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915 FXUS61 KPBZ 290143 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 943 PM EDT Fri Apr 28 2017 .SYNOPSIS... Unsettled but warm weather is expected for the weekend with a crossing warm front. && .NEAR TERM /THROUGH SATURDAY/... Minimal change was needed for the mid-evening update as showers and storms begin to invade from the west. The main area of deeper convection now just crossing central Ohio and will be entering the CWA shortly...exiting an hour or so after midnight. Upstream locations where cores have passed over reporting up to between an inch to 1.25" of rain over 6 hours...with values generally around a quarter inch under surrounding areas of more stratiform rain. If this continues flash flood guidance would not be exceeded, however, localized areas of minor flooding will be possible under stronger convection and higher rates overnight. Previous discussion follows... --- Showers and thunderstorms are expected tonight...mid to late evening as a MCC or it`s remnant MCV currently over Indiana crosses the forecast area. Although model runs do show this feature weakening over the course of the night...feel this (weakening) may be overdone as the complex should continue to ride along the nose of strong warm air and moisture advection and the resulting convergence allows elevated convection to continue as unstable air aloft is tapped. Gusty winds will be possible initially with any storms as rain falls into drier low levels. Later...after midnight a shortwave riding along the warm front beginning to lift north over the forecast area will result more showers/storms through mid-morning. Have increased overnight QPF amounts...especially across western zones given M-climate anomalies and model soundings showing continuity in PWAT values well above the max moving average...which are closer to 99th percentile values for mid to late June. Will need to monitor observed precipitation amounts upstream over the coming hours. Most models push the warm front north toward the New York and Pennsylvania border where it stalls late day Saturday. Have trended forecast in this direction, but confidence is not exceptionally high. SPC has maintained a marginal risk of severe, but with better dynamics well west of region through Saturday, for now think severe threat not high enough to mention. Rising dew points will help keep temperatures mild tonight, with warming behind the front Saturday. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... Warm front should remain near the New York border through Sunday night as heights rise aloft. This looks to keep a cap on thunderstorms Sunday. With mid level ridge on Sunday much warmer and more humid conditions will develop. Ridge begins to break down Monday as an occluded storm system in the western Great Lakes pushes a cold front across the region, with showers and thunderstorms with FROPA. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... A closed low will eventually move across Southern Canada Tuesday and Wednesday. The surface reflection will move directly under the 500 low, keeping the chance for showers in the forecast. A cooler and unsettled pattern will continue into late week as a mean mid level trough remains across the ERN CONUS. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... Periodic condition deterioration to MVFR/local IFR is expected later this evening and overnight as a cluster of showers and thunderstorms move along an approaching warm front. Low level jet and shortwave support should result in additional showers/thunderstorms overnight through early Saturday morning. Scattered showers/storms are possible through the day Saturday as the front stalls in the vicinity, though better upper support is progged to shift N of the area. Will mention VCSH in the TAFs for now. A period of MVFR ceilings are expected by Sat morning also, with improvement from S-N by afternoon. .Outlook... Restrictions are possible through Sun in vicinity of a surface front. Restriction are likely with a strong cold front Sunday night and Monday. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...None. OH...None. PA...None. WV...None. && $$

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