Area Forecast Discussion
Issued by NWS Blacksburg, VA
Issued by NWS Blacksburg, VA
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763 FXUS61 KRNK 240649 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 249 AM EDT Tue Sep 24 2024 .SYNOPSIS... A slow-moving cold front will meander along the Ohio River Valley over the next several days, triggering rounds of showers and thunderstorm activity that will persist through much of the workweek. PTC 9 lifting northward from the Gulf of Mexico toward the end of the work week may bring more widespread rainfall to the region. && .NEAR TERM /THROUGH TONIGHT/... As of 200 AM EDT Tuesday... Key Messages: 1) Thunderstorms this afternoon, a few may be strong to severe. 2) Heavy rain from training thunderstorms could result in areas of localized flooding. A look at the current surface analysis this morning indicates a warm front located across Central Virginia extending southeast into eastern North Carolina. Another boundary, currently stationary is situated across Kentucky and West Virginia. This has resulted in a highly moist boundary layer across much of Virginia and North Carolina. Weak isentropic lift associated with the warm front across Virginia has resulted in ongoing shower activity. CAM guidance suggests an uptick in this activity as the morning progresses and the front begins to gradually sag southwest through daybreak. Some uncertainty exist on how much this front can progress southwest by this afternoon. Upper divergence aloft associated with an approaching upper trough will pass over the region this afternoon and evening. Best forcing will be just to the west, however depending on the location of the backdoor front and amount of heating that can occur today will play a role in the intensity and coverage of thunderstorms. Should we see more sun than clouds today, storms will be capable of strong damaging winds and possibly a few instance of hail. A very anomalously moist airmass remains in place as well, thus any storm will be produce very efficient rainfall rates and could pose a threat for localized flooding. && .SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/... As of 200 AM EDT Tuesday... Key Messages: - Outer rain bands from Tropical Cyclone Nine could enter the area as early as Thursday night. - Seasonal temperatures and high humidity through the period. On Wednesday, an upper level low will wobble over the Ozarks while an upper level ridge sits off the southeast coast. The forecast area will be under the influence of the upper ridge into the day Thursday. With a southeasterly low level flow into the region, showers and a few thunderstorms are possible each afternoon, starting along the Blue Ridge. Late Thursday afternoon, Tropical Cyclone Nine is expected to move inland around the Tallahassee Florida area then tracks northward towards the southern Appalachian mountains (GA/TN/NC border). Outer rain bands of TC Nine could move over the area as early as Thursday night, continuing into Friday. However, the cone of uncertainty widens as this tropical system moves inland on days 3 and 4. Near normal temperatures are expected Wednesday and Thursday. Dewpoints will run from the mid 60s to lower 70s through the period. && .LONG TERM /SATURDAY THROUGH MONDAY/... As of 230 AM EDT Tuesday... Key Messages: - Confidence is increasing that Tropical Cyclone Nine will affect the area Friday and Saturday, though exact impacts remain uncertain. - High pressure wedge south across the area Sunday and Monday. Rain bands from Tropical Cyclone Nine are expected to move over the forecast area through the day Friday. These rain bands may also interact with a backdoor cold front Friday night into Saturday night. With PWATs running on the order of +1.50 inches, periods of moderate to heavy rain are possible going into the weekend. Models have the front wedging south on Sunday. The upper level low that was over the Ozarks should open into a trough on Monday and track over the Mid Atlantic states Monday and Tuesday. Dry high pressure returns to the area follow the passing of this trough. With rain expected Friday and Saturday, temperatures will run slightly cooler than normal. The backdoor front will bring cooler air into the area with temperatures around 10F cooler than normal. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... As of 200 AM EDT Monday... Fairly widespread IFR conditions overnight. Some improvement to MVFR after daybreak, however cigs will remain relatively low throughout the forecast period due to ample low level moisture and afternoon showers and thunderstorms. Fog is possible for all terminals in the early morning hours (08Z-12Z) with the highest confidence of impacts at KBLF and KLWB. Afternoon convection and precipitation chances are the highest at along and west of the Blue Ridge, with lesser confidence east of the Blue Ridge due to a backdoor front. A return to MVFR and IFR conditions due to fog and rain is possible for all sites towards the end of the forecast period. Widespread VFR conditions are not expected during the forecast period. EXTENDED AVIATION OUTLOOK... MVFR/IFR stratus and fog are expected to occur in rounds through at least the middle of the week, and increasingly likely to persist through the end of the workweek. Rounds of showers and thunderstorms will also continue to pass across the lower Mid- Atlantic. Low pressure lifting northward from the Gulf of Mexico toward the end of the week may bring more widespread rainfall and sub- VFR conditions to the region. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...BMG NEAR TERM...BMG SHORT TERM...RCS LONG TERM...RCS AVIATION...BMG/CG