


Area Forecast Discussion
Issued by NWS Pittsburgh, PA
Issued by NWS Pittsburgh, PA
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550 FXUS61 KPBZ 141747 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 147 PM EDT Mon Jul 14 2025 .SYNOPSIS... Rain and flooding chances today, relatively drier Tuesday, then additional rain with severe weather and flood chances to close out the week. Temperatures are expected to remain above normal. && .NEAR TERM /THROUGH TONIGHT/... KEY MESSAGES: - Rain and flooding chances today. - Dense fog possible tonight. --------------------------------------------------------------- This afternoon, the area will sit south of a surface boundary that gradually pushes south into the day. This had led to some low level convergence in air with an observed 1.75" PWAT (90th percentile), resulting in fairly widespread rain with embedded convective elements where saturation wet-bulbed the sfc to 600mb layer. Because most of this activity is below freezing, almost all rain is following warm rain processes. As a proxy for where most of the convection is, the sfc-3km mean wind is observed at 2kts as of 12Z. All of these elements will come together to increase a flooding risk this afternoon/evening. If there is an area to watch, it will primarily be the boundary sagging south, allowing for enhanced convergence and higher precipitation rates. Along the boundary, flooding has already been observed south of New Castle (2" to 3" per hour rainfall rates), showing the atmosphere is already capable. As the boundary pushes south, the timing of the threat may be maximized in southwest PA the northern WV panhandle, and southeast Ohio between 2pm to 7pm, before threats may maximize in the rest of northern West Virginia in roughly the 4pm to 9pm timeframe, though flooding cannot be rules out anywhere south of the boundary at any point. This timing matches a combination of frontal position and maximized solar heating and instability generation through the day. In line with what has already been observed and HREF maximum QPF totals, we might expect the high-end amounts in tropical rain to get close to 2" to 3" per hour, topping the rough 1.25" to 2" per hour FFGs. WPC has expanded the slight risk ERO across much of southwest PA and northern WV at the most recent update, with the highest probabilities of flooding toward the ridges. With plenty of moisture, severe chances remain very low today. As the front continues to sag south, return flow and an eastern low development may cause it to stall somewhere in the periphery of I-70 overnight, while rain could not be rules out completely in high moisture along a forcing axis, in general, the loss of daytime heating will preclude any notable probabilities overnight. On the other hand, with dew points in the upper 60s and low 70s behind the front with some cloud clearing, calm winds, and recent rains promoting high surface soil moisture, this may support locally dense fog overnight. && .SHORT TERM /TUESDAY THROUGH THURSDAY/... KEY MESSAGES: - Warmer with lower rain chances north of I-70 Tuesday; chance of rain and flooding near and south of I-70. - Increasing heat impacts, flood chances, and severe chances Wednesday and Thursday. ---------------------------------------------------------------- As mentioned before, the front will sit relatively still somewhere across the area into Tuesday, Wednesday, and Thursday which will allow a continued active pattern. Tuesday will likely be the most quiet day of the lot, with drier air filling in in subsidence aloft behind the front and through parts of the forecast area, which may keep skies mostly clear, most likely north of the front, which is most likely to reside around I-70. This will lower PWATS; with little forcing precipitation and especially flooding chances will be quite low. This will allow heat to creep back in, with forecast highs a few degrees warmer than Monday (into the upper 80s and low 90s). Some major heat risk may creep back in for urban and valley locations. South of the front, which again, is likely going to be somewhere in the I-70 corridor, some residual moisture and weak convergence along the stalled boundary in modeled 1.5" to 1.7" PWATs (near Morgantown) with weak flow will continue marginal flash flood mentions. Perhaps the highest local chances will be along the WV ridges with ridge-top convergence and forced ascent. Little temperature recovery is expected overnight with lows bottoming out near or above the 70F mark. Wednesday, the boundary will again remain, expect there may be a bit of return flow with some overrunning of the boundary possible. This will allow flood risks to perhaps continue, as the stalled front may come back north as a warm front. With this, moisture, clouds, and storm chances return. With drier air on the north side of the front, it seems there may be a chance of flooding and severe weather during the day. The flood risk is a bit more concrete with another push of 90th percentile PWATs on a boundary in flow generally weak flow (<10kts in the cloud layer). This will be most likely along and south of the front, but will depend of the frontal placement. Chances may be the highest south of PIT in the morning/early afternoon, pushing through and north of PIT in the afternoon/evening. Severe appears marginal, but occurrence will rely on the presence of dry air aloft north of the front and overrunning to realize a downburst wind threat. This increase of severe chances Wednesday is supported by CSU/NCAR ML and CIPS analogs. Because it will rely on dry air, chances may be a bit high around and north of PIT. Cloud cover chances have increased a bit Wednesday, witch may both complicate instability generation, and has also dropped the max temperature forecast slightly, though cumulative heat stress will linger, particularly for valleys and urban areas with heat risk maintaining moderate/major mentions. Again, little recovery is expected with lows in the 70s expected for most. Thursday, th region will be solidly in the warm sector, with another fount forecast off to the north somewhere in the vicinity of the lower Great Lakes. Another push of the pre- frontal, warm, and moist southwest flow will keep cognitions muggy and warm, with moderate/major heat risk lingering. While CIPS and ML linger some low probabilities of severe win the warm sector, LREF mean PWATS pushing 2" in long, skinny CAPE might allude to more of a continued, area-wide flood risk. && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... KEY MESSAGES: - Frontal passage on Friday will bring more seasonable temperatures. - A return to warm and wet expected next week. ------------------------------------------------------------------- Friday, the environment will be similar to Thursday before the cold frontal passage. The frontal passage Friday seems a bit more guaranteed than the prior update, but passage timing is slightly uncertain, with some ensembles moving it through in the morning, while others have it crossing as late at the evening. This will affect flood chances, severe chances, and temperatures. An earlier passage would mean lower chances of flooding/severe and keep temperatures near normal of Friday, while a later passage would provide warmer highs and higher severe/flood risks. The pattern remains in good agreement through the weekend and into next week. This would suggest the front comes back north as a warm front over the weekend, and the region stays in quasi- zonal flow with above average temperatures, continued rain chances, and non-zero flooding severe chances depending on the timing or amplitude of various shortwave passages. Long storm short, the pattern may remain the same for a little while longer. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... Numerous showers and a few thunderstorms will continue through late afternoon as a shortwave trough crosses the Upper Ohio Valley region. Included a prob30 for thunder for some sites, including PIT, where the latest meso analysis shows some instability. Ongoing showers and cloud cover will be the main limiting factors for storm development. The rain should end by evening, with partial clearing behind the shortwave. This should result in increasing fog/stratus development overnight, with IFR to LIFR at most airports. The fog should mix out Tuesday morning, with VFR returning. CU rule and model soundings indicate a scattered to broken diurnal cumulus layer should develop by mid to late morning, continuing into the afternoon. Most airports should remain dry Tuesday afternoon, though MGW could see some chance of a late day thunderstorm as a stationary surface front sets up to the south of I-70. Outlook... Daily shower and thunderstorm chances are expected to continue, especially in the afternoons and evenings, as a quasi stationary front drifts across the region. Early morning fog and stratus is also possible, especially where rainfall occurs in the afternoon and evening. && .PBZ WATCHES/WARNINGS/ADVISORIES... PA...None. OH...None. WV...None. && $$ SYNOPSIS...Milcarek NEAR TERM...Milcarek SHORT TERM...Milcarek LONG TERM...Milcarek AVIATION...WM