Area Forecast Discussion
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000 FXUS61 KPBZ 220445 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 1245 AM EDT Mon May 22 2017 .SYNOPSIS...
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Drier conditions will return for Monday. They will be short- lived, however, as rain reenters Tuesday with the approach of Mid-Atlantic low pressure.
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Meager instability remains along a weak frontal boundary moving across Ohio at this hour. Shear along the boundary seems sufficient to maintain scattered activity along it through the night as it emerges toward the ridges in the morning hours. Surface dewpoints fall off about 15 degrees along the front, so clearing should become fairly evident as the front passes through the morning hours. This will yield a much more comfortable environment going into the daytime on Monday. Even with the frontal passage, cold advection with the front is not particularly strong. Surface flow never really turns northerly at all, and the cold pool at 850 mb is shunted north of the area fairly quickly through the day. Thus, temperatures won`t really be cut back too much from recent days, and abundant sun will allow for insolation to work on the dry boundary layer yielding temperatures straddling 70 degrees yet again. Fries
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&& .SHORT TERM /TONIGHT THROUGH WEDNESDAY/... Conditions should improve by Monday afternoon under building high pressure and last through at least the start of Tuesday. The models continue to differ on the evolution of low pressure moving across the Tennessee valley on Tuesday. At this time, have opted to bump PoPs up based on some of the newer guidance and ensembles, as now the GFS seems to be the outlier. Departure of this low will be quickly followed by yet another system, again, which is being resolved a little differently between deterministic models. Opted to stay close to a model blend for midweek based on the uncertainty. Temperatures are expected to be near seasonal averages through the period. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... Upper trough and embedded shortwaves will start to shift eastward toward the end of the week, but it`s influence should maintain at least low chances for precipitation through the period based on model consensus. Temperatures will generally stay just below seasonal averages through the start of the weekend. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... As of 8pm, bulk of widespread precipitation from this afternoon has moved east into central Pennsylvania. A line of scattered thunderstorms extends from central Ohio into central Kentucky. Have gone with a tempo mention for thunderstorms at Zanesville considering the current scattered coverage of thunderstorms. Have gone with prevailing precipitation at all other terminals considering models suggest that coverage of precipitation will increase as it pushes farther east, and have also gone with low MVFR/IFR ceilings as rain moves in. While thunderstorms are possible at all terminals, did not include in TAFs at this time considering the isolated nature of storms that is expected due to a lack of daytime heating. Wind shift with the cold front itself still remains slightly west of the precipitation line, with winds veering from southerly to westerly. Ceilings should scatter out Monday morning into Monday afternoon from west to east. .Outlook... The next chance for widespread restrictions and precipitation is expected Wednesday night into Thursday. && .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.