FXUS61 KPBZ 150122
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
822 PM EST MON DEC 14 2009
.SYNOPSIS...
SCATTERED SHOWERS CAN BE EXPECTED AS A COLD FRONT MOVES THROUGH
TONIGHT. COLDER TEMPERATURES WILL RETURN FOR THE REST OF THE WORK
WEEK.
&&
.NEAR TERM /THROUGH TUESDAY/...
LOW PRESSURE WILL PUSH ACROSS THE EASTERN GREAT LAKES LATE TONIGHT.
A COLD FRONT WILL THE SYSTEM WILL PUSH ACROSS THE DISTRICT TOWARD
DAYBREAK BRINGING A CHANCE OF SHOWERS OVERNIGHT. AFTER THE COLD
FRONT MOVES THROUGH...FALLING TEMPERATURES WILL OCCUR...WITH THE
HIGH TEMPERATURE ON TUESDAY LIKELY OCCURRING TOWARD DAYBREAK IN MOST
LOCATIONS. WHILE PRECIPITATION SHOULD REMAIN IN THE FORM OF RAIN
OVERNIGHT...ANY PRECIPITATION LEFT OVER ON TUESDAY WILL EVENTUALLY
CHANGE OVER TO SNOW SHOWERS. WITH WEST- NORTHWESTERLY FLOW BEHIND THE
FRONT...LOCATIONS ALONG THE RIDGES AND NORTH OF I-80 WILL BE
FAVORED LOCATIONS FOR ANY MEASURABLE SNOWFALL LATE TUESDAY.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
HIGH PRESSURE WILL DOMINATE THE WEATHER FOR WEDNESDAY AND THURSDAY.
AS THE HIGH MOVES FROM THE CENTRAL PLAINS ON WEDNESDAY TO OUR AREA
ON THURSDAY...EXPECT NORTHWESTERLY FLOW AND LAKE EFFECT SNOW SHOWERS
TO BE ON THE DECREASE. NAM/GFS AGREE THAT THERE COULD BE AN UPPER
LEVEL SHORTWAVE SLIGHTLY INTENSIFYING ANY LEFT OVER SNOW SHOWERS ON
WEDNESDAY. TEMPERATURES WILL BE 5-10 DEGREES BELOW NORMAL DURING THE
TIME PERIOD.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
JUDGING FROM RECENT GEFS AND ECMWF MODEL OUTPUT A STRONG UPPER LEVEL
LOW CENTER WILL DEVELOP OVER EASTERN CANADA THIS PERIOD...AND IT
APPEARS ONE OF ITS SHORTWAVE LOBES WILL MOVE SOUTHWARD THROUGH THE
GREAT LAKES. IN ACCORDANCE WITH HPC GUIDANCE...THIS SHOULD INDUCE A
TREND TOWARD COLDER TEMPERATURES ACROSS THE UPPER OHIO VALLEY THIS
PERIOD. WITH SURFACE LAYER WINDS GENERALLY FROM THE NORTH...THERE IS
AN INCREASING CHANCE OF LAKE EFFECT AND OROGRAPHICALLY ENHANCED
INSTABILITY SNOW SHOWERS TOWARD MONDAY.
&&
.AVIATION /01Z TUESDAY THROUGH SATURDAY/...
CIGS WILL LOWER TO MVFR BY AROUND 04Z THIS EVENING...AS A COLD FRONT
APPROACHES. THIS FRONT WILL REACH WESTERN PORTS AROUND
6Z...PASSING EAST OF THE REGION BY 09Z. CIGS WILL LOWER INTO THE
IFR TO MVFR RANGE ALONG AND BEHIND THIS FRONT. A FEW SPOTTY
SHOWERS WILL ALSO BE POSSIBLE WITH THE FRONT.
FOR TUESDAY...PREVAILING MVFR IS EXPECTED WITH A FEW WIND GUSTS TO
AROUND 20 KNOTS POSSIBLE. A BRIEF PERIOD OF IFR WILL BE POSSIBLE
FKL/DUJ IN SNOW SHOWERS.
CONDITIONS WILL IMPROVE TO VFR TUESDAY NIGHT AND CONTINUE THROUGH
WEDNESDAY AS A HIGH PRESSURE RIDGE BUILDS NORTHEAST...EXCEPT
FKL/DUJ WHERE LAKE EFFECT CLOUDS AND SNOW SHOWERS COULD LEAD TO
OCCASIONAL LOWER CONDITIONS.
PREVAILING VFR CONDITIONS ARE THEN EXPECTED FOR THURSDAY THROUGH
SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
