Area Forecast Discussion
Issued by NWS Pittsburgh, PA
Issued by NWS Pittsburgh, PA
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406 FXUS61 KPBZ 270723 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 323 AM EDT Thu Jun 27 2024 .SYNOPSIS... Dry weather resumes today with shower and thunderstorm chances returning for the weekend. Near normal temperatures today will rise into the weekend. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... KEY MESSAGES: - Patchy morning fog will lift by mid-morning. - Dry weather resumes today with near normal temperatures. ------------------------------------------------------------------- A moist, cool airmass after recent precipitation along with relatively light wind and saturated low levels has resulted in patchy fog development and low stratus this morning. Have issued a SPS to cover this as no large scale sub 1/4 mile visibilities have been seen in obs or area webcams. Any stratus or fog should erode by mid- morning. Cool, dry northwest flow as high pressure builds in from the northwest along with increasing subsidence will diminish lingering stratocu through the morning, which should eventually turn into scattered afternoon cumulus. Cold advection and partial cloud cover will result in more seasonable afternoon temperature while post- frontal mixing may support NW wind gusts around 20 mph. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... KEY MESSAGES: - Dry weather continues. - Temperature rises above normal again Friday. ------------------------------------------------------------------- The surface high will shift over New England by Friday as heights aloft rise ahead of the next upper level shortwave trough. Positioning of the high will support weak warm, moist advection amid mostly clear skies to raise area temperature about 5 degrees above the daily average. Broad ascent may increase mid to high level clouds and even low probability showers Friday night as weak perturbations ahead of the main upper level trough axis. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... KEY MESSAGES: - Shower and thunderstorm chances return Saturday into Sunday with the next low pressure system. - Severe or flooding threat looks minimal at this time. ------------------------------------------------------------------- Broad ascent within warm, moist southwesterly flow ahead of the main upper level trough axis will support increasing shower and thunderstorm probabilities starting early Saturday morning. Arrival of a more notable embedded shortwave and the surface cold front Saturday afternoon and evening is likely to help concentrate convective activity (currently favoring NW PA) and spreading it southeast through Sunday morning. Variation in storm timing and environment remains large due to differences in upper trough depth/timing as well as convective evolution prior to its (and cold fronts) arrival. Latest analysis suggests a low probability risk for damaging wind (mean values currently show 30-40kts of 0-6km shear) and localized flooding (tall-skinny CAPE values around 1500 J/kg with PWATs approaching daily maxima). Will mention threat in HWO and monitor evolving forecasts for this period. Dry weather and seasonable temperature is likely by late Sunday into Monday as the upper trough axis moves east and high pressure builds in from the western Great Lakes. && .AVIATION /08Z THURSDAY THROUGH MONDAY/... Little change was made to the 06Z TAFs for tonight with much of the forecast still on track for some fog and low cloud development tonight. Probabilities of IFR vis restrictions remain highest to the west of KPIT with probabilities towards 60% due to anticipated clearing and recent rainfall. The probabilities of IFR cigs remain highest (70% to 90%) east of PIT, with plenty of moisture near the surface and nocturnal cooling. Some combination of restrictions was noted for all ports with lifting anticipated into the day. Broken decks are favored just after sunrise. By afternoon, there is a 80% to 50% probability that broken decks become scattered as we transition to VFR boundary layer cumulus. Cloud cover is expected to clear tomorrow night as mixing ceases. This may lend to patchy MVFR vis restrictions late overnight in fog. This remains most likely for river valley ports and north of I-80. .Outlook... VFR is expected through Fri amid high pressure. Restrictions are possible Fri night with a crossing warm front. Restrictions are likely Sat and Sat night with showers and thunderstorms ahead of and along a crossing cold front. VFR returns Sun under high pressure. && .PBZ WATCHES/WARNINGS/ADVISORIES... PA...None. OH...None. WV...None. && $$ SYNOPSIS...88 NEAR TERM...88 SHORT TERM...88 LONG TERM...Frazier/88 AVIATION...Milcarek