Area Forecast Discussion
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000 FXUS61 KPBZ 020619 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 119 AM EST MON MAR 2 2015 .SYNOPSIS... SNOW WILL WIND DOWN OVERNIGHT. A SECOND STORM...ACCOMPANIED BY MILDER TEMPERATURES...WILL BRING POTENTIALLY HEAVY RAINFALL TO THE REGION TUESDAY AND TUESDAY NIGHT...LIKELY BEGINNING AS A PERIOD OF SLEET AND FREEZING RAIN EARLIER IN THE DAY. ICE ACCUMULATIONS ARE POSSIBLE. && .NEAR TERM /THROUGH TODAY/... MINOR UPDATE TO SLIGHTLY DECREASE OVERNIGHT PRECIPITATION CHANCES AS THE LATEST MODEL SOUNDINGS SHOWING THE BOUNDARY LAYER QUICKLY DROPPING AS SUBSIDENCE BEHIND THE COLD FRONT NOW JUST ABOUT THROUGH THE FORECAST AREA. THE EXCEPTION WILL BE ALONG THE RIDGES WHERE THE COMBINATION OF MODERATE UPSLOPE FLOW AND SATURATED LOW LEVELS WILL BE ENOUGH TO SEE LIGHT SNOW PERSIST UNTIL RIGHT AROUND SUNRISE. ACCUMULATIONS WILL BE MINIMAL WITH TEMPERATURES EXPECTED TO STAY NEAR THE FREEZING MARK AND SNOW RATIOS AROUND 5:1. PREV DISCUSSION BELOW... MOST OF THE WIDESPREAD SNOW HAS MOVED OUT OF THE REGION. EVEN WHERE PRECIPITATION LINGERS...INTO LATROBE AND MORGANTOWN...TEMPERATURES REMAIN ABOVE FREEZING AND PRECIPITATION IS CURRENTLY FALLING AS RAIN. AT THIS POINT...HAVE DECIDED TO GO AHEAD AND CANCEL THE ENTIRE WINTER WEATHER ADVISORY. ANY ADDITIONAL SNOWFALL APPEARS TO BE AN INCH OR LESS CONSIDERING HOW SHALLOW ANY REMAINING INVERSION WOULD BE AT THE SURFACE AND HOW LOW SNOW RATIOS HAVE BEEN THROUGHOUT THE DAY. IN ADDITION...IT WILL STILL BE A FEW MORE HOURS UNTIL ALL LOCATIONS DROP BACK BELOW FREEZING. WITH THE EXTENSIVE CLOUD COVER OVERNIGHT...TEMPERATURES WILL ONLY DROP INTO THE MID 20S. THESE VALUES WILL BE THE FIRST TIME MUCH OF THE REGION HAS SEEN NEAR NORMAL LOW TEMPERATURES IN AT LEAST A WEEK. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY/... A BRIEF LULL IN PRECIPITATION IS FORECAST FOR MONDAY AS HIGH PRESSURE SLIDES ACROSS THE REGION. COLD ADVECTION SHOULD PREVENT HIGHS FROM RISING ABOVE FREEZING...HENCE NO MELT ISSUES ARE ANTICIPATED. COLD TUESDAY MORNING TEMPERATURES ARE QUESTIONABLE GIVEN THE EXPECTED DEVELOPMENT OF A WARM ADVECTION REGIME IN ADVANCE OF MIDWESTERN LOW PRESSURE. A COLD START WITH RAPID MOISTURE ADVECTION MAY SPAWN SOME FREEZING RAIN PROBLEMS AND A MENTION OF POSSIBLE HEADLINES WAS CONTINUED IN THE HAZARDOUS WEATHER OUTLOOK...BUT THE PRECIPITATION START TIME AND TEMPERATURE MAGNITUDE PROGNOSIS IS NOT MODEL CONSISTENT AND WILL HAVE TO BE MONITORED. IN ADDITION...PROLONGED WARM...MOIST ADVECTION IS EXPECTED TO SUPPORT SUSTAINED RAINFALL LATER ON TUESDAY AND TUESDAY NIGHT. WARMER AIR AND HIGHER DEWPOINTS WILL SUPPORT SNOW MELT UNTIL COLD FRONT PASSAGE ON TUESDAY NIGHT...BUT RAIN AMOUNTS AS DEPICTED BY THE MODELS ARE SHAKY AS USUAL IN WARM ADVECTION EVENTS...ESPECIALLY IN LIGHT OF THE LOW CENTER CROSSING THE GREAT LAKES. A LACK OF CONVECTION AND MID LEVEL FRONTOGENESIS WOULD CERTAINLY ROB THE POTENTIAL FOR SUSTAINED HEAVY RAINFALL. NEVERTHELESS...WITH SNOWMELT...SMALL STREAM AND RIVER RISES SHOULD BE ANTICIPATED AND SOME ICE COVER IS LIKELY TO POP...ESPECIALLY OVER SOUTHERN BASINS. THE RESULTING POTENTIAL FOR ICE JAM FLOODING WILL THUS REMAIN IN THE HAZARDOUS WEATHER OUTLOOK ALSO. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... MOST OF THE OPERATIONAL AND ENSEMBLE SOLUTIONS SHOW THE COLD FRONT RACING TOWARD THE EAST COAST WEDNESDAY NIGHT. THIS WOULD BRING A QUICK END TO LINGERING SNOW SHOWERS BEHIND THE FRONT. LARGE AREA OF HIGH PRESSURE WILL BUILD IN AND PROVIDE A QUIET BUT COLD END TO THE WEEK. TEMPS BEGIN TO MODERATE ON SATURDAY...BUT BY SUNDAY...FORECAST CONFIDENCE WANES AS MODEL SOLUTIONS SEPARATE. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... RESTRICTIONS WILL CONTINUE INTO THE AFTERNOON HOURS. A GENERAL MVFR FORECAST WITH OCCASIONAL IFR WITH LOW CIGS AND FOG THROUGH DAWN. AFTER THIS TIME...STUBBORN STRATOCU DECK WILL KEEP MVFR CONDITIONS THROUGH AT LEAST THE MORNING HOURS. IMPROVEMENT IS EXPECTED IN THE AFTERNOON AS SURFACE HIGH MOVES THROUGH THE DISTRICT. .OUTLOOK.../MONDAY NIGHT THROUGH FRIDAY/... LOW PRESSURE CROSSING THE GREAT LAKES IS LIKELY TO SPAWN WIDESPREAD RESTRICTIONS ONCE AGAIN BY TUESDAY AFTERNOON. && .HYDROLOGY... AN INCREASE IN FLOW AND STAGE IS EXPECTED TO CAUSE ICE MOVEMENT STARTING TUESDAY...BEGINNING ON THE SOUTHERNMOST RIVER BASINS. THE CURRENT FORECAST CONTINUES TO HAVE A HIGH LEVEL OF UNCERTAINTY ABOUT PRECIPITATION PHASE AND AMOUNTS AS WELL AS THE DEGREE OF SNOW MELT. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$

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