FXUS61 KPBZ 260638
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
140 AM EST SAT DEC 26 2009

.SYNOPSIS...
STRONG LOW PRESSURE MOVING SLOWLY ACROSS THE GREAT LAKES THIS
WEEKEND, WILL PUSH A COLD FRONT THROUGH THE AREA THIS MORNING.
ANOTHER ROUND OF SNOW SHOWERS ARE EXPECTED SUNDAY INTO EARLY
MONDAY.

&&

.NEAR TERM /THROUGH TODAY/...
EARLY GRIDS WILL INDICATE TIMING OF RAINFALL, WHICH IS SLOWLY
MOVING THROUGH THE AREA. RAIN IS AHEAD OF VORT LOBE ROTATING
AROUND MAIN UL. MODEL OUTPUT IS DISPLAYING A TIMING OF LATE
MORNING BEFORE THE BACK-EDGE OF THE PRECIP LEAVES MY NORTHEASTERN
ZONES. BY THIS TIME, ATMOSPHERE WILL HAVE COOLED THAT THE PRECIP
WILL LIKELY END AS SNOW.

ONCE THIS PRECIP EXITS, EXPECT DRY CONDITIONS FOR THE REMAINDER OF
THE DAY.

FORECASTED TEMPERATURES USING A BLEND OF GFS MOS AND SREF MODEL
OUTPUT. WITH CAA, MAINLY STEADY TEMPS SEEM A GOOD BET.

&&

.SHORT TERM /TONIGHT THROUGH MONDAY/...
JUDGING FROM RECENT SREF MODEL OUTPUT IT STILL APPEARS THAT
PROBABILITY OF INSTABILITY SNOW SHOWERS RELATED WITH THE EASTWARD
PASSAGE OF A COLD UPPER LOW CENTER THROUGH THE GREAT LAKES WILL
NOT INCREASE TO LIKELY UNTIL SUNDAY AFTERNOON AND SUNDAY NIGHT.
THIS CAN RESULT IN SNOW ACCUMULATION SUNDAY NIGHT INTO MONDAY. AT
THIS POINT, EXPECT 1 TO 3 INCHES ACROSS MUCH OF THE FORECAST AREA
WITH HIGHER AMOUNTS NORTH AND OVER THE RIDGES.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS UPPER LOW CENTER EXITS EASTWARD TO NEW ENGLAND...EXPECT SNOW
SHOWERS TO WIND DOWN TUESDAY.

SURFACE HIGH PRESSURE WILL BUILD INTO THE REGION TUESDAY AND
WEDNESDAY BRINGING DRY WEATHER. A LOW PRESSURE SYSTEM OVER THE
SOUTHEASTERN STATES WILL BRING MOISTURE AND A CHANCE OF SNOW
SHOWERS TO THE THE FORECAST AREA FOR WEDNESDAY NIGHT INTO THURSDAY.
ANOTHER WEAK SHORT WAVE WILL BRING MORE SNOW SHOWERS FOR FRIDAY.

CLOUD COVER WILL HOLD DAYTIME TEMPERATURES DOWN TO FEW DEGREES BELOW 
NORMAL THROUGH THE EXTENDED PERIOD.

&&

.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
UPPER LEVEL LOW PRESSURE SYSTEM WILL REMAIN ACROSS THE MIDWEST 
TODAY...WITH SCATTERED SHOWERS PIVOTING AROUND THE LOW ACROSS MAINLY 
TERMINALS DUJ/FKL OVERNIGHT THROUGH MID MORNING. EXPECT MVFR/AREAS 
OF IFR WITH THESE SHOWERS. FOR OTHER AREAS...VFR CONDITIONS 
CURRENTLY WILL WORSEN TO MVFR AS A DECK OF STRATOCUMULUS RE-ENVELOPS 
THE AREA OVERNIGHT. WINDS ALOFT ARE DECREASING WEST TO EAST...THUS 
WILL KEEP LLWS FOR PA TERMINALS FOR THE NEXT 2-4 HOURS...OTHERWISE 
WILL REMOVE. SE SURFACE WINDS WILL TURN TO THE S/SW OVERNIGHT AND 
GRADUALLY DECREASE. 

HIGH PRESSURE WILL BUILD IN FROM THE SOUTH TODAY...WITH VFR FOR
ALL BUT FKL/DUJ BY LATE MORNING...WITH FKL/DUJ VFR BY LATE AFTN.
THE UPPER LEVEL LOW ACROSS THE MIDWEST WILL FINALLY EJECT ACROSS
THE OHIO VALLEY SUNDAY/MONDAY. EXPECT SCATTERED TO NUMEROUS SNOW
SHOWERS AND MVFR/IFR RESTRICTIONS. HIGH PRESSURE WILL BUILD OVER
THE REGION TUESDAY/WEDNESDAY FOR DRY/VFR CONDITIONS.
&&

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

&&

$$