Area Forecast Discussion
Issued by NWS Blacksburg, VA
Issued by NWS Blacksburg, VA
840 FXUS61 KRNK 271904 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 304 PM EDT Mon Jul 27 2026 .WHAT HAS CHANGED... Aviation forecasts have been updated. Severe weather threat remains high for Tuesday morning through Tuesday night. && .KEY MESSAGES... Key Message 1: Severe weather threat remains high for early Tuesday morning through Tuesday night. && .DISCUSSION... Key Message 1: Severe weather threat remains high for Tuesday morning through Tuesday night. On satellite and radar imagery this afternoon, very strong MCSs were ongoing over the Great Lakes region into the OH Valley, and debris clouds were already moving through our forecast area. Storms in Chicagoland are extremely severe with 100 mph listed in the warnings, also possibly tornadic. Strong forcing for ascent was partially coming from an area of strong positive vorticity advection aloft along with a robust mid/upper level jet. High resolution guidance continues to indicate that a variation of this activity will dive SSE tonight and into the overnight hours, reaching SE WV and SW VA around 2 to 5 AM. Closer to our neck of the woods and in the lower levels, the primary area of low pressure will be located over the Delmarva Peninsula tomorrow, while a lee trough will extend from the low SSW along the Piedmont. This trough will be out ahead of a cold front moving through the TN Valley and central and southern Appalachians. These features will support widespread heavy rain and strong to severe thunderstorms, which may contain severe with damaging winds, in the form of one of more bowing linear MCSs traveling from the OH Valley. CAMs disagree on the evolution of these features, and it is possible the worst of it stays mostly to our west. However, areas especially west of a line from Lewisburg, WV to Martinsville will have the highest chance for severe weather in the morning hours. MUCAPE right ahead of the bowing segments of the MCS(s) look to be over 4000 J/kg, and the As the day progresses, the cold front moves south towards the region, along with a northward lifting warm front from the west. Strong short waves will continue to fuel redevelopment in the afternoon and evening. Severe weather in the afternoon will depend on how long the morning convection lasts and how much time the atmosphere has to recover ahead of the front/next upper level wave. It appears we should have at least a few hours with breaks in cloud cover before the front arrives in the afternoon. The ECMWF EFI and Shift of Tails for CAPE/shear continues to bullseye almost the entire forecast area with abnormally strong CAPE and shear. Deep layer shear will be around 40 to 50 kts, which will support supercells with damaging winds and large hail. The current timing of the boundaries and diving short wave energy/jet streaks are also around peak heating. Finally, there will be a tornado threat generally east of a Lynchburg to Danville line...closer to where the warm front will be in the afternoon. We continue to be outlooked on Tuesday for a Slight Risk of severe weather from SPC, and a Marginal Risk of excessive rainfall from WPC for flash flooding. The front and trough axis moves quickly southeast and out of the forecast area by midnight Tuesday. Upslope flow may bring a few showers to the mountains overnight, but the severe threat will be over. Thursday and Friday also look quiet, with a return to scattered afternoon showers and storms for the weekend. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... Quiet weather for the first half of TAF period, then strong to severe thunderstorms and heavy rain will shift into the region, as a line of strong storms is forecasted to reach KBLF, KLWB, ROA and KBCB between 8-13Z. Scattered showers and storms with heavy rain and damaging winds continue into tomorrow afternoon and evening as a cold front moves through. Wind gusts in general increase to 20 to 30 knots Monday night into Tuesday. Winds will generally be light and variable during the overnight time periods, and northwest to north during the day around 4 to 7 kts. EXTENDED AVIATION OUTLOOK... TSRA with heavy rain and damaging winds continue into tomorrow afternoon and evening as a cold front moves through. Wind gusts in general increase to 20 to 30 knots Monday night through late Wednesday night behind the front. Wednesday through Friday are forecasted to VFR, outside any morning fog/stratus. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ DISCUSSION...SH AVIATION...SH