Area Forecast Discussion
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000 FXUS61 KPBZ 152158 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 458 PM EST Mon Jan 15 2018 .SYNOPSIS...
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Low pressure will bring light snow to the region tonight and Tuesday.
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&& .NEAR TERM /THROUGH TUESDAY/...
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An early eve update was issued to adjust POPs up areawide as light snow has spread over the region on the van of low pressure digging toward the Great Lakes. Previous... As low pressure moves into the southern Great Lakes this evening, a cold front will push through Ohio eventually bringing snow areawide overnight. Most models spread modest snow across the forecast area but some show an initial area of enhancement north of I-70 in an area of favorable upper-level jet dynamics. The outlier to this point is the 12z NAM which really slows the cold front, maintains a layer of dry air near the surface, which ultimately delays snow onset and cuts into accumulations. 12z GFS and a number of hi-res models show a little more consistency, and thus were relied on a little more. The more moderate snow north of I-70 associated with the surface trough will carry through the pre-dawn before dissipating and moving northeast out of the area. Near dawn Tuesday, the upper trough will pull moisture northward, focusing snow over more of our southern zones. This snow is expected to continue well into Tuesday afternoon, before the dry slot can advance further. This will lengthen the residence time of snow over the Ridges, ultimately boosting their totals from previous forecasts. All told, kept forecast amounts a little general with 2-3" for most of the area over at least a 24hr period. The ridges could see 2-4" and despite the long duration event, a Winter Weather Advisory has been issued.
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&& .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... Any remaining snow showers will continue to taper down Tuesday night in the wake of the cold front. The core of the cold air will pass through Wednesday morning, bringing the coldest temperatures of the work week. Current forecast has relatively light winds during this time, but this period will need to be monitored for potential Wind Chill Advisory headlines. Heights begin to build into Wednesday, but northwest flow through the mid-levels will keep clouds and the potential for light snow, especially north of I-80. Ridging, albeit brief, will carry into Thursday, bringing an increase in sunshine and helping to further moderate temperatures. Still highs will be several degrees off the averages. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... Zonal flow tries to establish over the eastern CONUS late this week. From here, a slight pattern shift is expected as a trough deepens over the western CONUS. This will amplify the southeastern ridge and ultimately bring warmer conditions back to the area. Moist advection around the western flank of the ridge will keep at least chance PoPs in for for the early weekend. By this time, temperatures should be warm enough to support all rain. The western trough ejects and approaches our area by early next week. Enough consistency existed across model guidance to maintain the likely PoPs for Monday. && .AVIATION /22Z MONDAY THROUGH SATURDAY/...
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Widespread MVFR to IFR restrictions in snow can be expected until low pressure pulls a cdfnt acrs the region on Tuesday morning. Conditions should improve Tuesday afternoon as subsidence and dry advection ensue in the wake of the front. .OUTLOOK... Northwest flow may lead to further restrictions Wednesday.
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&& .PBZ WATCHES/WARNINGS/ADVISORIES... MD...Winter Weather Advisory from 2 AM to 10 PM EST Tuesday for MDZ001. OH...None. PA...Winter Weather Advisory from 2 AM to 7 PM EST Tuesday for PAZ076. WV...Winter Weather Advisory from 2 AM to 7 PM EST Tuesday for WVZ510-511. Winter Weather Advisory from 2 AM to 10 PM EST Tuesday for WVZ512>514. && $$

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