FXUS61 KPBZ 052341
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
641 PM EST SAT DEC 5 2009
.SYNOPSIS...
BUILDING HIGH PRESSURE WILL BRING DRY AND COLD CONDITIONS FOR
SUNDAY. THERE WILL BE A CHANCE OF SOME SNOW SHOWERS ON MONDAY AS A
WEAK DISTURBANCE CROSSES THE REGION...BUT THE BEST CHANCE FOR
WIDESPREAD WINTRY PRECIPITATION WILL COME WITH A MID WEEK LOW
PRESSURE SYSTEM.
&&
.NEAR TERM /THROUGH SUNDAY/...
SNOW DIMINISHED SUFFICIENTLY TO DROP THE EXTRA PRODUCTS WITH AN
EARLY EVENING UPDATE. WIDESPREAD SNOWFALL WILL RAPIDLY EXIT THE
REGION AS THE EVENING PROGRESSES...WITH THE CONTINUED
NORTHEASTWARD TREK OF THE LOW. THE SKY WILL CLEAR FOR MOST AREAS
OVERNIGHT...EXCEPT FAR NORTH WHERE COLD W/NW FLOW WILL RESULT IN
CLOUDS, AND SOME LIGHT SNOW SHOWERS PERSISTING IN VICINITY OF
I-80. HIGH PRESSURE WILL BUILD ACROSS THE AREA SUNDAY FOR MOSTLY
SUNNY SKIES...BUT WITH A COLD AIRMASS REMAINING IN PLACE...EXPECT
BELOW NORMAL TEMPERATURES TO CONTINUE...ESPECIALLY OVER THE RIDGES
WHERE SNOW COVER WILL SUPPORT A DROP TO NEAR SINGLE DIGITS.
&&
.SHORT TERM /SUNDAY NIGHT 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 QUITE 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/...
WARM ADVECITION ALOFT AHEAD OF AN APPROACHING LOW TUESDAY
NIGHT IS EXPECTED TO PRODUCE A WINTRY MIX OF PRECIPITATION.
CURRENT FORECASTS OF THERMAL PROFILES SUGGEST THAT A BAND OF
SLEET/FREEZING RAIN COULD DEVELOP AND MOVE NORTH ACROSS THE
FORECAST AREA TUESDAY NIGHT INTO EARLY WEDNESDAY. AS WARM AIR SURGES
NORTHWARD ON THE EASTERN FLANK OF GREAT LAKES LOW PRESSURE, A
CHANGE TO RAIN IS EXPECTED. THE SYSTEMS COLD FRONT IS THEN PROGGED
TO CROSS THE UPPER OHIO ON WEDNESDAY NIGHT AND CHANGE REMAINING
PRECIP 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 /00Z SUNDAY THROUGH THURSDAY/...
HIGH PRESSURE WILL BUILD IN FROM THE SOUTHWEST OVERNIGHT...WITH
VFR CONDITIONS PREVAILING ACROSS KMGW AND KZZV. AN MVFR
STRATOCUMULUS DECK WILL ADVECT ACROSS THE NORTHERN TERMINALS.
CEILINGS WILL BECOME MVFR FIRST AT KFKL AFTER 02Z WITH CEILINGS
DECREASING ALONG AND NORTH OF KPIT AFTER 04Z. SOME LIGHT SNOW
WITH MVFR VISIBILITIES OFF OF LAKE ERIE WILL BE POSSIBLE AT KFKL
THROUGH MIDNIGHT. KHLG...KAGC...AND KLBE SHOULD BE RIGHT ALONG THE
EDGE OF LOW- LEVEL MOISTURE...WITH CEILINGS HOVERING BETWEEN VFR
AND MVFR THROUGH 12Z SUNDAY.
ON SUNDAY...LOW-LEVEL MOISTURE WILL CONTINUE TO KEEP CEILINGS
ACROSS THE NORTHERN TERMINALS AT MVFR INTO THE EARLY MORNING...WITH
CLEARING FROM THE SOUTHWEST THROUGHOUT THE DAY. CONDITIONS WILL
FINALLY BECOME VFR AT KFKL/KDUJ BY SUNDAY AFTERNOON. WITH HIGH
PRESSURE CENTERED OVER THE AREA...VFR CONDITIONS WILL PREVAIL
ACROSS THE TERMINALS THROUGH MONDAY.
A COLD FRONT WILL APPROACH THE AREA FROM THE WEST ON MONDAY AND
CROSS THE AREA MONDAY NIGHT. THIS WILL BRING A MIX OF RAIN AND
SNOW TO THE AREA WITH REDUCED CEILINGS AND VISIBILITIES THAT WILL
CONTINUE INTO TUESDAY. A LOW WILL CROSS FROM THE OHIO VALLEY AND
MOVE INTO THE GREAT LAKES ON WEDNESDAY AND THURSDAY. THIS WILL
ALLOW FOR REDUCED CEILINGS AND VISIBILITIES AGAIN TO BE
POSSIBLE...THIS TIME WITH A WINTRY MIX OF PRECIPITATION.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
15/02
