Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 151630 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 1230 PM EDT Fri Mar 15 2024 .SYNOPSIS... A cold front works across the area this afternoon and evening. Disturbances will progress through the Great Lakes region Sunday into Monday with mainly gusty and colder conditions the impact on our region. && .NEAR TERM /THROUGH TONIGHT/... As of 949 AM EDT Friday... Key Messages: 1. Showers will be increasing in coverage but thunderstorms will be limited as will rainfall amounts. A lull in activity at the moment with main areas of convection across the southern Appalachians into the Gulf Coastal states. 12z RNK sounding showing a couple inversion in the 900-800mb range, and since clouds are moving in faster, seems instability will be more limited, so have backed off on thunder til this afternoon mainly confined it east of the mountains and moreso over the NC/VA piedmont. Looking at the prefrontal trough already in the piedmont with the actual front stretching from PA-central KY into west TN. This front enters our mountains by late afternoon. Will see increased shower coverage late this morning across the NC mountains/foothills where better deep moisture convergence lies with limited coverage further north. Latest high-res models vary on coverage with limited coverage along/north of Blacksburg/Roanoke. Temperatures started out warm, so bumped them up especially in the piedmont though showers/clouds should slow the rise somewhat in the west. Previous discussion... Persistent trough has shown signs of weakening/losing structure and CAM consensus agrees on this trend as it approaches the western CWA in the next few hours. This feature is well ahead of the sfc cold front which currently looks to be back in Ohio/Indiana. While the front may take it`s time under mainly zonal flow aloft, the deep layer moisture and perhaps a weak disturbance could allow for some redevelopment of convection during the day today. Progged SBCAPE could get near 500 J/kg along with daytime heating but this may be limited with any persistent cloud coverage/solar sheltering. All this being said, it`s possible some of the area could have a lull or skip in development while the Piedmont may get a bit greater chance later today if they are spared from some of the remnant clouds. There is more certainty on the decrease of pops going into this evening as the drier airmass behind the front finally advects SEWD. Some low stratocu could fill in to allow for a cool cloudy start to the weekend, though quickly scattering/mixing out after the morning. Confidence of shower/storm coverage today is low to medium. && .SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/...
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As of 1220 PM EDT Friday... Key Messages: 1. Mild through Sunday before a rapid cool down. 2. Gusty to very gusty northwest winds expected. 3. Limited amounts and coverage of rain/snow showers for SE WV. During this portion of the forecast, troughing across the US East Coast is expected to amplify. First, one sharp shortwave trough is expected to head east through the Great Lakes region. An 850mb front will cross our region Saturday night into Sunday in response. A second shortwave trough is expected shortly after the passage of the first which is expected to progress into a longwave trough centered over most of central CONUS by Monday morning. The axis of this longwave trough is expected to be above our area by the start of Monday evening. The result of the above transition is expected to be the following. Winds will turn gusty from the northwest Sunday night into Monday. Southeast West Virginia upslope rain/snow showers will be possible during this time with dry weather elsewhere. Monday night into Tuesday, with the passage of main trough axis we expect a boost in the northwest winds, leading to a continuation, if not a bit of an increase, in the Southeast West Virginia upslope precipitation. Although, but Monday night, drier air entering the region may mitigate the ability for any notable precipitation amounts. East of the crest of the Blue Ridge, these persistent northwest gusty winds will lead to subsidence which should greatly limit cloud cover, add a bit of compressional warming to slightly offset the impacts of cold air advection, and allow for likely drier than model forecast dew points to occur at the surface. Temperatures during this portion of the forecast are expected to be above normal through Sunday, but switch quickly to near or slightly below normal by Monday. Confidence in the above weather scenario is moderate to high.
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&& .LONG TERM /TUESDAY THROUGH FRIDAY/...
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As of 1205 PM EDT Friday... Key Messages: 1. Mainly dry through Thursday. 2. Turning much wetter Thursday night into Friday. 3. Trending milder through the period. During this portion of the forecast, the synoptic pattern is expected to transition from a relatively dry northwest flow cross our region Tuesday/Wednesday to a much wetter pattern by Friday. This will be thanks to low pressure on Tuesday near the Four Corners region, slowly progressing eastward and deepening as it moves through the Deep South on Friday. As early as Thursday night, southerly flow in advance of this low will start advecting moisture into our region within a region of isentropic lift. For Friday, there are differences within the guidance as to the track of the low, but all in some capacity offer a wet Friday for the region. Temperatures during this portion of the forecast are expected to trend milder through the period. Confidence in the above weather scenario is moderate to high on the overall synoptic transition, but low in regards to the specifics on the path and impact of the upper low on Friday.
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&& .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... As of 700 AM EDT Friday... Some remnant light rain could impact LYH and BLF early this morning from a decaying cluster of showers and storms. Otherwise showers and possible TSRA later this morning into afternoon with cigs mainly 4-10 kft then mainly MVFR cigs this evening into overnight behind the front and precip (possibly lower cigs and VSBYs for LYH and BLF). Winds today SW to west increasing 9-14 kts and possible gusts near 20 kts, then becoming more NW under 10 kts for this evening/overnight. Confidence in the above aviation scenario is low to medium. EXTENDED AVIATION OUTLOOK... Saturday through Saturday night, VFR conditions will prevail. Sunday into Monday, increasing and gusty northwest winds will bring a return of some sub-VFR clouds to the Southeast West Virginia mountains, along with isolated to scattered rain/snow showers. Confidence in the above aviation scenario is moderate. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...DS/WP NEAR TERM...WP/AB SHORT TERM...DS LONG TERM...DS AVIATION...SH/AB

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