FXUS61 KPBZ 061149
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
649 AM EST SUN DEC 6 2009

.SYNOPSIS...
HIGH PRESSURE WILL PROVIDE A DRY AND COLD DAY. THERE WILL BE A
CHANCE OF SNOW SHOWERS MONDAY, AS A WEAK FRONT CROSSES THE
REGION.

&&

.NEAR TERM /THROUGH TONIGHT/...
SFC HIGH BUILDS IN TODAY, ALLOWING FOR MAINLY MOSTLY SUNNY SKIES
AND COLD TEMPERATURES. PERSISTENT CLOUD COVER OVER NORTH AND
RIDGES SHOULD DISSIPATE DURING THE MORNING HOURS.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY/...
LOW AMPLITUDE RIDGING WILL PUSH TO THE EAST SUNDAY NIGHT, WITH A
SHORT WAVE TROUGH CROSSING THE AREA MONDAY/MONDAY NIGHT. DEEP
MOISTURE IS LIMITED, AND WITH THE GREATEST FORCING TO THE
NORTH, WILL KEEP POPS LOW END CHANCE FOR MONDAY/MONDAY NIGHT.
TUESDAY SHOULD BE MAINLY DRY AS SHORT WAVE RIDGING CROSSES THE
REGION. SLIGHTLY BELOW NORMAL TEMPERATURES WILL CONTINUE.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
CURRENT MODEL RUNS COMING IN WARMER, SHOWING LESS OF A WINTRY MIX
EVENT AND MORE OF A RAIN EVENT TUE NIGHT/WED. USING A BLEND OF
MODEL SOLUTIONS, EXPECT PRECIP TO START AS SNOW AND THEN
TRANSITION TO RAIN FROM SOUTHWEST TO NORTHEAST OVERNIGHT. IF THERE
IS GOING TO BE A MIX, NORTH AND EAST STAND THE BEST CHANCE. STILL
MUCH TO BE DETERMINED WITH MIDWEEK SYSTEM SO EXPECT CHANGES TO
FORECAST.

SYSTEM'S COLD FRONT IS THEN PROGGED TO CROSS THE UPPER OHIO ON
WEDNESDAY NIGHT AND CHANGE REMAINING PRECIP BACK OVER TO SNOW. A
COLD AND BLUSTERY DAY IS FORESEEN FOR THURSDAY WITH LAKE EFFECT
SNOW SHOWERS.

HIGH PRESSURE SHOULD BUILD OVER THE REGION BY FRIDAY, BUT WITH ZONAL
FLOW ALOFT, EXPECT SHORTWAVES TO MOVE THROUGH THE FLOW, AND HAVE
THUS KEPT POPS IN THE LATER PERIODS.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
BLEND OF RECENT SURFACE DATA AND SATELLITE IMAGES SHOW STILL A FEW
PATCHES OF MVFR STRATOCUMULUS ACROSS THE EASTERN PARTS OF THE
UPPER OHIO VALLEY. HOWEVER NAM MODEL PROFILES SHOW THESE SHOULD BE
DISSIPATING THIS MORNING ACROSS THE SOUTH AND THIS AFTERNOON
WITHIN THE I-80 CORRIDOR.

HIGH PRESSURE FROM KENTUCKY SHOULD MAINTAIN VFR CONDITIONS ACROSS
THE UPPER OHIO VALLEY TONIGHT AND AT LEAST MONDAY MORNING.

SURFACE WINDS WILL BE FROM THE SOUTHWEST NEAR 6 KTS TODAY...THEN
FROM THE SOUTH NEAR 3 KTS TONIGHT.

RECENT SREF MODEL OUTPUT AND NAM MODEL PROFILES SHOW A WEAK LOW
PRESSURE SYSTEM MOVING EASTWARD THROUGH THE GREAT LAKES MONDAY
NIGHT WHICH COULD INDUCE MVFR STRATOCUMULUS AND SCATTERED LIGHT
SNOW SHOWERS.

THEN RECENT GEFS MODEL OUTPUT SHOWS A STRONG LOW PRESSURE SYSTEM
FROM CALIFORNIA MOVING THROUGH THE UPPER OHIO VALLEY LATE TUESDAY
NIGHT INTO EARLY THURSDAY...WITH WIDESPREAD IFR RAIN AND STRATUS
CONDITIONS EXPECTED ACROSS THE UPPER OHIO VALLEY WEDNESDAY INTO
WEDNESDAY NIGHT...AND POST SYSTEM MVFR STRATOCUMULUS AND 
SCATTERED SNOW SHOWERS THURSDAY.

&&

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

&&

$$