Area Forecast Discussion
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000 FXUS61 KPBZ 271824 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 124 PM EST THU NOV 27 2014 .SYNOPSIS... COLD AIR WILL PUSH ACROSS THE REGION THROUGH TONIGHT WITH SCATTERED SNOW SHOWERS. HIGH PRESSURE WILL BRING DRY AND CHILLY CONDITIONS FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... WIND SHIFT HAS CROSSED THE RIDGES AT 17Z...MINOR UPDATES TO POPS FOR THE EARLY AFTERNOON UPDATE. MIXING HEIGHTS WILL RISE AS LARGE SCALE ASCENSION INCREASES AHEAD OF A SHORTWAVE TROUGH. COLDER AIR AT 850 MB WILL MARCH EASTWARD AND THE FLOW ALOFT WILL INCREASE AND BECOME BETTER ORGANIZED. MIXING HEIGHTS WILL RISE ENOUGH TO REACH THE SNOW GROWTH ZONE. WILL SLOWLY INCREASE POPS THIS AFTERNOON...WITH THE HIGHEST NUMBERS ACROSS THE NORTH AND RIDGES. LIGHT ACCUMULATIONS MAINLY ACROSS THE I-80 CORRIDOR AND RIDGES. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/... A SERIES OF WEAK UPPER LEVEL WAVES WILL CROSS THE AREA TONIGHT. THIS WILL DRIVE THE HEART OF THE COLD AIR SOUTHEASTWARD ACROSS THE REGION. FLOW WILL REMAIN GENERALLY OUT OF THE NORTHWEST TONIGHT...SO WILL EXPECT SNOW SHOWERS TO CONTINUE UNTIL THE SECOND WAVE EXITS AROUND DAWN FRIDAY. AGAIN...WILL FOCUS THE HIGHEST POPS ACROSS THE NORTH(LAKE INFLUENCE)...AND RIDGES(OROGRAPHIC EFFECT). SHORTWAVE WILL QUICKLY EXIT TO THE EAST FRIDAY MORNING... INVERSIONS WILL LOWER AND SUBSIDENCE WILL INCREASE AS BROAD HIGH PRESSURE MOVES EASTWARD ACROSS THE LOWER OHIO VALLEY. ANY LINGERING SNOW SHOWERS WILL QUICKLY END FRIDAY MORNING. THE COLD POOL ALOFT WILL SLOWLY EJECT TO THE NORTH WHICH WILL ALLOW FOR A DECREASE IN CLOUD COVER. WAA WILL CONTINUE SATURDAY NIGHT AS A WARM FRONT CROSSES THE AREA AND FLOW IN THE LOWER AND MID-LEVELS BECOMES SOUTH-SOUTHWESTERLY. MODELS ARE HINTING AT THE DEVELOPMENT OF ISOLATED SNOW SHOWERS DEVELOPING WITH THE PASSING FRONT. WILL INCLUDE SCHC POPS FRIDAY NIGHT. A WEAK DISTURBANCE WILL CROSS ON SATURDAY...WHICH WILL TEMPORARILY PUT THE BREAKS ON THE WAA. COULD SEE A PASSING SHOWER SATURDAY AFTERNOON...BUT DEEP MOISTURE IS LACKING AND THE WAVE IS UNIMPRESSIVE. FOR NOW WILL LEAVE SATURDAY DRY. TEMPERATURES WILL MODERATE ON SATURDAY. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... SHOWER CHANCES WILL INCREASE SUNDAY...AHEAD OF THE NEXT COLD FRONT. FRONT WILL CLEAR THE AREA EARLY MONDAY MORNING. SHOWERS WILL END BUT TEMPS WILL COOL DOWN ON MONDAY. HIGH PRESSURE WILL PROVIDE A DRY AND CHILLY TUESDAY...WITH TEMPS MODERATING ON WEDNESDAY. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/...
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MVFR CONDITIONS ARE EXPECTED THROUGH THE AFTERNOON AS AN AREA OF SNOW SHOWERS DRIFTS SOUTHWARD IN ADVANCE OF A SECONDARY COLD FRONT. OCCASIONAL IFR VSBYS ARE ANTICIPATED AS THIS AREA OF SNOW MOVES ACROSS THE TAF SITE...THUS TEMPO GROUPS WERE ADDED FOR THE NEXT SEVERAL HOURS WITH TIMING USED FROM RADAR. STRENGTHENING COLD ADVECTION AND NORTHWEST FLOW WILL SUPPORT LAKE ENHANCED AND UPSLOPE SNOWS THROUGH TONIGHT BUT CURRENT THINKING IS THAT RESTRICTIONS ASSOCIATED WITH SNOW SHOWERS WILL GENERALLY REMAIN CONFINED TO THE NORTHERN SITES. AN IMPROVEMENT TO VFR IS EXPECTED ON FRIDAY OUTLOOK.../FRIDAY THROUGH MONDAY/... VFR RETURNING BY FRIDAY AS RIDGE BUILDS EASTWARD. THE NEXT CHANCE FOR RESTRICTIONS WILL BE SUNDAY WITH THE PASSAGE OF A COLD FRONT.
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&& .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$

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