NAM AND GFS. IF THIS
SYSTEM AND ITS TRACK COMES TO FRUITION...HEADLINES WILL BE NEEDED.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
A COLD...WINTER PATTERN WILL CONTINUE FOR THE REST OF THE LONG
TERM. THE NEXT BEST CHANCE FOR SNOW SHOWERS WILL ARRIVE LATE IN
THE PERIOD.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
MVFR CONDITIONS WILL PERSIST THROUGH MUCH OF THE DAY TODAY. IFR
AND EVEN SPOTTY LIFR ARE POSSIBLE OVER THE NEXT FEW HOURS AS
INITIAL BATCH OF -SHSN MOVES THROUGH. UPSLOPE CONDITIONS WILL BE
SETTING UP THEREAFTER WITH GUSTY WNW WINDS...WITH DUJ AND LBE
SEEING THE MOST ACTIVITY. AFTER 18Z...SLOW IMPROVEMENT BEGINS AS
CIGS GRADUALLY BEGIN TO LIFT. SOME OF THE WESTERN TERMINALS MAY
SCATTER OUT TOWARDS THE END OF THE TAF PERIOD.

.OUTLOOK.../FRIDAY NIGHT THROUGH TUESDAY/...
IMPROVEMENTS CAN BE EXPECTED AS HIGH PRES BLDS ON SATURDAY.
HOWEVER...SNOW AND RESTRICTIONS ARE LIKELY WITH SUNDAY LOW PRES.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MDZ001.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
     PAZ007>009-015-016-023.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ074-
     076.
WV...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR WVZ023-
     041.

&&

$$








000
FXUS61 KPBZ 300540 AAC
AFDPBZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PITTSBURGH PA
1240 AM EST FRI JAN 30 2015

.SYNOPSIS...
COLDER TEMPERATURES AND SNOW SHOWERS TODAY. HIGH PRESSURE WILL
BUILD IN FROM THE WEST LATE THIS AFTERNOON...DIMINISHING THE RISK
FOR SNOW SHOWERS. A DRY SATURDAY WITH ANOTHER STORM FOR SUNDAY.

&&

.NEAR TERM /THROUGH TODAY/...
WIDESPREAD SNOW SHOWERS WITH EMBEDDED SQUALLS WILL CROSS THE AREA
LATE TONIGHT AHEAD OF A STRONG SHORTWAVE...WHICH WILL ALSO USHER
IN THE NEXT BLAST OF ARCTIC AIR. THIS SHORTWAVE IS RUSHING
EASTWARD AND WOULD EXPECT THE SNOW SHOWERS TO DISSIPATE ONCE IT
EXITS. UPSTREAM OBS AGREE WITH THIS ASSESSMENT AS MOST SITES ARE
NOW SNOW FREE. WILL NEED TO KEEP AN EYE ON THE POSSIBILITY FOR
PATCHY FREEZING DRIZZLE BEHIND THE SNOW AS MOISTURE ALOFT WILL
EXIT...PREVENTING THE INFUSION OF ICE CRYSTALS INTO THE LOWER CLOUD
DECK. HOWEVER...WITH SUCH STRONG CAA BEHIND THE AFOREMENTIONED
SHORTWAVE...SNOW GROWTH ZONES DROP QUICKLY AS WELL. IF FORECAST
SOUNDINGS ARE CORRECT...THE ATMOSPHERE SHOULD BE COLD ENOUGH TO
SUPPORT SCATTERED SNOW SHOWERS OR FLURRIES.

ANOTHER SHORTWAVE TROUGH WILL CROSS THE AREA THIS MORNING...
PROVIDING ANOTHER PUSH OF ARCTIC AIR. THIS WILL SUSTAIN THE RISK
FOR SNOW SHOWERS THROUGHOUT THE MORNING WITH THE BEST CHANCE
ACROSS THE NORTH AND ESPECIALLY THE RIDGES. UPSLOPE SNOW SHOWERS
IN THE RIDGES WILL BE CRANKING THROUGH THE MORNING HOURS AND THIS
WILL BE THE LOCATIONS WERE SNOW ACCUMULATIONS WILL BE OPTIMAL.
WILL KEEP THE ADVISORY AS IS.

STEERING WINDS BEGIN TO SHOW A MORE NORTHERLY COMPONENT THIS
AFTERNOON BEHIND THE EXITING TROUGH. THESE STRONG WINDS WILL DRIVE
THE ARCTIC AIR SOUTHWARD ACROSS MY ENTIRE CWA. THE SNOW SHOWER
THREAT WILL WANE THROUGHOUT THE AFTERNOON DUE TO THE VEERING AND
SHEAR IN THE WINDS AND ALSO THE LOWERING OF INVERSIONS. THE RIDGES
WILL HOLD ONTO SNOW SHOWERS THE LONGEST THANKS TO THE ALWAYS
PERSISTENT OROGRAPHIC EFFECTS.

HIGHS WILL BE REACHED IN THE MORNING...WITH TEMPS SLOWLY FALLING
THROUGHOUT THE DAY.

&&

.SHORT TERM /TONIGHT THROUGH SUNDAY/...
SNOW SHOWERS WILL END IN THE RIDGES THIS EVENING AS HIGH PRESSURE
SPREADS ACROSS THE REGION. THE ARCTIC AIR MASS WILL QUICKLY SHIFT
TOWARD THE NORTHEAST IN RESPONSE TO THE MID-LEVEL RIDGE THAT
BUILDS INTO THE UPPER MIDWEST.

HIGH PRESSURE WILL KEEP THE AREA DRY SATURDAY.

MODELS ARE BEGINNING TO COME INTO AGREEMENT FOR ANOTHER SNOW
PRODUCING STORM SUNDAY. STILL LOTS OF UNCERTAINTY ON THE EXACT
TRACK OF THE SYSTEM...BUT IT DOES APPEAR THAT MOST IF NOT ALL OF
THE AREA WILL BE ON THE COLD SIDE OF THE SURFACE LOW. MODEL
DEPICTIONS OF THIS SYSTEM HAVE VARIED GREATLY OVER THE PAST FEW
DAYS...SO THERE STILL IS A LOT OF UNCERTAINTY OF WHAT WILL BE THE
FINAL SOLUTION. FOR NOW WILL LEAN CLOSE TO THE 21Z SREF SOLUTION
AS IT SEEMS TO BE A NICE MIX OF THE 00Z NAM AND GFS. IF THIS
SYSTEM AND ITS TRACK COMES TO FRUITION...HEADLINES WILL BE NEEDED.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
A COLD...WINTER PATTERN WILL CONTINUE FOR THE REST OF THE LONG
TERM. THE NEXT BEST CHANCE FOR SNOW SHOWERS WILL ARRIVE LATE IN
THE PERIOD.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
CONDITION DETERIORATION IS UNDERWAY AND DEGRADATIONS CAN BE
EXPECTED INTO FRIDAY AS MIXED PCPN SPREADS OVR UPR OH TERMINALS
AND CHANGES TO SNOW WITH CDFNT PASSAGE THIS EVE. IFR CAN BE
EXPECTED IN SNOW SHWRS THIS EVE...AND IN WIDESPREAD STRATUS WHICH
WL ACCOMPANY THE COLD SURGE OVR THE REGION.

.OUTLOOK.../FRIDAY NIGHT THROUGH TUESDAY/...
IMPROVEMENTS CAN BE EXPECTED AS HIGH PRES BLDS LTR ON
SATURDAY...HOWEVER...SNOW AND RESTRICTIONS ARE LIKELY WITH SUNDAY
LOW PRES.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MDZ001.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
     PAZ007>009-015-016-023.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ074-
     076.
WV...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR WVZ023-
     041.

&&

$$








000
FXUS61 KPBZ 300159
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
859 PM EST THU JAN 29 2015

.SYNOPSIS...
A COLD FRONT WILL CROSS THE AREA TONIGHT...FOLLOWED BY BUILDING
HIGH PRESSURE FRIDAY AND SATURDAY. LOW PRESSURE MAY BRING MORE
WINTRY WEATHER SUNDAY.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
THE KITCHEN SINK AND POTPOURRI OF GOODNESS THAT HAS BEEN FALLING
FROM THE SKY OVER THE PAST ROUGHLY 12 HOURS IS ALREADY SHOWING
SIGNS OF TRANSITIONING TOWARD ALL SNOW TO OUR IMMEDIATE NORTH AND
WEST. SURFACE OBSERVATIONS AND DUAL POL SIGNATURES SUGGEST THIS IS
OCCURRING...AND MODEL SOUNDINGS INDICATE RAPIDLY STEEPENING LAPSE
RATES THROUGH THE EVENING...EVEN THOUGH SURFACE TEMPERATURES MAY
TAKE A FEW HOURS TO FALL OFF PRECIPITOUSLY. WHILE ALL BUT THE
NORTHERN TIER OF THE CWA IS LIKELY RAINING AT THE MOMENT...THE
TREND TOWARD FROZEN PRECIPITATION WILL BE RAPID THROUGH THE
EVENING HOURS.

THAT SAID...FREEZING SURFACE TEMPERATURES ARE ONLY REALLY NOTED IN
SURFACE OBSERVATIONS FROM LAWRENCE TO COSHOCTON COUNTIES AND TO
THE NORTH AND WEST. AS SUCH...SEVERAL HOURS OF SNOW ARE LIKELY
DURING THE EVENING WITH MARGINAL TEMPERATURES FOR ACCUMULATION AT
BEST. AS SUCH...THE INITIAL ONSLAUGHT OF SNOW THAT WILL BE LIKELY
DURING THE LATE EVENING IS FAIRLY UNLIKELY TO BE AN EFFICIENT
ACCUMULATOR. HOWEVER...THINGS WILL DRASTICALLY CHANGE OVERNIGHT
AFTER A BRIEF INTERLUDE BETWEEN THIS EVENING`S ACTIVITY AND THE
OVERNIGHT ACTIVITY IN WHICH THE DENDRITIC LAYER DRIES OUT. THIS
WILL ALLOW FOR A BRIEF PERIOD OF DRIZZLE OF FREEZING DRIZZLE TO
MOVE ACROSS THE AREA ALONG WITH SOME FAIRLY MALFORMED SNOW GRAINS
BEING GENERATED AS WELL. HOWEVER...AS DEEPER SATURATION RETURNS
OVERNIGHT...THAT ACTIVITY SHOULD END WITH A TRANSITION BACK TO
SNOW.

A DEEPER AND MUCH MORE THERMODYNAMICALLY ABRUPT SHORT WAVE AND LOW
LEVEL FRONTAL BOUNDARY COMBO WILL MOVE THROUGH THE AREA BETWEEN 06
AND 12Z TONIGHT. AS THIS OCCURS...THE DENDRITIC GROWTH ZONE WILL
TANK DOWN INTO THE SATURATED LAYER AND GIVEN FRONTOGENETICAL
LIFTING...THIS WILL LIKELY LEAD TO A PERIOD OF FAIRLY EFFICIENT
SNOW SHOWERS FOR ALL LOCATIONS GIVEN STEEP LAPSE RATES AND LARGE
SCALE FORCING FOR ASCENT. IN THE RIDGES...THIS LARGE SCALE ASCENT
WILL BE OVERLAID WITH UNIDIRECTIONAL NORTHWESTERLY UPSLOPE FLOW
WORKING ON VERY UNSTABLE LOW LEVEL LAPSE RATES. WHILE MOISTURE
FLUX INTO THE UNSTABLE LAYER FROM LAKE ERIE WILL LIKELY BE MINIMAL
DUE TO ABUNDANT ICE COVER...SATURATION BELOW THE INVERSION LEVEL
WILL NOT BE DEPENDENT UPON THIS...AND WITH
INSTABILITY...UPSLOPE...AND LARGE SCALE ASCENT ALL OVERLAYING
EACH OTHER IN THE OVERNIGHT HOURS...SNOW SHOWERS WILL LIKELY BE
HEAVY EFFICIENT DENDRITE PRODUCERS. AS SUCH...WHILE MOST LOCATIONS
WILL ONLY SEE 1-3 INCHES OF SNOW OVERNIGHT OUTSIDE THE
RIDGES...LOCATIONS IN THE HIGHER ELEVATIONS SEEM MORE LIKELY TO
END UP WITH 4 TO 8 GIVEN RATIOS SURGING TOWARD 25 TO 1 OVERNIGHT.

ALL ADVISORIES WILL REMAIN IN EFFECT FOR THE OVERNIGHT AND INTO
FRIDAY. HEAVY SNOW SHOWERS WILL LIKELY BE HANDLED INDIVIDUALLY
WITH SPS STATEMENTS THROUGH THE NIGHT. FRIES

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY/...
EXTENDED THE WINTER WEA ADVY THRU THE DAY FRI FOR THE
RIDGES...THOUGH WITH A FROZEN LAKE ERIE WL ALLOW FOR THE NW PA
PORTION EXPIRE AT FRI MRNG. UPSLOPE SNW SHWRS SHOULD CONT THRU THE
DAY IN THE RIDGES BEFORE THINNING MSTR IN THE SNW GROWTH RGN AND
LWRG TEMP INVERSIONS END THE PCPN. A CROSSING UPR TROF SHOULD
ALLOW FOR SOME SCT SNW SHWRS OUTSIDE OF THIS AREA AS WELL.

BLDG HIGH PRES SHOULD BRING DRY WEA FRI NGT INTO SAT.

BELOW SEASONAL AVG TEMPS WERE FCST USING THE LATEST SREF NMBRS.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
MODELS CONT TO JOUST IN HANDLING OF LOW PRES PROJECTED TWD THE MID
ATLANTIC REGION FM SATURDAY NGT INTO MONDAY. PERSISTENCE RMNS
PRUDENT WITH LATEST GFS IN GENL LINE WITH CURRENT THINKING OUTSIDE
OF TIMING ISSUES. MEANWHILE...ECMWF IS FORECASTING A SOUTHWARD
TRACK TO SFC SLOW CENTER AND PCPN SHIELD. BOTH MDLS CONT TO DEPICT
AN OPEN MID LVL WAVE.

BOTTOM LINE IS THAT AN EXTENDED PERIOD OF LGT...TO MODERATE...BUT
ACCUMULATING SNOW IS LIKELY...WITH CONFIDENCE BUILDING FOR AREAS
ALNG THE INTERSTATE 70 CORRIDOR.

COLDER WEATHER WL FOLLOW AS A SERIES OF SHRTWVS AGAIN DIG AN ERN
CONUS UPR TROUGH...DETAILS FOR WHICH WL BE REFINED WITH TIME.

&&

.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
CONDITION DETERIORATION IS UNDERWAY AND DEGRADATIONS CAN BE
EXPECTED INTO FRIDAY AS MIXED PCPN SPREADS OVR UPR OH TERMINALS
AND CHANGES TO SNOW WITH CDFNT PASSAGE THIS EVE. IFR CAN BE
EXPECTED IN SNOW SHWRS THIS EVE...AND IN WIDESPREAD STRATUS WHICH
WL ACCOMPANY THE COLD SURGE OVR THE REGION.

.OUTLOOK.../FRIDAY NIGHT THROUGH TUESDAY/...
IMPROVEMENTS CAN BE EXPECTED AS HIGH PRES BLDS LTR ON
SATURDAY...HOWEVER...SNOW AND RESTRICTIONS ARE LIKELY WITH SUNDAY
LOW PRES.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY UNTIL 7 PM EST FRIDAY FOR MDZ001.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL 10 AM EST FRIDAY FOR PAZ007>009-
     015-016-023.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST FRIDAY FOR PAZ074-076.
WV...WINTER WEATHER ADVISORY UNTIL 7 PM EST FRIDAY FOR WVZ023-041.

&&

$$







000
FXUS61 KPBZ 300159
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
859 PM EST THU JAN 29 2015

.SYNOPSIS...
A COLD FRONT WILL CROSS THE AREA TONIGHT...FOLLOWED BY BUILDING
HIGH PRESSURE FRIDAY AND SATURDAY. LOW PRESSURE MAY BRING MORE
WINTRY WEATHER SUNDAY.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
THE KITCHEN SINK AND POTPOURRI OF GOODNESS THAT HAS BEEN FALLING
FROM THE SKY OVER THE PAST ROUGHLY 12 HOURS IS ALREADY SHOWING
SIGNS OF TRANSITIONING TOWARD ALL SNOW TO OUR IMMEDIATE NORTH AND
WEST. SURFACE OBSERVATIONS AND DUAL POL SIGNATURES SUGGEST THIS IS
OCCURRING...AND MODEL SOUNDINGS INDICATE RAPIDLY STEEPENING LAPSE
RATES THROUGH THE EVENING...EVEN THOUGH SURFACE TEMPERATURES MAY
TAKE A FEW HOURS TO FALL OFF PRECIPITOUSLY. WHILE ALL BUT THE
NORTHERN TIER OF THE CWA IS LIKELY RAINING AT THE MOMENT...THE
TREND TOWARD FROZEN PRECIPITATION WILL BE RAPID THROUGH THE
EVENING HOURS.

THAT SAID...FREEZING SURFACE TEMPERATURES ARE ONLY REALLY NOTED IN
SURFACE OBSERVATIONS FROM LAWRENCE TO COSHOCTON COUNTIES AND TO
THE NORTH AND WEST. AS SUCH...SEVERAL HOURS OF SNOW ARE LIKELY
DURING THE EVENING WITH MARGINAL TEMPERATURES FOR ACCUMULATION AT
BEST. AS SUCH...THE INITIAL ONSLAUGHT OF SNOW THAT WILL BE LIKELY
DURING THE LATE EVENING IS FAIRLY UNLIKELY TO BE AN EFFICIENT
ACCUMULATOR. HOWEVER...THINGS WILL DRASTICALLY CHANGE OVERNIGHT
AFTER A BRIEF INTERLUDE BETWEEN THIS EVENING`S ACTIVITY AND THE
OVERNIGHT ACTIVITY IN WHICH THE DENDRITIC LAYER DRIES OUT. THIS
WILL ALLOW FOR A BRIEF PERIOD OF DRIZZLE OF FREEZING DRIZZLE TO
MOVE ACROSS THE AREA ALONG WITH SOME FAIRLY MALFORMED SNOW GRAINS
BEING GENERATED AS WELL. HOWEVER...AS DEEPER SATURATION RETURNS
OVERNIGHT...THAT ACTIVITY SHOULD END WITH A TRANSITION BACK TO
SNOW.

A DEEPER AND MUCH MORE THERMODYNAMICALLY ABRUPT SHORT WAVE AND LOW
LEVEL FRONTAL BOUNDARY COMBO WILL MOVE THROUGH THE AREA BETWEEN 06
AND 12Z TONIGHT. AS THIS OCCURS...THE DENDRITIC GROWTH ZONE WILL
TANK DOWN INTO THE SATURATED LAYER AND GIVEN FRONTOGENETICAL
LIFTING...THIS WILL LIKELY LEAD TO A PERIOD OF FAIRLY EFFICIENT
SNOW SHOWERS FOR ALL LOCATIONS GIVEN STEEP LAPSE RATES AND LARGE
SCALE FORCING FOR ASCENT. IN THE RIDGES...THIS LARGE SCALE ASCENT
WILL BE OVERLAID WITH UNIDIRECTIONAL NORTHWESTERLY UPSLOPE FLOW
WORKING ON VERY UNSTABLE LOW LEVEL LAPSE RATES. WHILE MOISTURE
FLUX INTO THE UNSTABLE LAYER FROM LAKE ERIE WILL LIKELY BE MINIMAL
DUE TO ABUNDANT ICE COVER...SATURATION BELOW THE INVERSION LEVEL
WILL NOT BE DEPENDENT UPON THIS...AND WITH
INSTABILITY...UPSLOPE...AND LARGE SCALE ASCENT ALL OVERLAYING
EACH OTHER IN THE OVERNIGHT HOURS...SNOW SHOWERS WILL LIKELY BE
HEAVY EFFICIENT DENDRITE PRODUCERS. AS SUCH...WHILE MOST LOCATIONS
WILL ONLY SEE 1-3 INCHES OF SNOW OVERNIGHT OUTSIDE THE
RIDGES...LOCATIONS IN THE HIGHER ELEVATIONS SEEM MORE LIKELY TO
END UP WITH 4 TO 8 GIVEN RATIOS SURGING TOWARD 25 TO 1 OVERNIGHT.

ALL ADVISORIES WILL REMAIN IN EFFECT FOR THE OVERNIGHT AND INTO
FRIDAY. HEAVY SNOW SHOWERS WILL LIKELY BE HANDLED INDIVIDUALLY
WITH SPS STATEMENTS THROUGH THE NIGHT. FRIES

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY/...
EXTENDED THE WINTER WEA ADVY THRU THE DAY FRI FOR THE
RIDGES...THOUGH WITH A FROZEN LAKE ERIE WL ALLOW FOR THE NW PA
PORTION EXPIRE AT FRI MRNG. UPSLOPE SNW SHWRS SHOULD CONT THRU THE
DAY IN THE RIDGES BEFORE THINNING MSTR IN THE SNW GROWTH RGN AND
LWRG TEMP INVERSIONS END THE PCPN. A CROSSING UPR TROF SHOULD
ALLOW FOR SOME SCT SNW SHWRS OUTSIDE OF THIS AREA AS WELL.

BLDG HIGH PRES SHOULD BRING DRY WEA FRI NGT INTO SAT.

BELOW SEASONAL AVG TEMPS WERE FCST USING THE LATEST SREF NMBRS.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
MODELS CONT TO JOUST IN HANDLING OF LOW PRES PROJECTED TWD THE MID
ATLANTIC REGION FM SATURDAY NGT INTO MONDAY. PERSISTENCE RMNS
PRUDENT WITH LATEST GFS IN GENL LINE WITH CURRENT THINKING OUTSIDE
OF TIMING ISSUES. MEANWHILE...ECMWF IS FORECASTING A SOUTHWARD
TRACK TO SFC SLOW CENTER AND PCPN SHIELD. BOTH MDLS CONT TO DEPICT
AN OPEN MID LVL WAVE.

BOTTOM LINE IS THAT AN EXTENDED PERIOD OF LGT...TO MODERATE...BUT
ACCUMULATING SNOW IS LIKELY...WITH CONFIDENCE BUILDING FOR AREAS
ALNG THE INTERSTATE 70 CORRIDOR.

COLDER WEATHER WL FOLLOW AS A SERIES OF SHRTWVS AGAIN DIG AN ERN
CONUS UPR TROUGH...DETAILS FOR WHICH WL BE REFINED WITH TIME.

&&

.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
CONDITION DETERIORATION IS UNDERWAY AND DEGRADATIONS CAN BE
EXPECTED INTO FRIDAY AS MIXED PCPN SPREADS OVR UPR OH TERMINALS
AND CHANGES TO SNOW WITH CDFNT PASSAGE THIS EVE. IFR CAN BE
EXPECTED IN SNOW SHWRS THIS EVE...AND IN WIDESPREAD STRATUS WHICH
WL ACCOMPANY THE COLD SURGE OVR THE REGION.

.OUTLOOK.../FRIDAY NIGHT THROUGH TUESDAY/...
IMPROVEMENTS CAN BE EXPECTED AS HIGH PRES BLDS LTR ON
SATURDAY...HOWEVER...SNOW AND RESTRICTIONS ARE LIKELY WITH SUNDAY
LOW PRES.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY UNTIL 7 PM EST FRIDAY FOR MDZ001.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL 10 AM EST FRIDAY FOR PAZ007>009-
     015-016-023.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST FRIDAY FOR PAZ074-076.
WV...WINTER WEATHER ADVISORY UNTIL 7 PM EST FRIDAY FOR WVZ023-041.

