Area Forecast Discussion
Issued by NWS Pittsburgh, PA
Issued by NWS Pittsburgh, PA
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922 FXUS61 KPBZ 070128 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 928 PM EDT Sat Jul 6 2024 .SYNOPSIS... Dry weather is anticipated to continue into Monday under high pressure. Fog potential increases early Sunday morning north of Pittsburgh, PA. && .NEAR TERM /THROUGH SUNDAY/... KEY MESSAGES: - Dry conditions and seasonable temperatures today. - Fog potential increases early Sunday morning with radiational cooling, especially for areas north of Pittsburgh. ------------------------------------------------------------------- 9:30PM Update: No major changes have been made to this forecast period. Previous Discussion: Dry, quiet weather will continue across the region under high pressure. Overnight low temperatures will be near the climatological average (low to mid-60s) across the region. With a prolong period of clearing overnight, radiational fog may develop for portions of the region. Hi-Res model guidance are focusing heavily near the I-80 region for fog due to elevated sfc moisture. However, confidence for a Dense Fog Advisory over the next 12 hours are low. Temperatures on Sunday will be slightly warmer than Saturday with slight warm advection aloft and diurnal mixing under a mostly clear sky. Temperatures will trend 5 degrees above the climatological average; heat index values south of Pittsburgh are anticipated to be near 90F. && .SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/... KEY MESSAGES: - High probability for dry weather and slightly above average temperature the rest of the weekend. - Fog potential for Sunday and Monday mornings. ------------------------------------------------------------------- With sufficient low level moisture, light wind, and breaks in cloud cover, early morning fog development could continue into Monday. With a noted 590dm heights at 500mb and 850mb temperatures around 20C by Monday, daytime highs temperatures are expected to range in the low to mid-90s across the region. && .LONG TERM /TUESDAY THROUGH SATURDAY/... KEY MESSAGES: - Unsettled weather returns Tuesday through at least mid-week. ------------------------------------------------------------------- Ensemble consensus continues to favor an Upper Midwest trough lifting through the Great Lakes region Tuesday into Wednesday morning along with a weak surface trough. Moist advection ahead of the wave is likely to foster a warm, humid environment translating to likely showers and thunderstorms ahead of the feature. Environmental conditions remain varied, but with ensemble means showing near 90F highs and 70F dewpoints, there appears to be at least a low probability for flash flood risk and potential other severe hazards. Latest CSU machine learning output supports this. Variations become post-shortwave passage depending on high pressure strength to the north as well as potential pattern impact from the remnants of Hurricane Beryl. The main takeaways for the long range period is that 500mb mean heights suggest a continuation of near to above normal temperature and precipitation chances tied to shortwave movement. Trends are difficult to pin down at this time, but after the remnants of Beryl moves east, the cold front will finally pass through leading to potentially drier weather to end the forecast period. && .AVIATION /02Z SUNDAY THROUGH THURSDAY/... Mostly a high confidence forecast over the next 24 hours as high pressure remains in control. Remaining cumulus will continue to collapse with sunset, leaving just a few cirrus clouds overnight. The lower confidence portion of the forecast remains the potential for fog development towards sunrise. Limited TAF mention to LBE/MGW/ZZV, where LAMP probabilities and NBM guidance show the highest probabilities. Efficient dry air mixing during the daylight hours may lead to less fog than currently depicted, as crossover temperatures may be hard to reach in some cases. Any fog will largely dissipate by 12Z, leaving VFR conditions for Sunday, with scattered afternoon cumulus development once again. A weaker surface pressure gradient will lead to lighter wind, with W/NW wind remaining under 10 knots. .Outlook... Monday...VFR Tuesday - Thursday: MVFR weather with scattered showers and thunderstorms, but most of the time VFR. && .PBZ WATCHES/WARNINGS/ADVISORIES... PA...None. OH...None. WV...None. && $$ SYNOPSIS...Hefferan NEAR TERM...Hefferan SHORT TERM...Frazier/Shallenberger/88 LONG TERM...Frazier/Shallenberger/88 AVIATION...CL/McMullen