Area Forecast Discussion
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000 FXUS61 KPBZ 222351 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 651 PM EST Mon Jan 22 2018 .SYNOPSIS... Unseasonably warm conditions are expected until the passage of a cold front tonight. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... 450pm update...made some very minor adjustments to PoPs in response to latest radar trends and hires model guidance. Overnight temperatures were modified as well. Previous discussion... Line of showers associated with a wave out ahead of the cold front will slowly make progress toward the region. Most, if not all, of the model guidance has slowed the onset of precipitation significantly - resulting in a complete reconstruction of PoPs and timing. This has been done based on the HRRR, with the front not expected to make full passage across the upper Ohio Valley until Tuesday morning. Until this time, strong warm advection will continue, with a non diurnal trend forecast. Some cooling QPF amounts still look reasonable, with the combination of recent snow melt and rainfall tonight not likely to pose many hydrologic issues outside of where some ice jam movement is possible. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/... Low over Missouri will lift northeastward toward the Great Lakes through Tuesday. Expect high temperatures Tuesday to be realized early as cold advection brings values down through the afternoon. Some insolation may slow this downturn in temps, but generally anticipate cooling values with an eventual changeover to snow. Model profiles do not maintain saturation deep enough into the snow growth zone for very long, outside of any upslope later Tuesday evening/night, so any snow accumulation will be light or negligible with the warmth of the last couple of days. Northwesterly flow will maintain snow chances, again with the likelihood best in the terrain, through Wednesday before high pressure builds overhead for the remainder of the period. Expect seasonable temperatures for Wednesday and Thursday. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... Building high pressure in advance of another low emerging over the Plains is likely to dry and warm conditions before rain chances return for next weekend. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/...
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Prefrontal rain showers will remain VFR for the most part this evening, although low level wind shear will be a concern for the night as low level flow increases above a surface inversion. There may be a brief break in precipitation overnight ahead of the main frontal precip band, which should bring MVFR conditions. Still can`t rule out a rumble of thunder, but chances remain too low for inclusion. Behind the front, mixing should bring ceilings back up to VFR for a time, as well as west-southwest gusts reaching the 25 to 30 knot range by midday. Ceilings may then float back down to borderline MVFR levels during the afternoon, with lingering rain showers mixing to snow north of Pittsburgh by sunset. .OUTLOOK... Restriction potential will continue until high pressure builds on Wednesday.
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&& .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.