&&

$$








000
FXUS61 KPBZ 300013
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
713 PM EST THU JAN 29 2015

.SYNOPSIS...
A COLD FRONT WILL CROSS THE AREA TONIGHT...FOLLOWED BY BUILDING
HIGH PRESSURE FRIDAY AND SATURDAY. LOW PRESSURE MAY BRING MORE
WINTRY WEATHER SUNDAY.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
THE KITCHEN SINK AND POTPOURRI OF GOODNESS THAT HAS BEEN FALLING
FROM THE SKY OVER THE PAST ROUGHLY 12 HOURS IS ALREADY SHOWING
SIGNS OF TRANSITIONING TOWARD ALL SNOW TO OUR IMMEDIATE NORTH AND
WEST. SURFACE OBSERVATIONS AND DUAL POL SIGNATURES SUGGEST THIS IS
OCCURRING...AND MODEL SOUNDINGS INDICATE RAPIDLY STEEPENING LAPSE
RATES THROUGH THE EVENING...EVEN THOUGH SURFACE TEMPERATURES MAY
TAKE A FEW HOURS TO FALL OFF PRECIPITOUSLY. AS SUCH...WHILE ALL
BUT THE NORTHERN TIER OF THE CWA IS LIKELY RAINING AT THE
MOMENT...THE TREND TOWARD FROZEN PRECIPITATION WILL BE RAPID
THROUGH THE EVENING HOURS.

THAT SAID...FREEZING SURFACE TEMPERATURES ARE ONLY REALLY NOTED IN
SURFACE OBSERVATIONS FROM CLEVELAND TO THE NORTH AND WEST. AS
SUCH...SEVERAL HOURS OF SNOW ARE LIKELY DURING THE EVENING WITH
MARGINAL TEMPERATURES FOR ACCUMULATION AT BEST. AS SUCH...THE
INITIAL ONSLAUGHT OF SNOW THAT WILL BE LIKELY DURING THE EVENING IS
FAIRLY UNLIKELY TO BE AN EFFICIENT ACCUMULATOR. HOWEVER...THINGS
WILL DRASTICALLY CHANGE OVERNIGHT.

A DEEPER AND MUCH MORE THERMODYNAMICALLY ABRUPT SHORT WAVE AND LOW
LEVEL FRONTAL BOUNDARY COMBO WILL MOVE THROUGH THE AREA BETWEEN 06
AND 12Z TONIGHT. AS THIS OCCURS...THE DENDRITIC GROWTH ZONE WILL
TANK DOWN INTO THE SATURATED LAYER AND GIVEN FRONTOGENETICAL
LIFTING...THIS WILL LIKELY LEAD TO A PERIOD OF FAIRLY EFFICIENT
SNOW SHOWERS FOR ALL LOCATIONS GIVEN STEEP LAPSE RATES AND LARGE
SCALE FORCING FOR ASCENT. IN THE RIDGES...THIS LARGE SCALE ASCENT
WILL BE OVERLAID WITH UNIDIRECTIONAL NORTHWESTERLY UPSLOPE FLOW
WORKING ON VERY UNSTABLE LOW LEVEL LAPSE RATES. WHILE MOISTURE
FLUX INTO THE UNSTABLE LAYER FROM LAKE ERIE WILL LIKELY BE MINIMAL
DUE TO ABUNDANT ICE COVER...SATURATION BELOW THE INVERSION LEVEL
WILL NOT BE DEPENDENT UPON THIS...AND WITH
INSTABILITY...UPSLOPE...AND LARGE SCALE ASCENT ALL OVERLAYING
EACH OTHER IN THE OVERNIGHT HOURS...SNOW SHOWERS WILL LIKELY BE
HEAVY EFFICIENT DENDRITE PRODUCERS. AS SUCH...WHILE MOST LOCATIONS
WILL ONLY SEE 1-3 INCHES OF SNOW OVERNIGHT OUTSIDE THE
RIDGES...LOCATIONS IN THE HIGHER ELEVATIONS SEEM MORE LIKELY TO
END UP WITH 4 TO 8 GIVEN RATIOS SURGING TOWARD 25 TO 1 OVERNIGHT.

ALL ADVISORIES WILL REMAIN IN EFFECT FOR THE OVERNIGHT AND INTO
FRIDAY. HEAVY SNOW SHOWERS WILL LIKELY BE HANDLED INDIVIDUALLY
WITH SPS STATEMENTS THROUGH THE NIGHT. FRIES

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY/...
EXTENDED THE WINTER WEA ADVY THRU THE DAY FRI FOR THE
RIDGES...THOUGH WITH A FROZEN LAKE ERIE WL ALLOW FOR THE NW PA
PORTION EXPIRE AT FRI MRNG. UPSLOPE SNW SHWRS SHOULD CONT THRU THE
DAY IN THE RIDGES BEFORE THINNING MSTR IN THE SNW GROWTH RGN AND
LWRG TEMP INVERSIONS END THE PCPN. A CROSSING UPR TROF SHOULD
ALLOW FOR SOME SCT SNW SHWRS OUTSIDE OF THIS AREA AS WELL.

BLDG HIGH PRES SHOULD BRING DRY WEA FRI NGT INTO SAT.

BELOW SEASONAL AVG TEMPS WERE FCST USING THE LATEST SREF NMBRS.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
MODELS CONT TO JOUST IN HANDLING OF LOW PRES PROJECTED TWD THE MID
ATLANTIC REGION FM SATURDAY NGT INTO MONDAY. PERSISTENCE RMNS
PRUDENT WITH LATEST GFS IN GENL LINE WITH CURRENT THINKING OUTSIDE
OF TIMING ISSUES. MEANWHILE...ECMWF IS FORECASTING A SOUTHWARD
TRACK TO SFC SLOW CENTER AND PCPN SHIELD. BOTH MDLS CONT TO DEPICT
AN OPEN MID LVL WAVE.

BOTTOM LINE IS THAT AN EXTENDED PERIOD OF LGT...TO MODERATE...BUT
ACCUMULATING SNOW IS LIKELY...WITH CONFIDENCE BUILDING FOR AREAS
ALNG THE INTERSTATE 70 CORRIDOR.

COLDER WEATHER WL FOLLOW AS A SERIES OF SHRTWVS AGAIN DIG AN ERN
CONUS UPR TROUGH...DETAILS FOR WHICH WL BE REFINED WITH TIME.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
CONDITION DETERIORATION IS UNDERWAY AND DEGRADATIONS CAN BE
EXPECTED INTO FRIDAY AS MIXED PCPN SPREADS OVR UPR OH TERMINALS
AND CHANGES TO SNOW WITH CDFNT PASSAGE THIS EVE. IFR CAN BE
EXPECTED IN SNOW SHWRS THIS EVE...AND IN WIDESPREAD STRATUS WHICH
WL ACCOMPANY THE COLD SURGE OVR THE REGION.

.OUTLOOK.../FRIDAY NIGHT THROUGH TUESDAY/...
IMPROVEMENTS CAN BE EXPECTED AS HIGH PRES BLDS LTR ON
SATURDAY...HOWEVER...SNOW AND RESTRICTIONS ARE LIKELY WITH SUNDAY
LOW PRES.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY UNTIL 7 PM EST FRIDAY FOR MDZ001.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL 10 AM EST FRIDAY FOR PAZ007>009-
     015-016-023.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST FRIDAY FOR PAZ074-076.
WV...WINTER WEATHER ADVISORY UNTIL 7 PM EST FRIDAY FOR WVZ023-041.

&&

$$







000
FXUS61 KPBZ 300013
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
713 PM EST THU JAN 29 2015

.SYNOPSIS...
A COLD FRONT WILL CROSS THE AREA TONIGHT...FOLLOWED BY BUILDING
HIGH PRESSURE FRIDAY AND SATURDAY. LOW PRESSURE MAY BRING MORE
WINTRY WEATHER SUNDAY.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
THE KITCHEN SINK AND POTPOURRI OF GOODNESS THAT HAS BEEN FALLING
FROM THE SKY OVER THE PAST ROUGHLY 12 HOURS IS ALREADY SHOWING
SIGNS OF TRANSITIONING TOWARD ALL SNOW TO OUR IMMEDIATE NORTH AND
WEST. SURFACE OBSERVATIONS AND DUAL POL SIGNATURES SUGGEST THIS IS
OCCURRING...AND MODEL SOUNDINGS INDICATE RAPIDLY STEEPENING LAPSE
RATES THROUGH THE EVENING...EVEN THOUGH SURFACE TEMPERATURES MAY
TAKE A FEW HOURS TO FALL OFF PRECIPITOUSLY. AS SUCH...WHILE ALL
BUT THE NORTHERN TIER OF THE CWA IS LIKELY RAINING AT THE
MOMENT...THE TREND TOWARD FROZEN PRECIPITATION WILL BE RAPID
THROUGH THE EVENING HOURS.

THAT SAID...FREEZING SURFACE TEMPERATURES ARE ONLY REALLY NOTED IN
SURFACE OBSERVATIONS FROM CLEVELAND TO THE NORTH AND WEST. AS
SUCH...SEVERAL HOURS OF SNOW ARE LIKELY DURING THE EVENING WITH
MARGINAL TEMPERATURES FOR ACCUMULATION AT BEST. AS SUCH...THE
INITIAL ONSLAUGHT OF SNOW THAT WILL BE LIKELY DURING THE EVENING IS
FAIRLY UNLIKELY TO BE AN EFFICIENT ACCUMULATOR. HOWEVER...THINGS
WILL DRASTICALLY CHANGE OVERNIGHT.

A DEEPER AND MUCH MORE THERMODYNAMICALLY ABRUPT SHORT WAVE AND LOW
LEVEL FRONTAL BOUNDARY COMBO WILL MOVE THROUGH THE AREA BETWEEN 06
AND 12Z TONIGHT. AS THIS OCCURS...THE DENDRITIC GROWTH ZONE WILL
TANK DOWN INTO THE SATURATED LAYER AND GIVEN FRONTOGENETICAL
LIFTING...THIS WILL LIKELY LEAD TO A PERIOD OF FAIRLY EFFICIENT
SNOW SHOWERS FOR ALL LOCATIONS GIVEN STEEP LAPSE RATES AND LARGE
SCALE FORCING FOR ASCENT. IN THE RIDGES...THIS LARGE SCALE ASCENT
WILL BE OVERLAID WITH UNIDIRECTIONAL NORTHWESTERLY UPSLOPE FLOW
WORKING ON VERY UNSTABLE LOW LEVEL LAPSE RATES. WHILE MOISTURE
FLUX INTO THE UNSTABLE LAYER FROM LAKE ERIE WILL LIKELY BE MINIMAL
DUE TO ABUNDANT ICE COVER...SATURATION BELOW THE INVERSION LEVEL
WILL NOT BE DEPENDENT UPON THIS...AND WITH
INSTABILITY...UPSLOPE...AND LARGE SCALE ASCENT ALL OVERLAYING
EACH OTHER IN THE OVERNIGHT HOURS...SNOW SHOWERS WILL LIKELY BE
HEAVY EFFICIENT DENDRITE PRODUCERS. AS SUCH...WHILE MOST LOCATIONS
WILL ONLY SEE 1-3 INCHES OF SNOW OVERNIGHT OUTSIDE THE
RIDGES...LOCATIONS IN THE HIGHER ELEVATIONS SEEM MORE LIKELY TO
END UP WITH 4 TO 8 GIVEN RATIOS SURGING TOWARD 25 TO 1 OVERNIGHT.

ALL ADVISORIES WILL REMAIN IN EFFECT FOR THE OVERNIGHT AND INTO
FRIDAY. HEAVY SNOW SHOWERS WILL LIKELY BE HANDLED INDIVIDUALLY
WITH SPS STATEMENTS THROUGH THE NIGHT. FRIES

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY/...
EXTENDED THE WINTER WEA ADVY THRU THE DAY FRI FOR THE
RIDGES...THOUGH WITH A FROZEN LAKE ERIE WL ALLOW FOR THE NW PA
PORTION EXPIRE AT FRI MRNG. UPSLOPE SNW SHWRS SHOULD CONT THRU THE
DAY IN THE RIDGES BEFORE THINNING MSTR IN THE SNW GROWTH RGN AND
LWRG TEMP INVERSIONS END THE PCPN. A CROSSING UPR TROF SHOULD
ALLOW FOR SOME SCT SNW SHWRS OUTSIDE OF THIS AREA AS WELL.

BLDG HIGH PRES SHOULD BRING DRY WEA FRI NGT INTO SAT.

BELOW SEASONAL AVG TEMPS WERE FCST USING THE LATEST SREF NMBRS.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
MODELS CONT TO JOUST IN HANDLING OF LOW PRES PROJECTED TWD THE MID
ATLANTIC REGION FM SATURDAY NGT INTO MONDAY. PERSISTENCE RMNS
PRUDENT WITH LATEST GFS IN GENL LINE WITH CURRENT THINKING OUTSIDE
OF TIMING ISSUES. MEANWHILE...ECMWF IS FORECASTING A SOUTHWARD
TRACK TO SFC SLOW CENTER AND PCPN SHIELD. BOTH MDLS CONT TO DEPICT
AN OPEN MID LVL WAVE.

BOTTOM LINE IS THAT AN EXTENDED PERIOD OF LGT...TO MODERATE...BUT
ACCUMULATING SNOW IS LIKELY...WITH CONFIDENCE BUILDING FOR AREAS
ALNG THE INTERSTATE 70 CORRIDOR.

COLDER WEATHER WL FOLLOW AS A SERIES OF SHRTWVS AGAIN DIG AN ERN
CONUS UPR TROUGH...DETAILS FOR WHICH WL BE REFINED WITH TIME.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
CONDITION DETERIORATION IS UNDERWAY AND DEGRADATIONS CAN BE
EXPECTED INTO FRIDAY AS MIXED PCPN SPREADS OVR UPR OH TERMINALS
AND CHANGES TO SNOW WITH CDFNT PASSAGE THIS EVE. IFR CAN BE
EXPECTED IN SNOW SHWRS THIS EVE...AND IN WIDESPREAD STRATUS WHICH
WL ACCOMPANY THE COLD SURGE OVR THE REGION.

.OUTLOOK.../FRIDAY NIGHT THROUGH TUESDAY/...
IMPROVEMENTS CAN BE EXPECTED AS HIGH PRES BLDS LTR ON
SATURDAY...HOWEVER...SNOW AND RESTRICTIONS ARE LIKELY WITH SUNDAY
LOW PRES.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY UNTIL 7 PM EST FRIDAY FOR MDZ001.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL 10 AM EST FRIDAY FOR PAZ007>009-
     015-016-023.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST FRIDAY FOR PAZ074-076.
WV...WINTER WEATHER ADVISORY UNTIL 7 PM EST FRIDAY FOR WVZ023-041.

&&

$$








000
FXUS61 KPBZ 291953
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
253 PM EST THU JAN 29 2015

.SYNOPSIS...
A COLD FRONT WILL CROSS THE AREA TONIGHT...FOLLOWED BY BUILDING
HIGH PRESSURE FRIDAY AND SATURDAY. LOW PRESSURE MAY BRING MORE
WINTRY WEATHER SUNDAY.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
A CDFNT WL MOVE ACRS THE RGN THIS EVE WITH ADDNL SNW SHWRS. SOME
RAIN COULD MIX IN ERLY THIS EVE S OF I 80. WITH LK ERIE MOSTLY
FROZEN...ONLY A LIMITED CONNECTION OFF LK HURON IS EXPD MAINLY ACRS
NW PA. FAVORABLE CONDS FOR UPSLOPE SNW SET UP OVRNGT WITH INCRG MSTR
IN THE SNW GROWTH RGN AND NW FLOW. CONTD WINTER WEA ADVY FOR THE
RIDGES AND NW PA THRU FRI WITH SEVERAL INCHES OF SNW EXPD. TEMPS
WERE FCST USING A LAMP/SREF BLEND.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY/...
EXTENDED THE WINTER WEA ADVY THRU THE DAY FRI FOR THE
RIDGES...THOUGH WITH A FROZEN LAKE ERIE WL ALLOW FOR THE NW PA
PORTION EXPIRE AT FRI MRNG. UPSLOPE SNW SHWRS SHOULD CONT THRU THE
DAY IN THE RIDGES BEFORE THINNING MSTR IN THE SNW GROWTH RGN AND
LWRG TEMP INVERSIONS END THE PCPN. A CROSSING UPR TROF SHOULD
ALLOW FOR SOME SCT SNW SHWRS OUTSIDE OF THIS AREA AS WELL.

BLDG HIGH PRES SHOULD BRING DRY WEA FRI NGT INTO SAT.

BELOW SEASONAL AVG TEMPS WERE FCST USING THE LATEST SREF NMBRS.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
MODELS CONT TO JOUST IN HANDLING OF LOW PRES PROJECTED TWD THE MID
ATLANTIC REGION FM SATURDAY NGT INTO MONDAY. PERSISTENCE RMNS
PRUDENT WITH LATEST GFS IN GENL LINE WITH CURRENT THINKING OUTSIDE
OF TIMING ISSUES. MEANWHILE...ECMWF IS FORECASTING A SOUTHWARD
TRACK TO SFC SLOW CENTER AND PCPN SHIELD. BOTH MDLS CONT TO DEPICT
AN OPEN MID LVL WAVE.

BOTTOM LINE IS THAT AN EXTENDED PERIOD OF LGT...TO MODERATE...BUT
ACCUMULATING SNOW IS LIKELY...WITH CONFIDENCE BUILDING FOR AREAS
ALNG THE INTERSTATE 70 CORRIDOR.

COLDER WEATHER WL FOLLOW AS A SERIES OF SHRTWVS AGAIN DIG AN ERN
CONUS UPR TROUGH...DETAILS FOR WHICH WL BE REFINED WITH TIME.

&&

.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
CONDITION DETERIORATION IS UNDERWAY AND DEGRADATIONS CAN BE
EXPECTED INTO FRIDAY AS MIXED PCPN SPREADS OVR UPR OH TERMINALS
AND CHANGES TO SNOW WITH CDFNT PASSAGE THIS EVE. IFR CAN BE
EXPECTED IN SNOW SHWRS THIS EVE...AND IN WIDESPREAD STRATUS WHICH
WL ACCOMPANY THE COLD SURGE OVR THE REGION.

.OUTLOOK.../FRIDAY NIGHT THROUGH TUESDAY/...
IMPROVEMENTS CAN BE EXPECTED AS HIGH PRES BLDS LTR ON
SATURDAY...HOWEVER...SNOW AND RESTRICTIONS ARE LIKELY WITH SUNDAY
LOW PRES.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY UNTIL 7 PM EST FRIDAY FOR MDZ001.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL 10 AM EST FRIDAY FOR PAZ007>009-
     015-016-023.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST FRIDAY FOR PAZ074-076.
WV...WINTER WEATHER ADVISORY UNTIL 7 PM EST FRIDAY FOR WVZ023-041.

&&

$$

07/15






000
FXUS61 KPBZ 291953
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
253 PM EST THU JAN 29 2015

.SYNOPSIS...
A COLD FRONT WILL CROSS THE AREA TONIGHT...FOLLOWED BY BUILDING
HIGH PRESSURE FRIDAY AND SATURDAY. LOW PRESSURE MAY BRING MORE
WINTRY WEATHER SUNDAY.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
A CDFNT WL MOVE ACRS THE RGN THIS EVE WITH ADDNL SNW SHWRS. SOME
RAIN COULD MIX IN ERLY THIS EVE S OF I 80. WITH LK ERIE MOSTLY
FROZEN...ONLY A LIMITED CONNECTION OFF LK HURON IS EXPD MAINLY ACRS
NW PA. FAVORABLE CONDS FOR UPSLOPE SNW SET UP OVRNGT WITH INCRG MSTR
IN THE SNW GROWTH RGN AND NW FLOW. CONTD WINTER WEA ADVY FOR THE
RIDGES AND NW PA THRU FRI WITH SEVERAL INCHES OF SNW EXPD. TEMPS
WERE FCST USING A LAMP/SREF BLEND.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY/...
EXTENDED THE WINTER WEA ADVY THRU THE DAY FRI FOR THE
RIDGES...THOUGH WITH A FROZEN LAKE ERIE WL ALLOW FOR THE NW PA
PORTION EXPIRE AT FRI MRNG. UPSLOPE SNW SHWRS SHOULD CONT THRU THE
DAY IN THE RIDGES BEFORE THINNING MSTR IN THE SNW GROWTH RGN AND
LWRG TEMP INVERSIONS END THE PCPN. A CROSSING UPR TROF SHOULD
ALLOW FOR SOME SCT SNW SHWRS OUTSIDE OF THIS AREA AS WELL.

BLDG HIGH PRES SHOULD BRING DRY WEA FRI NGT INTO SAT.

BELOW SEASONAL AVG TEMPS WERE FCST USING THE LATEST SREF NMBRS.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
MODELS CONT TO JOUST IN HANDLING OF LOW PRES PROJECTED TWD THE MID
ATLANTIC REGION FM SATURDAY NGT INTO MONDAY. PERSISTENCE RMNS
PRUDENT WITH LATEST GFS IN GENL LINE WITH CURRENT THINKING OUTSIDE
OF TIMING ISSUES. MEANWHILE...ECMWF IS FORECASTING A SOUTHWARD
TRACK TO SFC SLOW CENTER AND PCPN SHIELD. BOTH MDLS CONT TO DEPICT
AN OPEN MID LVL WAVE.

BOTTOM LINE IS THAT AN EXTENDED PERIOD OF LGT...TO MODERATE...BUT
ACCUMULATING SNOW IS LIKELY...WITH CONFIDENCE BUILDING FOR AREAS
ALNG THE INTERSTATE 70 CORRIDOR.

COLDER WEATHER WL FOLLOW AS A SERIES OF SHRTWVS AGAIN DIG AN ERN
CONUS UPR TROUGH...DETAILS FOR WHICH WL BE REFINED WITH TIME.

&&

.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
CONDITION DETERIORATION IS UNDERWAY AND DEGRADATIONS CAN BE
EXPECTED INTO FRIDAY AS MIXED PCPN SPREADS OVR UPR OH TERMINALS
AND CHANGES TO SNOW WITH CDFNT PASSAGE THIS EVE. IFR CAN BE
EXPECTED IN SNOW SHWRS THIS EVE...AND IN WIDESPREAD STRATUS WHICH
WL ACCOMPANY THE COLD SURGE OVR THE REGION.

.OUTLOOK.../FRIDAY NIGHT THROUGH TUESDAY/...
IMPROVEMENTS CAN BE EXPECTED AS HIGH PRES BLDS LTR ON
SATURDAY...HOWEVER...SNOW AND RESTRICTIONS ARE LIKELY WITH SUNDAY
LOW PRES.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY UNTIL 7 PM EST FRIDAY FOR MDZ001.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL 10 AM EST FRIDAY FOR PAZ007>009-
     015-016-023.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST FRIDAY FOR PAZ074-076.
WV...WINTER WEATHER ADVISORY UNTIL 7 PM EST FRIDAY FOR WVZ023-041.

&&

$$

07/15







000
FXUS61 KPBZ 291859
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
159 PM EST THU JAN 29 2015

.SYNOPSIS...
CROSSING LOW PRESSURE WILL BRING A WINTRY MIX OF PRECIPITATION TO
THE UPPER OHIO REGION TODAY AND SNOW EARLY ON FRIDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
QUICK UPDT TO END FRZG RAIN ADVYS. BAND OF PCPN...MAINLY SNW AND
SLEET...WL CONT TO WORK EWD THE REST OF THE AFTN. ADDNL PCPN IS
EXPD AS A CDFNT APCHS THE RGN THIS EVE. EXP A SLOW TEMP RISE AS
PCPN ENDS.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
A CDFNT WL CROSS THE RGN THIS EVE WITH ANY PCPN CHG TO SNW. A
CROSSING UPR TROF WL KEEP SNW SHWR CHCS IN THE RGN THRU FRI. GOOD
UPSLOPE FLOW WL ALLOW FOR ADVY LVL SNW ACCUMULATIONS IN THE
RIDGES...AND SOME LTD CONNECTION OFF LK HURON COULD ENHANCE
ACCUMULATIONS ACRS NW PA. WL CONT THE WINTER WEA ADVYS AS IS ATTM.

