Area Forecast Discussion
Issued by NWS Pittsburgh, PA
Issued by NWS Pittsburgh, PA
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006 FXUS61 KPBZ 240758 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 358 AM EDT Tue Sep 24 2024 .SYNOPSIS... An active weather pattern is expected through most of the week with a Marginal Risk for severe weather today south and west of Pittsburgh. Even with the clouds and threat of rain, temperatures will remain warm through the week. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... KEY MESSAGES: - More widespread showers/storms possible today. - Strong to severe storms remain a threat. ------------------------------------------------------------------- A surface warm front will slowly move northward through the region later today. The front is associated with a surface low moving across the midwest. A shortwave, swinging northeastward on the eastern side of the digging midwest trough, will help to push the front through the region. Showers and storms are expected to develop along the front. The threat for strong to severe storms will continue, particularly over portions of Ohio, SW PA (south of PIT), and northern WV. The greater threat exists over these locales due to an increasingly unstable atmosphere that will occur in the warm sector south of the surface boundary. Along with the destabilization, wind shear will strengthen this afternoon, values will approach 50kts close to and south of the front. The question for today is can convection initiate. Models are all in good agreement that there will be plenty of cloud cover today. Additionally, warm air advection aloft will create a cap which will work against parcels reaching the LFC. The strengthening shear will intensify any updrafts in storms that do develop which may be enough to push through the cap. The current marginal risk area from SPC is focused over the portion of the region that will see the most instability, so this continues to look reasonable. Model hodographs would support rotating storms, so if strong storms do develop, this will be a concern. A wide range of temperatures are expected today, those in the warm sector, upper 70s to lower 80s, and those north of the warm sector, upper 60s to lower 70s. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/... KEY MESSAGES: - Rain chances continue through mid-week. ------------------------------------------------------------------- The digging midwest trough is favored to cut off into a closed low across the south-central CONUS with some uncertainty in the timing and depth of a northern stream trough north of the Great Lakes on Wednesday. Rain chances will continue with rounds of shortwaves and general troughiness in southwest flow aloft. With generally weaker forcing, 24 hour totals ending Thursday morning look on the lighter side, mostly less than 0.5", though a much lower probability solution with a deeper, phased trough exists with higher amounts. Temperatures through mid-week will be cooler owing to increased cloud coverage and precipitation. A weak boundary may pass through the area sometime Thursday, but seeing significant spread in the ensembles on the timing which will impact when we lose the rain chances. Ensemble clusters exhibit quite a bit of disagreement at this point with how the upper level pattern evolves. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... KEY MESSAGES: - Uncertainty increases greatly for the end of the week with potential tropical low interaction. - Rain chances will continue through the end of the week. ------------------------------------------------------------------- The central CONUS trough may interact with the remnants of now PTC 9 as it moves inland out of the Gulf. Meanwhile, the northern stream trough will be sliding across the Northeast states. Ensemble clusters all show that the remnants will be absorbed by the trough but with much uncertainty after that. The highest probability scenario at this time is that the northern stream trough deflects the remnants off to our west and rain chances here are lower. There are potential wetter solutions with a track further east, but until we get a better idea on the evolution, will stick with NBM given all of the uncertainty which advertises low end rain chances into the weekend. && .AVIATION /08Z TUESDAY THROUGH SATURDAY/... Ample cloud coverage is expected to keep IFR visibility restrictions to a minimum, but a brief drop to MVFR visibility overnight cannot be ruled out with ample low-level moisture and air near saturation, particularly for DUJ and perhaps FKL. Winds are generally expected to remain light and out of the southeast. A passing wave will allow for some light rain locally, with more substantial amounts for MGW through sunrise. Save FKL/DUJ, ceilings are generally expected to remain VFR though brief drops in cigs to MVFR are possible in isolated showers. As for FKL/DUJ, there is 40% to 60% chance of IFR cigs and may continue through the period with continued rain chances. Into today, convective coverage is expected to increase with increasing instability. Flow will accelerate slightly out of the southeast. Storms will remain possible through the day, but TAFs attempted to capture the most favorable window for now. The environment is supportive of damaging wind, hail, and isolated tornadoes, but intensity is still highly questionable with uncertainties in instability. Restrictions are likely in any more intense storms. Uncertainties in instability and mixing also truckle down to cigs, which may hover around the VFR/MVFR range, depending on how much heating the area can tap into during the day. Deterioration is expected tonight, particularly for areas which it has rained. Ceilings are expected to lower to the MVFR/IFR range once again. Winds lighten out of the southeast. .Outlook... Some improvement is expected Wednesday, with a 80% chance of VFR, though very isolated showers and storms may bring temporary cig/vis drops. Restriction chances increase Thursday morning, before VFR returns to close out the work-week. && .PBZ WATCHES/WARNINGS/ADVISORIES... PA...None. OH...None. WV...None. && $$ SYNOPSIS...22/MLB NEAR TERM...22 SHORT TERM...22/MLB LONG TERM...MLB AVIATION...Milcarek