Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 280149 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 949 PM EDT Mon Mar 27 2017 .SYNOPSIS... Moist southerly flow will continue tonight into Tuesday, with several rounds of showers and thunderstorms possible. Low pressure in the Ohio Valley with a trailing cold front will lift east tonight into Tuesday. Behind the front, drier air will arrive for midweek. && .NEAR TERM /THROUGH TUESDAY/... As of 940 PM EDT Monday... Changes to the forecast this evening amount to mainly very short term adjustment to chances of additional showers and and storm through the next few hours. Adjustments will be based upon the latest radar trends, which place isolated to scattered coverage across the far southeast portion of the forecast area, and soon-to-be arriving scattered showers and a few storms across the far western portions of the area. As the night progresses, the forecast will reflect progressively increasing chances of showers from west to east as a cold front approaches the area through the Ohio and Tennessee Valleys. As of 350 PM EDT Monday... Isolated to scattered convection developing ahead of the cold front this afternoon in the warm and unstable air. This convection is developing ahead of a lead shortwave moving ahead of an upper trough. The convective outlook for Day 1 places the marginal risk of severe weather to our west with the best instability and dynamics. Highres models like the HRRR and ARW showed isolated convection developing this afternoon into tonight, especially along the southern Blue ridge. Models enhance lift and low level convergence across the Blue Ridge into the foothills after midnight into the overnight as the front approach the Appalachians. Low temperatures tonight will range from the upper 40s in the mountains to near 60 degrees in the Piedmont. A strong cold front will move across our region Tuesday into Tuesday night. Scattered showers and Thunderstorms will develop ahead and along this boundary. The SWODY2 has placed eastern portions of CWA in a marginal risk for Tuesday. The timing of the shortwave on Tuesday with a favorable area of forcing for ascent moving across eastern portions during the afternoon during peak heating. The shortwave should move offshore around 29/00Z. The strongest storms could produce hail and locally damaging wind gusts. High temperatures Tuesday will vary from the upper 50s in the mountains to the mid 70s in the Piedmont. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... As of 349 PM EDT Monday... A cold front will move across the region Tuesday night with showers exiting the piedmont during the evening. Some low level moisture may squeeze out a few showers along western slopes overnight as the theta-E boundary tracks south across the mountains. There is not much cold air air behind this front, so any precipitation along western slopes or across the mountains will be liquid and not frozen. High pressure will move south out of Canada Wednesday, then wedge down the east coast Wednesday night into Thursday. This wedge will initial be dry and mostly clear Wednesday. Wednesday afternoon temperatures will warm into the 60s west to 70s east. A strong area of low pressure will track out of the Rockies Wednesday then across the Midwest Thursday night. This system will throw warm moist air over the wedge, increasing clouds and eventually the chance for rain/drizzle. Saturation of the environment should not occur until late Wednesday night into Thursday morning. Isentropic lift increases during the day Thursday. With this in mind, we have delayed the onset of stratiform rain/drizzle until late Thursday morning and moreso along eastern slopes of the North Carolina High Country and Grayson Highlands. The combination of rain falling into a linger wedge will produce cool temperatures with highs in the 50s areawide Thursday. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... As of 349 PM EDT Monday... A strong area on low pressure will track from the Midwest to the south-central Appalachian mountains Thursday night into Friday. This low will erode the wedge of cooler air that moved into the region Wednesday. Dynamics from this low and with a retreating wedge boundary, there is the possibility strong storms could develop across the region Friday into Friday evening. However, timing is everything with this event. Currently, models have dynamics and retreating wedge environment occuring during the morning, which lowers the threat for severe weather. If this event occurs later in the day, then the threat for severe weather will increase. With an eroding wedge, temperatures will increase Thursday night and into the day Friday. Lows Thursday night will occur around midnight (upper 40s), then rise into the low to mid 60s Friday afternoon. This low pressure system and associated showers will exit the mid Atlantic coast Friday night. Dry high pressure and near normal temperatures will follow for the weekend. && .AVIATION /02Z TUESDAY THROUGH SATURDAY/... As of 805 PM EDT Monday... Widespread mid and high VFR clouds will cover the Mid Atlantic region tonight and Tuesday ahead of an upper low that will cross through the Ohio Valley. Isolated to scattered showers and thunderstorms with MVFR ceilings and visibilities are expected through 06Z/2AM. A cold front will extend from a low in Ohio across the Tennessee Valley by 12Z. Numerous showers and scattered thunderstorms with MVFR ceilings and visibilities are expected late tonight and through Tuesday along and ahead of the front. MVFR to IFR ceilings will develop late tonight along the Appalachians. Low confidence with how extensive the lower clouds will be. Winds will be from the south to southeast ahead of the front and from the west behind the front. Extended Aviation Discussion... The cold front exits the Virginia and North Carolina piedmont after 00z Wednesday with lingering sub-VFR cigs in BLF/LWB with VFR in the east of the Blue Ridge. High pressure builds in from the north Wednesday into Thursday with next storm system moving in the Mississippi Valley. A threat for sub-VFR cigs appears likely as the high wedges southwest Wed night into Thursday for most sites. The highest probability of rain will be on Friday. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...KK NEAR TERM...DS/KK SHORT TERM...RCS LONG TERM...RCS AVIATION...AMS is the U.S. government's official web portal to all federal, state and local government web resources and services.