INVERSION LVLS LWR AND BLDG HIGH PRES SHOULD END ANY SNW SHWRS FRI
BY FRI EVE. DRY WEA SHOULD CONT SAT UNDER THE HIGH. WELL BELOW
SEASONAL AVG TEMPS WL CONT.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
MODELS CONT TO JOUST IN HANDLING OF LOW PRES PROJECTED TWD THE MID
ATLANTIC REGION FM SATURDAY NGT INTO MONDAY. PERSISTENCE RMNS
PRUDENT WITH LATEST GFS IN GENL LINE WITH CURRENT THINKING OUTSIDE
OF TIMING ISSUES. MEANWHILE...ECMWF IS FORECASTING A SOUTHWARD
TRACK TO SFC SLOW CENTER AND PCPN SHIELD. BOTH MDLS CONT TO DEPICT
AN OPEN MID LVL WAVE.

BOTTOM LINE IS THAT AN EXTENDED PERIOD OF LGT...TO MODERATE...BUT
ACCUMULATING SNOW IS LIKELY...WITH CONFIDENCE BUILDING FOR AREAS
ALNG THE INTERSTATE 70 CORRIDOR.

COLDER WEATHER WL FOLLOW AS A SERIES OF SHRTWVS AGAIN DIG AN ERN
CONUS UPR TROUGH...DETAILS FOR WHICH WL BE REFINED WITH TIME.

&&

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
CONDITION DETERIORATION IS UNDERWAY AND DEGRADATIONS CAN BE
EXPECTED INTO FRIDAY AS MIXED PCPN SPREADS OVR UPR OH TERMINALS
AND CHANGES TO SNOW WITH CDFNT PASSAGE THIS EVE. IFR CAN BE
EXPECTED IN SNOW SHWRS THIS EVE...AND IN WIDESPREAD STRATUS WHICH
WL ACCOMPANY THE COLD SURGE OVR THE REGION.

.OUTLOOK.../FRIDAY NIGHT THROUGH TUESDAY/...
IMPROVEMENTS CAN BE EXPECTED AS HIGH PRES BLDS LTR ON
SATURDAY...HOWEVER...SNOW AND RESTRICTIONS ARE LIKELY WITH SUNDAY
LOW PRES.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY UNTIL 7 PM EST FRIDAY FOR MDZ001.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL 10 AM EST FRIDAY FOR PAZ007>009-
     015-016-023.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST FRIDAY FOR PAZ074-076.
WV...WINTER WEATHER ADVISORY UNTIL 7 PM EST FRIDAY FOR WVZ023-041.

&&

$$

07/15






000
FXUS61 KPBZ 291859
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
159 PM EST THU JAN 29 2015

.SYNOPSIS...
CROSSING LOW PRESSURE WILL BRING A WINTRY MIX OF PRECIPITATION TO
THE UPPER OHIO REGION TODAY AND SNOW EARLY ON FRIDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
QUICK UPDT TO END FRZG RAIN ADVYS. BAND OF PCPN...MAINLY SNW AND
SLEET...WL CONT TO WORK EWD THE REST OF THE AFTN. ADDNL PCPN IS
EXPD AS A CDFNT APCHS THE RGN THIS EVE. EXP A SLOW TEMP RISE AS
PCPN ENDS.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
A CDFNT WL CROSS THE RGN THIS EVE WITH ANY PCPN CHG TO SNW. A
CROSSING UPR TROF WL KEEP SNW SHWR CHCS IN THE RGN THRU FRI. GOOD
UPSLOPE FLOW WL ALLOW FOR ADVY LVL SNW ACCUMULATIONS IN THE
RIDGES...AND SOME LTD CONNECTION OFF LK HURON COULD ENHANCE
ACCUMULATIONS ACRS NW PA. WL CONT THE WINTER WEA ADVYS AS IS ATTM.

INVERSION LVLS LWR AND BLDG HIGH PRES SHOULD END ANY SNW SHWRS FRI
BY FRI EVE. DRY WEA SHOULD CONT SAT UNDER THE HIGH. WELL BELOW
SEASONAL AVG TEMPS WL CONT.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
MODELS CONT TO JOUST IN HANDLING OF LOW PRES PROJECTED TWD THE MID
ATLANTIC REGION FM SATURDAY NGT INTO MONDAY. PERSISTENCE RMNS
PRUDENT WITH LATEST GFS IN GENL LINE WITH CURRENT THINKING OUTSIDE
OF TIMING ISSUES. MEANWHILE...ECMWF IS FORECASTING A SOUTHWARD
TRACK TO SFC SLOW CENTER AND PCPN SHIELD. BOTH MDLS CONT TO DEPICT
AN OPEN MID LVL WAVE.

BOTTOM LINE IS THAT AN EXTENDED PERIOD OF LGT...TO MODERATE...BUT
ACCUMULATING SNOW IS LIKELY...WITH CONFIDENCE BUILDING FOR AREAS
ALNG THE INTERSTATE 70 CORRIDOR.

COLDER WEATHER WL FOLLOW AS A SERIES OF SHRTWVS AGAIN DIG AN ERN
CONUS UPR TROUGH...DETAILS FOR WHICH WL BE REFINED WITH TIME.

&&

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
CONDITION DETERIORATION IS UNDERWAY AND DEGRADATIONS CAN BE
EXPECTED INTO FRIDAY AS MIXED PCPN SPREADS OVR UPR OH TERMINALS
AND CHANGES TO SNOW WITH CDFNT PASSAGE THIS EVE. IFR CAN BE
EXPECTED IN SNOW SHWRS THIS EVE...AND IN WIDESPREAD STRATUS WHICH
WL ACCOMPANY THE COLD SURGE OVR THE REGION.

.OUTLOOK.../FRIDAY NIGHT THROUGH TUESDAY/...
IMPROVEMENTS CAN BE EXPECTED AS HIGH PRES BLDS LTR ON
SATURDAY...HOWEVER...SNOW AND RESTRICTIONS ARE LIKELY WITH SUNDAY
LOW PRES.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY UNTIL 7 PM EST FRIDAY FOR MDZ001.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL 10 AM EST FRIDAY FOR PAZ007>009-
     015-016-023.
     WINTER WEATHER ADVISORY UNTIL 7 PM EST FRIDAY FOR PAZ074-076.
WV...WINTER WEATHER ADVISORY UNTIL 7 PM EST FRIDAY FOR WVZ023-041.

&&

$$

07/15





000
FXUS61 KPBZ 291607
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1107 AM EST THU JAN 29 2015

.SYNOPSIS...
CROSSING LOW PRESSURE WILL BRING A WINTRY MIX OF PRECIPITATION TO
THE UPPER OHIO REGION TODAY AND SNOW EARLY ON FRIDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PCPN CONTS TO ADVANCE INTO THE RGN WITH AN APCHG SHRTWV. AIR AND
ROAD TEMPS RMN BLO FRZG ACRS WRN PA...AND WERE HOVERING NR FRZG
ACRS OH. MGW HAS RISEN ABV FRZG BUT GIVEN LOW DEW PTS AND A COLD
START SOME FRZG RAIN WL RMN PSBL INTO ERLY AFTN. ONCE WET BULBING
ENDS EXP SOME TEWMP RECOVERY IN WRM ADVCTN. SOME SNW COULD MIX IN
N OF I 80 AND IN THE RIDGES ESP BY LT AFTN. NUDGED TEMPS TO THE
LATEST LAMP NMBRS.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
A CDFNT WL CROSS THE RGN THIS EVE WITH ANY PCPN CHG TO SNW. A
CROSSING UPR TROF WL KEEP SNW SHWR CHCS IN THE RGN THRU FRI. GOOD
UPSLOPE FLOW WL ALLOW FOR ADVY LVL SNW ACCUMULATIONS IN THE
RIDGES...AND SOME LTD CONNECTION OFF LK HURON COULD ENHANCE
ACCUMULATIONS ACRS NW PA. WL CONT THE WINTER WEA ADVYS AS IS ATTM.

INVERSION LVLS LWR AND BLDG HIGH PRES SHOULD END ANY SNW SHWRS FRI
BY FRI EVE. DRY WEA SHOULD CONT SAT UNDER THE HIGH. WELL BELOW
SEASONAL AVG TEMPS WL CONT.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
HIGH LEVELS OF UNCERTAINTY IN THE LONG TERM PARTICULARLY WITH THE
SYSTEM THAT COULD AFFECT THE AREA DURING THE SUNDAY/MONDAY TIME
FRAME. FOR NOW...CONSISTENCY WILL BE THE NAME OF THE GAME UNTIL
THE MODELS PROVIDE A BETTER PICTURE. COLD PATTERN WILL CONTINUE
THROUGH THE REMAINDER OF THE LONG TERM.

&&

.AVIATION /16Z THURSDAY THROUGH MONDAY/...
CONDITION DETERIORATION IS UNDERWAY AND DEGRADATIONS CAN BE
EXPECTED INTO FRIDAY AS MIXED PCPN SPREADS OVR UPR OH TERMINALS
AND CHANGES TO SNOW WITH CDFNT PASSAGE THIS EVE. IFR CAN BE
EXPECTED IN SNOW SHWRS THIS EVE...AND IN WIDESPREAD STRATUS WHICH
WL ACCOMPANY THE COLD SURGE OVR THE REGION.

.OUTLOOK.../THURSDAY NIGHT THROUGH MONDAY/...
IMPROVEMENTS CAN BE EXPECTED AS HIGH PRES BLDS LTR ON
SATURDAY...HOWEVER...SNOW AND RESTRICTIONS ARE LIKELY WITH SUNDAY
LOW PRES.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY UNTIL 10 AM EST FRIDAY FOR MDZ001.
OH...FREEZING RAIN ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
     OHZ039>041-048>050-057>059-068-069.
PA...WINTER WEATHER ADVISORY UNTIL 10 AM EST FRIDAY FOR PAZ007>009-
     015-016-023-074-076.
     FREEZING RAIN ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
     PAZ013-014-020>022-029-031-073-075.
WV...FREEZING RAIN ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
     WVZ001>004-012.
     WINTER WEATHER ADVISORY UNTIL 10 AM EST FRIDAY FOR WVZ023-041.
     FREEZING RAIN ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
     WVZ021-022.

&&

$$

07/15








000
FXUS61 KPBZ 291351
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
851 AM EST THU JAN 29 2015

.SYNOPSIS...
CROSSING LOW PRESSURE WILL BRING A WINTRY MIX OF PRECIPITATION TO
THE UPPER OHIO REGION TODAY AND SNOW EARLY ON FRIDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
QUICK UPDT TO EXPAND THE FRZG RAIN ADVY ACRS MUCH OF THE AREA WITH
AN APCHG SHRTWV AND CDFNT. PCPN IS ALREADY IN THE OH COUNTIES MOVG
E...AND SHOULD RCH THE AREA THRU THE REST OF THE MRNG/ERLY AFTN.
AIR TEMPS WL BE RISING...THOUGH LOW DEW PTS SHOULD RESULT IN SOME
WET BULBING LIMITING THAT RISE. WITH RECENT COLD WEA ROAD TEMPS
ARE BLO FRZG AND WL LIKELY RMN THERE INTO ERLY AFTN...EVEN IF AIR
TEMPS CLIMB JUST ABV FRZG. FURTHER N AND IN THE RIDGES...CONTD WITH
WINTER WEA ADVYS AS THUICKNESSES/SOUNDING PROFILES INDICATE PCPN
WL LIKELY BE A MIX OF SNW AND FRZG RAIN. NUDGED TEMPS TO THE
LATEST LAMP AND NAM NMBRS.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
THERMAL PROFILES QUICKLY BECOME MORE UNSTABLE TONIGHT. COLD
ADVECTION BEGINS IN EARNEST ALOFT AS TWO SHORT WAVE TROUGHS ARE
SET TO CROSS THE AREA THROUGH FRIDAY MORNING. THIS WILL OCCUR
SIMULTANEOUSLY TO THE DRIER AIR COMING IN...HOWEVER THE DENDRITIC
GROWTH LAYER LOOKS TO CRASH TOWARD THE SURFACE TONIGHT IN THE
RIDGES...WELL BEFORE THE MOISTURE PEELS OFF. CONSENSUS SNOW TO
LIQUID RATIOS FROM THE NAM AND GFS VIA BUFKIT SUGGEST AROUND 25 TO
1 BEGIN OVERNIGHT. GIVEN INSTABILITY AND UNIDIRECTIONAL
UPSLOPE...THIS SHOULD RESULT IN VERY EFFICIENT SNOW GROWTH. MODEL
QPF IS GENERALLY ONLY A COUPLE OF TENTHS...AND GIVEN ICE COVER
UPSTREAM ON LAKE ERIE...A TON OF QPF IS VERY UNLIKELY.
HOWEVER...EVEN LIGHT QPF IN THIS CASE IS LIKELY TO ADD UP TO
SEVERAL INCHES OF SNOW. GIVEN THAT AHEAD OF THE SYSTEM ON THURSDAY
THERE COULD BE AN INCH OR SO IN SOME OF THE SHELTERED HIGHER
ELEVATIONS...AND ANOTHER 2 TO 5 SEEM LIKELY IN THE UPSLOPE THROUGH
FRIDAY WITH ADDITIONAL SYNOPTIC HELP VIA TWO ADDITIONAL WAVES
CROSSING THE AREA...3 TO 6 INCH TOTALS SEEM REASONABLE IN THE
RIDGES BY FRIDAY MORNING. WINTER WEATHER ADVISORIES WERE EXPANDED
TO ACCOMMODATE THIS.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
HIGH LEVELS OF UNCERTAINTY IN THE LONG TERM PARTICULARLY WITH THE
SYSTEM THAT COULD AFFECT THE AREA DURING THE SUNDAY/MONDAY TIME
FRAME. FOR NOW...CONSISTENCY WILL BE THE NAME OF THE GAME UNTIL
THE MODELS PROVIDE A BETTER PICTURE. COLD PATTERN WILL CONTINUE
THROUGH THE REMAINDER OF THE LONG TERM.

&&

.AVIATION /14Z THURSDAY THROUGH MONDAY/...
HANGING ON TO VFR CONDITIONS AT THE START OF THE TAF PERIOD WITH
MID CLOUDS INVADING...BUT THIS WILL START TO CHANGE SOON.
PRECIPITATION BEGINS TO MOVE IN AFTER 14Z ASSOCIATED WITH GREAT
LAKES LOW. STILL LOOKING AT BEST FZRA POSSIBILITIES AT
ZZV...FKL...AND DUJ. STILL CANNOT RULE OUT BRIEF PERIOD OF FZRA AT
HLG AND PIT/AGC...BUT STILL UNCERTAIN ENOUGH TO NOT INCLUDE YET.
OTHERWISE...RA OR A RA/SN MIX.  FLIGHT CONDITIONS WILL DETERIORATE
THROUGH MVFR LATER THIS MORNING/MIDDAY TO IFR DURING THE
AFTERNOON. COLD FRONT SWEEPS THROUGH AFTER 00Z CHANGING ALL PRECIP
TO SNOW WITH CONTINUED IFR CONDITIONS...WITH ZZV/MGW CLINGING TO
MVFR. SLIGHT IMPROVEMENT TOWARDS 12Z AT WESTERN TERMINALS AS MORE
OF A NW FLOW/UPSLOPE PATTERN TAKES HOLD. CL

.OUTLOOK.../THURSDAY NIGHT THROUGH MONDAY/...
RESTRICTIONS WILL CONTINUE THROUGH FRIDAY MORNING...WITH
IMPROVEMENT DURING THE AFTERNOON. NEXT CHANCE OF WIDESPREAD
RESTRICTIONS ARRIVES SUNDAY WITH NEXT STORM SYSTEM.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY UNTIL 10 AM EST FRIDAY FOR MDZ001.
OH...FREEZING RAIN ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
     OHZ039>041-048>050-057>059-068-069.
PA...WINTER WEATHER ADVISORY UNTIL 10 AM EST FRIDAY FOR PAZ007>009-
     015-016-023-074-076.
     FREEZING RAIN ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
     PAZ013-014-020>022-029-031-073-075.
WV...FREEZING RAIN ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
     WVZ001>004-012.
     WINTER WEATHER ADVISORY UNTIL 10 AM EST FRIDAY FOR WVZ023-041.
     FREEZING RAIN ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
     WVZ021-022.

&&

$$







000
FXUS61 KPBZ 291351
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
851 AM EST THU JAN 29 2015

.SYNOPSIS...
CROSSING LOW PRESSURE WILL BRING A WINTRY MIX OF PRECIPITATION TO
THE UPPER OHIO REGION TODAY AND SNOW EARLY ON FRIDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
QUICK UPDT TO EXPAND THE FRZG RAIN ADVY ACRS MUCH OF THE AREA WITH
AN APCHG SHRTWV AND CDFNT. PCPN IS ALREADY IN THE OH COUNTIES MOVG
E...AND SHOULD RCH THE AREA THRU THE REST OF THE MRNG/ERLY AFTN.
AIR TEMPS WL BE RISING...THOUGH LOW DEW PTS SHOULD RESULT IN SOME
WET BULBING LIMITING THAT RISE. WITH RECENT COLD WEA ROAD TEMPS
ARE BLO FRZG AND WL LIKELY RMN THERE INTO ERLY AFTN...EVEN IF AIR
TEMPS CLIMB JUST ABV FRZG. FURTHER N AND IN THE RIDGES...CONTD WITH
WINTER WEA ADVYS AS THUICKNESSES/SOUNDING PROFILES INDICATE PCPN
WL LIKELY BE A MIX OF SNW AND FRZG RAIN. NUDGED TEMPS TO THE
LATEST LAMP AND NAM NMBRS.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
THERMAL PROFILES QUICKLY BECOME MORE UNSTABLE TONIGHT. COLD
ADVECTION BEGINS IN EARNEST ALOFT AS TWO SHORT WAVE TROUGHS ARE
SET TO CROSS THE AREA THROUGH FRIDAY MORNING. THIS WILL OCCUR
SIMULTANEOUSLY TO THE DRIER AIR COMING IN...HOWEVER THE DENDRITIC
GROWTH LAYER LOOKS TO CRASH TOWARD THE SURFACE TONIGHT IN THE
RIDGES...WELL BEFORE THE MOISTURE PEELS OFF. CONSENSUS SNOW TO
LIQUID RATIOS FROM THE NAM AND GFS VIA BUFKIT SUGGEST AROUND 25 TO
1 BEGIN OVERNIGHT. GIVEN INSTABILITY AND UNIDIRECTIONAL
UPSLOPE...THIS SHOULD RESULT IN VERY EFFICIENT SNOW GROWTH. MODEL
QPF IS GENERALLY ONLY A COUPLE OF TENTHS...AND GIVEN ICE COVER
UPSTREAM ON LAKE ERIE...A TON OF QPF IS VERY UNLIKELY.
HOWEVER...EVEN LIGHT QPF IN THIS CASE IS LIKELY TO ADD UP TO
SEVERAL INCHES OF SNOW. GIVEN THAT AHEAD OF THE SYSTEM ON THURSDAY
THERE COULD BE AN INCH OR SO IN SOME OF THE SHELTERED HIGHER
ELEVATIONS...AND ANOTHER 2 TO 5 SEEM LIKELY IN THE UPSLOPE THROUGH
FRIDAY WITH ADDITIONAL SYNOPTIC HELP VIA TWO ADDITIONAL WAVES
CROSSING THE AREA...3 TO 6 INCH TOTALS SEEM REASONABLE IN THE
RIDGES BY FRIDAY MORNING. WINTER WEATHER ADVISORIES WERE EXPANDED
TO ACCOMMODATE THIS.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
HIGH LEVELS OF UNCERTAINTY IN THE LONG TERM PARTICULARLY WITH THE
SYSTEM THAT COULD AFFECT THE AREA DURING THE SUNDAY/MONDAY TIME
FRAME. FOR NOW...CONSISTENCY WILL BE THE NAME OF THE GAME UNTIL
THE MODELS PROVIDE A BETTER PICTURE. COLD PATTERN WILL CONTINUE
THROUGH THE REMAINDER OF THE LONG TERM.

&&

.AVIATION /14Z THURSDAY THROUGH MONDAY/...
HANGING ON TO VFR CONDITIONS AT THE START OF THE TAF PERIOD WITH
MID CLOUDS INVADING...BUT THIS WILL START TO CHANGE SOON.
PRECIPITATION BEGINS TO MOVE IN AFTER 14Z ASSOCIATED WITH GREAT
LAKES LOW. STILL LOOKING AT BEST FZRA POSSIBILITIES AT
ZZV...FKL...AND DUJ. STILL CANNOT RULE OUT BRIEF PERIOD OF FZRA AT
HLG AND PIT/AGC...BUT STILL UNCERTAIN ENOUGH TO NOT INCLUDE YET.
OTHERWISE...RA OR A RA/SN MIX.  FLIGHT CONDITIONS WILL DETERIORATE
THROUGH MVFR LATER THIS MORNING/MIDDAY TO IFR DURING THE
AFTERNOON. COLD FRONT SWEEPS THROUGH AFTER 00Z CHANGING ALL PRECIP
TO SNOW WITH CONTINUED IFR CONDITIONS...WITH ZZV/MGW CLINGING TO
MVFR. SLIGHT IMPROVEMENT TOWARDS 12Z AT WESTERN TERMINALS AS MORE
OF A NW FLOW/UPSLOPE PATTERN TAKES HOLD. CL

.OUTLOOK.../THURSDAY NIGHT THROUGH MONDAY/...
RESTRICTIONS WILL CONTINUE THROUGH FRIDAY MORNING...WITH
IMPROVEMENT DURING THE AFTERNOON. NEXT CHANCE OF WIDESPREAD
RESTRICTIONS ARRIVES SUNDAY WITH NEXT STORM SYSTEM.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY UNTIL 10 AM EST FRIDAY FOR MDZ001.
OH...FREEZING RAIN ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
     OHZ039>041-048>050-057>059-068-069.
PA...WINTER WEATHER ADVISORY UNTIL 10 AM EST FRIDAY FOR PAZ007>009-
     015-016-023-074-076.
     FREEZING RAIN ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
     PAZ013-014-020>022-029-031-073-075.
WV...FREEZING RAIN ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
     WVZ001>004-012.
     WINTER WEATHER ADVISORY UNTIL 10 AM EST FRIDAY FOR WVZ023-041.
     FREEZING RAIN ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
     WVZ021-022.

&&

$$








000
FXUS61 KPBZ 291122
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
622 AM EST THU JAN 29 2015

.SYNOPSIS...
CROSSING LOW PRESSURE WILL BRING A WINTRY MIX OF PRECIPITATION TO
THE UPPER OHIO REGION TODAY AND SNOW EARLY ON FRIDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
620 AM...FORECAST STILL IN DECENT SHAPE. PRECIP TIMING STILL LOOKS
GOOD...ALTHOUGH WILL NEED TO SEE IF IT IS A HAIR FASTER OVER THE
NEXT FEW HOURS. MINOR CHANGES TO GRIDS OVER THE NEXT FEW HOURS. CL

PREVIOUS DISCUSSION...

