Area Forecast Discussion
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827 FXUS61 KPBZ 171749 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 1249 PM EST Tue Jan 17 2017 .SYNOPSIS... A warm front will lift north across the area with occasional rain expected today. A crossing cold front will keep shower chances through Wednesday before high pressure returns dry weather for Thursday. && .NEAR TERM /UNTIL 10 PM THIS EVENING/... Precipitation with a warm front should clear the forecast area by the afternoon. Although synoptic models suggest that more rain will occur across most locations through the afternoon, the HRRR agrees more with current radar trends, and have decided to leave most locations with a chance of rain. The one exception will be a line of showers along the cold front itself, and have tried to time likely pops with the expected frontal passage. Most locations should warm well into the 50s during the daytime. && .SHORT TERM /10 PM THIS EVENING THROUGH FRIDAY/... Shower chances should continue tonight and Wednesday as the surface low`s associated cold front passes, and subsequent upper troughing crosses the area. The rain could mix with snow in cold advection Wed especially N of I 80 and in the ridges, though no accumulation is expected. Building high pressure should result in a return of dry weather to the forecast Wednesday night and Thursday. Temperatures should cool behind the front, but are still expected to average around 10 degrees above seasonal levels by mid week. A deep upper trough across the Plains is progged to advance NEWD Thursday night and Friday, and is expected to be situated from the Upper Midwest to the OH Valley region by Friday. With decent model agreement on deep layer moisture, ascent and upper support increased POPs to likely for rain. Temperatures should continue to average around 15 degrees above seasonal levels to end the week. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... The upper trough should slowly exit the region through Saturday with decreasing rain chances. Unsettled and relatively warm weather is expected through the rest of the period as operational and ensemble model progs indicate the development of a closed low advancing from the Southern Plains to the Ohio Valley region from Sunday through early next week. Tweaked Superblend guidance output was used for much of the period to depict the general trends and smooth out operation model differences. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/...
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Restrictions likely through the day as a frontal system continues to migrate across the region. Precipitation will be widely scattered outside of the vicinity of the crossing cold front and have timed frontal passage of TAFs based on latest radar trends and guidance. Lower cigs and rain chances will return early in the morning as the parent upper trough moves overhead. Not much improvement expected during the day on Wednesday with plenty of low level moisture trapped under the subsidence inversion. Conditions may improve by late afternoon as the boundary layer depth decreases. The LLWS threat will lessen tonight as winds decrease above the inversion. .OUTLOOK... Restrictions are likely through Wednesday with crossing low pressure. Thereafter, expect general VFR until the next system moves in on Friday.
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&& .PBZ WATCHES/WARNINGS/ADVISORIES... MD...None. OH...None. PA...None. WV...None. && $$

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