Area Forecast Discussion
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000 FXUS61 KPBZ 280532 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 132 AM EDT Wed Sep 28 2016 .SYNOPSIS... An encroaching upper low will return rain to the Upper Ohio Region for the latter half of the week. && .NEAR TERM /THROUGH TODAY/... For now, made only minor changes to sky cover and hourly temperatures through the overnight hours. Rest of forecast unchanged. && .SHORT TERM /TONIGHT THROUGH FRIDAY/... The Great Lakes upper low is forecast to dig southward across the Mid, and Upper Ohio Valley for the latter half of the week. As models have come into more consistent depictions, confidence in the forecast of showery weather with reduced low-to-high temperature spread has improved sufficiently to increase POPs to likely and categorical numbers. The better chances for sustained rainfall is over areas north of I 70 where a southeasterly wind will briefly support transport of deeper Atlantic moisture into a frontal zone rotating around the upper low on Thursday. Overdone, to inconsistent omega fields and dry air encroachment into the mid levels of the mature low with inconsistent frontal placement do not lend confidence to placement of a heavy rain axis; thus, QPF was tempered between WPC/RFC solutions over the past couple of forecast runs. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... Most of the models lift the stubborn upper low from the middle Ohio Valley at the start of the period into the eastern Great Lakes by 12Z Sunday. Details of individual waves rotating around the low remain tricky at this distance, so kept PoPs fairly general, with a slow decreasing trend through the weekend. Expect Sunday night into the first portion of next week to be dry as a flattening ridge arrives. Near-climatological temperatures will edge back above normal by the end of the period with the departure of the upper low. SuperBlend values were slightly knocked back early in the period, but later numbers looked reasonable. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... VFR conditions are expected through the day today, but clouds will be on the increase as a strong upper level low pressure center drops into the Ohio Valley. Showers are first expected this afternoon in southeast Ohio near the upper low, and along the eastern ridges as easterly flow allows moisture to pool. After sunset, many locations will see ceilings drop to MVFR levels and showers will slowly become more numerous. Cannot rule out a thunderstorm in southeast Ohio before sunset, but chances are too low to include in the TAF. .OUTLOOK /WEDNESDAY NIGHT THROUGH SUNDAY/... Periodic restrictions will remain through Saturday as the upper level low lingers over the region. && .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.