Area Forecast Discussion
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000 FXUS61 KPBZ 180641 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 141 AM EST THU DEC 18 2014 .SYNOPSIS... IT WILL BE CLOUDY WITH NEAR SEASONAL TEMPERATURES THROUGH THE END OF THE WEEK. && .NEAR TERM /THROUGH TODAY/... LIGHT SNOW SHOWERS AND FLURRIES PERSIST AS THE TAIL VORT PASSES EAST EMBEDDED IN THE UPPER TROF AXIS. AS THE AXIS PASSES...LOW TO MID-LEVEL FLOW WILL VEER FROM WRLY TO NWRLY ALLOWING FOR CONTINUED PENETRATION OF LAKE MOISTURE INTO OUR NRN ZONES...EVEN AS THE SFC WINDS REMAIN LARGELY OUT OF THE WEST. DRY MID-LEVEL AIR WILL BE SLOWLY SHUNTING THE DEEPER MOISTURE TO THE NE AT LEAST TEMPORARILY THIS MORNING...SO AM EXPECTING LIGHT SNOW SHOWERS OVER THE PITTSBURGH METRO AREA TO CEASE. COLDEST H85 TEMPS ARE BEING REALIZED NOW THROUGH ABOUT 12Z PER THE NAM BUFR SOUNDINGS...AND THE DENDRITIC GROWTH ZONE OVERLAPS THE SHALLOW MOIST LAYER. EXPECTING THE BEST CHANCES FOR ACCUMULATING SNOW THROUGH 12Z...ALTHOUGH GENERALLY LESS THAN AN INCH IS EXPECTED. LAKE ENHANCED MOISTURE...SATURATING AND DEEPENING THE BOUNDARY...LAYER WILL REMAIN OVER OUR NRN 1/3 OF THE CWA TODAY WITH CHANCES OF SNOW SHOWERS PERSISTING THROUGHOUT. THIS AFTERNOON HI-RES MODELS KEEP LAKE EFFECT SNOW PRODUCTION ACTIVE DESPITE NAM BUFR SOUNDINGS SHOW INVERSION HEIGHTS LOWERING AND A SLIGHT WARMING OF THE MID-LEVELS. WITH THIS IN MIND...AM EXPECTING SPATIAL COVERAGE AND INTENSITY TO DWINDLE SIGNIFICANTLY FROM MID-MORNING THOUGH THE EVENING. ELSEWHERE...CLOUDS WILL CONTINUE TO BE EVER-PRESENT...BUT INSUFFICIENT MOISTURE WILL PRECLUDE ANY PRECIPITATION. WITH LACK OF SUNSHINE AND NO REAL CHANGE TO THE AIR MASS TO SPEAK OF...HIGH TEMPS WILL REMAIN BELOW AVERAGE WITH MOST LOCATIONS FLIRTING WITH THE FREEZING MARK. WINDS COULD MAKE IT FEEL ABOUT 5-10 DEGREES COLDER. TAX && .SHORT TERM /TONIGHT THROUGH SATURDAY/... FAST MOVING SHORTWAVE WILL KEEP CLOUDS AND A FEW SNOW SHOWERS MAINLY ACROSS THE NORTH THURSDAY NIGHT...ENDING EARLY FRIDAY AS SURFACE RIDGE NOSES INTO THE REGION. WEAK SOUTHERN STREAM SYSTEM WILL APPROACH LATE SATURDAY WITH CHC POPS ACROSS THE FAR SOUTH FOR LIGHT SNOW. BULK OF MOISTURE WITH THIS SYSTEM WILL REMAIN WELL SOUTH OF THE REGION AS IT QUICKLY SHIFTS EAST BY EARLY SUNDAY. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... THE LONG TERM PD IS PROGGED TO FEATURE REDVLPMNT OF HIGHER AMPLITUDE FLOW OVR THE CONUS AS A TROF DIGS OVR THE PLNS AND DEEPENS EWD. INITIAL SEASONAL TEMPS FOR THE UPR OH REGION ARE THUS EXPECTED TO MODERATE AS WARM ADVCTN INTENSIFIES ON THE ERN FLANK OF THAT SYSTEM. LATE PD POP TRENDS WL BE DEPENDANT ON PLACEMENT AND PROGRESS OF THE MID/UPR LOW CNTR...VERY QNABLE GIVEN THE CUTOFF CURRENTLY FORECAST BY MODEL WORLD. IN GENL...WPC GUIDANCE WAS USED WITH TWEAKS FOR COLLABORATIVE THRESHOLDS. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... GENL MVFR...AND PERIODIC IFR FOR NRN PORTS...CAN BE EXPECTED FOR THE TAF PD AS STRATOCU BLANKET IS MAINTAINED OVR THE UPR OH REGION VIA COLD ADVCTN AT THE TOP OF THE BNDRY LYR. ANOTHER SHOT OF COLD AIR TONIGHT WILL ALSO BRING THE THREAT FOR SNOW SHOWERS/FLURRIES... PARTICULARLY AT NORTHERN PORTS. OUTLOOK.../TUESDAY NIGHT THROUGH SUNDAY/... PERIODIC CIG RESTRICTIONS ARE EXPECTED UNTIL BNDRY LYR FLOW BACKS ON SATURDAY IN ADVN OF LOW PRES. THAT SYSTEM IS FORECAST TO INTIATE ANOTHER ROUND OF GENL RESTRICTIONS BY SATURDAY NGT. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$

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