


Area Forecast Discussion
Issued by NWS Pittsburgh, PA
Issued by NWS Pittsburgh, PA
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788 FXUS61 KPBZ 161714 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 114 PM EDT Thu Oct 16 2025 .SYNOPSIS... Dry weather is expected for most of the area through Saturday as high pressure moves east across the region, though a weak warm front will bring a chance for light rain showers west and north of Pittsburgh late Friday night. A strong cold front will bring showers, possible thunderstorms, and gusty wind for Sunday. && .NEAR TERM /THROUGH TONIGHT/... KEY MESSAGES: - Dry weather continues under high pressure. - Frost/freeze threat again tonight into early Friday morning --------------------------------------------------------------- Similar conditions are expected tonight compared to last night, but with higher confidence in calmer wind and colder overnight lows. The probability for the vast majority of the area to see frost is high at 80-100% (lowest in the urban areas and immediately along the Ohio River). Continuing to see lower probabilities for temperatures <32F in the HREF than I would normally like, but with high pressure centered more directly over the area I have higher confidence that winds will settle more than it seems to suggest. Therefore, favoring NBM probabilities for tonight`s freeze potential, which shows a 60-80% chance for counties north of Pittsburgh and along the ridges of SW PA and northern WV. Taking this into consideration, opted to upgrade to a Freeze Warning for those counties, while a Frost Advisory was favored for the rest of the area. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... KEY MESSAGES: - Well above normal temperatures for the weekend - Scattered showers possible Friday night - Cold front passage Sunday offers higher rain chances and windy conditions ---------------------------------------------------------------- We`ll finally get some mid-level height rises locally as the ridge axis shifts eastward. Surface high pressure remains situated overhead and plenty of subsidence will keep dry conditions in place, though clouds will be on the increase from northwest to southeast through the daytime hours as some increase in mid and upper level moisture rides around the ridge. We`ll bring some warm advection/weak shortwave driven rain shower chances in late Friday into very early Saturday, but this shouldn`t amount to a whole lot as lingering dry air in the sfc-700mb layer will result in a fair amount of sub-cloud evaporation. The most likely areas to see some accumulation (on the order of a few hundredths of an inch) are north of I-80, while farther south most of the area might just see some intermittent sprinkles resulting in little or no accumulation. Saturday will be a transition day of sorts as a more complex pattern begins to take shape. A trough deepens over the central CONUS and pushes the narrow upper ridge over the eastern seaboard eastward over the Atlantic. A rather potent shortwave ejects eastward from the central Rockies during the day Saturday, traversing the Plains and reaching the Mississippi Valley overnight Saturday into early Sunday morning. Meanwhile, a surface low develops in the IA/WI/IL vicinity, which rapidly deepens and lifts northeast towards the Great Lakes, eventually becoming vertically stacked beneath the parent shortwave. As all of this occurs, it causes deep-layer southwesterly flow to strengthen downstream over the Ohio Valley and lower Great Lakes, which in turn brings moisture and unsettled weather back to the local area Saturday night through Sunday night. This will also result in a warming trend for temperatures Saturday and Sunday, with highs climbing into the low 70s each day. Sunday`s forecast becomes more interesting with a dynamic system bringing a two-fold threat. First, the stacked low moves closer in proximity to the local area as it crosses the Michigan lower peninsula and southern Ontario, which will cause the pressure gradient between it and a broad surface high centered off the southeastern U.S. coast to tighten. In addition, ensembles suggest the deep-layer flow to be quite strong as expected this time of year with around a 50-60% chance for 925 mb wind to exceed 35 knots which forecast soundings suggest will be easily mixed down to the surface. This will result in an uptick in non-convective winds. Latest probabilities for max wind gusts exceeding 30 mph on Sunday are have increased notably across the entire area with 80-100%, while probabilities for max gusts exceeding 40 mph have followed the same trend up to 40-70%. The second hazard will be showers and thunderstorms associated with this system. A cold front will pass through sometime on Sunday, though latest ensemble clusters still show a very low confidence pattern with the majority of uncertainty stemming from a timing issue with the parent trough. There`s about an even split between those members who suggest it`s quicker and through the area Sunday afternoon while the others hold it back until later Sunday evening. This evolution will impact frontal passage timing and potential thunderstorm development. This will be a high shear/low CAPE setup with mean NBM SBCAPE around 200-400 J/kg and 90th percentile values (contingent on any low probability scattering of clouds) sneaking up as high as 600 J/kg. Deep layer shear will be strong (LREF mean sfc-500mb shear up to or even in excess of 50 knots), so if any deep updrafts are able to form, they will be in an environment that supports at least a limited damaging wind threat, though such a high shear/low CAPE environment lends question as to whether or not there could be too much shear for the little CAPE in place. This will all be ironed out more in the coming days. && .LONG TERM /SUNDAY THROUGH THURSDAY/... KEY MESSAGES: - Cooler weather returns next week - Periodic rain chances for the first half of the week ------------------------------------------------------------------- Notable upper level pattern discrepancy continues and increases into next week with some ensembles holding the trough back and closing it off into an upper low while others quickly progress it offshore as an open wave. The slower, deeper solution could result in rain chances remaining on Monday with low level cold advection and periodic shortwave passage while a quicker one allows high pressure and drier air to sneak in quicker. Think that we likely will keep some showers around Monday morning with lingering low level moisture and cold advection reinforcing steeper low level lapse rates, and the latest NBM offers 20-30% PoPs which seems reasonable at this juncture. High pressure does eventually build behind the departing low, though how long it stays around is uncertain as ensembles develop another surface low off to our northwest with additional rain chances returning as early as Tuesday. Given cascading differences among solutions even for this coming weekend, confidence beyond that timeframe is very low at this time. && .AVIATION /17Z THURSDAY THROUGH MONDAY/... VFR is expected through the TAF period as high pressure moves across the region. River valley steam fog is likely tonight, though no significant impact to the TAF sites are expected. Increasing mid and high level clouds are expected Friday under warm advection aloft. .OUTLOOK... VFR is expected through Saturday with increasing mid/high clouds ahead of an approaching cold front. This front will bring showers, possible thunderstorms, and gusty wind to the region as it crosses on Sunday. Restrictions, gusty wind, and showers are likely to continue through early Monday under subsequent upper troughing. High pressure should return VFR by Monday afternoon. && .PBZ WATCHES/WARNINGS/ADVISORIES... PA...Frost Advisory from 2 AM to 9 AM EDT Friday for PAZ007-013-020- 021-029-031. Freeze Warning from 2 AM to 9 AM EDT Friday for PAZ008-009- 014>016-022-073>078. OH...Frost Advisory from 2 AM to 9 AM EDT Friday for OHZ039>041- 048>050-057>059-068-069. WV...Frost Advisory from 2 AM to 9 AM EDT Friday for WVZ001>004-012- 021-509-510. Freeze Warning from 2 AM to 9 AM EDT Friday for WVZ511>514. && $$ SYNOPSIS...MLB NEAR TERM...Cermak/MLB SHORT TERM...Cermak/MLB LONG TERM...Cermak/MLB AVIATION...WM