Area Forecast Discussion
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000 FXUS61 KPBZ 252132 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 432 PM EST TUE NOV 25 2014 .SYNOPSIS... LOW PRESSURE SYSTEM IS EXPECTED TO DEVELOP AND RIDE NORTHWARD ALONG THE COAST ON WEDNESDAY...BRINGING ACCUMULATING SNOW TO AREAS SOUTH AND EAST OF PITTSBURGH. A SECOND WEAKER SYSTEM WILL USHER IN COLDER TEMPERATURES AND LINGERING SNOW SHOWER CHANCES THROUGH THE END OF THE WEEK. && .NEAR TERM /THROUGH WEDNESDAY/... QUIET WEATHER IN THE INTERIM AS A SURFACE LOW PRESSURE SYSTEM BEGINS TO DEVELOP ALONG THE SOUTHEAST COAST THIS EVENING. THIS LOW WILL THEN LIFT NORTHEASTWARD WITH THE HELP OF A DIGGING UPPER LEVEL SHORTWAVE OVER THE PLAINS AND A STRENGTHENING UPPER LEVEL JET....RIDING ALONG THE COLD FRONT THAT CROSSED THE REGION YESTERDAY. DESPITE THE EXPECTED INCREASE IN CLOUDS IN ADVANCE OF THE LOW...CLEARING SKIES EARLY SHOULD HELP TO DROP TEMPERATURES INTO THE 30`S TONIGHT ACROSS MUCH OF THE REGION. THE GENERAL MODEL CONSENSUS IS THAT SNOW WILL BEGIN TO OVERSPREAD THE REGION EARLY TOMORROW MORNING FROM SOUTHEAST TO NORTHWEST AS THE LOW IS LIFTED NORTHWARD. THE NAM SEEMS TO BE THE OUTLIER...WITH VERY HIGH OMEGA VALUES AND THUS SNOWFALL ACCUMULATIONS IN COMPARISON TO ALL OF THE OTHER MODELS...AND SEVERAL RUNS OF THE MODELS. WITH THAT BEING SAID...THE QPF VALUES HAVE INCREASED A BIT AMONG ALL OF THE MODELS...WHICH EVEN WITH MODEST SNOW RATIOS LEADS TO WARNING CRITERIA SNOW IN THE HIGHER ELEVATIONS OF GARRETT...PRESTON...AND TUCKER COUNTIES AND JUST EXCEEDING WARNING CRITERIA IN THE CHESTNUT AND LAUREL RIDGES. A BIT OF AN EXPANSION WESTWARD IN THE TRACK HAS ALSO LEAD TO THE ISSUANCE OF AN ADVISORY FOR 2-4 INCHES IN THE COUNTIES IMMEDIATELY ADJACENT TO THE WARNING...WITH LESSER AMOUNTS EXPECTED FURTHER NORTH AND WEST. IT IS EXPECTED THAT THE BULK OF THE SNOWFALL WILL BE OVER BY LATE AFTERNOON AS THE SYSTEM PULLS OFF TO THE EAST. WITH WETBULBING EXPECTED...HIGH TEMPERATURES WILL STRUGGLE TO MOVE OUT OF THE LOW TO MID 30`S TOMORROW. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/... DIGGING SHORTWAVE INTO THE WESTERN GREAT LAKES WILL BRING LIGHT SNOW SHOWERS EARLY THURSDAY...WITH A TRANSITION TO LAKE ENHANCED SNOW SHOWERS LATER THURSDAY AFTERNOON AND THURSDAY NIGHT. MODELS STILL PROG 850MB TEMPS TO FALL TO NEAR -10C BY THURSDAY NIGHT AND WITH A DECENT LAKE FETCH EXPECT SOME LIGHT ACCUMULATIONS IN THE RIDGES AND I-80 CORRIDOR. TEMPERATURES WILL BE AROUND 10 DEGREES BELOW SEASONAL AVERAGE. DRY HIGH PRESSURE WILL MOVE ACROSS THE REGION FRIDAY WITH CONTINUED COLD TEMPERATURES. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... A STREAM OF MOISTURE FROM THE CANADIAN ROCKIES WILL KEEP CLOUDS AND PRECIPITATION CHANCES IN THROUGH THE WEEKEND AS NW FLOW HOLDS INTO EARLY SUN. HIGH PRESSURE WILL SLIDE SOUTH INTO THE NRN PLAINS OVER THE LATTER PART OF THE WEEKEND...DISLODGING A WEAK COLORADO LOW WITH RELATIVELY LOW MOISTURE INTO OUR AREA. WHILE THIS MEANS MORE LIGHT PRECIPITATION...THE GOOD NEWS IS A TRANSITION TO SWERLY FLOW AND OVERALL WARMING INTO NEXT WEEK. MODELS HAVE MADE REMARKABLE PROGRESS IN CONSISTENCY OVER THE LAST 24HRS LENDING TO HIGHER CONFIDENCE IN THE EXTENDED TRENDS. && .AVIATION /21Z TUESDAY THROUGH SUNDAY/... GENERAL VFR OVERNIGHT UNTIL CLOUDS AND MOISTURE SPREAD NORTHWEST FROM COASTAL LOW DEVELOPING TONIGHT. PRECIP SHIELD WILL SPREAD IFR SNOW FROM PITTSBURGH AND MORGANTOWN EAST MAINLY FROM 12-18Z THEN IMPROVING LATE DAY. GUSTY WEST WINDS WILL DIMINISH THIS EVENING. LIGHT NORTH TO NORTHEAST WINDS LATER TONIGHT THROUGH WEDNESDAY. OUTLOOK.../WEDNESDAY NIGHT THROUGH SUNDAY/... RESTRICTIONS POSSIBLE THURSDAY IN SNOW SHOWERS. A FRONT WILL BRING POSSIBLE RESTRICTIONS IN SHOWERS SUNDAY INTO MONDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...WINTER STORM WARNING FROM 4 AM TO 6 PM EST WEDNESDAY FOR MDZ001. OH...NONE. PA...WINTER STORM WARNING FROM 4 AM TO 6 PM EST WEDNESDAY FOR PAZ074-076. WINTER WEATHER ADVISORY FROM 4 AM TO 6 PM EST WEDNESDAY FOR PAZ023-073-075. WV...WINTER STORM WARNING FROM 4 AM TO 6 PM EST WEDNESDAY FOR WVZ023-041. WINTER WEATHER ADVISORY FROM 4 AM TO 6 PM EST WEDNESDAY FOR WVZ021-022. && $$

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