Area Forecast Discussion
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000 FXUS61 KPBZ 221135 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 635 AM EST Sun Jan 22 2017 .SYNOPSIS... The run of mild weather will continue through midweek. Rain will move back over the area later today and continue into Tuesday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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Minor adjustments to hourly trends for the pre dawn update. Previous...Still seeing the models trying to get the final solution for the upper level low which will be the main player in our weather through early Tuesday. Even ensemble data is struggling to come to a consensus on the path and speed of the upper level low. Have backed off on the timing of the showers today as ensembles have slowed the eastward movement of the system and are advertising a track that is a bit further south. Operational models, including the hires variety, agree with this idea, as qpf only reaches Southern West Virginia by this afternoon. This is mostly due to the aforementioned more southern path of the upper low and also the further suppression south of the main jet swinging around the low. Additionally, the first upper level wave that is pushing the showers northward, splits from the main flow and heads eastward into the still prevalent, although weak, eastern ridge. Have continued to lean away from the NAM op solution, as it has been an outlier during the entire evolution of the system. Today`s PoPs will mainly cover the southern third of the region and will begin the process of overspreading these locales during the afternoon. Temperatures again will be well above normal.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/... Model depictions of the cutoff low pressure set to dig toward the Upper Ohio Region, have deviated from previous days solutions with a more westward track of the center. Increasing ascent via deformed flow and warm advection with increased moisture through the mid levels all support escalating precip probabilities to categorical numbers tonight and into Monday. With the northern branch of split flow holding colder air north and west of the region, and with warm advection into the mid levels of the cutoff, this looks to remain a rain event. The NAM again deviates from other model solutions and develops sub-zero air over the region at the 850mb level despite moist advection and an otherwise warm column. Will continue to move away from the NAM solution. This choice is also further supported when viewing the plumes from the SREF and GEFS model. If colder air does make it into the area, it would likely be late Monday night, when most of the precipitation will have exited the area. QPF was progged using a RFC/WPC blend for the period. An inch to inch and a half is anticipated for the early week with limitations imposed by low pressure progression and mid level dry slotting. Relative warmth will continue, although the diurnal temperature spread will be restricted by clouds and precip. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... By the beginning of the long term, upper level ridging will take over, but will not last long as the next system quickly moves across the northern plains/upper midwest and across the northern Great Lakes on Wednesday. Scattered showers will cross the area Wednesday and above normal temperatures will remain. A pattern change is expected to ensue on Thursday, with a return to January temperatures that will remain through the remainder of the long term. Snow showers will return as well. && .AVIATION /11Z SUNDAY THROUGH THURSDAY/...
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Patchy MVFR to IFR fog is expected to dissipate this morning as mixing begins. Otherwise, expect VFR conditions today with mid clouds ahead of approaching low pressure. The approaching low should result in deterioration to MVFR with rain tonight. Increasing E winds are expected especially tonight with an increasing pressure gradient. .OUTLOOK... Restrictions are likely through Tuesday with slow moving low pressure, and again with a Thursday cold front.
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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.