Area Forecast Discussion
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000 FXUS61 KPBZ 271840 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 240 PM EDT Sat May 27 2017 .SYNOPSIS... After a mostly dry overnight period, low pressure and a crossing front will bring rain chances Sunday and Sunday night. Morning showers on Memorial Day will be followed by some afternoon sun. && .NEAR TERM /THROUGH TONIGHT/... Capping so far has managed to keep convective development just south of the CWA through the early afternoon. Still foresee some scattered storms forming mainly south of the Mason-Dixon line, where chance PoPs were maintained, but the bulk of the activity will lie farther south of the boundary across OH/WV. Any severe threat will be isolated at best, as CAPE and bulk shear are quite marginal. Any activity will fade this evening with the loss of heating, leading to a mostly quiet overnight period as midlevel ridging passes through. The leading edge of precipitation may sneak into ZZV around sunrise as isentropic lift develops here late tonight. Overnight low temperatures will be a few degrees above climatology. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... The first portion of this period looks rather wet. Shortwave energy rotating across the upper Midwest and Great Lakes will help to guide a surface low across Michigan into Ontario. This will eventually push a cold front across the region Sunday night. Fairly rich moisture feed out ahead of the boundary will push PWAT values to near 1.5 inches for a time. Timing rounds of showers and storms remains tricky, but had sufficient confidence for high likely and categorical PoPs across the forecast area. SPC has a marginal risk of severe storms for Sunday. Much will depend on how much instability we can develop, but the southwest portion of the CWA may have enough deep shear to support severe storms conditionally. Also, some locations could see a period of moderate to heavy rain, with storm total rainfall above an inch certainly possible. For now, think any water issues would be highly localized and would depend on storm training. Areas of SW PA into northern WV have the lowest FFG values at present. The front should clear the ridges by around 12Z Monday, with lingering morning showers behind it. Monday afternoon and evening appear dry as surface ridging slides through. In the developing upper troughing pattern, some isolated showers could sneak into the northern counties late Monday night as a shortwave skims the region. Daytime temperatures will be fairly seasonable, but overnight lows will likely be above climatology as clouds and mixing reduce diurnal ranges. && .LONG TERM /TUESDAY THROUGH SATURDAY/... Periodic shower chances will continue through midweek, as shortwaves rotate through a broad upper trough over the NE CONUS and Great Lakes. Drier weather is figured for Thursday and Friday as surface high pressure travels through the ridge, although rain chances may return for Friday night/Saturday behind the high. Temperatures should average near to a few degrees below seasonal levels. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... IFR ceilings remain across the PIT/AGC/LBE corridor as of 17Z, but the lower clouds are expected to eventually mix out, allowing for a return to VFR conditions. Scattered showers are beginning to develop across southeastern Ohio and northern West Virginia, and chose to continue a VCTS mention at MGW. Did not have enough confidence to go as far north as ZZV with a precipitation mention. Clouds will scatter out late this afternoon and evening, but restrictions are expected to develop again late tonight at all other terminals other than DUJ. While much of the model guidance indicates IFR ceilings/visibilities, have decided to only trend conditions to low MVFR at most sites. With potential for MGW to receive thunderstorms this afternoon, decided to go IFR there with extra low level moisture available. Terminals should return to VFR conditions late Sunday morning before precipitation begins to enter the forecast area. .Outlook... Rain and restriction potential will continue with a cold front Sunday night. Fronts Tuesday and Wednesday will allow for additional intermittent restrictions. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...None. OH...None. PA...None. WV...None. && $$ is the U.S. government's official web portal to all federal, state and local government web resources and services.