FXUS61 KPBZ 041129 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 729 AM EDT Wed Jun 4 2025 .SYNOPSIS... Dry and warmer weather is expected today under high pressure. Shower and thunderstorm chances return Thursday with an approaching cold front. The front is then expected to drift southward across the region through Saturday, keeping unsettled weather across the area. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... KEY MESSAGES: - Dry and warm today --------------------------------------------------------------- Made a few adjustments to temperatures and other forecast elements based on the latest observations. Otherwise, height rises will continue today as a ridge strengthens across the Eastern CONUS. 500 mb heights are expected to range from 587-589 decameters across the Upper Ohio Valley region, with 850 mb temps progged to peak from 16-18 deg C. This should result in high temperatures in the mid to upper 80s for much of the area, with a few of the warmer locations near 90. Dew points are also expected to increase some from yesterday, though heat indices are progged to remain near the air temperature. Recent RAP and HRRR model smoke fields indicate some haze/smoke aloft will be present today, though concentrations are expected to be less than yesterday. A diurnal cumulus cloud layer is also expected to develop as temperatures warm to convective thresholds, though a strong mid level cap in place should preclude any shower activity from developing. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... KEY MESSAGES: - Showers/thunderstorms return Thursday, a few could be severe - Locally heavy rain also possible Thursday and Friday ---------------------------------------------------------------- Dry weather will continue tonight as the ridge begins to move eastward. A surface cold front is then expected to approach the region on Thursday. An initial shortwave trough will likely add support for showers/storm development especially Thursday afternoon as the front sinks slowly southward. Capping should initially limit storm development, though this cap should erode as the front approaches. Surface based CAPE is expected to range from 1500-2000 j/kg by mid to late afternoon, with relatively weak shear. Dry mid level air is expected to be in place, enhancing DCAPE values, and resulting in a damaging wind potential with any storms that are able to become organized. With the relatively weak flow aloft, there is a potential for slower moving or training storms, which could result in a heavy rainfall potential. The thunderstorm intensity should diminish Thursday evening with the loss of daytime heating, though some limited elevated instability will remain. The front is expected to be stalled across central OH into western PA Thursday night and Friday with the flow aloft parallel to it. A few showers and thunderstorms will continue Thursday night with this front in place. Expect shower/storm coverage to increase Friday with building diurnal instability, though the potential for severe storms is expected to be lower than Thursday with less available instability. A shortwave is expected to track east toward the Upper Ohio Valley region Friday night into early Saturday, with another round of showers/storms expected. Locally heavy rainfall will again be possible. && .LONG TERM /SATURDAY THROUGH TUESDAY/... KEY MESSAGES: - Shower and thunderstorm chances continue Saturday - Mainly dry Sunday - Unsettled weather early next week ------------------------------------------------------------------- The passing shortwave should result in a wind shift to the west aloft, slowly driving the surface front out of the region by Saturday evening. Shower and thunderstorm chances will continue during the day Saturday as the front completes its passage. Sunday should be mainly dry as weak surface high pressure briefly builds across the region. A deepening trough is progged to advance from the Midwest to the Great Lakes and Upper Ohio Valley region early next week. Shower and thunderstorm chances are expected to increase again with the approach and passage of this trough. Temperatures are expected to average near seasonable levels through the period. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... VFR continues through the TAF period with high pressure. Latest guidance continues to indicate near-surface smoke density will be lower today than observed yesterday when VIS restrictions were minimal. High level smoke/haze is expected to continue. Winds remain generally light and SW'erly through the period, with the exception being possible gusts to near 20kt at FKL with daytime mixing. Outlook... The next potential impact period will be on Thursday when shower and thunderstorm chances increase (and restrictions mainly tied to convection). A series of shortwaves crossing the region will return shower and thunderstorm chances Friday and Saturday as well. && .PBZ WATCHES/WARNINGS/ADVISORIES... PA...None. OH...None. WV...None. && $$ SYNOPSIS...WM NEAR TERM...WM SHORT TERM...WM LONG TERM...WM AVIATION...Rackley/AK