Area Forecast Discussion
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000
FXUS61 KPBZ 201445
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
945 AM EST SAT DEC 20 2014

.SYNOPSIS...
BUILDING HIGH PRESSURE IS EXPECTED THROUGH THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
SHORTWAVE TROUGH WILL SWING THROUGH THE OHIO VALLEY AND ACROSS THE
CWA DURING THE EARLY PART OF THE NIGHT. EXPECTING CLOUD COVER TO
BE MAINTAINED THROUGH THE PERIOD WITH AN OVERALL THIN BUT
PERSISTENT MOISTURE LAYER A COUPLE THOUSAND FEET UP.  WHILE
MOISTURE IS OTHERWISE FAIRLY MEAGER AT PRESENT...SW FLOW AT H850
WILL HELP PUSH MARGINALLY BETTER PWAT VALUES INTO THE SOUTHERN
COUNTIES BY SUNSET. THIS COMBINED WITH MODEST SUPPORT FROM SHORTWAVE MAY
ALLOW A FEW SNOWFLAKES TO SQUEEZE OUT...SO ADDED A SLIGHT CHANCE
POP TO THE GRIDS...MAINLY FOR THE EVENING...GENERALLY SOUTH OF A
HLG/PIT/IDI LINE. ANY ACTIVITY SHOULD END SOON AFTER 06Z WITH
SHORTWAVE DEPARTURE. TEMPERATURE FORECAST LOOKS DECENT OVERALL AT
THIS TIME.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY/...
MODELS ARE SHOWING SOME IMPROVEMENT SUNDAY...PARTICULARLY OVER
THE WEST AND FAR SOUTH. HOWEVER...MODEL SOUNDINGS FOR THE REST OF
THE REGION STILL WANT TO MAINTAIN A SATURATED LAYER AROUND 2500FT
FOR MOST OF THE DAY...WHICH DOES NOT PRESENT MUCH HOPE FOR
SUNSHINE. CLOUDS WILL BE TRICKY ON SUNDAY...TRYING TO DETERMINE
HOW MUCH OF THE CLOUD DECK WILL BE ERODED.

SPLIT FLOW DEVELOPS ON MONDAY WITH A LARGE SYSTEM TO THE WEST AND
ANOTHER SYSTEM TO THE SOUTH-SOUTHEAST. IT APPEARS THAT THE AREA
WILL LIE IN BETWEEN LIMITING THE CHANCES FOR PRECIPITATION. WAA
WILL CONTINUE ON MONDAY AND LOW-LEVEL MOISTURE INCREASES ONCE
AGAIN. LOOKS LIKE A GOOD DEAL OF CLOUD COVER AGAIN MONDAY. A WEAK
AND UNORGANIZED SHORTWAVE TROUGH WILL SWING THROUGH MONDAY...
ALLOWING FOR THE POSSIBILITY OF SOME LIGHT PRECIP...MAINLY OVER
THE SOUTHERN RIDGES. THIS WILL NEED TO BE FINE TUNED AS THE WARMER
AIR ALOFT MAY OCCUR BEFORE SURFACE TEMPS RESPOND. CONFIDENCE IS
LOW THAT ANY PRECIP WILL OCCUR...SO FOR FORECAST WILL LEAVE OUT.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
STILL SEEING SOME MINOR DIFFERENCES IN MEDIUM RANGE MODEL
SOLUTIONS FOR MIDWEEK SYSTEM. THINK MUCH OF TUESDAY COULD BE DRY
OR JUST LIGHT SHOWERS AS AREA WILL BE WELL INTO THE WARM SECTOR. RAIN
WILL OVERSPREAD THE AREA TUESDAY NIGHT AHEAD OF OCCLUDED FRONT AND
CONTINUE THROUGH WEDNESDAY. COLDER AIR WILL MOVE IN LATER
WEDNESDAY NIGHT CHANGING ANY LINGERING SHOWERS TO SNOW SHOWERS.
COULD SEE A BRIEF UPTICK IN SNOW SHOWER COVERAGE EARLY THURSDAY
MORNING AS MAIN TROUGH SWINGS THROUGH. COLD AIR WILL BE IN PLACE
THURSDAY...BUT WIND DIRECTION NOT OPTIMAL FOR LAKE INFLUENCED SNOW
SHOWERS.

WARMER AIR WILL MOVE BACK IN THURSDAY NIGHT AND FRIDAY.

&&

.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
LOW LEVEL MOISTURE WILL REMAIN TRAPPED UNDER A STRONG INVERSION
AOB 4KFT AS LOW LEVEL WINDS BECOME LIGHT....MAINTAINING HIGH MVFR
TO LOW VFR CONDITIONS OVER THE NEXT 24 HOURS. PRECIPITATION
CHANCES ARE MINIMAL GIVEN THE SHALLOW DEPTH OF THE SATURATED
LAYER AND ABSENCE OF ANY LIFT.

OUTLOOK.../SATURDAY NIGHT THROUGH WEDNESDAY/...
STRATUS AND RESTRICTIONS MAY PERSIST THROUGH THE WEEKEND. NEXT STORM
SYSTEM WILL BEGIN TO IMPACT THE REGION ON TUESDAY AND RESULT IN
WIDESPREAD RAIN...CIG/VIS RESTRICTIONS...AND PERIODS OF LLWS
THROUGH WEDNESDAY.

&&

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

&&

$$





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