Area Forecast Discussion
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000 FXUS61 KPBZ 211100 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 600 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 /UNTIL 6 PM THIS EVENING/... 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. && .SHORT TERM /6 PM THIS EVENING 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 /12Z SATURDAY THROUGH WEDNESDAY/...
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Patchy fog will be an issue right at the start of the TAF period. Visibilities varied all night due to a puff of wind just at the top of the boundary layer, and they continue to vary from VFR to LIFR. Fog will lift and burn off by mid-morning at most locations. Thereafter, mostly VFR conditions with light winds will prevail through the rest of the day, with ceilings mostly at or above 4000 feet. There may be another round of fog later tonight, but with more clouds, it is not expected to be as dense. Most rain should hold off until after 12Z Sunday. .OUTLOOK... More restrictions are likely Sunday into Monday with slow moving low pressure.
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&& .PBZ WATCHES/WARNINGS/ADVISORIES... 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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