MODELS ARE COMING INTO GOOD AGREEMENT WITH TIMING OF
PRECIPITATION AHEAD OF FRONT AND THE STRONG WAA AS WELL. THE KEY
IS WHAT WILL THE SURFACE TEMPS DO. MODELS ARE INDICATING A SLOW
RESPONSE TO THE WAA AT THE SURFACE BUT I HAVE MY DOUBTS THAT IT
WILL BE FAST ENOUGH TO PREVENT SOME ICING AT THE BEGINNING OF THE
EVENT. BECAUSE OF THIS...A FREEZING RAIN ADVISORY IS IN EFFECT
OVER MOST OF MY OHIO ZONES. THERE ARE A LOT OF FACTORS AT PLAY
HERE WHICH MAKES THIS A VERY DIFFICULT FORECAST. FIRST ALOFT. ALL
THE MODELS ARE SHOWING A STRONG SURGE OF WARMER AIR ENVELOPING MY
ENTIRE CWA TODAY. THIS SHOWS UP QUIET WELL IN THE THERMAL PATTERN
AT 850MB AND IN THE LOW AND MID-LEVEL THICKNESS PATTERNS. I HAVE
DECIDED TO CHANGE VERY LITTLE FROM PREVIOUS THINKING ON PRECIP
TYPES. THE THING TO WATCH WILL BE HOW THE ATMOSPHERE RESPONDS ONCE
THE PRECIP BEGINS AND THE WET BULBING EFFECTS COME INTO PLAY.
MODEL SOUNDINGS SHOW A PROFILE VERY CLOSE TO THE 0 DEGREE LINE
WHICH WILL KEEP THE DIFFERENCE BETWEEN LIQUID OR FROZEN VERY
CLOSE. AT THE SURFACE. MODELS DO SHOW SURFACE TEMPS RISING QUICKLY
AS THE PRECIP APPROACHES. HOWEVER...MY CONCERN IS THAT WITH SUCH
COLD DEWPOINTS AT THE SURFACE...WET BULBING WILL ALLOW FOR A
PERIOD OF FREEZING RAIN...AT LEAST IN OHIO AT THE ONSET OF THE
EVENT. OTHER FACTORS THAT NEED TO BE CONSIDERED ARE THE WIDESPREAD
SNOW PACK AND LOCALIZED EFFECTS...MAINLY SHELTERED AREAS WHERE
TEMPS WILL TAKE LONGER TO RECOVER. AS THE LINE OF PRECIPITATION
MOVES EASTWARD THIS MORNING...SURFACE TEMPERATURES WILL NEED TO BE
CLOSELY MONITORED.

MAIN AREA OF PRECIPITATION WILL EXIT THIS AFTERNOON AS THE SURFACE
FRONT SWINGS INTO CENTRAL PA. THE ONSET OF CAA WILL BE RIGHT
BEHIND THE EXITING FRONT.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
THERMAL PROFILES QUICKLY BECOME MORE UNSTABLE TONIGHT. COLD
ADVECTION BEGINS IN EARNEST ALOFT AS TWO SHORT WAVE TROUGHS ARE
SET TO CROSS THE AREA THROUGH FRIDAY MORNING. THIS WILL OCCUR
SIMULTANEOUSLY TO THE DRIER AIR COMING IN...HOWEVER THE DENDRITIC
GROWTH LAYER LOOKS TO CRASH TOWARD THE SURFACE TONIGHT IN THE
RIDGES...WELL BEFORE THE MOISTURE PEELS OFF. CONSENSUS SNOW TO
LIQUID RATIOS FROM THE NAM AND GFS VIA BUFKIT SUGGEST AROUND 25 TO
1 BEGIN OVERNIGHT. GIVEN INSTABILITY AND UNIDIRECTIONAL
UPSLOPE...THIS SHOULD RESULT IN VERY EFFICIENT SNOW GROWTH. MODEL
QPF IS GENERALLY ONLY A COUPLE OF TENTHS...AND GIVEN ICE COVER
UPSTREAM ON LAKE ERIE...A TON OF QPF IS VERY UNLIKELY.
HOWEVER...EVEN LIGHT QPF IN THIS CASE IS LIKELY TO ADD UP TO
SEVERAL INCHES OF SNOW. GIVEN THAT AHEAD OF THE SYSTEM ON THURSDAY
THERE COULD BE AN INCH OR SO IN SOME OF THE SHELTERED HIGHER
ELEVATIONS...AND ANOTHER 2 TO 5 SEEM LIKELY IN THE UPSLOPE THROUGH
FRIDAY WITH ADDITIONAL SYNOPTIC HELP VIA TWO ADDITIONAL WAVES
CROSSING THE AREA...3 TO 6 INCH TOTALS SEEM REASONABLE IN THE
RIDGES BY FRIDAY MORNING. WINTER WEATHER ADVISORIES WERE EXPANDED
TO ACCOMMODATE THIS.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
HIGH LEVELS OF UNCERTAINTY IN THE LONG TERM PARTICULARLY WITH THE
SYSTEM THAT COULD AFFECT THE AREA DURING THE SUNDAY/MONDAY TIME
FRAME. FOR NOW...CONSISTENCY WILL BE THE NAME OF THE GAME UNTIL
THE MODELS PROVIDE A BETTER PICTURE. COLD PATTERN WILL CONTINUE
THROUGH THE REMAINDER OF THE LONG TERM.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
HANGING ON TO VFR CONDITIONS AT THE START OF THE TAF PERIOD WITH
MID CLOUDS INVADING...BUT THIS WILL START TO CHANGE SOON.
PRECIPITATION BEGINS TO MOVE IN AFTER 14Z ASSOCIATED WITH GREAT
LAKES LOW. STILL LOOKING AT BEST FZRA POSSIBILITIES AT
ZZV...FKL...AND DUJ. STILL CANNOT RULE OUT BRIEF PERIOD OF FZRA AT
HLG AND PIT/AGC...BUT STILL UNCERTAIN ENOUGH TO NOT INCLUDE YET.
OTHERWISE...RA OR A RA/SN MIX.  FLIGHT CONDITIONS WILL DETERIORATE
THROUGH MVFR LATER THIS MORNING/MIDDAY TO IFR DURING THE
AFTERNOON. COLD FRONT SWEEPS THROUGH AFTER 00Z CHANGING ALL PRECIP
TO SNOW WITH CONTINUED IFR CONDITIONS...WITH ZZV/MGW CLINGING TO
MVFR. SLIGHT IMPROVEMENT TOWARDS 12Z AT WESTERN TERMINALS AS MORE
OF A NW FLOW/UPSLOPE PATTERN TAKES HOLD. CL

.OUTLOOK.../THURSDAY NIGHT THROUGH MONDAY/...
RESTRICTIONS WILL CONTINUE THROUGH FRIDAY MORNING...WITH
IMPROVEMENT DURING THE AFTERNOON. NEXT CHANCE OF WIDESPREAD
RESTRICTIONS ARRIVES SUNDAY WITH NEXT STORM SYSTEM.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 10 AM EST
     FRIDAY FOR MDZ001.
OH...FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR OHZ039>041-
     048>050-057>059.
PA...WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 10 AM EST
     FRIDAY FOR PAZ007>009-015-016-023-074-076.
WV...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     FRIDAY FOR WVZ023-041.

&&

$$







000
FXUS61 KPBZ 291122
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
622 AM EST THU JAN 29 2015

.SYNOPSIS...
CROSSING LOW PRESSURE WILL BRING A WINTRY MIX OF PRECIPITATION TO
THE UPPER OHIO REGION TODAY AND SNOW EARLY ON FRIDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
620 AM...FORECAST STILL IN DECENT SHAPE. PRECIP TIMING STILL LOOKS
GOOD...ALTHOUGH WILL NEED TO SEE IF IT IS A HAIR FASTER OVER THE
NEXT FEW HOURS. MINOR CHANGES TO GRIDS OVER THE NEXT FEW HOURS. CL

PREVIOUS DISCUSSION...

MODELS ARE COMING INTO GOOD AGREEMENT WITH TIMING OF
PRECIPITATION AHEAD OF FRONT AND THE STRONG WAA AS WELL. THE KEY
IS WHAT WILL THE SURFACE TEMPS DO. MODELS ARE INDICATING A SLOW
RESPONSE TO THE WAA AT THE SURFACE BUT I HAVE MY DOUBTS THAT IT
WILL BE FAST ENOUGH TO PREVENT SOME ICING AT THE BEGINNING OF THE
EVENT. BECAUSE OF THIS...A FREEZING RAIN ADVISORY IS IN EFFECT
OVER MOST OF MY OHIO ZONES. THERE ARE A LOT OF FACTORS AT PLAY
HERE WHICH MAKES THIS A VERY DIFFICULT FORECAST. FIRST ALOFT. ALL
THE MODELS ARE SHOWING A STRONG SURGE OF WARMER AIR ENVELOPING MY
ENTIRE CWA TODAY. THIS SHOWS UP QUIET WELL IN THE THERMAL PATTERN
AT 850MB AND IN THE LOW AND MID-LEVEL THICKNESS PATTERNS. I HAVE
DECIDED TO CHANGE VERY LITTLE FROM PREVIOUS THINKING ON PRECIP
TYPES. THE THING TO WATCH WILL BE HOW THE ATMOSPHERE RESPONDS ONCE
THE PRECIP BEGINS AND THE WET BULBING EFFECTS COME INTO PLAY.
MODEL SOUNDINGS SHOW A PROFILE VERY CLOSE TO THE 0 DEGREE LINE
WHICH WILL KEEP THE DIFFERENCE BETWEEN LIQUID OR FROZEN VERY
CLOSE. AT THE SURFACE. MODELS DO SHOW SURFACE TEMPS RISING QUICKLY
AS THE PRECIP APPROACHES. HOWEVER...MY CONCERN IS THAT WITH SUCH
COLD DEWPOINTS AT THE SURFACE...WET BULBING WILL ALLOW FOR A
PERIOD OF FREEZING RAIN...AT LEAST IN OHIO AT THE ONSET OF THE
EVENT. OTHER FACTORS THAT NEED TO BE CONSIDERED ARE THE WIDESPREAD
SNOW PACK AND LOCALIZED EFFECTS...MAINLY SHELTERED AREAS WHERE
TEMPS WILL TAKE LONGER TO RECOVER. AS THE LINE OF PRECIPITATION
MOVES EASTWARD THIS MORNING...SURFACE TEMPERATURES WILL NEED TO BE
CLOSELY MONITORED.

MAIN AREA OF PRECIPITATION WILL EXIT THIS AFTERNOON AS THE SURFACE
FRONT SWINGS INTO CENTRAL PA. THE ONSET OF CAA WILL BE RIGHT
BEHIND THE EXITING FRONT.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
THERMAL PROFILES QUICKLY BECOME MORE UNSTABLE TONIGHT. COLD
ADVECTION BEGINS IN EARNEST ALOFT AS TWO SHORT WAVE TROUGHS ARE
SET TO CROSS THE AREA THROUGH FRIDAY MORNING. THIS WILL OCCUR
SIMULTANEOUSLY TO THE DRIER AIR COMING IN...HOWEVER THE DENDRITIC
GROWTH LAYER LOOKS TO CRASH TOWARD THE SURFACE TONIGHT IN THE
RIDGES...WELL BEFORE THE MOISTURE PEELS OFF. CONSENSUS SNOW TO
LIQUID RATIOS FROM THE NAM AND GFS VIA BUFKIT SUGGEST AROUND 25 TO
1 BEGIN OVERNIGHT. GIVEN INSTABILITY AND UNIDIRECTIONAL
UPSLOPE...THIS SHOULD RESULT IN VERY EFFICIENT SNOW GROWTH. MODEL
QPF IS GENERALLY ONLY A COUPLE OF TENTHS...AND GIVEN ICE COVER
UPSTREAM ON LAKE ERIE...A TON OF QPF IS VERY UNLIKELY.
HOWEVER...EVEN LIGHT QPF IN THIS CASE IS LIKELY TO ADD UP TO
SEVERAL INCHES OF SNOW. GIVEN THAT AHEAD OF THE SYSTEM ON THURSDAY
THERE COULD BE AN INCH OR SO IN SOME OF THE SHELTERED HIGHER
ELEVATIONS...AND ANOTHER 2 TO 5 SEEM LIKELY IN THE UPSLOPE THROUGH
FRIDAY WITH ADDITIONAL SYNOPTIC HELP VIA TWO ADDITIONAL WAVES
CROSSING THE AREA...3 TO 6 INCH TOTALS SEEM REASONABLE IN THE
RIDGES BY FRIDAY MORNING. WINTER WEATHER ADVISORIES WERE EXPANDED
TO ACCOMMODATE THIS.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
HIGH LEVELS OF UNCERTAINTY IN THE LONG TERM PARTICULARLY WITH THE
SYSTEM THAT COULD AFFECT THE AREA DURING THE SUNDAY/MONDAY TIME
FRAME. FOR NOW...CONSISTENCY WILL BE THE NAME OF THE GAME UNTIL
THE MODELS PROVIDE A BETTER PICTURE. COLD PATTERN WILL CONTINUE
THROUGH THE REMAINDER OF THE LONG TERM.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
HANGING ON TO VFR CONDITIONS AT THE START OF THE TAF PERIOD WITH
MID CLOUDS INVADING...BUT THIS WILL START TO CHANGE SOON.
PRECIPITATION BEGINS TO MOVE IN AFTER 14Z ASSOCIATED WITH GREAT
LAKES LOW. STILL LOOKING AT BEST FZRA POSSIBILITIES AT
ZZV...FKL...AND DUJ. STILL CANNOT RULE OUT BRIEF PERIOD OF FZRA AT
HLG AND PIT/AGC...BUT STILL UNCERTAIN ENOUGH TO NOT INCLUDE YET.
OTHERWISE...RA OR A RA/SN MIX.  FLIGHT CONDITIONS WILL DETERIORATE
THROUGH MVFR LATER THIS MORNING/MIDDAY TO IFR DURING THE
AFTERNOON. COLD FRONT SWEEPS THROUGH AFTER 00Z CHANGING ALL PRECIP
TO SNOW WITH CONTINUED IFR CONDITIONS...WITH ZZV/MGW CLINGING TO
MVFR. SLIGHT IMPROVEMENT TOWARDS 12Z AT WESTERN TERMINALS AS MORE
OF A NW FLOW/UPSLOPE PATTERN TAKES HOLD. CL

.OUTLOOK.../THURSDAY NIGHT THROUGH MONDAY/...
RESTRICTIONS WILL CONTINUE THROUGH FRIDAY MORNING...WITH
IMPROVEMENT DURING THE AFTERNOON. NEXT CHANCE OF WIDESPREAD
RESTRICTIONS ARRIVES SUNDAY WITH NEXT STORM SYSTEM.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 10 AM EST
     FRIDAY FOR MDZ001.
OH...FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR OHZ039>041-
     048>050-057>059.
PA...WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 10 AM EST
     FRIDAY FOR PAZ007>009-015-016-023-074-076.
WV...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     FRIDAY FOR WVZ023-041.

&&

$$








000
FXUS61 KPBZ 290918 AAA
AFDPBZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PITTSBURGH PA
418 AM EST THU JAN 29 2015

.SYNOPSIS...
CROSSING LOW PRESSURE WILL BRING A WINTRY MIX OF PRECIPITATION TO
THE UPPER OHIO REGION TODAY AND SNOW EARLY ON FRIDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MODELS ARE COMING INTO GOOD AGREEMENT WITH TIMING OF
PRECIPITATION AHEAD OF FRONT AND THE STRONG WAA AS WELL. THE KEY
IS WHAT WILL THE SURFACE TEMPS DO. MODELS ARE INDICATING A SLOW
RESPONSE TO THE WAA AT THE SURFACE BUT I HAVE MY DOUBTS THAT IT
WILL BE FAST ENOUGH TO PREVENT SOME ICING AT THE BEGINNING OF THE
EVENT. BECAUSE OF THIS...A FREEZING RAIN ADVISORY IS IN EFFECT
OVER MOST OF MY OHIO ZONES. THERE ARE A LOT OF FACTORS AT PLAY
HERE WHICH MAKES THIS A VERY DIFFICULT FORECAST. FIRST ALOFT. ALL
THE MODELS ARE SHOWING A STRONG SURGE OF WARMER AIR ENVELOPING MY
ENTIRE CWA TODAY. THIS SHOWS UP QUIET WELL IN THE THERMAL PATTERN
AT 850MB AND IN THE LOW AND MID-LEVEL THICKNESS PATTERNS. I HAVE
DECIDED TO CHANGE VERY LITTLE FROM PREVIOUS THINKING ON PRECIP
TYPES. THE THING TO WATCH WILL BE HOW THE ATMOSPHERE RESPONDS ONCE
THE PRECIP BEGINS AND THE WET BULBING EFFECTS COME INTO PLAY.
MODEL SOUNDINGS SHOW A PROFILE VERY CLOSE TO THE 0 DEGREE LINE
WHICH WILL KEEP THE DIFFERENCE BETWEEN LIQUID OR FROZEN VERY
CLOSE. AT THE SURFACE. MODELS DO SHOW SURFACE TEMPS RISING QUICKLY
AS THE PRECIP APPROACHES. HOWEVER...MY CONCERN IS THAT WITH SUCH
COLD DEWPOINTS AT THE SURFACE...WET BULBING WILL ALLOW FOR A
PERIOD OF FREEZING RAIN...AT LEAST IN OHIO AT THE ONSET OF THE
EVENT. OTHER FACTORS THAT NEED TO BE CONSIDERED ARE THE WIDESPREAD
SNOW PACK AND LOCALIZED EFFECTS...MAINLY SHELTERED AREAS WHERE
TEMPS WILL TAKE LONGER TO RECOVER. AS THE LINE OF PRECIPITATION
MOVES EASTWARD THIS MORNING...SURFACE TEMPERATURES WILL NEED TO BE
CLOSELY MONITORED.

MAIN AREA OF PRECIPITATION WILL EXIT THIS AFTERNOON AS THE SURFACE
FRONT SWINGS INTO CENTRAL PA. THE ONSET OF CAA WILL BE RIGHT
BEHIND THE EXITING FRONT.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
THERMAL PROFILES QUICKLY BECOME MORE UNSTABLE TONIGHT. COLD
ADVECTION BEGINS IN EARNEST ALOFT AS TWO SHORT WAVE TROUGHS ARE
SET TO CROSS THE AREA THROUGH FRIDAY MORNING. THIS WILL OCCUR
SIMULTANEOUSLY TO THE DRIER AIR COMING IN...HOWEVER THE DENDRITIC
GROWTH LAYER LOOKS TO CRASH TOWARD THE SURFACE TONIGHT IN THE
RIDGES...WELL BEFORE THE MOISTURE PEELS OFF. CONSENSUS SNOW TO
LIQUID RATIOS FROM THE NAM AND GFS VIA BUFKIT SUGGEST AROUND 25 TO
1 BEGIN OVERNIGHT. GIVEN INSTABILITY AND UNIDIRECTIONAL
UPSLOPE...THIS SHOULD RESULT IN VERY EFFICIENT SNOW GROWTH. MODEL
QPF IS GENERALLY ONLY A COUPLE OF TENTHS...AND GIVEN ICE COVER
UPSTREAM ON LAKE ERIE...A TON OF QPF IS VERY UNLIKELY.
HOWEVER...EVEN LIGHT QPF IN THIS CASE IS LIKELY TO ADD UP TO
SEVERAL INCHES OF SNOW. GIVEN THAT AHEAD OF THE SYSTEM ON THURSDAY
THERE COULD BE AN INCH OR SO IN SOME OF THE SHELTERED HIGHER
ELEVATIONS...AND ANOTHER 2 TO 5 SEEM LIKELY IN THE UPSLOPE THROUGH
FRIDAY WITH ADDITIONAL SYNOPTIC HELP VIA TWO ADDITIONAL WAVES
CROSSING THE AREA...3 TO 6 INCH TOTALS SEEM REASONABLE IN THE
RIDGES BY FRIDAY MORNING. WINTER WEATHER ADVISORIES WERE EXPANDED
TO ACCOMMODATE THIS.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
HIGH LEVELS OF UNCERTAINTY IN THE LONG TERM PARTICULARLY WITH THE
SYSTEM THAT COULD AFFECT THE AREA DURING THE SUNDAY/MONDAY TIME
FRAME. FOR NOW...CONSISTENCY WILL BE THE NAME OF THE GAME UNTIL
THE MODELS PROVIDE A BETTER PICTURE. COLD PATTERN WILL CONTINUE
THROUGH THE REMAINDER OF THE LONG TERM.

&&

.AVIATION /09Z THURSDAY THROUGH MONDAY/...
VFR OVERNIGHT THROUGH SUNRISE WITH THICKENING MID/HI CLOUDS.
PRECIPITATION RETURNS AFTER 14Z WITH LOW PRESSURE TRACKING TO THE
NORTH. EXPECT A DROP TO MVFR SOON AFTER PRECIP ONSET...WITH IFR
CIGS TO FOLLOW AT MOST TERMINALS DURING THE AFTERNOON AND EVENING.
PRECIP TYPES ARE THE MAIN DIFFICULTY. STILL THINK BEST CHANCES OF
FZRA WILL LIE IN OHIO AND AT FKL/DUJ DURING THE FIRST FEW HOURS OF
PRECIPITATION. CANNOT RULE OUT AT LEAST A BRIEF PERIOD OF FZRA
ANYWHERE SAVE PERHAPS MGW. CHANGOVER TO SNOW WILL OCCUR AFTER 00Z
AS A COLD FRONT SWEEPS THROUGH. WINDS WILL STRENGTHEN OUT OF THE
SOUTH AROUND MIDDAY AND REMAIN GUSTY AS THEY VEER TOWARDS SW/W
WITH TIME. WILL CONTINUE TO MONITOR FOR LLWS POSSIBILITIES.  CL

.OUTLOOK.../THURSDAY NIGHT THROUGH MONDAY/...
RSTRNS ARE LIKELY THRU ERLY FRI AS A CDFNT EXITS. WDSRPD RSTRNS
ARE LIKELY AGAIN WITH ADVNG LOW PRES SUN AND MON.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 10 AM EST
     FRIDAY FOR MDZ001.
OH...FREEZING RAIN ADVISORY FROM 8 AM THIS MORNING TO NOON EST
     TODAY FOR OHZ039>041-048>050-057>059.
PA...WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 10 AM EST
     FRIDAY FOR PAZ007>009-015-016-023-074-076.
WV...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     FRIDAY FOR WVZ023-041.

&&

$$







000
FXUS61 KPBZ 290918 AAA
AFDPBZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PITTSBURGH PA
418 AM EST THU JAN 29 2015

.SYNOPSIS...
CROSSING LOW PRESSURE WILL BRING A WINTRY MIX OF PRECIPITATION TO
THE UPPER OHIO REGION TODAY AND SNOW EARLY ON FRIDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MODELS ARE COMING INTO GOOD AGREEMENT WITH TIMING OF
PRECIPITATION AHEAD OF FRONT AND THE STRONG WAA AS WELL. THE KEY
IS WHAT WILL THE SURFACE TEMPS DO. MODELS ARE INDICATING A SLOW
RESPONSE TO THE WAA AT THE SURFACE BUT I HAVE MY DOUBTS THAT IT
WILL BE FAST ENOUGH TO PREVENT SOME ICING AT THE BEGINNING OF THE
EVENT. BECAUSE OF THIS...A FREEZING RAIN ADVISORY IS IN EFFECT
OVER MOST OF MY OHIO ZONES. THERE ARE A LOT OF FACTORS AT PLAY
HERE WHICH MAKES THIS A VERY DIFFICULT FORECAST. FIRST ALOFT. ALL
THE MODELS ARE SHOWING A STRONG SURGE OF WARMER AIR ENVELOPING MY
ENTIRE CWA TODAY. THIS SHOWS UP QUIET WELL IN THE THERMAL PATTERN
AT 850MB AND IN THE LOW AND MID-LEVEL THICKNESS PATTERNS. I HAVE
DECIDED TO CHANGE VERY LITTLE FROM PREVIOUS THINKING ON PRECIP
TYPES. THE THING TO WATCH WILL BE HOW THE ATMOSPHERE RESPONDS ONCE
THE PRECIP BEGINS AND THE WET BULBING EFFECTS COME INTO PLAY.
MODEL SOUNDINGS SHOW A PROFILE VERY CLOSE TO THE 0 DEGREE LINE
WHICH WILL KEEP THE DIFFERENCE BETWEEN LIQUID OR FROZEN VERY
CLOSE. AT THE SURFACE. MODELS DO SHOW SURFACE TEMPS RISING QUICKLY
AS THE PRECIP APPROACHES. HOWEVER...MY CONCERN IS THAT WITH SUCH
COLD DEWPOINTS AT THE SURFACE...WET BULBING WILL ALLOW FOR A
PERIOD OF FREEZING RAIN...AT LEAST IN OHIO AT THE ONSET OF THE
EVENT. OTHER FACTORS THAT NEED TO BE CONSIDERED ARE THE WIDESPREAD
SNOW PACK AND LOCALIZED EFFECTS...MAINLY SHELTERED AREAS WHERE
TEMPS WILL TAKE LONGER TO RECOVER. AS THE LINE OF PRECIPITATION
MOVES EASTWARD THIS MORNING...SURFACE TEMPERATURES WILL NEED TO BE
CLOSELY MONITORED.

