FXUS61 KPBZ 050938
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
438 AM EST SUN FEB 5 2012

.SYNOPSIS...
ANY REMAINING MIX OF LIGHT RAIN AND SNOW WILL END THIS MORNING, AS
UPPER LEVEL DISTURBANCE EXITS EAST. HIGH PRESSURE WILL THEN FOLLOW
TO BRING SOME SUN BY AFTERNOON, AND AGAIN ON MONDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
RECENT RADAR DATA TRENDS AND HRRR AND WRF-NMM MODEL OUTPUT
CONTINUE TO SHOW ANY LIGHT MIX OF RAIN AND WET SNOW WILL END
BEFORE MID-MORNING, AS AN UPPER LEVEL JETSTREAM MAX EXITS EAST.
THERE MAY BE A SMALL ACCUMULATION OF WET SNOW OVER THE HIGHER
MOUNTAINS.

RECENT SURFACE DATA SHOWS SIGNS THAT THE LOW CLOUDS RESULTING IN
AREAS OF FOG OVER THE HIGHER PA-WV-MD MOUNTAINS, HAS BEGUN TO
LIFT. SO EXPECT ANY REMAINING HIGHER ELEVATION FOG TO HAVE ENDED
BY 9 AM.

PER TRENDS IN RECENT SATELLITE DATA AND SUPPORT FROM RECENT HRRR
AND NAM MODEL OUTPUT, EXPECT CLOUDS TO ALSO DECREASE, NORTH TO
SOUTH, THIS MORNING, YIELDING A DECENT AMOUNT OF SUNSHINE THIS
AFTERNOON.

HAVE CONTINUED TO FINE TUNE TEMPERATURE FORECAST PER RECENT HRRR
AND GFS LAMP MODEL OUTPUT. EXPECT AFTERNOON HIGHS TO BE 2 TO 5
DEGREES WARMER THAN NORMAL, WHICH IS ALSO SUPPORTED BY RECENT NAM
AND GFS MOS.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
BLEND OF RECENT SREF AND ECMWF MODEL OUTPUT SHOWS SPRAWLING HIGH
PRESSURE, EXTENDING FROM THE PLAINS TO THE APPALACHIANS, WILL
PROVIDE NO MORE THAN SCATTERED CLOUDS ACROSS THE UPPER OHIO VALLEY
TONIGHT INTO TUESDAY. THIS WILL MAINTAIN MILD CONDITIONS, WITH
LOWS AND HIGHS GENERALLY 5 TO 8 DEGREES WARMER THAN NORMAL.

MODELS THEN SHOW STRONG HIGH PRESSURE SPREADING SOUTHEASTWARD FROM
THE CANADIAN PLAINS. THIS WILL PUSH A COLD FRONT SOUTHWARD THROUGH
THE UPPER OHIO VALLEY TUESDAY NIGHT INTO WEDNESDAY. THE FRONT MAY
HAVE LITTLE MOISTURE TO INGEST, SO MAINTAINED A SLIGHT CHANCE OF
PREFRONTAL SHOWERS TUESDAY NIGHT, AND A CHANCE OF POSTFRONTAL SHOWERS
WEDNESDAY.

THE PRECIPITATION TYPE WILL BE A MIX OF RAIN AND SNOW, AS SURFACE
LAYER TEMPERATURES WILL STRADDLE THE FREEZING POINT. THIS IDEA IS
SUPPORTED BY RECENT GFS AND NAM MOS WHICH SHOW TEMPERATURES TO
LOWER TO SEASONABLE LEVELS.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
BLEND OF RECENT ECMWF AND NAEFS MODEL OUTPUT SHOWS A DEEP UPPER
LOW PASSING EASTWARD THROUGH EASTERN CANADA LATE WEEK. HENCE
EXPECT A COLD FRONT, WITH A MIX OF RAIN AND SNOW SHOWERS, TO PASS
THROUGH THE UPPER OHIO VALLEY AROUND FRIDAY. FOR NOW HAVE
CONTINUED FORECAST OF NEAR-SEASONABLE POSTFRONTAL TEMPERATURES FOR
SATURDAY. HOWEVER, RECENT NAEFS MEDIAN VALUES AND GFS MOS SUGGEST
TEMPERATURES SATURDAY COULD BECOME 5 TO 10 DEGREES COLDER THAN
NORMAL.

&&

.AVIATION /09Z SUNDAY THROUGH THURSDAY/...
IFR CONDITIONS IN FOG AND STRATUS MAY REMAIN ACROSS KMGW AND THE
MOUNTAINS EAST INTO MID MORNING AS LOW LEVEL MOISTURE FROM
PREVIOUS LIGHT MIXED PRECIPITATION WILL BE TRAPPED UNTIL SURFACE
HIGH CAN MIX BOUNDARY LAYER.

FARTHER NORTH, ACROSS THE KZZV-KPIT-KLBE CORRIDOR, HAVE LOWERING
CONFIDENCE THAT CURRENT MVFR VISIBILITY RESTRICTIONS BY FOG WILL
DETERIORATE TO IFR THIS MORNING. IF STRATUS FAILS TO DEVELOP,
VISIBILITIES WILL IMPROVE TO VFR BY LATE MORNING.

NORTHERN TERMINALS, KFKL AND KDUJ, WILL STAY VFR THROUGH PERIOD. WINDS
WILL BE LIGHT NORTHERLY INTO THE AFTERNOON.

OUTLOOK...SUNDAY NIGHT THROUGH THURSDAY...
GENERAL VFR CONDITIONS ARE EXPECTED THROUGH TUESDAY. A SERIES OF
SHORT WAVES MAY BRING RESTRICTIONS AT TIMES IN SNOW SHOWERS
WEDNESDAY INTO THURSDAY.

&&

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

&&

$$



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