FXUS61 KPBZ 010518 CCA
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1217 AM EST TUE DEC 1 2009
.SYNOPSIS...
COLD NORTHWEST WINDS WILL BRING SOME SNOW SHOWERS TO THE UPPER
OHIO VALLEY OVERNIGHT INTO TUESDAY MORNING. HIGH PRESSURE WILL
THEN BRING DRY CONDITIONS LATER TUESDAY AND TUESDAY NIGHT. A
DEEPENING LOW PRESSURE SYSTEM MOVING NORTH FROM THE GULF STATES
WILL BRING RAIN WEDNESDAY AND WEDNESDAY NIGHT FOLLOWED BY SNOW
SHOWERS LATER THURSDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
JUDGING FROM RECENT SURFACE AND RADAR DATA COUPLED WITH SREF MODEL
OUTPUT AND NAM MODEL PROFILES...CONTINUE TO EXPECT THE BULK OF LAKE
EFFECT SNOW SHOWERS OVERNIGHT INTO TUESDAY MORNING TO AFFECT THE
I-80 CORRIDOR AND APPALACHIAN MOUNTAINS. WITH SURFACE LAYER WINDS
TURNING WESTERLY OVERNIGHT...MOST SNOW ACCUMULATIONS SHOULD BE
MAINLY LESS THAN AN INCH. THE REST OF THE UPPER OHIO VALLEY WILL
MAINLY GET ISOLATED SNOW SHOWERS WITH LITTLE IF ANY ACCUMULATION.
RECENT SREF MODEL OUTPUT CONTINUES TO SHOW AN UPPER TROUGH MOVING
THROUGH WESTERN NEW YORK STATE TUESDAY MORNING THAT CAN BRUSH
NORTHERN VENANGO AND FOREST COUNTIES WITH A SMALL SNOW ACCUMULATION
THEN. ELSEWHERE...NAM MODEL PROFILES SHOW THE SURFACE LAYER
STABILIZING AND VERTICALLY SHRINKING AND WINDS TURNING WESTERLY...SO
SNOW SHOWERS WILL BE ENDING BY AFTERNOON.
SURFACE WINDS CAN GUST TO 20-25 MPH.
FORECASTED TEMPERATURES USING A BLEND OF RECENT RUC AND SREF MODEL
OUTPUT COUPLED WITH GFS MOS. ALTHOUGH CONDITIONS FEEL
COLD...ACTUAL TEMPERATURES THIS PERIOD WILL BE ACTUALLY CLOSE TO
NORMAL.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
MODELS HAVE COME INTO BETTER AGREEMENT OVERALL WITH SOUTHERN
STREAM CLOSED LOW OPENING AND QUICKLY MOVING NORTHEAST WEDNESDAY
AND WEDNESDAY NIGHT WITH SURFACE LOW MOVING QUICKLY TO OHIO VALLEY
BY THURSDAY MORNING AND THEN TO NEW YORK STATE BY LATE DAY. RAIN
WILL OVERSPREAD THE REGION WEDNESDAY AND CONTINUE INTO WEDNESDAY
NIGHT. DRY SLOT WILL THEN WORK INTO REGION THURSDAY MORNING AS
SURFACE LOW HEADS NORTH AND COLDER AIR WRAPS IN BEHIND SYSTEM
CHANGING PRECIP TO SNOW SHOWERS BY EVENING. MILD AHEAD OF
WEDNESDAY THEN COOLER THURSDAY BEHIND FROPA.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
DEEP DIGGING CLOSED LOW WILL MOVE FROM NORTHERN PLAINS TO GREAT
LAKES THROUGH PERIOD BRINGING COLDEST AIR OF SEASON WITH OFF AND
ON SNOW SHOWERS DUE TO LAKE EFFECT AND DISTURBANCES MOVING UNDER
CLOSED LOW. NOT MUCH TO ARGUE WITH FROM HPC PROGS AND FOLLOWED.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
ISOLATED TO SCATTERED SNOW SHOWERS ARE EXITING TO THE
NORTHEAST...WITH BROKEN TO OVERCAST MID DECK CEILINGS PREVAILING.
CLOUDS WILL DECREASE ACROSS EASTERN OHIO IN THE NEXT COUPLE OF
HOURS...WITH MID DECK PERSISTING ACROSS WESTERN PA THROUGH THE
MORNING/EARLY AFTN HOURS. SOUTHWEST WINDS WILL INCREASE TO AROUND 10
KT BY MORNING...WITH A FEW GUSTS TO 18-20KT THIS AFTN. HIGH PRESSURE
WILL BUILD OVER THE REGION BY TUESDAY EVENING...WITH FEW CLOUDS FOR
MOST OF THE AREA FOR LATE NIGHT TUESDAY.
HIGH PRESSURE WILL EXIT THE AREA WEDNESDAY...WITH MID DECK CLOUDS
INCREASING. A STRONG STORM SYSTEM WILL MOVE NORTHEAST FROM THE
DEEP SOUTH...CROSSING THE AREA WEDNESDAY NIGHT/THURSDAY...BRINGING
RESTRICTIONS IN RAIN. CHANCES FOR RESTRICTIONS WILL CONTINUE FRIDAY
AND SATURDAY AS POST SYSTEM LAKE ENHANCED SNOW SHOWERS WILL PREVAIL.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