MAIN AREA OF PRECIPITATION WILL EXIT THIS AFTERNOON AS THE SURFACE
FRONT SWINGS INTO CENTRAL PA. THE ONSET OF CAA WILL BE RIGHT
BEHIND THE EXITING FRONT.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
THERMAL PROFILES QUICKLY BECOME MORE UNSTABLE TONIGHT. COLD
ADVECTION BEGINS IN EARNEST ALOFT AS TWO SHORT WAVE TROUGHS ARE
SET TO CROSS THE AREA THROUGH FRIDAY MORNING. THIS WILL OCCUR
SIMULTANEOUSLY TO THE DRIER AIR COMING IN...HOWEVER THE DENDRITIC
GROWTH LAYER LOOKS TO CRASH TOWARD THE SURFACE TONIGHT IN THE
RIDGES...WELL BEFORE THE MOISTURE PEELS OFF. CONSENSUS SNOW TO
LIQUID RATIOS FROM THE NAM AND GFS VIA BUFKIT SUGGEST AROUND 25 TO
1 BEGIN OVERNIGHT. GIVEN INSTABILITY AND UNIDIRECTIONAL
UPSLOPE...THIS SHOULD RESULT IN VERY EFFICIENT SNOW GROWTH. MODEL
QPF IS GENERALLY ONLY A COUPLE OF TENTHS...AND GIVEN ICE COVER
UPSTREAM ON LAKE ERIE...A TON OF QPF IS VERY UNLIKELY.
HOWEVER...EVEN LIGHT QPF IN THIS CASE IS LIKELY TO ADD UP TO
SEVERAL INCHES OF SNOW. GIVEN THAT AHEAD OF THE SYSTEM ON THURSDAY
THERE COULD BE AN INCH OR SO IN SOME OF THE SHELTERED HIGHER
ELEVATIONS...AND ANOTHER 2 TO 5 SEEM LIKELY IN THE UPSLOPE THROUGH
FRIDAY WITH ADDITIONAL SYNOPTIC HELP VIA TWO ADDITIONAL WAVES
CROSSING THE AREA...3 TO 6 INCH TOTALS SEEM REASONABLE IN THE
RIDGES BY FRIDAY MORNING. WINTER WEATHER ADVISORIES WERE EXPANDED
TO ACCOMMODATE THIS.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
HIGH LEVELS OF UNCERTAINTY IN THE LONG TERM PARTICULARLY WITH THE
SYSTEM THAT COULD AFFECT THE AREA DURING THE SUNDAY/MONDAY TIME
FRAME. FOR NOW...CONSISTENCY WILL BE THE NAME OF THE GAME UNTIL
THE MODELS PROVIDE A BETTER PICTURE. COLD PATTERN WILL CONTINUE
THROUGH THE REMAINDER OF THE LONG TERM.

&&

.AVIATION /09Z THURSDAY THROUGH MONDAY/...
VFR OVERNIGHT THROUGH SUNRISE WITH THICKENING MID/HI CLOUDS.
PRECIPITATION RETURNS AFTER 14Z WITH LOW PRESSURE TRACKING TO THE
NORTH. EXPECT A DROP TO MVFR SOON AFTER PRECIP ONSET...WITH IFR
CIGS TO FOLLOW AT MOST TERMINALS DURING THE AFTERNOON AND EVENING.
PRECIP TYPES ARE THE MAIN DIFFICULTY. STILL THINK BEST CHANCES OF
FZRA WILL LIE IN OHIO AND AT FKL/DUJ DURING THE FIRST FEW HOURS OF
PRECIPITATION. CANNOT RULE OUT AT LEAST A BRIEF PERIOD OF FZRA
ANYWHERE SAVE PERHAPS MGW. CHANGOVER TO SNOW WILL OCCUR AFTER 00Z
AS A COLD FRONT SWEEPS THROUGH. WINDS WILL STRENGTHEN OUT OF THE
SOUTH AROUND MIDDAY AND REMAIN GUSTY AS THEY VEER TOWARDS SW/W
WITH TIME. WILL CONTINUE TO MONITOR FOR LLWS POSSIBILITIES.  CL

.OUTLOOK.../THURSDAY NIGHT THROUGH MONDAY/...
RSTRNS ARE LIKELY THRU ERLY FRI AS A CDFNT EXITS. WDSRPD RSTRNS
ARE LIKELY AGAIN WITH ADVNG LOW PRES SUN AND MON.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 10 AM EST
     FRIDAY FOR MDZ001.
OH...FREEZING RAIN ADVISORY FROM 8 AM THIS MORNING TO NOON EST
     TODAY FOR OHZ039>041-048>050-057>059.
PA...WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 10 AM EST
     FRIDAY FOR PAZ007>009-015-016-023-074-076.
WV...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     FRIDAY FOR WVZ023-041.

&&

$$








000
FXUS61 KPBZ 290731
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
231 AM EST THU JAN 29 2015

.SYNOPSIS...
CROSSING LOW PRESSURE WILL BRING A WINTRY MIX OF PRECIPITATION TO
THE UPPER OHIO REGION TODAY AND SNOW EARLY ON FRIDAY.

&&

.NEAR TERM /THROUGH TODAY/...
MODELS ARE COMING INTO GOOD AGREEMENT WITH TIMING OF
PRECIPITATION AHEAD OF FRONT AND THE STRONG WAA AS WELL. THE KEY
IS WHAT WILL THE SURFACE TEMPS DO. MODELS ARE INDICATING A SLOW
RESPONSE TO THE WAA AT THE SURFACE BUT I HAVE MY DOUBTS THAT IT
WILL BE FAST ENOUGH TO PREVENT SOME ICING AT THE BEGINNING OF THE
EVENT. BECAUSE OF THIS...HAVE EXTENDED THE FREEZING RAIN ADVISORY
TO COVER MOST OF MY OHIO ZONES. THERE ARE A LOT OF FACTORS AT
PLAY HERE WHICH MAKES THIS A VERY DIFFICULT FORECAST. FIRST ALOFT.
ALL THE MODELS ARE SHOWING A STRONG SURGE OF WARMER AIR ENVELOPING
MY ENTIRE CWA TODAY. THIS SHOWS UP QUIET WELL IN THE THERMAL
PATTERN AT 850MB AND IN THE LOW AND MID-LEVEL THICKNESS PATTERNS.
I HAVE DECIDED TO CHANGE VERY LITTLE FROM PREVIOUS THINKING ON
PRECIP TYPES. THE THING TO WATCH WILL BE HOW THE ATMOSPHERE
RESPONDS ONCE THE PRECIP BEGINS AND THE WET BULBING EFFECTS COME
INTO PLAY. MODEL SOUNDINGS SHOW A PROFILE VERY CLOSE TO THE 0
DEGREE LINE WHICH WILL KEEP THE DIFFERENCE BETWEEN LIQUID OR
FROZEN VERY CLOSE. AT THE SURFACE. MODELS DO SHOW SURFACE TEMPS
RISING QUICKLY AS THE PRECIP APPROACHES. HOWEVER...MY CONCERN IS
THAT WITH SUCH COLD DEWPOINTS AT THE SURFACE...WET BULBING WILL
ALLOW FOR A PERIOD OF FREEZING RAIN...AT LEAST IN OHIO AT THE
ONSET OF THE EVENT. OTHER FACTORS THAT NEED TO BE CONSIDERED ARE
THE WIDESPREAD SNOW PACK AND LOCALIZED EFFECTS...MAINLY SHELTERED
AREAS WHERE TEMPS WILL TAKE LONGER TO RECOVER.

MAIN AREA OF PRECIPITATION WILL EXIT THIS AFTERNOON AS THE SURFACE
FRONT SWINGS INTO CENTRAL PA. THE ONSET OF CAA WILL BE RIGHT
BEHIND THE EXITING FRONT.

&&

.SHORT TERM /TONIGHT THROUGH SATURDAY/...
THERMAL PROFILES QUICKLY BECOME MORE UNSTABLE TONIGHT. COLD
ADVECTION BEGINS IN EARNEST ALOFT AS TWO SHORT WAVE TROUGHS ARE
SET TO CROSS THE AREA THROUGH FRIDAY MORNING. THIS WILL OCCUR
SIMULTANEOUSLY TO THE DRIER AIR COMING IN...HOWEVER THE DENDRITIC
GROWTH LAYER LOOKS TO CRASH TOWARD THE SURFACE TONIGHT IN THE
RIDGES...WELL BEFORE THE MOISTURE PEELS OFF. CONSENSUS SNOW TO
LIQUID RATIOS FROM THE NAM AND GFS VIA BUFKIT SUGGEST AROUND 25 TO
1 BEGIN OVERNIGHT. GIVEN INSTABILITY AND UNIDIRECTIONAL
UPSLOPE...THIS SHOULD RESULT IN VERY EFFICIENT SNOW GROWTH. MODEL
QPF IS GENERALLY ONLY A COUPLE OF TENTHS...AND GIVEN ICE COVER
UPSTREAM ON LAKE ERIE...A TON OF QPF IS VERY UNLIKELY.
HOWEVER...EVEN LIGHT QPF IN THIS CASE IS LIKELY TO ADD UP TO
SEVERAL INCHES OF SNOW. GIVEN THAT AHEAD OF THE SYSTEM ON THURSDAY
THERE COULD BE AN INCH OR SO IN SOME OF THE SHELTERED HIGHER
ELEVATIONS...AND ANOTHER 2 TO 5 SEEM LIKELY IN THE UPSLOPE THROUGH
FRIDAY WITH ADDITIONAL SYNOPTIC HELP VIA TWO ADDITIONAL WAVES
CROSSING THE AREA...3 TO 6 INCH TOTALS SEEM REASONABLE IN THE
RIDGES BY FRIDAY MORNING. WINTER WEATHER ADVISORIES WERE EXPANDED
TO ACCOMMODATE THIS.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
HIGH LEVELS OF UNCERTAINTY IN THE LONG TERM PARTICULARLY WITH THE
SYSTEM THAT COULD AFFECT THE AREA DURING THE SUNDAY/MONDAY TIME
FRAME. FOR NOW...CONSISTENCY WILL BE THE NAME OF THE GAME UNTIL
THE MODELS PROVIDE A BETTER PICTURE. COLD PATTERN WILL CONTINUE
THROUGH THE REMAINDER OF THE LONG TERM.

&&

.AVIATION /08Z THURSDAY THROUGH MONDAY/...
VFR OVERNIGHT THROUGH SUNRISE WITH THICKENING MID/HI CLOUDS.
PRECIPITATION RETURNS AFTER 14Z WITH LOW PRESSURE TRACKING TO THE
NORTH. EXPECT A DROP TO MVFR SOON AFTER PRECIP ONSET...WITH IFR
CIGS TO FOLLOW AT MOST TERMINALS DURING THE AFTERNOON AND EVENING.
PRECIP TYPES ARE THE MAIN DIFFICULTY. STILL THINK BEST CHANCES OF
FZRA WILL LIE IN OHIO AND AT FKL/DUJ DURING THE FIRST FEW HOURS OF
PRECIPITATION. CANNOT RULE OUT AT LEAST A BRIEF PERIOD OF FZRA
ANYWHERE SAVE PERHAPS MGW. CHANGOVER TO SNOW WILL OCCUR AFTER 00Z
AS A COLD FRONT SWEEPS THROUGH. WINDS WILL STRENGTHEN OUT OF THE
SOUTH AROUND MIDDAY AND REMAIN GUSTY AS THEY VEER TOWARDS SW/W
WITH TIME. WILL CONTINUE TO MONITOR FOR LLWS POSSIBILITIES.  CL

.OUTLOOK.../THURSDAY NIGHT THROUGH MONDAY/...
RSTRNS ARE LIKELY THRU ERLY FRI AS A CDFNT EXITS. WDSRPD RSTRNS
ARE LIKELY AGAIN WITH ADVNG LOW PRES SUN AND MON.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 10 AM EST
     FRIDAY FOR MDZ001.
OH...FREEZING RAIN ADVISORY FROM 8 AM THIS MORNING TO NOON EST
     TODAY FOR OHZ039>041-048>050-057>059.
PA...WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 10 AM EST
     FRIDAY FOR PAZ007>009-015-016-023-074-076.
WV...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     FRIDAY FOR WVZ023-041.

&&

$$








000
FXUS61 KPBZ 290731
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
231 AM EST THU JAN 29 2015

.SYNOPSIS...
CROSSING LOW PRESSURE WILL BRING A WINTRY MIX OF PRECIPITATION TO
THE UPPER OHIO REGION TODAY AND SNOW EARLY ON FRIDAY.

&&

.NEAR TERM /THROUGH TODAY/...
MODELS ARE COMING INTO GOOD AGREEMENT WITH TIMING OF
PRECIPITATION AHEAD OF FRONT AND THE STRONG WAA AS WELL. THE KEY
IS WHAT WILL THE SURFACE TEMPS DO. MODELS ARE INDICATING A SLOW
RESPONSE TO THE WAA AT THE SURFACE BUT I HAVE MY DOUBTS THAT IT
WILL BE FAST ENOUGH TO PREVENT SOME ICING AT THE BEGINNING OF THE
EVENT. BECAUSE OF THIS...HAVE EXTENDED THE FREEZING RAIN ADVISORY
TO COVER MOST OF MY OHIO ZONES. THERE ARE A LOT OF FACTORS AT
PLAY HERE WHICH MAKES THIS A VERY DIFFICULT FORECAST. FIRST ALOFT.
ALL THE MODELS ARE SHOWING A STRONG SURGE OF WARMER AIR ENVELOPING
MY ENTIRE CWA TODAY. THIS SHOWS UP QUIET WELL IN THE THERMAL
PATTERN AT 850MB AND IN THE LOW AND MID-LEVEL THICKNESS PATTERNS.
I HAVE DECIDED TO CHANGE VERY LITTLE FROM PREVIOUS THINKING ON
PRECIP TYPES. THE THING TO WATCH WILL BE HOW THE ATMOSPHERE
RESPONDS ONCE THE PRECIP BEGINS AND THE WET BULBING EFFECTS COME
INTO PLAY. MODEL SOUNDINGS SHOW A PROFILE VERY CLOSE TO THE 0
DEGREE LINE WHICH WILL KEEP THE DIFFERENCE BETWEEN LIQUID OR
FROZEN VERY CLOSE. AT THE SURFACE. MODELS DO SHOW SURFACE TEMPS
RISING QUICKLY AS THE PRECIP APPROACHES. HOWEVER...MY CONCERN IS
THAT WITH SUCH COLD DEWPOINTS AT THE SURFACE...WET BULBING WILL
ALLOW FOR A PERIOD OF FREEZING RAIN...AT LEAST IN OHIO AT THE
ONSET OF THE EVENT. OTHER FACTORS THAT NEED TO BE CONSIDERED ARE
THE WIDESPREAD SNOW PACK AND LOCALIZED EFFECTS...MAINLY SHELTERED
AREAS WHERE TEMPS WILL TAKE LONGER TO RECOVER.

MAIN AREA OF PRECIPITATION WILL EXIT THIS AFTERNOON AS THE SURFACE
FRONT SWINGS INTO CENTRAL PA. THE ONSET OF CAA WILL BE RIGHT
BEHIND THE EXITING FRONT.

&&

.SHORT TERM /TONIGHT THROUGH SATURDAY/...
THERMAL PROFILES QUICKLY BECOME MORE UNSTABLE TONIGHT. COLD
ADVECTION BEGINS IN EARNEST ALOFT AS TWO SHORT WAVE TROUGHS ARE
SET TO CROSS THE AREA THROUGH FRIDAY MORNING. THIS WILL OCCUR
SIMULTANEOUSLY TO THE DRIER AIR COMING IN...HOWEVER THE DENDRITIC
GROWTH LAYER LOOKS TO CRASH TOWARD THE SURFACE TONIGHT IN THE
RIDGES...WELL BEFORE THE MOISTURE PEELS OFF. CONSENSUS SNOW TO
LIQUID RATIOS FROM THE NAM AND GFS VIA BUFKIT SUGGEST AROUND 25 TO
1 BEGIN OVERNIGHT. GIVEN INSTABILITY AND UNIDIRECTIONAL
UPSLOPE...THIS SHOULD RESULT IN VERY EFFICIENT SNOW GROWTH. MODEL
QPF IS GENERALLY ONLY A COUPLE OF TENTHS...AND GIVEN ICE COVER
UPSTREAM ON LAKE ERIE...A TON OF QPF IS VERY UNLIKELY.
HOWEVER...EVEN LIGHT QPF IN THIS CASE IS LIKELY TO ADD UP TO
SEVERAL INCHES OF SNOW. GIVEN THAT AHEAD OF THE SYSTEM ON THURSDAY
THERE COULD BE AN INCH OR SO IN SOME OF THE SHELTERED HIGHER
ELEVATIONS...AND ANOTHER 2 TO 5 SEEM LIKELY IN THE UPSLOPE THROUGH
FRIDAY WITH ADDITIONAL SYNOPTIC HELP VIA TWO ADDITIONAL WAVES
CROSSING THE AREA...3 TO 6 INCH TOTALS SEEM REASONABLE IN THE
RIDGES BY FRIDAY MORNING. WINTER WEATHER ADVISORIES WERE EXPANDED
TO ACCOMMODATE THIS.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
HIGH LEVELS OF UNCERTAINTY IN THE LONG TERM PARTICULARLY WITH THE
SYSTEM THAT COULD AFFECT THE AREA DURING THE SUNDAY/MONDAY TIME
FRAME. FOR NOW...CONSISTENCY WILL BE THE NAME OF THE GAME UNTIL
THE MODELS PROVIDE A BETTER PICTURE. COLD PATTERN WILL CONTINUE
THROUGH THE REMAINDER OF THE LONG TERM.

&&

.AVIATION /08Z THURSDAY THROUGH MONDAY/...
VFR OVERNIGHT THROUGH SUNRISE WITH THICKENING MID/HI CLOUDS.
PRECIPITATION RETURNS AFTER 14Z WITH LOW PRESSURE TRACKING TO THE
NORTH. EXPECT A DROP TO MVFR SOON AFTER PRECIP ONSET...WITH IFR
CIGS TO FOLLOW AT MOST TERMINALS DURING THE AFTERNOON AND EVENING.
PRECIP TYPES ARE THE MAIN DIFFICULTY. STILL THINK BEST CHANCES OF
FZRA WILL LIE IN OHIO AND AT FKL/DUJ DURING THE FIRST FEW HOURS OF
PRECIPITATION. CANNOT RULE OUT AT LEAST A BRIEF PERIOD OF FZRA
ANYWHERE SAVE PERHAPS MGW. CHANGOVER TO SNOW WILL OCCUR AFTER 00Z
AS A COLD FRONT SWEEPS THROUGH. WINDS WILL STRENGTHEN OUT OF THE
SOUTH AROUND MIDDAY AND REMAIN GUSTY AS THEY VEER TOWARDS SW/W
WITH TIME. WILL CONTINUE TO MONITOR FOR LLWS POSSIBILITIES.  CL

.OUTLOOK.../THURSDAY NIGHT THROUGH MONDAY/...
RSTRNS ARE LIKELY THRU ERLY FRI AS A CDFNT EXITS. WDSRPD RSTRNS
ARE LIKELY AGAIN WITH ADVNG LOW PRES SUN AND MON.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 10 AM EST
     FRIDAY FOR MDZ001.
OH...FREEZING RAIN ADVISORY FROM 8 AM THIS MORNING TO NOON EST
     TODAY FOR OHZ039>041-048>050-057>059.
PA...WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 10 AM EST
     FRIDAY FOR PAZ007>009-015-016-023-074-076.
WV...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     FRIDAY FOR WVZ023-041.

&&

$$







000
FXUS61 KPBZ 290549
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1249 AM EST THU JAN 29 2015

.SYNOPSIS...
CROSSING LOW PRESSURE WILL BRING A WINTRY MIX OF PRECIPITATION TO
THE UPPER OHIO REGION TODAY AND SNOW EARLY ON FRIDAY.

&&

.NEAR TERM /THROUGH TODAY/...
OVERNIGHT IN GOOD SHAPE. JUST NEED TO KEEP UP WITH THE TEMPS.

MODELS ARE COMING INTO GOOD AGREEMENT WITH TIMING OF PRECIPITATION
AHEAD OF FRONT AND THE STRONG WAA AS WELL. THE KEY IS WHAT WILL
THE SURFACE TEMPS DO. MODELS ARE INDICATING A SLOW RESPONSE TO THE
WAA AT THE SURFACE BUT I HAVE MY DOUBTS THAT IT WILL BE FAST
ENOUGH TO PREVENT SOME ICING AT THE BEGINNING OF THE EVENT. THERE
ARE A LOT OF FACTORS AT PLAY HERE WHICH MAKES THIS A VERY
DIFFICULT FORECAST. FIRST ALOFT. ALL THE MODELS ARE SHOWING A
STRONG SURGE OF WARMER AIR ENVELOPING MY ENTIRE CWA TODAY. THIS
SHOWS UP QUIET WELL IN THE THERMAL PATTERN AT 850MB AND IN THE LOW
AND MID-LEVEL THICKNESS PATTERNS. I HAVE DECIDED TO CHANGE VERY
LITTLE FROM PREVIOUS THINKING ON PRECIP TYPES. THE THING TO WATCH
WILL BE HOW THE ATMOSPHERE RESPONDS ONCE THE PRECIP BEGINS AND THE
WET BULBING EFFECTS COME INTO PLAY. MODEL SOUNDINGS SHOW A PROFILE
VERY CLOSE TO THE 0 DEGREE LINE WHICH WILL KEEP THE DIFFERENCE
BETWEEN LIQUID OR FROZEN VERY CLOSE. AT THE SURFACE. MODELS DO
SHOW SURFACE TEMPS RISING QUICKLY AS THE PRECIP APPROACHES.
HOWEVER...MY CONCERN IS THAT WITH SUCH COLD DEWPOINTS AT THE
SURFACE...WET BULBING WILL ALLOW FOR A PERIOD OF FREEZING
RAIN...AT LEAST IN OHIO AT THE ONSET OF THE EVENT. OTHER FACTORS
THAT NEED TO BE CONSIDERED ARE THE WIDESPREAD SNOW PACK AND
LOCALIZED EFFECTS...MAINLY SHELTERED AREAS WHERE TEMPS WILL TAKE
LONGER TO RECOVER.

MAIN AREA OF PRECIPITATION WILL EXIT THIS AFTERNOON AS THE SURFACE
FRONT SWINGS INTO CENTRAL PA. THE ONSET OF CAA WILL BE RIGHT
BEHIND THE EXITING FRONT.

