Area Forecast Discussion
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161 FXUS61 KPBZ 201007 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 607 AM EDT Thu Oct 20 2016 .SYNOPSIS... Low pressure and a crossing cold front will bring widespread rain to the region from late today into Friday. Much cooler weather will follow for the weekend. && .NEAR TERM /THROUGH TONIGHT/...
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Updated for continuing rain and thunderstorms north of I-80. This activity will continue to lift northward over the next few hours as the warm sector advances northward a bit. Rest unchanged for now. Previous discussion... The warm front will continue to lift north today as a midlevel trough continues to dig in the Mississippi Valley...putting a good portion of the CWA in the warm sector. This will suppress precipitation across much of the area through at least midday, while some showers remain possible mainly north and west of Pittsburgh. As low pressure rides up the Ohio Valley later today along the advancing cold front, showers and some thunderstorms will advance across the area mainly after 18Z. Likely and low-end categorical PoPs reappear by 00Z. Lift and moisture is maximized tonight with frontal passage and the approach of the still-digging and negatively-tilting shortwave, leading to near 100 PoPs. Going to hold off on the issuance of any flood watches for now until areas of best rainfall can be ascertained later today. However, amounts will need to be monitored along the aforementioned heavy rain band from this morning. An additional one to two inches may be seen in general from late afternoon into tomorrow morning, and we may not be able to totally rule out isolated flooding issues. Will mention in HWO. Also of concern is marginal risk of severe storms across the region as outlined by SPC. Increasing speed shear is noted on model soundings for the afternoon, with 40 knots of flow at 700 mb. Lack of deep instability may be a limiting factor in a more significant severe threat. Still, isolated strong to even damaging gusts are a possibility, with large hail a lesser threat. Will also mention this in HWO. Increased high temperatures today, especially in the southeast, with the influence of the warm sector. Readings in the 80s appear likely here. Little change to lows tonight...mainly in the upper 40s to the mid 50s.
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&& .SHORT TERM /FRIDAY THROUGH SATURDAY/... The frontal precipitation will drift eastward Friday morning with additional showers developing behind the boundary in the strong cold air advection and passage of the upper level trough axis. Much colder weather will follow for the weekend as the upper trough develops over the Eastern CONUS. Scattered showers will remain in the forecast through at least Saturday morning, with focus shifting to the north and ridge zones, as cold advection continues and shortwaves in northwest flow traverse the area. By Saturday afternoon, the much drier air aloft, which will work to suppress inversion heights, will eventually make it closer to the surface, bringing and end to any lingering showers. Still expect to see a good deal of cu over the area Saturday with the cold pool aloft remaining anchored over the area. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... Dry, but seasonably cool conditions will return Sunday as warmer air slowly works back into the area. Ensemble solutions continue to push a weak front through the area sometime on Monday, which may provide another risk for scattered showers. High pressure builds in for the remainder of the long term. && .AVIATION /10Z THURSDAY THROUGH MONDAY/...
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Rain and thunderstorms are currently mainly north of I-80, and are expected to lift northward over the next few hours as the warm sector becomes more established. Most terminals will remain VFR through the morning hours, save for FKL early and possibly DUJ if a few showers can survive. Winds may gust to between 15 and 20 knots this afternoon from the southwest. Conditions will deteriorate overnight as numerous showers and a few thunderstorms develop from west to east. Expect all terminals to drop through MVFR this evening to IFR tonight, as rain is expected to be moderate to possibly heavy at times. While visibility may fluctuate a bit, ceilings will stay at IFR through 12Z, with LIFR possible especially north and west of PIT. .OUTLOOK /THURSDAY NIGHT THROUGH MONDAY/... Periodic restrictions are expected through Saturday as low pressure and subsequent upper troughing cross the area.
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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.