Area Forecast Discussion
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084 FXUS61 KPBZ 070305 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 1005 PM EST SAT FEB 6 2016 .SYNOPSIS... WARM TEMPERATURES ARE EXPECTED SUNDAY. HOWEVER...LOW PRESSURE WILL SPREAD RAIN AND SNOW OVER THE REGION ON MONDAY AND TUESDAY. && .NEAR TERM /THROUGH SUNDAY/... WHAT HIGH DECK THERE WAS HAS DEPARTED TO THE SOUTHEAST AHEAD OF THE PASSING UPPER SHORTWAVE TROUGH. WEAK WARM ADVECTION WILL CONTINUE IN THE TROUGHS WAKE...WITH SURFACE RIDGING REMAINING DOMINANT OVERNIGHT THROUGH SUNDAY. THUS...ONLY MINOR ADJUSTMENTS WERE MADE TO THE FORECAST TONIGHT...WITH THE MOST NOTABLE CHANGE MADE TO DEWPOINTS AS MID TEEN VALUES CONTINUE TO REMAIN PRESENT. MODEL GUIDANCE SUPPORTS INCREASING VALUES...BUT NOT TO THE DEGREE AT WHICH THEY WERE FORECAST. SINCE WE WILL LIKELY DECOUPLE...TEMPERATURES SIMILAR TO LAST NIGHTS VALUES ARE FORECAST. WE WILL REMAIN IN THE RIDGING BETWEEN TWO LOW PRESSURE SYSTEMS...OVER THE UPPER MISSISSIPPI VALLEY AND SOUTHEASTERN U.S...ON SUNDAY. TEMPERATURES WILL REMAIN SLIGHTLY ABOVE SEASONAL AVERAGES. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... THE UPR MS LOW IS CURRENTLY FORECAST TO DEEPEN OVR THE GREAT LAKES AND MIDWEST...HENCE AMPLIFYING THE SOUTHWEST...TO SOUTHERLY FLOW OVR THE UPR OH FOR SUNDAY NIGHT AND MONDAY. IMPROVED MOISTURE AND ASCENT FIELDS WILL THUS SUPPORT INCREASED PRECIP PROBS OVER WESTERN ZONES ON SUNDAY NIGHT WITH EASTWARD ENHANCEMENT ON MONDAY. THE MARGINAL TEMP PROFILE AND WARM BOUNDARY LAYER IN THE WARM ADVECTION REGIME ON THE EASTERN FLANK OF THAT SYSTEM ARE LIKELY TO COMPROMISE SNOW POTENTIAL AND PRECLUDE SERIOUS ACCUMULATION THROUGH MONDAY...HOWEVER...THE SYSTEMS FRONTAL PASSAGE WILL DECISIVELY CHANGE THE TEMP PROFILE AS NIGHT FALLS ACCORDING TO CURRENT TIMING. FORTUNATELY...THE ENCROACHMENT OF THE MID/UPR LOW CENTER SHOULD SUFFICIENTLY WEAKEN THE WIND/FRONTOGENESIS POTENTIAL AND OVERALL ASCENT FIELDS AND THUS OFFSET THE IMPROVED TEMP PROFILE FOR SNOW. THE FORECAST IS THUS OF PROLONGED SNOW SHOWER POTENTIAL THROUGH TUESDAY WITH RELATIVELY MINOR ACCUMULATION GIVEN THE TIME FRAME. THE EXCEPTION LOOKS TO BE THE RIDGES AS USUAL WHERE OROGRAPHIC SUPPORT SHOULD SUPPORT MORE SIGNIFICANT ACCUMULATION. A MENTION IN THE HAZARDOUS WEATHER OUTLOOK WAS INCLUDED FOR THAT POTENTIAL. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... THE AFOREMENTIONED LOW IS GFS/ECMWF FORECAST TO CUTOFF AND DEVELOP EASTWARD BEFORE FILLING/PHASING INTO THE LONGWAVE PATTERN BY MIDWEEK. NEVERTHELESS...OVERALL UPPER TROUGHING IS PROGGED OVR THE GREAT LAKES/UPR OHIO REGION FOR THE LONG-TERM PERIOD...WITH AMPLIFICATION INDICATED TOWARD THE WEEKEND. SUB-AVG TEMPS AND PERSISTENT SNOW SHOWER CHANCES WERE MAINTAINED FOR THE PERIOD...WITH FOCUS TOWARD THE I-80 CORRIDOR AND RIDGES DURING THE LATTER HALF OF THE WEEK. THE LONG TERM WAS CONSTRUCTED USING THE SUPERBLEND GUIDANCE. && .AVIATION /03Z SUNDAY THROUGH THURSDAY/... VFR CONDITIONS WILL CONTINUE THROUGH THE NIGHT AND INTO SATURDAY. LIGHT SOUTHWESTERLY FLOW WILL TURN MORE SOUTHERLY ON SATURDAY...WITH A FEW GUSTS POSSIBLE BY AFTERNOON. FRIES .OUTLOOK.../SUNDAY NIGHT THROUGH THURSDAY/... RESTRICTIONS ARE LIKELY SUNDAY NIGHT INTO MONDAY WITH A PASSING SYSTEM. NORTHWESTERLY FLOW WILL CONTINUE THROUGH MOST OF NEXT WEEK...MEANING STRATUS AND SNOW SHOWERS WILL CONTINUE SOME RESTRICTIONS THROUGH MUCH OF THE WEEK. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$

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