Area Forecast Discussion
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337 FXUS61 KPBZ 212136 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 536 PM EDT Wed Jun 21 2017 .SYNOPSIS... Chances of showers and storms will continue into the weekend. Cooler weather arrives next week. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... With 5:30pm update, made some minimal changes to pops, shrinking the area expected to see showers and isolated thunderstorms through sunset. Showers have already decreased in intensity from earlier this afternoon, and will continue to do so. Previous discussion follows. Temperatures have climbed fairly aggressively through the early afternoon, resulting in convective temperatures being reached. This has allowed for clouds to build up fairly quickly. Likewise, a diffuse frontal boundary lies over the area with a decent pool of mid-level moisture ahead of it at 700 mb. An incoming weak short wave trough will work with this moisture and modest instability ahead of the front to generate a few showers and thunderstorms into the early evening. As the short wave tracks eastward, mid-level moisture will peel off with it, and the front should exit likewise. This will allow for a bit of a dry period for most areas later in the evening. While we emerge in the post-frontal air mass briefly, warm advection looks to be quick to resume as a warm front advances northward toward the area by late tonight. Deeper saturation should return with this front, and modest lift along it will start to generate an increasing chance of showers late tonight into Thursday morning as it moves northeastward. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/... Much warmer and more humid air will push into the region on Thursday as the area emerges into the warm sector. Southwesterly flow and increased mixing depths should likewise allow for temperatures to run up fairly aggressively in the afternoon. This will occur as 850 mb temperatures jump up into the upper teens Celsius. The more interesting weather comes late Thursday night through Friday night as the remnants of TS Cindy recurve toward the Middle Atlantic. The model consensus suggests the heaviest rainfall associated with the remnants will either just scrape the southern fringe of the area or remain south of the area. However, tropical moisture will be streaming northward into the area on southwesterly flow through the period. As a cold front dives toward the area Friday, PWATs ahead of it surge toward 2.1 inches, roughly double climo. As such, warm rain processes and moderate instability will likely mean heavy rainfall along the front as it passes through the area, even if the remnants of TS Cindy remain to the south. This will be monitored going forward. Drier air sags toward the area on Saturday as the cold front pushes eastward. This will allow for the area to finally start to dry out and cool down. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... A stark shift in the upper level pattern looks to occur by early next week. Model and ensemble projections all favor deep troughing settling over the region by that juncture. With this, much colder air aloft combined with northwesterly surface flow will mean temperatures well below normal with chances of showers as cold air aloft migrates through the region. && .AVIATION /22Z WEDNESDAY THROUGH MONDAY/... General VFR will be marred only by scattered showers and storms that develop along a frontal boundary near ZZV and MGW. That front will be pulled northward on Thursday with the chance for scattered convective activity continuing. .OUTLOOK... Widespread restrictions are likely Friday with the encroachment of a cold front. && .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.