Area Forecast Discussion
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000 FXUS61 KPBZ 210543 AAD AFDPBZ Area Forecast Discussion...UPDATED National Weather Service Pittsburgh PA 1243 AM EST Sat Jan 21 2017 .SYNOPSIS... Mild weather will continue through the weekend. Widespread rain is expected to move back into the region Sunday afternoon. && .NEAR TERM /THROUGH TODAY/...
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Issuing a dense fog advisory for northern counties. Many ob sites are reporting one-quarter mile or less. Will start immediately and continue until 13z. No major changes to the overnight period. Just some minor adjustments to cloud cover and temperatures have been updated with a blend of hires guidance. Ridging aloft will keep the area dry today. However, plenty of moisture will be trapped below the ridge, so clouds will hang around. Temperatures will be well above normal.
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&& .SHORT TERM /TONIGHT THROUGH MONDAY/... Operational models are coming into better agreement on the overall pattern during the short term. Upper level energy will cutoff over the Texas panhandle this evening and move eastward tonight, reaching TN/AL by Sunday evening. A powerful jet will swing around the 500mb low and drive northward toward the Mid-Atlantic region. This will pump copious amounts of moisture northward through the Mid-Atlantic and into the Ohio Valley on Sunday/Sunday night. In addition to the moisture, waves of energy, revolving around the upper low, will also move northward Sunday afternoon. At the surface, low pressure will rapidly develop beneath the upper low tonight and move quickly eastward on Sunday with the strong upper level support. Seeing some differences between the NAM/GFS on the surface low placement Sunday afternoon, so will lean toward the GFS, as it is showing better agreement with both the GEFS and EPS. Showers will quickly overspread the area Sunday afternoon and continue through Monday. The upper level low will become negatively tilted on Monday and slow down, as it battles the responding ridge that will stretch from the Atlantic Ocean northward over Northern New England. With the placement of the upper low and the strong jet on its eastern flank, the heaviest rain would likely move through our region late Sunday night and Monday morning. After this time, the jet axis will take aim at Eastern Pennsylvania, shifting the highest qpf into the areas. With the absence of arctic air, all of the precipitation on Monday will remain in the liquid form. Temperatures Sunday and Monday will again be above normal, but Monday will be noticeably cooler. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... On Monday night, operational models begin to move away from the ensemble data, and even the ensemble data is not agreeing on what the lows track will be on Tuesday. Still expect showers on Tuesday, but depending on what the surface low actually does, snow flakes may mix as colder air wraps around the exiting system. Additionally, the ending of the precipitation is not set in stone due to the aforementioned model differences. Warmer air will quickly move back into the area on Wednesday as southwest flow will ensue ahead of the next system, which will move from the Upper Midwest to the Great Lakes late Tuesday night and Wednesday. This midweek system will bring scattered showers back into the area. By the end of the long term, a return to more normal January air is expected with snow showers possible. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... VFR conditions, that are currently being experienced at several of the TAF sites south of KFKL and KDUJ, which are in the vicinity of the warm front, will slowly diminish as the night progresses. With plenty of low level moisture, and strengthening inversion expected, it appears that conditions should fall back to low mvfr/ifr in fog and/or stratus. Confidence is greatest to the north, where little improvement is expected the entire night. As you go further south, it may be more of a late night/early morning fog concern than a stratus concern. Have adjusted the TAFS accordingly based on these thoughts and the latest consensus of model guidance and bufkit profiles. Wind will remain light out of the wsw through the period. .OUTLOOK... More restrictions are likely Saturday night into Monday with slow moving low pressure. && .PBZ WATCHES/WARNINGS/ADVISORIES...
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MD...None. OH...None. PA...Dense Fog Advisory until 8 AM EST this morning FOR PAZ007>009- 015-016-023. WV...None.
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