FXUS61 KPBZ 101924
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
224 PM EST THU DEC 10 2009

.SYNOPSIS...

AS HIGH PRESSURE BEGINS TO BUILDS IN FOR THE FIRST HALF OF THE WEEKEND...A
COLD NIGHT IS IN STORE FOR TONIGHT. A LOW PRESSURE SYSTEM WILL
BRING A WINTRY MIX OF PRECIPITATION TO THE REGION SUNDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...

SNOW SHOWERS AND CLOUDS WILL CONTINUE TO DIMINISH THIS EVENING
OVER THE SOUTHERN THREE QUARTERS OF THE CWA...AS A HIGH PRESSURE
RIDGE BEGINS TO BUILD IN. LAKE ENHANCEMENT WILL KEEP SNOW SHOWERS
GOING NORTH. A FAIRLY TIGHT PRESSURE GRADIENT SHOULD KEEP WINDS UP
OVERNIGHT. THE GUSTY WINDS COUPLED WITH CONTINUED CAA AND
CLEARING...WILL LEAD TO SUB ZERO WIND CHILLS. WILL ISSUE AN
ADVISORY OVER EASTERN COUNTIES.

&&

.SHORT TERM /FRIDAY THROUGH SUNDAY/...

WHILE HIGH PRESSURE BUILDING IN WILL PROVIDE SOME SUNSHINE SOUTH
FRIDAY...THE TURN IN THE FLOW WILL LEAD TO AN INCREASE IN CLOUD
COVER NORTH...WITH LAKE EFFECT SNOW SHOWERS. AS THE FLOW RELAXES AND
TURNS MORE WEST TO SOUTHWEST FRIDAY NIGHT INTO SATURDAY...THE
REMAINING SNOW SHOWERS AND CLOUDS WILL DISSIPATE NORTH...WITH
MAINLY CLEAR SKIES EXPECTED SOUTH. 

THE TIMING OF THE ARRIVAL OF PRECIP SUNDAY MORNING AHEAD OF THE
LOW PRESSURE SYSTEM WILL BE CRITICAL IN THE PRECIP TYPE FORECAST. THE
CURRENT FORECAST TIMING WITH THE WAA ALOFT AND COOL SURFACE
TEMPS...SUGGESTS A WINTRY MIX OF FREEZING RAIN/SNOW POSSIBLE AT
THE ONSET FOR A FEW HOURS...BEFORE MOST OF THE CWA CHANGES OVER TO
RAIN BY SUNDAY AFTERNOON.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...

A COLD FRONT IS PROGGED TO APPROACH THE AREA SUNDAY NIGHT...SWEEPING
ACROSS THE AREA MONDAY/MONDAY NIGHT. WILL RAISE POPS SOME...WITH
MID RANGE CHANCE POPS AREA WIDE. WILL ALSO INCREASE HIGH TEMPS
MONDAY IN WARMER AIR IN ADVANCE OF THE FRONT...WITH 50S POSSIBLE 
SOUTH OF PIT. COLDER AIR/TROUGHINESS WILL PREVAIL FOR TUESDAY 
THROUGH THURSDAY WITH CHANCES OF SNOW SHOWERS.

&&

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...

MVFR CIGS WITH AREAS OF IFR VISIBILITIES WILL PREVAIL THROUGH MOST 
OF THIS AFTN...AS FLURRIES/SNOW SHOWERS CONTINUE. SNOW SHOWER 
ACTIVITY WILL DIMINISH FOR PORTS PIT/BVI SOUTH BY TNGT...AS LOW 
PRESSURE MOVES TO THE NORTHEAST...WITH CLOUDS SCATTERING OUT BY 
MIDNIGHT. FURTHER NORTH...SNOW SHOWERS WILL BE MORE 
PERSISTENT...CONTINUING THROUGH THE OVERNIGHT...DIMINISHING FRIDAY 
MORNING. WINDS WILL REMAIN IN THE 15-22 KT RANGE...WITH GUSTS TO 
30-35 KT THROUGH THIS AFTN...WITH ONLY A MINOR DECREASE TNGT.

VFR CONDITIONS WILL WORK ACROSS ALL AREAS FRIDAY AS HIGH PRESSURE 
BUILDS OVER THE REGION...CONTINUING THROUGH SATURDAY. RESTRICTIONS 
WILL PREVAIL SUNDAY THROUGH EARLY NEXT WEEK...AS THE NEXT SYSTEM 
AFFECTS THE AREA...WITH SOME POTENTIAL FOR MIXED WINTRY 
PRECIPITATION SUNDAY.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EST FRIDAY 
     FOR MDZ001.
OH...NONE.
PA...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EST FRIDAY 
     FOR PAZ009-015-016-022-023-030-032.
WV...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EST FRIDAY 
     FOR WVZ023-041.

&&

$$