FXUS61 KPBZ 261640
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1140 AM EST THU NOV 26 2009
.SYNOPSIS...
A COLD FRONT WILL PUSH EAST OF THE AREA TODAY...WITH A COLD
NORTHWESTERLY FLOW IN ITS WAKE. THIS WILL ALLOW FOR RAIN AND SNOW
SHOWERS TONIGHT TURNING OVER TO ALL SNOW SHOWERS ACROSS THE AREA BY
FRIDAY AS MUCH COLDER AIR MOVES OVER THE REGION. HIGH PRESSURE
WILL THEN BUILD IN...WITH A DRY WEEKEND EXPECTED.
&&
.NEAR TERM /THROUGH TONIGHT/...
16Z RUC 500MB ANALYSIS INDICATES A CLOSED LOW ACROSS SRN MICHIGAN
WITH A TROF AXIS EXTENDING SWWD INTO THE TN VALLEY. THIS DEEP TROF
IS THE DOMINANT FEATURE ACROSS THE ERN HALF OF THE CONUS...WITH
RIDGING ACROSS THE WEST. AT THE SURFACE...A 1004 MB LOW IS ACROSS
NRN MICHIGAN WITH A TROF EXTENDING SWWD INTO ILLINOIS. AN AREA OF
STRATIFORM PRECIP IS ADVECTING INTO NWRN OHIO. THIS AREA OF PRECIP
IS ALL RAIN...WITH THE BEST CAA BEHIND THE TROF AXIS ACROSS THE
UPPER MIDWEST. LOCALLY...PARTLY CLOUDY SKIES CONTINUE TO ADVECT
ACROSS THE AREA WITH TEMPS RANGING FROM THE LOWER 40S NORTH OF
I-80 TO THE LOWER 50S IN N-CNTRL WV.
THIS AFTERNOON AND TONIGHT...THE SFC TROF WILL ADVECT EWD ACROSS
THE OHIO VALLEY...REACHING WRN PA AFTER MIDNIGHT. CLOUD COVERAGE WILL
CONTINUE TO INCREASE FROM THE WEST TODAY...WITH THE DEEPEST
MOISTURE ASSOCD WITH THE LOW REACHING THE E-CNTRL OH BY 06Z.
ASIDE FROM THE SCHC OF A SHOWER EARLY THIS EVENING...SHOWERS WILL
MOVE INTO THE AREA WITH THE TROF AXIS OVERNIGHT. INITIALLY
STARTING AS RAIN SHOWERS...SHOWERS WILL FIRST TURN TO SNOW ACROSS
THE HIGHER ELEVATIONS...WITH SNOW SHOWERS ACROSS THE AREA BY THE
PRE- DAWN HOURS FRIDAY. SOME LIGHT ACCUMULATION IS POSSIBLE ACROSS
WRN PA AND N-CNTRL WV WITH SNOW SHOWERS POSSIBLE AT AN OPTIMAL
TIME FOR ACCUMULATION BEFORE DAYBREAK...WITH 1 TO 2 INCHES POSSIBLE
ACROSS THE HIGHER ELEVATIONS OF THE EASTERN RIDGES. TEMPS TODAY
WILL BE A FEW DEGREES ABOVE NORMAL...WITH CAA BRINGING TEMPS INTO
THE UPPER 20S TO LOWER 30S FOR OVERNIGHT LOWS.
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
THE GREATEST RISK FOR SNOW ACCUMULATION WILL BE CENTERED OVER
COUNTIES IN LEE OF THE LAKES AND ESPECIALLY OVER RIDGE ZONES WHERE
UPSLOPE ENHANCEMENT AND MID LEVEL COLD POOL SHOULD SUPPORT
ACCUMULATING SNOW AND POSSIBLE ADVISORIES FOR FRIDAY. SNOW SHOWERS
WILL CONTINUE INTO FRIDAY NIGHT WITH TEMPERATURES REMAINING BELOW
NORMAL.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
BY SATURDAY HIGH PRESSURE BUILDING INTO THE DISTRICT WILL WEAKEN
THE NORTHWEST FLOW AND BRING AN END TO THE SNOW SHOWERS. HIGH
PRESSURE PUSHING EAST WILL BRING DRY WEATHER FOR SATURDAY NIGHT
INTO SUNDAY. A LOW PRESSURE SYSTEM WILL COME FROM THE LOWER
MISSISSIPPI VALLEY AND SPREAD RAIN SHOWERS ACROSS THE UPPER VALLEY
MONDAY AND TUESDAY...WHICH SHOULD BE EXITING WEDNESDAY.
EXPECT TEMPERATURES NEAR NORMAL THIS PERIOD BASED ON HPC AND GFS
MOS GUIDANCE.
&&
.AVIATION /16Z THURSDAY THROUGH MONDAY/...
EXPECT PREDOMINATELY VFR CONDITIONS THROUGH 06Z FRIDAY WITH CEILINGS
BETWEEN 3000 AND 5000 FEET...BUT MVFR RESTRICTIONS ARE POSSIBLE IN
SCATTERED SHOWERS THROUGH EARLY TONIGHT.
AS COLDER AIR BEHIND A COLD FRONT MOVES INTO THE REGION TONIGHT...
SCATTERED RAIN SHOWERS WILL CHANGE OVER TO SNOW SHOWERS AND
CONDITIONS WILL GENERALLY LOWER TO MVFR. GREATEST COVERAGE OF SNOW
SHOWERS SHOULD BE ACROSS THE NORTH AT KDUJ AND KFKL....WHERE BRIEF
IFR PERIODS ARE POSSIBLE IN HEAVIER SNOW SHOWERS LATE THURSDAY NIGHT
THROUGH FRIDAY NIGHT.
HIGH PRESSURE WILL PROVIDE PREVAILING VFR CONDITIONS FOR SATURDAY
AND SUNDAY. REDUCED CONDITIONS WILL AGAIN BE POSSIBLE SUNDAY NIGHT
AND MONDAY AS ANOTHER LOW PRESSURE SYSTEM AFFECTS THE AREA.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