&&

.SHORT TERM /TONIGHT THROUGH SATURDAY/...
THERMAL PROFILES QUICKLY BECOME MORE UNSTABLE TONIGHT. COLD
ADVECTION BEGINS IN EARNEST ALOFT AS TWO SHORT WAVE TROUGHS ARE
SET TO CROSS THE AREA THROUGH FRIDAY MORNING. THIS WILL OCCUR
SIMULTANEOUSLY TO THE DRIER AIR COMING IN...HOWEVER THE DENDRITIC
GROWTH LAYER LOOKS TO CRASH TOWARD THE SURFACE TONIGHT IN THE
RIDGES...WELL BEFORE THE MOISTURE PEELS OFF. CONSENSUS SNOW TO
LIQUID RATIOS FROM THE NAM AND GFS VIA BUFKIT SUGGEST AROUND 25 TO
1 BEGIN OVERNIGHT. GIVEN INSTABILITY AND UNIDIRECTIONAL
UPSLOPE...THIS SHOULD RESULT IN VERY EFFICIENT SNOW GROWTH. MODEL
QPF IS GENERALLY ONLY A COUPLE OF TENTHS...AND GIVEN ICE COVER
UPSTREAM ON LAKE ERIE...A TON OF QPF IS VERY UNLIKELY.
HOWEVER...EVEN LIGHT QPF IN THIS CASE IS LIKELY TO ADD UP TO
SEVERAL INCHES OF SNOW. GIVEN THAT AHEAD OF THE SYSTEM ON THURSDAY
THERE COULD BE AN INCH OR SO IN SOME OF THE SHELTERED HIGHER
ELEVATIONS...AND ANOTHER 2 TO 5 SEEM LIKELY IN THE UPSLOPE THROUGH
FRIDAY WITH ADDITIONAL SYNOPTIC HELP VIA TWO ADDITIONAL WAVES
CROSSING THE AREA...3 TO 6 INCH TOTALS SEEM REASONABLE IN THE
RIDGES BY FRIDAY MORNING. WINTER WEATHER ADVISORIES WERE EXPANDED
TO ACCOMMODATE THIS.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
HIGH LEVELS OF UNCERTAINTY IN THE LONG TERM PARTICULARLY WITH THE
SYSTEM THAT COULD AFFECT THE AREA DURING THE SUNDAY/MONDAY TIME
FRAME. FOR NOW...CONSISTENCY WILL BE THE NAME OF THE GAME UNTIL
THE MODELS PROVIDE A BETTER PICTURE. COLD PATTERN WILL CONTINUE
THROUGH THE REMAINDER OF THE LONG TERM.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
VFR OVERNIGHT THROUGH SUNRISE WITH THICKENING MID/HI CLOUDS.
PRECIPITATION RETURNS AFTER 14Z WITH LOW PRESSURE TRACKING TO THE
NORTH. EXPECT A DROP TO MVFR SOON AFTER PRECIP ONSET...WITH IFR
CIGS TO FOLLOW AT MOST TERMINALS DURING THE AFTERNOON AND EVENING.
PRECIP TYPES ARE THE MAIN DIFFICULTY. STILL THINK BEST CHANCES OF
FZRA WILL LIE IN OHIO AND AT FKL/DUJ DURING THE FIRST FEW HOURS OF
PRECIPITATION. CANNOT RULE OUT AT LEAST A BRIEF PERIOD OF FZRA
ANYWHERE SAVE PERHAPS MGW. CHANGOVER TO SNOW WILL OCCUR AFTER 00Z
AS A COLD FRONT SWEEPS THROUGH. WINDS WILL STRENGTHEN OUT OF THE
SOUTH AROUND MIDDAY AND REMAIN GUSTY AS THEY VEER TOWARDS SW/W
WITH TIME. WILL CONTINUE TO MONITOR FOR LLWS POSSIBILITIES.  CL

.OUTLOOK.../THURSDAY NIGHT THROUGH MONDAY/...
RSTRNS ARE LIKELY THRU ERLY FRI AS A CDFNT EXITS. WDSRPD RSTRNS
ARE LIKELY AGAIN WITH ADVNG LOW PRES SUN AND MON.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 10 AM EST
     FRIDAY FOR MDZ001.
OH...FREEZING RAIN ADVISORY FROM 8 AM THIS MORNING TO NOON EST
     TODAY FOR OHZ048-057.
PA...WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 10 AM EST
     FRIDAY FOR PAZ007>009-015-016-023-074-076.
WV...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     FRIDAY FOR WVZ023-041.

&&

$$








000
FXUS61 KPBZ 290549
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1249 AM EST THU JAN 29 2015

.SYNOPSIS...
CROSSING LOW PRESSURE WILL BRING A WINTRY MIX OF PRECIPITATION TO
THE UPPER OHIO REGION TODAY AND SNOW EARLY ON FRIDAY.

&&

.NEAR TERM /THROUGH TODAY/...
OVERNIGHT IN GOOD SHAPE. JUST NEED TO KEEP UP WITH THE TEMPS.

MODELS ARE COMING INTO GOOD AGREEMENT WITH TIMING OF PRECIPITATION
AHEAD OF FRONT AND THE STRONG WAA AS WELL. THE KEY IS WHAT WILL
THE SURFACE TEMPS DO. MODELS ARE INDICATING A SLOW RESPONSE TO THE
WAA AT THE SURFACE BUT I HAVE MY DOUBTS THAT IT WILL BE FAST
ENOUGH TO PREVENT SOME ICING AT THE BEGINNING OF THE EVENT. THERE
ARE A LOT OF FACTORS AT PLAY HERE WHICH MAKES THIS A VERY
DIFFICULT FORECAST. FIRST ALOFT. ALL THE MODELS ARE SHOWING A
STRONG SURGE OF WARMER AIR ENVELOPING MY ENTIRE CWA TODAY. THIS
SHOWS UP QUIET WELL IN THE THERMAL PATTERN AT 850MB AND IN THE LOW
AND MID-LEVEL THICKNESS PATTERNS. I HAVE DECIDED TO CHANGE VERY
LITTLE FROM PREVIOUS THINKING ON PRECIP TYPES. THE THING TO WATCH
WILL BE HOW THE ATMOSPHERE RESPONDS ONCE THE PRECIP BEGINS AND THE
WET BULBING EFFECTS COME INTO PLAY. MODEL SOUNDINGS SHOW A PROFILE
VERY CLOSE TO THE 0 DEGREE LINE WHICH WILL KEEP THE DIFFERENCE
BETWEEN LIQUID OR FROZEN VERY CLOSE. AT THE SURFACE. MODELS DO
SHOW SURFACE TEMPS RISING QUICKLY AS THE PRECIP APPROACHES.
HOWEVER...MY CONCERN IS THAT WITH SUCH COLD DEWPOINTS AT THE
SURFACE...WET BULBING WILL ALLOW FOR A PERIOD OF FREEZING
RAIN...AT LEAST IN OHIO AT THE ONSET OF THE EVENT. OTHER FACTORS
THAT NEED TO BE CONSIDERED ARE THE WIDESPREAD SNOW PACK AND
LOCALIZED EFFECTS...MAINLY SHELTERED AREAS WHERE TEMPS WILL TAKE
LONGER TO RECOVER.

MAIN AREA OF PRECIPITATION WILL EXIT THIS AFTERNOON AS THE SURFACE
FRONT SWINGS INTO CENTRAL PA. THE ONSET OF CAA WILL BE RIGHT
BEHIND THE EXITING FRONT.

&&

.SHORT TERM /TONIGHT THROUGH SATURDAY/...
THERMAL PROFILES QUICKLY BECOME MORE UNSTABLE TONIGHT. COLD
ADVECTION BEGINS IN EARNEST ALOFT AS TWO SHORT WAVE TROUGHS ARE
SET TO CROSS THE AREA THROUGH FRIDAY MORNING. THIS WILL OCCUR
SIMULTANEOUSLY TO THE DRIER AIR COMING IN...HOWEVER THE DENDRITIC
GROWTH LAYER LOOKS TO CRASH TOWARD THE SURFACE TONIGHT IN THE
RIDGES...WELL BEFORE THE MOISTURE PEELS OFF. CONSENSUS SNOW TO
LIQUID RATIOS FROM THE NAM AND GFS VIA BUFKIT SUGGEST AROUND 25 TO
1 BEGIN OVERNIGHT. GIVEN INSTABILITY AND UNIDIRECTIONAL
UPSLOPE...THIS SHOULD RESULT IN VERY EFFICIENT SNOW GROWTH. MODEL
QPF IS GENERALLY ONLY A COUPLE OF TENTHS...AND GIVEN ICE COVER
UPSTREAM ON LAKE ERIE...A TON OF QPF IS VERY UNLIKELY.
HOWEVER...EVEN LIGHT QPF IN THIS CASE IS LIKELY TO ADD UP TO
SEVERAL INCHES OF SNOW. GIVEN THAT AHEAD OF THE SYSTEM ON THURSDAY
THERE COULD BE AN INCH OR SO IN SOME OF THE SHELTERED HIGHER
ELEVATIONS...AND ANOTHER 2 TO 5 SEEM LIKELY IN THE UPSLOPE THROUGH
FRIDAY WITH ADDITIONAL SYNOPTIC HELP VIA TWO ADDITIONAL WAVES
CROSSING THE AREA...3 TO 6 INCH TOTALS SEEM REASONABLE IN THE
RIDGES BY FRIDAY MORNING. WINTER WEATHER ADVISORIES WERE EXPANDED
TO ACCOMMODATE THIS.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
HIGH LEVELS OF UNCERTAINTY IN THE LONG TERM PARTICULARLY WITH THE
SYSTEM THAT COULD AFFECT THE AREA DURING THE SUNDAY/MONDAY TIME
FRAME. FOR NOW...CONSISTENCY WILL BE THE NAME OF THE GAME UNTIL
THE MODELS PROVIDE A BETTER PICTURE. COLD PATTERN WILL CONTINUE
THROUGH THE REMAINDER OF THE LONG TERM.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
VFR OVERNIGHT THROUGH SUNRISE WITH THICKENING MID/HI CLOUDS.
PRECIPITATION RETURNS AFTER 14Z WITH LOW PRESSURE TRACKING TO THE
NORTH. EXPECT A DROP TO MVFR SOON AFTER PRECIP ONSET...WITH IFR
CIGS TO FOLLOW AT MOST TERMINALS DURING THE AFTERNOON AND EVENING.
PRECIP TYPES ARE THE MAIN DIFFICULTY. STILL THINK BEST CHANCES OF
FZRA WILL LIE IN OHIO AND AT FKL/DUJ DURING THE FIRST FEW HOURS OF
PRECIPITATION. CANNOT RULE OUT AT LEAST A BRIEF PERIOD OF FZRA
ANYWHERE SAVE PERHAPS MGW. CHANGOVER TO SNOW WILL OCCUR AFTER 00Z
AS A COLD FRONT SWEEPS THROUGH. WINDS WILL STRENGTHEN OUT OF THE
SOUTH AROUND MIDDAY AND REMAIN GUSTY AS THEY VEER TOWARDS SW/W
WITH TIME. WILL CONTINUE TO MONITOR FOR LLWS POSSIBILITIES.  CL

.OUTLOOK.../THURSDAY NIGHT THROUGH MONDAY/...
RSTRNS ARE LIKELY THRU ERLY FRI AS A CDFNT EXITS. WDSRPD RSTRNS
ARE LIKELY AGAIN WITH ADVNG LOW PRES SUN AND MON.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 10 AM EST
     FRIDAY FOR MDZ001.
OH...FREEZING RAIN ADVISORY FROM 8 AM THIS MORNING TO NOON EST
     TODAY FOR OHZ048-057.
PA...WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 10 AM EST
     FRIDAY FOR PAZ007>009-015-016-023-074-076.
WV...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     FRIDAY FOR WVZ023-041.

&&

$$







000
FXUS61 KPBZ 290537 AAC
AFDPBZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PITTSBURGH PA
1237 AM EST THU JAN 29 2015

.SYNOPSIS...
CROSSING LOW PRESSURE WILL BRING A WINTRY MIX OF PRECIPITATION TO
THE UPPER OHIO REGION TODAY AND SNOW EARLY ON FRIDAY.

&&

.NEAR TERM /THROUGH TODAY/...
OVERNIGHT IN GOOD SHAPE. JUST NEED TO KEEP UP WITH THE TEMPS.

MODELS ARE COMING INTO GOOD AGREEMENT WITH TIMING OF PRECIPITATION
AHEAD OF FRONT AND THE STRONG WAA AS WELL. THE KEY IS WHAT WILL
THE SURFACE TEMPS DO. MODELS ARE INDICATING A SLOW RESPONSE TO THE
WAA AT THE SURFACE BUT I HAVE MY DOUBTS THAT IT WILL BE FAST
ENOUGH TO PREVENT SOME ICING AT THE BEGINNING OF THE EVENT. THERE
ARE A LOT OF FACTORS AT PLAY HERE WHICH MAKES THIS A VERY
DIFFICULT FORECAST. FIRST ALOFT. ALL THE MODELS ARE SHOWING A
STRONG SURGE OF WARMER AIR ENVELOPING MY ENTIRE CWA TODAY. THIS
SHOWS UP QUIET WELL IN THE THERMAL PATTERN AT 850MB AND IN THE LOW
AND MID-LEVEL THICKNESS PATTERNS. I HAVE DECIDED TO CHANGE VERY
LITTLE FROM PREVIOUS THINKING ON PRECIP TYPES. THE THING TO WATCH
WILL BE HOW THE ATMOSPHERE RESPONDS ONCE THE PRECIP BEGINS AND THE
WET BULBING EFFECTS COME INTO PLAY. MODEL SOUNDINGS SHOW A PROFILE
VERY CLOSE TO THE 0 DEGREE LINE WHICH WILL KEEP THE DIFFERENCE
BETWEEN LIQUID OR FROZEN VERY CLOSE. AT THE SURFACE. MODELS DO
SHOW SURFACE TEMPS RISING QUICKLY AS THE PRECIP APPROACHES.
HOWEVER...MY CONCERN IS THAT WITH SUCH COLD DEWPOINTS AT THE
SURFACE...WET BULBING WILL ALLOW FOR A PERIOD OF FREEZING
RAIN...AT LEAST IN OHIO AT THE ONSET OF THE EVENT. OTHER FACTORS
THAT NEED TO BE CONSIDERED ARE THE WIDESPREAD SNOW PACK AND
LOCALIZED EFFECTS...MAINLY SHELTERED AREAS WHERE TEMPS WILL TAKE
LONGER TO RECOVER.

MAIN AREA OF PRECIPITATION WILL EXIT THIS AFTERNOON AS THE SURFACE
FRONT SWINGS INTO CENTRAL PA. THE ONSET OF CAA WILL BE RIGHT
BEHIND THE EXITING FRONT.

&&

.SHORT TERM /TONIGHT THROUGH SATURDAY/...
THERMAL PROFILES QUICKLY BECOME MORE UNSTABLE TONIGHT. COLD
ADVECTION BEGINS IN EARNEST ALOFT AS TWO SHORT WAVE TROUGHS ARE
SET TO CROSS THE AREA THROUGH FRIDAY MORNING. THIS WILL OCCUR
SIMULTANEOUSLY TO THE DRIER AIR COMING IN...HOWEVER THE DENDRITIC
GROWTH LAYER LOOKS TO CRASH TOWARD THE SURFACE TONIGHT IN THE
RIDGES...WELL BEFORE THE MOISTURE PEELS OFF. CONSENSUS SNOW TO
LIQUID RATIOS FROM THE NAM AND GFS VIA BUFKIT SUGGEST AROUND 25 TO
1 BEGIN OVERNIGHT. GIVEN INSTABILITY AND UNIDIRECTIONAL
UPSLOPE...THIS SHOULD RESULT IN VERY EFFICIENT SNOW GROWTH. MODEL
QPF IS GENERALLY ONLY A COUPLE OF TENTHS...AND GIVEN ICE COVER
UPSTREAM ON LAKE ERIE...A TON OF QPF IS VERY UNLIKELY.
HOWEVER...EVEN LIGHT QPF IN THIS CASE IS LIKELY TO ADD UP TO
SEVERAL INCHES OF SNOW. GIVEN THAT AHEAD OF THE SYSTEM ON THURSDAY
THERE COULD BE AN INCH OR SO IN SOME OF THE SHELTERED HIGHER
ELEVATIONS...AND ANOTHER 2 TO 5 SEEM LIKELY IN THE UPSLOPE THROUGH
FRIDAY WITH ADDITIONAL SYNOPTIC HELP VIA TWO ADDITIONAL WAVES
CROSSING THE AREA...3 TO 6 INCH TOTALS SEEM REASONABLE IN THE
RIDGES BY FRIDAY MORNING. WINTER WEATHER ADVISORIES WERE EXPANDED
TO ACCOMMODATE THIS.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
HIGH LEVELS OF UNCERTAINTY IN THE LONG TERM PARTICULARLY WITH THE
SYSTEM THAT COULD AFFECT THE AREA DURING THE SUNDAY/MONDAY TIME
FRAME. FOR NOW...CONSISTENCY WILL BE THE NAME OF THE GAME UNTIL
THE MODELS PROVIDE A BETTER PICTURE. COLD PATTERN WILL CONTINUE
THROUGH THE REMAINDER OF THE LONG TERM.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
HIGH PRESSURE WILL KEEP WINDS LIGHT OVERNIGHT WITH ONLY HIGH
CLOUDS. LOW PRESSURE MOVING OVER THE EASTERN GREAT LAKES WILL
BRING PRECIPITATION TO ALL SITES FROM LATE MORNING TO EARLY
AFTERNOON. PRECIPITATION TYPE WILL BE TRICKY...WITH MGW THE ONLY
SITE WITH HIGH CONFIDENCE THAT WILL NOT HAVE FREEZING RAIN. HAVE
ONLY MENTIONED FZRA EXPLICITLY IN THE TAFS FOR FKL/DUJ FOR A
COUPLE HOUR TIME PERIOD...BUT A BRIEF 1-3 HOUR PERIOD OF FREEZING
RAIN CANNOT BE RULED OUT AT OTHER TERMINALS. SIMILIARLY...WHILE
LOW LEVEL WIND SHEAR IS ONLY INCLUDED IN THE ZZV TAF...CANNOT RULE
OUT A BRIEF 1-3 HOUR PERIOD OF LLWS AT OTHER TERMINALS BEFORE
PRECIPITATION STARTS AND HIGHER WINDS ALOFT ARE ABLE TO MIX OUT AS
GUSTS. OVERALL TREND WILL BE FOR VFR CONDITIONS TO QUICKLY DROP TO
IFR IN PRECIPITATION AS LOWER CEILINGS MOVE IN FROM THE NORTHWEST.

.OUTLOOK.../THURSDAY NIGHT THROUGH MONDAY/...
RSTRNS ARE LIKELY THRU ERLY FRI AS A CDFNT EXITS. WDSRPD RSTRNS
ARE LIKELY AGAIN WITH ADVNG LOW PRES SUN AND MON.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 10 AM EST
     FRIDAY FOR MDZ001.
OH...FREEZING RAIN ADVISORY FROM 8 AM THIS MORNING TO NOON EST
     TODAY FOR OHZ048-057.
PA...WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 10 AM EST
     FRIDAY FOR PAZ007>009-015-016-023-074-076.
WV...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     FRIDAY FOR WVZ023-041.

&&

$$








000
FXUS61 KPBZ 290537 AAC
AFDPBZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PITTSBURGH PA
1237 AM EST THU JAN 29 2015

.SYNOPSIS...
CROSSING LOW PRESSURE WILL BRING A WINTRY MIX OF PRECIPITATION TO
THE UPPER OHIO REGION TODAY AND SNOW EARLY ON FRIDAY.

&&

.NEAR TERM /THROUGH TODAY/...
OVERNIGHT IN GOOD SHAPE. JUST NEED TO KEEP UP WITH THE TEMPS.

MODELS ARE COMING INTO GOOD AGREEMENT WITH TIMING OF PRECIPITATION
AHEAD OF FRONT AND THE STRONG WAA AS WELL. THE KEY IS WHAT WILL
THE SURFACE TEMPS DO. MODELS ARE INDICATING A SLOW RESPONSE TO THE
WAA AT THE SURFACE BUT I HAVE MY DOUBTS THAT IT WILL BE FAST
ENOUGH TO PREVENT SOME ICING AT THE BEGINNING OF THE EVENT. THERE
ARE A LOT OF FACTORS AT PLAY HERE WHICH MAKES THIS A VERY
DIFFICULT FORECAST. FIRST ALOFT. ALL THE MODELS ARE SHOWING A
STRONG SURGE OF WARMER AIR ENVELOPING MY ENTIRE CWA TODAY. THIS
SHOWS UP QUIET WELL IN THE THERMAL PATTERN AT 850MB AND IN THE LOW
AND MID-LEVEL THICKNESS PATTERNS. I HAVE DECIDED TO CHANGE VERY
LITTLE FROM PREVIOUS THINKING ON PRECIP TYPES. THE THING TO WATCH
WILL BE HOW THE ATMOSPHERE RESPONDS ONCE THE PRECIP BEGINS AND THE
WET BULBING EFFECTS COME INTO PLAY. MODEL SOUNDINGS SHOW A PROFILE
VERY CLOSE TO THE 0 DEGREE LINE WHICH WILL KEEP THE DIFFERENCE
BETWEEN LIQUID OR FROZEN VERY CLOSE. AT THE SURFACE. MODELS DO
SHOW SURFACE TEMPS RISING QUICKLY AS THE PRECIP APPROACHES.
HOWEVER...MY CONCERN IS THAT WITH SUCH COLD DEWPOINTS AT THE
SURFACE...WET BULBING WILL ALLOW FOR A PERIOD OF FREEZING
RAIN...AT LEAST IN OHIO AT THE ONSET OF THE EVENT. OTHER FACTORS
THAT NEED TO BE CONSIDERED ARE THE WIDESPREAD SNOW PACK AND
LOCALIZED EFFECTS...MAINLY SHELTERED AREAS WHERE TEMPS WILL TAKE
LONGER TO RECOVER.

MAIN AREA OF PRECIPITATION WILL EXIT THIS AFTERNOON AS THE SURFACE
FRONT SWINGS INTO CENTRAL PA. THE ONSET OF CAA WILL BE RIGHT
BEHIND THE EXITING FRONT.

&&

.SHORT TERM /TONIGHT THROUGH SATURDAY/...
THERMAL PROFILES QUICKLY BECOME MORE UNSTABLE TONIGHT. COLD
ADVECTION BEGINS IN EARNEST ALOFT AS TWO SHORT WAVE TROUGHS ARE
SET TO CROSS THE AREA THROUGH FRIDAY MORNING. THIS WILL OCCUR
SIMULTANEOUSLY TO THE DRIER AIR COMING IN...HOWEVER THE DENDRITIC
GROWTH LAYER LOOKS TO CRASH TOWARD THE SURFACE TONIGHT IN THE
RIDGES...WELL BEFORE THE MOISTURE PEELS OFF. CONSENSUS SNOW TO
LIQUID RATIOS FROM THE NAM AND GFS VIA BUFKIT SUGGEST AROUND 25 TO
1 BEGIN OVERNIGHT. GIVEN INSTABILITY AND UNIDIRECTIONAL
UPSLOPE...THIS SHOULD RESULT IN VERY EFFICIENT SNOW GROWTH. MODEL
QPF IS GENERALLY ONLY A COUPLE OF TENTHS...AND GIVEN ICE COVER
UPSTREAM ON LAKE ERIE...A TON OF QPF IS VERY UNLIKELY.
HOWEVER...EVEN LIGHT QPF IN THIS CASE IS LIKELY TO ADD UP TO
SEVERAL INCHES OF SNOW. GIVEN THAT AHEAD OF THE SYSTEM ON THURSDAY
THERE COULD BE AN INCH OR SO IN SOME OF THE SHELTERED HIGHER
ELEVATIONS...AND ANOTHER 2 TO 5 SEEM LIKELY IN THE UPSLOPE THROUGH
FRIDAY WITH ADDITIONAL SYNOPTIC HELP VIA TWO ADDITIONAL WAVES
CROSSING THE AREA...3 TO 6 INCH TOTALS SEEM REASONABLE IN THE
RIDGES BY FRIDAY MORNING. WINTER WEATHER ADVISORIES WERE EXPANDED
TO ACCOMMODATE THIS.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
HIGH LEVELS OF UNCERTAINTY IN THE LONG TERM PARTICULARLY WITH THE
SYSTEM THAT COULD AFFECT THE AREA DURING THE SUNDAY/MONDAY TIME
FRAME. FOR NOW...CONSISTENCY WILL BE THE NAME OF THE GAME UNTIL
THE MODELS PROVIDE A BETTER PICTURE. COLD PATTERN WILL CONTINUE
THROUGH THE REMAINDER OF THE LONG TERM.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
HIGH PRESSURE WILL KEEP WINDS LIGHT OVERNIGHT WITH ONLY HIGH
CLOUDS. LOW PRESSURE MOVING OVER THE EASTERN GREAT LAKES WILL
BRING PRECIPITATION TO ALL SITES FROM LATE MORNING TO EARLY
AFTERNOON. PRECIPITATION TYPE WILL BE TRICKY...WITH MGW THE ONLY
SITE WITH HIGH CONFIDENCE THAT WILL NOT HAVE FREEZING RAIN. HAVE
ONLY MENTIONED FZRA EXPLICITLY IN THE TAFS FOR FKL/DUJ FOR A
COUPLE HOUR TIME PERIOD...BUT A BRIEF 1-3 HOUR PERIOD OF FREEZING
RAIN CANNOT BE RULED OUT AT OTHER TERMINALS. SIMILIARLY...WHILE
LOW LEVEL WIND SHEAR IS ONLY INCLUDED IN THE ZZV TAF...CANNOT RULE
OUT A BRIEF 1-3 HOUR PERIOD OF LLWS AT OTHER TERMINALS BEFORE
PRECIPITATION STARTS AND HIGHER WINDS ALOFT ARE ABLE TO MIX OUT AS
GUSTS. OVERALL TREND WILL BE FOR VFR CONDITIONS TO QUICKLY DROP TO
IFR IN PRECIPITATION AS LOWER CEILINGS MOVE IN FROM THE NORTHWEST.

