Area Forecast Discussion
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357 FXUS61 KPBZ 231835 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 135 PM EST Thu Feb 23 2017 .SYNOPSIS... Warm weather will continue until the passage of a Saturday cold front. && .NEAR TERM /THROUGH TONIGHT/... With 11am update, kept isolated showers in the forecast to the southeast of Pittsburgh, but backed off from scattered coverage as radar has gone quiet across that area. Still expect showers this afternoon to be mainly limited to northern zones, as a frontal boundary is progged to stall in in the vicinity of the I-80 corridor before lifting back to the north as a warm front. Model guidance continues to suggest the possibility of a few thunderstorms in the mix as well, however, chances are too low to include in the forecast as warm air aloft is more likely to keep any activity capped off. && .SHORT TERM /FRIDAY THROUGH SUNDAY/... Any remaining shower activity that develops across northern zones will diminish this evening as the warm front lifts north. With the forecast area well withing the warm sector, temperatures on Friday look to be the warmest yet since beginning this prolonged period of well above normal temperatures. The current forecast includes record breaking temperatures at all climate locations and dry conditions. Friday night southerly winds will increase as the cold front approaches and this along with plenty of cloud coverage will likely result in record high minimums overnight. There is higher confidence in timing of frontal passage...not pushing it back later and keeping the inherited forecast as-is as the modTrends tool is finally showing a flat linear regression slope regarding the eastern CONUS trough. The front will cross Saturday morning into early afternoon with The timing of the passage would still not seem to favor much of a severe threat given the expected lack of buoyancy, but with strong flow and plenty of shear to enhance updrafts, any storms may need to be monitored for wind gusts. In any case winds will be strong ahead and behind the front through early Sunday...with isolated gusts up to 40mph possible. && .LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/... Broad southwest flow aloft is in place for the first portion of the extended period, before a trend towards a troughing pattern towards the end. While guidance generally agrees with this, details on shortwaves and surface systems remain murky, with model disagreement continuing. The flow and increasing moisture with time will support chances for scattered showers Monday and Tuesday. A more significant system appears possible for later Tuesday night and Wednesday, for which likely PoPs were maintained. Once again, this system will produce nealy all liquid, save for some backside snow showers later Wednesday night. Northwest flow activity may linger on Thursday. Made modifications to the SuperBlend guidance to shade more towards continuity. A trend from normal to above normal temperatures will be felt from Monday through Wednesday, before seasonal values return for Thursday. && .AVIATION /19Z THURSDAY THROUGH TUESDAY/... MVFR ceilings will linger into tonight with abundant low level moisture associated with a frontal boundary. Scattered showers are possible this afternoon, mainly north of PIT. Ceilings may fall a bit after sunset, with areas near and north of I-80 possibly sinking to IFR levels. Once the front lifts north and the region gets into the warm sector, ceilings will begin to rise back to VFR levels late this evening and overnight, with FKL/DUJ possibly that level shortly after sunrise. VFR conditions will then continue through Friday with thinning clouds by afternoon. Cannot rule out patchy MVFR fog overnight but elected not to include for now as the boundary layer should remain mixed. .OUTLOOK... Widespread restrictions are likely with the approach and passage of a cold front on Friday night and early Saturday. && .CLIMATE... Record high temperatures for climate sites: Thu Fri -------- -------- PIT 70 (1922) 70 (1875,1906) ZZV 64 (2000) 70 (1961) MGW 68 (1996) 75 (1975) DUJ 63 (1985) 60 (1985) HLG 62 (2000) 63 (2016) PHD 69 (1975) 66 (1985) && .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.