Area Forecast Discussion
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000 FXUS61 KPBZ 211316 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 816 AM EST Sun Jan 21 2018 .SYNOPSIS... Warming temperatures and patchy light rain will be interrupted by a Monday night cold front. && .NEAR TERM /THROUGH TONIGHT/... Only change needed at 8 AM was to add fog to portions of the CWA as warm advection continues over the melting snowpack. Starting to get spotty reports of visibilities below 1/2 mile, and if these become more widespread and persistent, a dense fog advisory may be necessary. Previous... Warm,moist advection will continue today over the Upper Ohio Region as the area is in the broad eastern flank/warm sector of deep low pressure emerging from the Four- Corners Region. No real changes were needed for the near term forecast as chances for light rain were maintained with a temperature forecast about 10 degrees above the averages. Despite abundant cloud cover, condensational heating from the increasing boundary layer dampness will escalate the melt of the remaining snowpack and aid the rot of river ice before more widespread rain arrives late Monday. No flood-headlines are thus anticipated. && .SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/... The aforementioned low is projected to deepen as it digs toward the Great Lakes through Monday. Warm but damp weather can thus be expected over the immediate area until that system pulls a cold front across the Upper Ohio on Monday night. Precip probabilities for Monday were adjusted for warm frontal positioning, a change which features likely numbers(albeit still for light rain) for northern zones during the morning followed by a transitional period as the low to the west matures. The low is projected across the Great Lakes by early Tuesday with more widespread rain anticipated locally with cold frontal passage on Monday night. Categorical POPs were maintained and QPF is still limited to a half inch or less as per rapid system progression and dry slot encroachment. That QPF limitation and timing, along with the prior reduction in snowpack should alleviate broad flood issues. Seasonable temperature in the wake of the front is expected to change rain showers to snow on Tuesday with upper support via the crossing mid level trough. Progression and a relatively warm boundary layer should limit accumulation potential before snow shower chances taper off with building high pressure on Wednesday. && .LONG TERM /THURSDAY THROUGH SATURDAY/... Building high pressure in advance of another low emerging over the Plains is likely to dry and warm conditions before rain chances return for next weekend. && .AVIATION /13Z SUNDAY THROUGH THURSDAY/... Degraded conditions in the form of IFR, and occasionally MVFR stratus can be expected with drizzle and light rain throughout the TAF period as moisture advection continues on SSW wind. .OUTLOOK... Restriction potential continues for the first half of the week with the approach and passage of a frontal system. && .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.