.OUTLOOK.../THURSDAY NIGHT THROUGH MONDAY/...
RSTRNS ARE LIKELY THRU ERLY FRI AS A CDFNT EXITS. WDSRPD RSTRNS
ARE LIKELY AGAIN WITH ADVNG LOW PRES SUN AND MON.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 10 AM EST
     FRIDAY FOR MDZ001.
OH...FREEZING RAIN ADVISORY FROM 8 AM THIS MORNING TO NOON EST
     TODAY FOR OHZ048-057.
PA...WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 10 AM EST
     FRIDAY FOR PAZ007>009-015-016-023-074-076.
WV...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
     FRIDAY FOR WVZ023-041.

&&

$$







000
FXUS61 KPBZ 290309
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1009 PM EST WED JAN 28 2015

.SYNOPSIS...
CROSSING LOW PRESSURE WILL BRING A WINTRY MIX OF PRECIPITATION TO
THE UPPER OHIO REGION ON THURSDAY AND SNOW EARLY ON FRIDAY.

&&

.NEAR TERM /THROUGH THURSDAY/...
OVERNIGHT CONDITIONS LOOK TO REMAIN RATHER QUIET AS DECOUPLING HAS
ALREADY OCCURRED RAPIDLY THIS EVENING. SOME TRANSLUCENT CIRRUS
COVER IS ADVANCING SOUTHEASTWARD AT THIS HOUR AHEAD OF THE NEXT
SYSTEM...HOWEVER IT SEEMS TO BE HAVING LITTLE EFFECT ON
TEMPERATURE FALLS AT THE MOMENT. DEWPOINTS FROM WALL TO WALL
ACROSS THE CWA ARE NO HIGHER THAN THE LOWER TEENS...WITH MOST OF
THE NORTHEASTERN HALF OF THE CWA GENERALLY IN THE SINGLE DIGITS.
THIS COMBINED WITH NEW SNOW COVER WILL ALLOW FOR FAIRLY DECENT
BOUNDARY LAYER TEMPERATURE FALLS UNDER THE INVERSION LEVELS EVEN
WHILE FAIRLY RAPID WARM ADVECTION IS LIKELY TO CONTINUE TO OCCUR
ALOFT. TEMPERATURES IN THE ISOLATED VALLEYS OF THE EASTERN
PORTIONS OF THE CWA HAVE ALREADY DROPPED WELL INTO THE SINGLE
DIGITS...AND IT WOULD NOT BE SHOCKING TO SEE AN ISOLATED NEGATIVE
NUMBER OR TWO IN THOSE REACHES...HOWEVER ELSEWHERE...LOWS
GENERALLY IN THE TEENS AND SINGLE DIGITS ABOVE ZERO SEEM MOST
LIKELY.

MODEL 850 MB TEMPERATURES GENERALLY SURPASS 0C OVER THE MAJORITY
OF THE CWA EXCEPT THE NORTHEASTERN FRINGE ON THE CONSENSUS BY 12Z
THURSDAY. THIS IS EVIDENT IN SOUNDINGS ACROSS THE CWA...HOWEVER
THE MODELS LIKELY ARE FAR TOO RAPID MIXING OUT THE INVERSIONS AS
THE ADVECTION KICKS IN ALOFT. LIKEWISE...DYNAMICAL MODEL DEWPOINT
VALUES START OFF FAR TOO MOIST ACROSS THE CWA...AND WILL LIKELY
AGAIN AFFECT THE WET BULB TEMPERATURE PROFILES GOING INTO THE
MORNING ACROSS THE AREA. AS SUCH...THE FORECAST WAS ADJUSTED
TOWARD THE COLDER END OF GUIDANCE THROUGH THE NIGHT...EVEN WITH
EASTWARD ADVANCING CLOUDS AND WARM ADVECTION ALOFT BUILDING IN.

THE REAL FUN BEGINS SHORTLY AFTER SUNRISE IN OHIO...AND SPREADS
EASTWARD ACROSS THE CWA THROUGH THE REST OF THE MORNING AND EARLY
AFTERNOON. A FAIRLY POTENT 500 MB SHORT WAVE TROUGH FIRMLY
ENTRENCHED IN THE LEFT EXIT OF A 120 KT JET STREAK BLISTERS
THROUGH THE AREA ON THURSDAY. AN UNSEASONABLY STRONG LLJ DEVELOPS
AHEAD OF THIS...WITH LOW LEVEL CONVERGENCE MAXIMIZED ON ITS
NOSE...WHICH COINCIDENTALLY RUNS ALONG THE OHIO VALLEY THROUGH
EARLY AFTERNOON ON THURSDAY. THIS POINTS TOWARD WARM ADVECTION
BEING VERY EFFICIENT ACROSS THE AREA BY THAT JUNCTURE...AND SHOULD
ALLOW MUCH OF THE AREA TO RUN UP ABOVE FREEZING ON THURSDAY.
HOWEVER...BEFORE THAT OCCURS...COLD AIR WILL NEED TO BE
DISPLACED...AND WET BULB EFFECTS WILL NEED TO BE OVERCOME. IN THE
INTERIM...THIS MEANS A PERIOD OF FREEZING RAIN WILL BE POSSIBLE AS
WARM AIR WORKS IN OFF THE SURFACE BEFORE IN THE BOUNDARY LAYER.

MODEL SOUNDINGS ACROSS OHIO SUGGEST THE BEST CHANCE OF FREEZING
RAIN WILL BE OVER OUR FAR WESTERN COUNTIES AS THE PRECIPITATION
ONSET WILL BE CLOSEST TO SUNRISE THERE. AS A RESULT...OVERNIGHT
INVERSIONS ARE UNLIKELY TO HAVE BEEN WIPED OUT BY THAT
JUNCTURE...RESULTING IN A PERIOD OF ICING BEING LIKELY. FARTHER
EAST...THE DETAILS GET A LITTLE BIT MURKY.

THE RACE BETWEEN ONSET...WET BULBING...BOUNDARY LAYER MIX
OUT...AND WARM ADVECTION WILL BE A CLOSE RACE VIRTUALLY
EVERYWHERE. AT THE MOMENT...IT SEEMS AT LEAST FOR A TIME...THAT
NORTH OF THE TURNPIKE...AT LEAST A PERIOD OF SNOW/ICE WILL BE
POSSIBLE...WITH REALLY ONLY ACCUMULATING SNOW LIKELY BY AFTERNOON
ALONG I-80 AND IN THE RIDGES OF PA AND MD. ELSEWHERE...A LATE
ONSET SHOULD ALLOW FOR GROUND TEMPERATURES TO RISE ENOUGH SUCH
THAT PLAIN RAIN WILL DOMINATE AND PRECLUDE MUCH IN THE WAY OF
ICING. FRIES

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
WHILE WARM ADVECTION LOOKS RAPID AHEAD OF THE FIRST WAVE ON
THURSDAY AFTERNOON...THERMAL PROFILES QUICKLY BECOME MUCH MORE
UNSTABLE BY THURSDAY EVENING. COLD ADVECTION BEGINS IN EARNEST
ALOFT AS TWO MORE SHORT WAVE TROUGHS ARE SET TO CROSS THE AREA
THROUGH FRIDAY MORNING. THIS WILL OCCUR SIMULTANEOUSLY TO THE
SOME DRIER AIR COMING IN...HOWEVER THE DENDRITIC GROWTH LAYER
LOOKS TO ABSOLUTELY CRASH TOWARD THE SURFACE ON THURSDAY NIGHT IN
THE RIDGES...WELL BEFORE THE MOISTURE PEELS OFF. CONSENSUS SNOW TO
LIQUID RATIOS FROM THE NAM AND GFS VIA BUFKIT SUGGEST AROUND 25 TO
1 BEGIN LIKELY OVERNIGHT. GIVEN INSTABILITY AND UNIDIRECTIONAL
UPSLOPE...THIS SHOULD RESULT IN VERY EFFICIENT SNOW GROWTH. MODEL
QPF IS GENERALLY ONLY A COUPLE OF TENTHS...AND GIVEN ICE COVER
UPSTREAM ON LAKE ERIE...A TON OF QPF IS VERY UNLIKELY.
HOWEVER...EVEN LIGHT QPF IN THIS CASE IS LIKELY TO ADD UP TO
SEVERAL INCHES OF SNOW. GIVEN THAT AHEAD OF THE SYSTEM ON THURSDAY
THERE COULD BE AN INCH OR SO IN SOME OF THE SHELTERED HIGHER
ELEVATIONS...AND ANOTHER 2 TO 5 SEEM LIKELY IN THE UPSLOPE THROUGH
FRIDAY WITH ADDITIONAL SYNOPTIC HELP VIA TWO ADDITIONAL WAVES
CROSSING THE AREA...3 TO 6 INCH TOTALS SEEM REASONABLE IN THE
RIDGES BY FRIDAY MORNING. WINTER WEATHER ADVISORIES WERE EXPANDED
TO ACCOMMODATE THIS. FRIES

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
COLD ARCTIC HIGH SHIFTS EAST INTO SATURDAY WITH SNOW SHOWERS IN
NORTHWEST FLOW FRIDAY ENDING FRIDAY NIGHT. WITH 850MB TEMPS
PROGGED NEAR -20C BY 00Z SATURDAY TEMPERATURES FRIDAY WILL BE
STEADY OR FALL. CLOUDS SHOULD BEGIN TO BREAK AS CENTER OF HIGH
MOVES INTO REGION FRIDAY NIGHT...WITH LOWS BELOW ZERO NORTH AND
SINGLE DIGITS SOUTH. IF CONDITIONS GO CLEAR AND CALM FRIDAY NIGHT
MAY GO BELOW ZERO ACROSS THE ENTIRE REGION. TEMPERATURES RECOVER
TO MAINLY THE 20S SATURDAY. A SIGNIFICANT STORM LOOKS POSSIBLE FOR
SUNDAY INTO EARLY MONDAY BEFORE ARCTIC AIR RETURNS TO START THE
WORK WEEK.

&&

.AVIATION /03Z THURSDAY THROUGH MONDAY/...
HIGH PRESSURE WILL KEEP WINDS LIGHT OVERNIGHT WITH ONLY HIGH
CLOUDS. LOW PRESSURE MOVING OVER THE EASTERN GREAT LAKES WILL
BRING PRECIPITATION TO ALL SITES FROM LATE MORNING TO EARLY
AFTERNOON. PRECIPITATION TYPE WILL BE TRICKY...WITH MGW THE ONLY
SITE WITH HIGH CONFIDENCE THAT WILL NOT HAVE FREEZING RAIN. HAVE
ONLY MENTIONED FZRA EXPLICITLY IN THE TAFS FOR FKL/DUJ FOR A
COUPLE HOUR TIME PERIOD...BUT A BRIEF 1-3 HOUR PERIOD OF FREEZING
RAIN CANNOT BE RULED OUT AT OTHER TERMINALS. SIMILIARLY...WHILE
LOW LEVEL WIND SHEAR IS ONLY INCLUDED IN THE ZZV TAF...CANNOT RULE
OUT A BRIEF 1-3 HOUR PERIOD OF LLWS AT OTHER TERMINALS BEFORE
PRECIPITATION STARTS AND HIGHER WINDS ALOFT ARE ABLE TO MIX OUT AS
GUSTS. OVERALL TREND WILL BE FOR VFR CONDITIONS TO QUICKLY DROP TO
IFR IN PRECIPITATION AS LOWER CEILINGS MOVE IN FROM THE NORTHWEST.

.OUTLOOK.../THURSDAY NIGHT THROUGH MONDAY/...
RSTRNS ARE LIKELY THRU ERLY FRI AS A CDFNT EXITS. WDSRPD RSTRNS
ARE LIKELY AGAIN WITH ADVNG LOW PRES SUN AND MON.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY FROM 11 AM THURSDAY TO 10 AM EST
     FRIDAY FOR MDZ001.
OH...FREEZING RAIN ADVISORY FROM 8 AM TO NOON EST THURSDAY FOR
     OHZ048-057.
PA...WINTER WEATHER ADVISORY FROM 11 AM THURSDAY TO 10 AM EST
     FRIDAY FOR PAZ007>009-015-016-023-074-076.
WV...WINTER WEATHER ADVISORY FROM 7 PM THURSDAY TO 10 AM EST FRIDAY
     FOR WVZ023-041.

&&

$$







000
FXUS61 KPBZ 290309
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1009 PM EST WED JAN 28 2015

.SYNOPSIS...
CROSSING LOW PRESSURE WILL BRING A WINTRY MIX OF PRECIPITATION TO
THE UPPER OHIO REGION ON THURSDAY AND SNOW EARLY ON FRIDAY.

&&

.NEAR TERM /THROUGH THURSDAY/...
OVERNIGHT CONDITIONS LOOK TO REMAIN RATHER QUIET AS DECOUPLING HAS
ALREADY OCCURRED RAPIDLY THIS EVENING. SOME TRANSLUCENT CIRRUS
COVER IS ADVANCING SOUTHEASTWARD AT THIS HOUR AHEAD OF THE NEXT
SYSTEM...HOWEVER IT SEEMS TO BE HAVING LITTLE EFFECT ON
TEMPERATURE FALLS AT THE MOMENT. DEWPOINTS FROM WALL TO WALL
ACROSS THE CWA ARE NO HIGHER THAN THE LOWER TEENS...WITH MOST OF
THE NORTHEASTERN HALF OF THE CWA GENERALLY IN THE SINGLE DIGITS.
THIS COMBINED WITH NEW SNOW COVER WILL ALLOW FOR FAIRLY DECENT
BOUNDARY LAYER TEMPERATURE FALLS UNDER THE INVERSION LEVELS EVEN
WHILE FAIRLY RAPID WARM ADVECTION IS LIKELY TO CONTINUE TO OCCUR
ALOFT. TEMPERATURES IN THE ISOLATED VALLEYS OF THE EASTERN
PORTIONS OF THE CWA HAVE ALREADY DROPPED WELL INTO THE SINGLE
DIGITS...AND IT WOULD NOT BE SHOCKING TO SEE AN ISOLATED NEGATIVE
NUMBER OR TWO IN THOSE REACHES...HOWEVER ELSEWHERE...LOWS
GENERALLY IN THE TEENS AND SINGLE DIGITS ABOVE ZERO SEEM MOST
LIKELY.

MODEL 850 MB TEMPERATURES GENERALLY SURPASS 0C OVER THE MAJORITY
OF THE CWA EXCEPT THE NORTHEASTERN FRINGE ON THE CONSENSUS BY 12Z
THURSDAY. THIS IS EVIDENT IN SOUNDINGS ACROSS THE CWA...HOWEVER
THE MODELS LIKELY ARE FAR TOO RAPID MIXING OUT THE INVERSIONS AS
THE ADVECTION KICKS IN ALOFT. LIKEWISE...DYNAMICAL MODEL DEWPOINT
VALUES START OFF FAR TOO MOIST ACROSS THE CWA...AND WILL LIKELY
AGAIN AFFECT THE WET BULB TEMPERATURE PROFILES GOING INTO THE
MORNING ACROSS THE AREA. AS SUCH...THE FORECAST WAS ADJUSTED
TOWARD THE COLDER END OF GUIDANCE THROUGH THE NIGHT...EVEN WITH
EASTWARD ADVANCING CLOUDS AND WARM ADVECTION ALOFT BUILDING IN.

THE REAL FUN BEGINS SHORTLY AFTER SUNRISE IN OHIO...AND SPREADS
EASTWARD ACROSS THE CWA THROUGH THE REST OF THE MORNING AND EARLY
AFTERNOON. A FAIRLY POTENT 500 MB SHORT WAVE TROUGH FIRMLY
ENTRENCHED IN THE LEFT EXIT OF A 120 KT JET STREAK BLISTERS
THROUGH THE AREA ON THURSDAY. AN UNSEASONABLY STRONG LLJ DEVELOPS
AHEAD OF THIS...WITH LOW LEVEL CONVERGENCE MAXIMIZED ON ITS
NOSE...WHICH COINCIDENTALLY RUNS ALONG THE OHIO VALLEY THROUGH
EARLY AFTERNOON ON THURSDAY. THIS POINTS TOWARD WARM ADVECTION
BEING VERY EFFICIENT ACROSS THE AREA BY THAT JUNCTURE...AND SHOULD
ALLOW MUCH OF THE AREA TO RUN UP ABOVE FREEZING ON THURSDAY.
HOWEVER...BEFORE THAT OCCURS...COLD AIR WILL NEED TO BE
DISPLACED...AND WET BULB EFFECTS WILL NEED TO BE OVERCOME. IN THE
INTERIM...THIS MEANS A PERIOD OF FREEZING RAIN WILL BE POSSIBLE AS
WARM AIR WORKS IN OFF THE SURFACE BEFORE IN THE BOUNDARY LAYER.

MODEL SOUNDINGS ACROSS OHIO SUGGEST THE BEST CHANCE OF FREEZING
RAIN WILL BE OVER OUR FAR WESTERN COUNTIES AS THE PRECIPITATION
ONSET WILL BE CLOSEST TO SUNRISE THERE. AS A RESULT...OVERNIGHT
INVERSIONS ARE UNLIKELY TO HAVE BEEN WIPED OUT BY THAT
JUNCTURE...RESULTING IN A PERIOD OF ICING BEING LIKELY. FARTHER
EAST...THE DETAILS GET A LITTLE BIT MURKY.

THE RACE BETWEEN ONSET...WET BULBING...BOUNDARY LAYER MIX
OUT...AND WARM ADVECTION WILL BE A CLOSE RACE VIRTUALLY
EVERYWHERE. AT THE MOMENT...IT SEEMS AT LEAST FOR A TIME...THAT
NORTH OF THE TURNPIKE...AT LEAST A PERIOD OF SNOW/ICE WILL BE
POSSIBLE...WITH REALLY ONLY ACCUMULATING SNOW LIKELY BY AFTERNOON
ALONG I-80 AND IN THE RIDGES OF PA AND MD. ELSEWHERE...A LATE
ONSET SHOULD ALLOW FOR GROUND TEMPERATURES TO RISE ENOUGH SUCH
THAT PLAIN RAIN WILL DOMINATE AND PRECLUDE MUCH IN THE WAY OF
ICING. FRIES

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
WHILE WARM ADVECTION LOOKS RAPID AHEAD OF THE FIRST WAVE ON
THURSDAY AFTERNOON...THERMAL PROFILES QUICKLY BECOME MUCH MORE
UNSTABLE BY THURSDAY EVENING. COLD ADVECTION BEGINS IN EARNEST
ALOFT AS TWO MORE SHORT WAVE TROUGHS ARE SET TO CROSS THE AREA
THROUGH FRIDAY MORNING. THIS WILL OCCUR SIMULTANEOUSLY TO THE
SOME DRIER AIR COMING IN...HOWEVER THE DENDRITIC GROWTH LAYER
LOOKS TO ABSOLUTELY CRASH TOWARD THE SURFACE ON THURSDAY NIGHT IN
THE RIDGES...WELL BEFORE THE MOISTURE PEELS OFF. CONSENSUS SNOW TO
LIQUID RATIOS FROM THE NAM AND GFS VIA BUFKIT SUGGEST AROUND 25 TO
1 BEGIN LIKELY OVERNIGHT. GIVEN INSTABILITY AND UNIDIRECTIONAL
UPSLOPE...THIS SHOULD RESULT IN VERY EFFICIENT SNOW GROWTH. MODEL
QPF IS GENERALLY ONLY A COUPLE OF TENTHS...AND GIVEN ICE COVER
UPSTREAM ON LAKE ERIE...A TON OF QPF IS VERY UNLIKELY.
HOWEVER...EVEN LIGHT QPF IN THIS CASE IS LIKELY TO ADD UP TO
SEVERAL INCHES OF SNOW. GIVEN THAT AHEAD OF THE SYSTEM ON THURSDAY
THERE COULD BE AN INCH OR SO IN SOME OF THE SHELTERED HIGHER
ELEVATIONS...AND ANOTHER 2 TO 5 SEEM LIKELY IN THE UPSLOPE THROUGH
FRIDAY WITH ADDITIONAL SYNOPTIC HELP VIA TWO ADDITIONAL WAVES
CROSSING THE AREA...3 TO 6 INCH TOTALS SEEM REASONABLE IN THE
RIDGES BY FRIDAY MORNING. WINTER WEATHER ADVISORIES WERE EXPANDED
TO ACCOMMODATE THIS. FRIES

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
COLD ARCTIC HIGH SHIFTS EAST INTO SATURDAY WITH SNOW SHOWERS IN
NORTHWEST FLOW FRIDAY ENDING FRIDAY NIGHT. WITH 850MB TEMPS
PROGGED NEAR -20C BY 00Z SATURDAY TEMPERATURES FRIDAY WILL BE
STEADY OR FALL. CLOUDS SHOULD BEGIN TO BREAK AS CENTER OF HIGH
MOVES INTO REGION FRIDAY NIGHT...WITH LOWS BELOW ZERO NORTH AND
SINGLE DIGITS SOUTH. IF CONDITIONS GO CLEAR AND CALM FRIDAY NIGHT
MAY GO BELOW ZERO ACROSS THE ENTIRE REGION. TEMPERATURES RECOVER
TO MAINLY THE 20S SATURDAY. A SIGNIFICANT STORM LOOKS POSSIBLE FOR
SUNDAY INTO EARLY MONDAY BEFORE ARCTIC AIR RETURNS TO START THE
WORK WEEK.

