FXUS61 KPBZ 140622 AAB
AFDPBZ
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PITTSBURGH PA
122 AM EST TUE FEB 14 2012
.SYNOPSIS...
A WEAK UPPER LEVEL DISTURBANCE WILL BRING A MIX OF SNOW AND RAIN
LATER TODAY. HIGH PRESSURE WILL FOLLOW WITH A DRY WEDNESDAY, BUT
MORE PRECIPITATION CAN BE EXPECTED WEDNESDAY NIGHT AND THURSDAY.
&&
.NEAR TERM /THROUGH TODAY/...
NEEDED TO SLOW DOWN ONSET OF SNOWFALL OVERNIGHT AND THIS MORNING.
FOR NEXT UPDATE MAY NEED TO SLOW DOWN EVEN MORE. 
LIMITING FACTORS, VERY DRY AIR AT THE SURFACE AND DRY AIR IN THE
MID-LEVELS MOVING IN AHEAD OF UL WAVE.
LATEST RADAR IMAGES ARE SHOWING LOTS OF RETURNS, HOWEVER NONE OF
THESE ARE REACHING THE GROUND. THERE MAY BE A FEW FLURRIES ACROSS
THE NORTH, BUT THAT IS IT. DRY LL ATMOSPHERE, AS SEEN WITH SFC TDS
STILL MAINLY IN THE TEENS AND BY THE 00Z SOUNDING, IS CAUSING THE
PRECIPITATION TO EVAPORATE BEFORE REACHING THE GROUND. ANOTHER
FACTOR, WHICH THE 00Z NAM IS INDICATING AND CAN BEEN SEEN ON
LATEST SAT IMAGES, IS THE DRY MID-LEVEL AIR MOVING NORTHWARD OVER
THE UPPER OHIO VALLEY.
THINKING FOR FORECAST WOULD BE THE BEST AREAS TO SEE SNOWFALL THIS
MORNING WOULD BE ACROSS THE NORTH AND FAR WEST. THINK THAT IT WILL
TAKE UNTIL LATE THIS MORNING OR EARLY AFT FOR THE MAIN PRECIP
SHIELD TO REACH THE AREA. THIS WOULD BE IN LINE WITH THE TROUGH
AXIS, WHICH WILL REACH FAR E OH BY 18Z AND THEN C PA BY 00Z.
KEEPING IN MIND THAT ALL THE PRECIP WITH THIS WEAK SYSTEM WILL BE
LIGHT, TRYING TO FIGURE OUT PRECIP TYPE HAS BEEN A BIT OF A
HEADACHE. WITH SUCH A DRY LL ATMOSPHERE, EXPECT TO SEE SOME
COOLING AS THE LOWER LEVELS SATURATE. FOR THE PRECIP, HAVE TRIED
TO GO TOWARD A COOLER SOLUTION, ALLOWING FOR SOME MIXING OR CHANGE
OVER THIS AFTERNOON. THINK THAT THE MOST LIKELY PLACE FOR ALL
RAIN, WOULD BE ACROSS THE FAR SOUTH DURING THE AFTERNOON HOURS.
NOT EXPECTING MUCH SNOW ACCUMULATION. THERE COULD BE SOME LIGHT
ACCUMULATION ACROSS THE NORTHERN HALF THIS MORNING, BUT WITH TEMPS
EXPECTED TO WARM ABOVE FREEZING, ACCUMULATIONS WILL BE LIMITED.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY/...
SREF MODEL OUTPUT CONTINUES TO SHOW ENSUING HIGH PRESSURE
PROVIDING A DRY BREAK WEDNESDAY INTO WEDNESDAY EVENING. THEN A
SECOND LOW PRESSURE SYSTEM, MORE DEVELOPED THAN TUESDAY'S SYSTEM,
WILL COME NORTHEASTWARD FROM KANSAS, AND PROVIDE ANOTHER BOUT OF
SHOWERS OF SNOW AND RAIN LATE WEDNESDAY NIGHT AND THURSDAY. 
THE ONSET OF THE PRECIP WITH THIS SYSTEM WILL BE DIFFICULT AS
WELL. ALL INDICATIONS ARE THAT THERE WILL BE STRONG WAA AHEAD OF
THE SFC LOW, WHICH WILL ALLOW FOR RISING TEMPS WED NIGHT. THE
AREAS THAT WILL NEED TO BE CLOSELY WATCHED, WILL BE ACROSS THE FAR
NORTHEAST AND GARRETT COUNTY. THIS WILL COME MORE INTO FOCUS IN
LATER MODEL RUNS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AN UPPER TROUGH AND ASSOCIATED SURFACE LOW WILL MOVE NORTHEAST INTO 
EASTERN CANADA BY FRIDAY. SCATTERED RAIN AND SNOW SHOWERS SHOULD 
BEGIN TO TAPER OFF BY FRIDAY MORNING. LINGERING MOISTURE AND 
NORTHWEST FLOW SHOULD MAINTAIN A FEW SHOWERS OVER THE FORECAST AREA 
ESPECIALLY NORTH OF I-80 FRIDAY AFTERNOON. WEAK SYSTEMS PASSING TO 
OUR NORTH COUPLED WITH MOIST NORTHWEST FLOW WILL MAINTAIN CLOUDS AND 
ISOLATED SHOWERS OVER THE REGION DURING THE WEEKEND.
SURFACE HIGH PRESSURE WITH DRIER AIR SHOULD PROVIDE MORE SUNSHINE  
ON MONDAY.
TEMPERATURES ARE FORECAST TO BE A FEW DEGREES ABOVE NORMAL DURING
THE EXTENDED PERIOD.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
VFR CONDITIONS WILL CONTINUE OVERNIGHT AS THE UPPER LEVEL SHORTWAVE 
APPROACHES FROM THE WEST. BASED OFF OF CURRENT SURFACE AND SATELLITE 
OBSERVATIONS...THINK THAT THE INITIAL PRECIPITATION WILL IMPACT 
PORTS FROM KBVI NORTH. HOWEVER...DRY AIR AT THE SURFACE...AS 
INDICATIVE FROM THE 00Z UPPER AIR SOUNDING AND DEWPOINTS WILL KEEP 
PRECIP FROM REACHING THE GROUND INITIALLY. THUS...HAVE GONE WITH A 
LATER ONSET TIME STARTING AT 10-12Z AT ZZV...FKL...AND DUJ WITH MVFR