Area Forecast Discussion
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000 FXUS61 KPBZ 220353 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 1153 PM EDT Tue Mar 21 2017 .SYNOPSIS... Cold front will sweep through tonight, bringing much colder temperatures on Wednesday. A return to warmth is expected by late this week, persisting into early next week as rain chances increase. && .NEAR TERM /THROUGH WEDNESDAY NIGHT/...
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Increased winds and cold air advection overnight as a cold front dives south across the forecast area. Although light snow is not out of the realm of possibility for a brief period of time in the vicinity of the front...have opted to remove any mention from the forecast based on latest satellite and radar trends as well as forecast soundings continuing to show strong subsidence/shallow boundary layer. The main change to sensible weather will be the decrease in temperatures and increase in temperatures dip into the twenties and wind gusts between 25-30mph on average develop behind the front with a strong pressure gradient. Continued strong cold advection will result in temperatures 10-15 degrees below normal today as high pressure builds overhead. Winds will subside by tonight allowing winds to decouple...allowing for a strong radiational cooling night under clear skies. Temperatures will drop into the mid-teens in many locations.
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&& .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... High pressure will maintain dry conditions through Thursday with moderating temperatures expected. Thursday night is a meteorological challenge, as cold (sub- freezing) air will linger at the surface as strong warm air advection begins aloft. Given the southeasterly low-level flow, it is quite plausible that low-level warming will lag the arrival of the warm air aloft, leading to the possibility of a light freezing rain/sleet event. At this time, the possibility has been highlighted in the HWO. The warm air aloft will mix rapidly to the surface Friday morning in the warm sector, with temperatures rebounding to near 60F by afternoon. && .LONG TERM /SATURDAY THROUGH TUESDAY/... A fairly-active, split-stream jet pattern is expected for the remainder of the forecast, with a series of closed lows expected in the swrn CONUS and a progressive northern stream. Moisture spreading ahead of these southern-stream lows will bring a wetter and cloudier (but warmer) period into early next week. Maxima in the 60s and minima in the upper 40s are expected. Precipitation will be driven by the passage of these ejecting lows, the timing of which is not clear at this time. The most-consistent chance of rain /per MEX trends/ looks to be late Sunday afternoon. && .AVIATION /04Z WEDNESDAY THROUGH SUNDAY/... Gusty WNW wind will gradually turn more northerly over the evening hours as more cold air moves in, especially aloft. While all sites will start to a broken mid-deck, cold air off the surface and increasing low level instability will allow for some lake-induced stratocumulus to start to move into the area, however really only KFKL and KDUJ should manage much of a ceiling out of it. Wind gusts will continue through the day on Wednesday, however drier air advancing southward should really start to eviscerate cloud cover quickly after sunrise. That said, by 15z or so, all sites should again be VFR. Outlook... The next chance for widespread restrictions should come on Friday with a front tracking across the lower Great Lakes. && .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.