&&

.AVIATION /03Z THURSDAY THROUGH MONDAY/...
HIGH PRESSURE WILL KEEP WINDS LIGHT OVERNIGHT WITH ONLY HIGH
CLOUDS. LOW PRESSURE MOVING OVER THE EASTERN GREAT LAKES WILL
BRING PRECIPITATION TO ALL SITES FROM LATE MORNING TO EARLY
AFTERNOON. PRECIPITATION TYPE WILL BE TRICKY...WITH MGW THE ONLY
SITE WITH HIGH CONFIDENCE THAT WILL NOT HAVE FREEZING RAIN. HAVE
ONLY MENTIONED FZRA EXPLICITLY IN THE TAFS FOR FKL/DUJ FOR A
COUPLE HOUR TIME PERIOD...BUT A BRIEF 1-3 HOUR PERIOD OF FREEZING
RAIN CANNOT BE RULED OUT AT OTHER TERMINALS. SIMILIARLY...WHILE
LOW LEVEL WIND SHEAR IS ONLY INCLUDED IN THE ZZV TAF...CANNOT RULE
OUT A BRIEF 1-3 HOUR PERIOD OF LLWS AT OTHER TERMINALS BEFORE
PRECIPITATION STARTS AND HIGHER WINDS ALOFT ARE ABLE TO MIX OUT AS
GUSTS. OVERALL TREND WILL BE FOR VFR CONDITIONS TO QUICKLY DROP TO
IFR IN PRECIPITATION AS LOWER CEILINGS MOVE IN FROM THE NORTHWEST.

.OUTLOOK.../THURSDAY NIGHT THROUGH MONDAY/...
RSTRNS ARE LIKELY THRU ERLY FRI AS A CDFNT EXITS. WDSRPD RSTRNS
ARE LIKELY AGAIN WITH ADVNG LOW PRES SUN AND MON.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY FROM 11 AM THURSDAY TO 10 AM EST
     FRIDAY FOR MDZ001.
OH...FREEZING RAIN ADVISORY FROM 8 AM TO NOON EST THURSDAY FOR
     OHZ048-057.
PA...WINTER WEATHER ADVISORY FROM 11 AM THURSDAY TO 10 AM EST
     FRIDAY FOR PAZ007>009-015-016-023-074-076.
WV...WINTER WEATHER ADVISORY FROM 7 PM THURSDAY TO 10 AM EST FRIDAY
     FOR WVZ023-041.

&&

$$








000
FXUS61 KPBZ 290137
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
836 PM EST WED JAN 28 2015

.SYNOPSIS...
CROSSING LOW PRESSURE WILL BRING A WINTRY MIX OF PRECIPITATION TO
THE UPPER OHIO REGION ON THURSDAY AND SNOW EARLY ON FRIDAY.

&&

.NEAR TERM /THROUGH THURSDAY/...
OVERNIGHT CONDITIONS LOOK TO REMAIN RATHER QUIET AS DECOUPLING HAS
ALREADY OCCURRED RAPIDLY THIS EVENING. SOME TRANSLUCENT CIRRUS
COVER IS ADVANCING SOUTHEASTWARD AT THIS HOUR AHEAD OF THE NEXT
SYSTEM...HOWEVER IT SEEMS TO BE HAVING LITTLE EFFECT ON
TEMPERATURE FALLS AT THE MOMENT. DEWPOINTS FROM WALL TO WALL
ACROSS THE CWA ARE NO HIGHER THAN THE LOWER TEENS...WITH MOST OF
THE NORTHEASTERN HALF OF THE CWA GENERALLY IN THE SINGLE DIGITS.
THIS COMBINED WITH NEW SNOW COVER WILL ALLOW FOR FAIRLY DECENT
BOUNDARY LAYER TEMPERATURE FALLS UNDER THE INVERSION LEVELS EVEN
WHILE FAIRLY RAPID WARM ADVECTION IS LIKELY TO CONTINUE TO OCCUR
ALOFT.

MODEL 850 MB TEMPERATURES GENERALLY SURPASS 0C OVER THE MAJORITY
OF THE CWA EXCEPT THE NORTHEASTERN FRINGE ON THE CONSENSUS BY 12Z
THURSDAY. THIS IS EVIDENT IN SOUNDINGS ACROSS THE CWA...HOWEVER
THE MODELS LIKELY ARE FAR TOO RAPID MIXING OUT THE INVERSIONS AS
THE ADVECTION KICKS IN ALOFT. LIKEWISE...DYNAMICAL MODEL DEWPOINT
VALUES START OFF FAR TOO MOIST ACROSS THE CWA...AND WILL LIKELY
AGAIN AFFECT THE WET BULB TEMPERATURE PROFILES GOING INTO THE
MORNING ACROSS THE AREA. AS SUCH...THE FORECAST WAS ADJUSTED
TOWARD THE COLDER END OF GUIDANCE THROUGH THE NIGHT...EVEN WITH
EASTWARD ADVANCING CLOUDS AND WARM ADVECTION ALOFT BUILDING IN.

THE REAL FUN BEGINS SHORTLY AFTER SUNRISE IN OHIO...AND SPREADS
EASTWARD ACROSS THE CWA THROUGH THE REST OF THE MORNING AND EARLY
AFTERNOON. A FAIRLY POTENT 500 MB SHORT WAVE TROUGH FIRMLY
ENTRENCHED IN THE LEFT EXIT OF A 120 KT JET STREAK BLISTERS
THROUGH THE AREA ON THURSDAY. AN UNSEASONABLY STRONG LLJ DEVELOPS
AHEAD OF THIS...WITH LOW LEVEL CONVERGENCE MAXIMIZED ON ITS
NOSE...WHICH COINCIDENTALLY RUNS ALONG THE OHIO VALLEY THROUGH
EARLY AFTERNOON ON THURSDAY. THIS POINTS TOWARD WARM ADVECTION
BEING VERY EFFICIENT ACROSS THE AREA BY THAT JUNCTURE...AND SHOULD
ALLOW MUCH OF THE AREA TO RUN UP ABOVE FREEZING ON THURSDAY.
HOWEVER...BEFORE THAT OCCURS...COLD AIR WILL NEED TO BE
DISPLACED...AND WET BULB EFFECTS WILL NEED TO BE OVERCOME. IN THE
INTERIM...THIS MEANS A PERIOD OF FREEZING RAIN WILL BE POSSIBLE AS
WARM AIR WORKS IN OFF THE SURFACE BEFORE IN THE BOUNDARY LAYER.

MODEL SOUNDINGS ACROSS OHIO SUGGEST THE BEST CHANCE OF FREEZING
RAIN WILL BE OVER OUR FAR WESTERN COUNTIES AS THE PRECIPITATION
ONSET WILL BE CLOSEST TO SUNRISE THERE. AS A RESULT...OVERNIGHT
INVERSIONS ARE UNLIKELY TO HAVE BEEN WIPED OUT BY THAT
JUNCTURE...RESULTING IN A PERIOD OF ICING BEING LIKELY. FARTHER
EAST...THE DETAILS GET A LITTLE BIT MURKY.

THE RACE BETWEEN ONSET...WET BULBING...BOUNDARY LAYER MIX
OUT...AND WARM ADVECTION WILL BE A CLOSE RACE VIRTUALLY
EVERYWHERE. AT THE MOMENT...IT SEEMS AT LEAST FOR A TIME...THAT
NORTH OF THE TURNPIKE...AT LEAST A PERIOD OF SNOW/ICE WILL BE
POSSIBLE...WITH REALLY ONLY ACCUMULATING SNOW LIKELY BY AFTERNOON
ALONG I-80 AND IN THE RIDGES OF PA AND MD. ELSEWHERE...A LATE
ONSET SHOULD ALLOW FOR GROUND TEMPERATURES TO RISE ENOUGH SUCH
THAT PLAIN RAIN WILL DOMINATE AND PRECLUDE MUCH IN THE WAY OF
ICING. FRIES

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
WHILE WARM ADVECTION LOOKS RAPID AHEAD OF THE FIRST WAVE ON
THURSDAY AFTERNOON...THERMAL PROFILES QUICKLY BECOME MUCH MORE
UNSTABLE BY THURSDAY EVENING. COLD ADVECTION BEGINS IN EARNEST
ALOFT AS TWO MORE SHORT WAVE TROUGHS ARE SET TO CROSS THE AREA
THROUGH FRIDAY MORNING. THIS WILL OCCUR SIMULTANEOUSLY TO THE
SOME DRIER AIR COMING IN...HOWEVER THE DENDRITIC GROWTH LAYER
LOOKS TO ABSOLUTELY CRASH TOWARD THE SURFACE ON THURSDAY NIGHT IN
THE RIDGES...WELL BEFORE THE MOISTURE PEELS OFF. CONSENSUS SNOW TO
LIQUID RATIOS FROM THE NAM AND GFS VIA BUFKIT SUGGEST AROUND 25 TO
1 BEGIN LIKELY OVERNIGHT. GIVEN INSTABILITY AND UNIDIRECTIONAL
UPSLOPE...THIS SHOULD RESULT IN VERY EFFICIENT SNOW GROWTH. MODEL
QPF IS GENERALLY ONLY A COUPLE OF TENTHS...AND GIVEN ICE COVER
UPSTREAM ON LAKE ERIE...A TON OF QPF IS VERY UNLIKELY.
HOWEVER...EVEN LIGHT QPF IN THIS CASE IS LIKELY TO ADD UP TO
SEVERAL INCHES OF SNOW. GIVEN THAT AHEAD OF THE SYSTEM ON THURSDAY
THERE COULD BE AN INCH OR SO IN SOME OF THE SHELTERED HIGHER
ELEVATIONS...AND ANOTHER 2 TO 5 SEEM LIKELY IN THE UPSLOPE THROUGH
FRIDAY WITH ADDITIONAL SYNOPTIC HELP VIA TWO ADDITIONAL WAVES
CROSSING THE AREA...3 TO 6 INCH TOTALS SEEM REASONABLE IN THE
RIDGES BY FRIDAY MORNING. WINTER WEATHER ADVISORIES WERE EXPANDED
TO ACCOMMODATE THIS. FRIES

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
COLD ARCTIC HIGH SHIFTS EAST INTO SATURDAY WITH SNOW SHOWERS IN
NORTHWEST FLOW FRIDAY ENDING FRIDAY NIGHT. WITH 850MB TEMPS
PROGGED NEAR -20C BY 00Z SATURDAY TEMPERATURES FRIDAY WILL BE
STEADY OR FALL. CLOUDS SHOULD BEGIN TO BREAK AS CENTER OF HIGH
MOVES INTO REGION FRIDAY NIGHT...WITH LOWS BELOW ZERO NORTH AND
SINGLE DIGITS SOUTH. IF CONDITIONS GO CLEAR AND CALM FRIDAY NIGHT
MAY GO BELOW ZERO ACROSS THE ENTIRE REGION. TEMPERATURES RECOVER
TO MAINLY THE 20S SATURDAY. A SIGNIFICANT STORM LOOKS POSSIBLE FOR
SUNDAY INTO EARLY MONDAY BEFORE ARCTIC AIR RETURNS TO START THE
WORK WEEK.

&&

.AVIATION /01Z THURSDAY THROUGH MONDAY/...
HIGH PRESSURE WILL KEEP WINDS LIGHT OVERNIGHT WITH ONLY HIGH
CLOUDS. LOW PRESSURE MOVING OVER THE EASTERN GREAT LAKES WILL
BRING PRECIPITATION TO ALL SITES FROM LATE MORNING TO EARLY
AFTERNOON. PRECIPITATION TYPE WILL BE TRICKY...WITH MGW THE ONLY
SITE WITH HIGH CONFIDENCE THAT WILL NOT HAVE FREEZING RAIN. HAVE
ONLY MENTIONED FZRA EXPLICITLY IN THE TAFS FOR FKL/DUJ FOR A
COUPLE HOUR TIME PERIOD...BUT A BRIEF 1-3 HOUR PERIOD OF FREEZING
RAIN CANNOT BE RULED OUT AT OTHER TERMINALS. SIMILIARLY...WHILE
LOW LEVEL WIND SHEAR IS ONLY INCLUDED IN THE ZZV TAF...CANNOT RULE
OUT A BRIEF 1-3 HOUR PERIOD OF LLWS AT OTHER TERMINALS BEFORE
PRECIPITATION STARTS AND HIGHER WINDS ALOFT ARE ABLE TO MIX OUT AS
GUSTS. OVERALL TREND WILL BE FOR VFR CONDITIONS TO QUICKLY DROP TO
IFR IN PRECIPITATION AS LOWER CEILINGS MOVE IN FROM THE NORTHWEST.

.OUTLOOK.../THURSDAY NIGHT THROUGH MONDAY/...
RSTRNS ARE LIKELY THRU ERLY FRI AS A CDFNT EXITS. WDSRPD RSTRNS
ARE LIKELY AGAIN WITH ADVNG LOW PRES SUN AND MON.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY FROM 11 AM THURSDAY TO 10 AM EST
     FRIDAY FOR MDZ001.
OH...FREEZING RAIN ADVISORY FROM 8 AM TO NOON EST THURSDAY FOR
     OHZ048-057.
PA...WINTER WEATHER ADVISORY FROM 11 AM THURSDAY TO 10 AM EST
     FRIDAY FOR PAZ007>009-015-016-023-074-076.
WV...WINTER WEATHER ADVISORY FROM 7 PM THURSDAY TO 10 AM EST FRIDAY
     FOR WVZ023-041.

&&

$$







000
FXUS61 KPBZ 290137
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
836 PM EST WED JAN 28 2015

.SYNOPSIS...
CROSSING LOW PRESSURE WILL BRING A WINTRY MIX OF PRECIPITATION TO
THE UPPER OHIO REGION ON THURSDAY AND SNOW EARLY ON FRIDAY.

&&

.NEAR TERM /THROUGH THURSDAY/...
OVERNIGHT CONDITIONS LOOK TO REMAIN RATHER QUIET AS DECOUPLING HAS
ALREADY OCCURRED RAPIDLY THIS EVENING. SOME TRANSLUCENT CIRRUS
COVER IS ADVANCING SOUTHEASTWARD AT THIS HOUR AHEAD OF THE NEXT
SYSTEM...HOWEVER IT SEEMS TO BE HAVING LITTLE EFFECT ON
TEMPERATURE FALLS AT THE MOMENT. DEWPOINTS FROM WALL TO WALL
ACROSS THE CWA ARE NO HIGHER THAN THE LOWER TEENS...WITH MOST OF
THE NORTHEASTERN HALF OF THE CWA GENERALLY IN THE SINGLE DIGITS.
THIS COMBINED WITH NEW SNOW COVER WILL ALLOW FOR FAIRLY DECENT
BOUNDARY LAYER TEMPERATURE FALLS UNDER THE INVERSION LEVELS EVEN
WHILE FAIRLY RAPID WARM ADVECTION IS LIKELY TO CONTINUE TO OCCUR
ALOFT.

MODEL 850 MB TEMPERATURES GENERALLY SURPASS 0C OVER THE MAJORITY
OF THE CWA EXCEPT THE NORTHEASTERN FRINGE ON THE CONSENSUS BY 12Z
THURSDAY. THIS IS EVIDENT IN SOUNDINGS ACROSS THE CWA...HOWEVER
THE MODELS LIKELY ARE FAR TOO RAPID MIXING OUT THE INVERSIONS AS
THE ADVECTION KICKS IN ALOFT. LIKEWISE...DYNAMICAL MODEL DEWPOINT
VALUES START OFF FAR TOO MOIST ACROSS THE CWA...AND WILL LIKELY
AGAIN AFFECT THE WET BULB TEMPERATURE PROFILES GOING INTO THE
MORNING ACROSS THE AREA. AS SUCH...THE FORECAST WAS ADJUSTED
TOWARD THE COLDER END OF GUIDANCE THROUGH THE NIGHT...EVEN WITH
EASTWARD ADVANCING CLOUDS AND WARM ADVECTION ALOFT BUILDING IN.

THE REAL FUN BEGINS SHORTLY AFTER SUNRISE IN OHIO...AND SPREADS
EASTWARD ACROSS THE CWA THROUGH THE REST OF THE MORNING AND EARLY
AFTERNOON. A FAIRLY POTENT 500 MB SHORT WAVE TROUGH FIRMLY
ENTRENCHED IN THE LEFT EXIT OF A 120 KT JET STREAK BLISTERS
THROUGH THE AREA ON THURSDAY. AN UNSEASONABLY STRONG LLJ DEVELOPS
AHEAD OF THIS...WITH LOW LEVEL CONVERGENCE MAXIMIZED ON ITS
NOSE...WHICH COINCIDENTALLY RUNS ALONG THE OHIO VALLEY THROUGH
EARLY AFTERNOON ON THURSDAY. THIS POINTS TOWARD WARM ADVECTION
BEING VERY EFFICIENT ACROSS THE AREA BY THAT JUNCTURE...AND SHOULD
ALLOW MUCH OF THE AREA TO RUN UP ABOVE FREEZING ON THURSDAY.
HOWEVER...BEFORE THAT OCCURS...COLD AIR WILL NEED TO BE
DISPLACED...AND WET BULB EFFECTS WILL NEED TO BE OVERCOME. IN THE
INTERIM...THIS MEANS A PERIOD OF FREEZING RAIN WILL BE POSSIBLE AS
WARM AIR WORKS IN OFF THE SURFACE BEFORE IN THE BOUNDARY LAYER.

MODEL SOUNDINGS ACROSS OHIO SUGGEST THE BEST CHANCE OF FREEZING
RAIN WILL BE OVER OUR FAR WESTERN COUNTIES AS THE PRECIPITATION
ONSET WILL BE CLOSEST TO SUNRISE THERE. AS A RESULT...OVERNIGHT
INVERSIONS ARE UNLIKELY TO HAVE BEEN WIPED OUT BY THAT
JUNCTURE...RESULTING IN A PERIOD OF ICING BEING LIKELY. FARTHER
EAST...THE DETAILS GET A LITTLE BIT MURKY.

THE RACE BETWEEN ONSET...WET BULBING...BOUNDARY LAYER MIX
OUT...AND WARM ADVECTION WILL BE A CLOSE RACE VIRTUALLY
EVERYWHERE. AT THE MOMENT...IT SEEMS AT LEAST FOR A TIME...THAT
NORTH OF THE TURNPIKE...AT LEAST A PERIOD OF SNOW/ICE WILL BE
POSSIBLE...WITH REALLY ONLY ACCUMULATING SNOW LIKELY BY AFTERNOON
ALONG I-80 AND IN THE RIDGES OF PA AND MD. ELSEWHERE...A LATE
ONSET SHOULD ALLOW FOR GROUND TEMPERATURES TO RISE ENOUGH SUCH
THAT PLAIN RAIN WILL DOMINATE AND PRECLUDE MUCH IN THE WAY OF
ICING. FRIES

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
WHILE WARM ADVECTION LOOKS RAPID AHEAD OF THE FIRST WAVE ON
THURSDAY AFTERNOON...THERMAL PROFILES QUICKLY BECOME MUCH MORE
UNSTABLE BY THURSDAY EVENING. COLD ADVECTION BEGINS IN EARNEST
ALOFT AS TWO MORE SHORT WAVE TROUGHS ARE SET TO CROSS THE AREA
THROUGH FRIDAY MORNING. THIS WILL OCCUR SIMULTANEOUSLY TO THE
SOME DRIER AIR COMING IN...HOWEVER THE DENDRITIC GROWTH LAYER
LOOKS TO ABSOLUTELY CRASH TOWARD THE SURFACE ON THURSDAY NIGHT IN
THE RIDGES...WELL BEFORE THE MOISTURE PEELS OFF. CONSENSUS SNOW TO
LIQUID RATIOS FROM THE NAM AND GFS VIA BUFKIT SUGGEST AROUND 25 TO
1 BEGIN LIKELY OVERNIGHT. GIVEN INSTABILITY AND UNIDIRECTIONAL
UPSLOPE...THIS SHOULD RESULT IN VERY EFFICIENT SNOW GROWTH. MODEL
QPF IS GENERALLY ONLY A COUPLE OF TENTHS...AND GIVEN ICE COVER
UPSTREAM ON LAKE ERIE...A TON OF QPF IS VERY UNLIKELY.
HOWEVER...EVEN LIGHT QPF IN THIS CASE IS LIKELY TO ADD UP TO
SEVERAL INCHES OF SNOW. GIVEN THAT AHEAD OF THE SYSTEM ON THURSDAY
THERE COULD BE AN INCH OR SO IN SOME OF THE SHELTERED HIGHER
ELEVATIONS...AND ANOTHER 2 TO 5 SEEM LIKELY IN THE UPSLOPE THROUGH
FRIDAY WITH ADDITIONAL SYNOPTIC HELP VIA TWO ADDITIONAL WAVES
CROSSING THE AREA...3 TO 6 INCH TOTALS SEEM REASONABLE IN THE
RIDGES BY FRIDAY MORNING. WINTER WEATHER ADVISORIES WERE EXPANDED
TO ACCOMMODATE THIS. FRIES

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
COLD ARCTIC HIGH SHIFTS EAST INTO SATURDAY WITH SNOW SHOWERS IN
NORTHWEST FLOW FRIDAY ENDING FRIDAY NIGHT. WITH 850MB TEMPS
PROGGED NEAR -20C BY 00Z SATURDAY TEMPERATURES FRIDAY WILL BE
STEADY OR FALL. CLOUDS SHOULD BEGIN TO BREAK AS CENTER OF HIGH
MOVES INTO REGION FRIDAY NIGHT...WITH LOWS BELOW ZERO NORTH AND
SINGLE DIGITS SOUTH. IF CONDITIONS GO CLEAR AND CALM FRIDAY NIGHT
MAY GO BELOW ZERO ACROSS THE ENTIRE REGION. TEMPERATURES RECOVER
TO MAINLY THE 20S SATURDAY. A SIGNIFICANT STORM LOOKS POSSIBLE FOR
SUNDAY INTO EARLY MONDAY BEFORE ARCTIC AIR RETURNS TO START THE
WORK WEEK.

&&

.AVIATION /01Z THURSDAY THROUGH MONDAY/...
HIGH PRESSURE WILL KEEP WINDS LIGHT OVERNIGHT WITH ONLY HIGH
CLOUDS. LOW PRESSURE MOVING OVER THE EASTERN GREAT LAKES WILL
BRING PRECIPITATION TO ALL SITES FROM LATE MORNING TO EARLY
AFTERNOON. PRECIPITATION TYPE WILL BE TRICKY...WITH MGW THE ONLY
SITE WITH HIGH CONFIDENCE THAT WILL NOT HAVE FREEZING RAIN. HAVE
ONLY MENTIONED FZRA EXPLICITLY IN THE TAFS FOR FKL/DUJ FOR A
COUPLE HOUR TIME PERIOD...BUT A BRIEF 1-3 HOUR PERIOD OF FREEZING
RAIN CANNOT BE RULED OUT AT OTHER TERMINALS. SIMILIARLY...WHILE
LOW LEVEL WIND SHEAR IS ONLY INCLUDED IN THE ZZV TAF...CANNOT RULE
OUT A BRIEF 1-3 HOUR PERIOD OF LLWS AT OTHER TERMINALS BEFORE
PRECIPITATION STARTS AND HIGHER WINDS ALOFT ARE ABLE TO MIX OUT AS
GUSTS. OVERALL TREND WILL BE FOR VFR CONDITIONS TO QUICKLY DROP TO
IFR IN PRECIPITATION AS LOWER CEILINGS MOVE IN FROM THE NORTHWEST.

.OUTLOOK.../THURSDAY NIGHT THROUGH MONDAY/...
RSTRNS ARE LIKELY THRU ERLY FRI AS A CDFNT EXITS. WDSRPD RSTRNS
ARE LIKELY AGAIN WITH ADVNG LOW PRES SUN AND MON.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY FROM 11 AM THURSDAY TO 10 AM EST
     FRIDAY FOR MDZ001.
OH...FREEZING RAIN ADVISORY FROM 8 AM TO NOON EST THURSDAY FOR
     OHZ048-057.
PA...WINTER WEATHER ADVISORY FROM 11 AM THURSDAY TO 10 AM EST
     FRIDAY FOR PAZ007>009-015-016-023-074-076.
WV...WINTER WEATHER ADVISORY FROM 7 PM THURSDAY TO 10 AM EST FRIDAY
     FOR WVZ023-041.

&&

$$








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