UPDATED 9:45 AM: Rain slacking after pounding U.S. 220 corridor — Greensboro/Henry County/Franklin County/Roanoke Valley
UPDATE 9:45 AM: The rain will be ending rapidly in the Roanoke Valley — as it already has at points to the south — as the large rain area pulls northward. There are widespread reports of 2 to 5 inches in the counties under flash flood warnings — Botetourt, Bedford, Roanoke, Franklin and Henry — with locally up to 8 inches for the last 24 hours in Henry County. Rainfall amounts drop off rapidly going west from there and dwindle a bit going east until growing again toward central Virginia. Local flash flood reports turned into the National Weather Service in Blacksburg include Tinker Creek being out of its banks near 13th street in Northeast Roanoke, Doe Run Creek out its banks east of Rocky Mount, and several reports of water over roads in Martinsville and Henry County. END UPDATE
UPDATE 7:15 AM: Roanoke County and Roanoke city plus Bedford County and eastern Botetourt County have just been placed under a flash flood warning until 1 p.m as heavy rain continues to pound the Roanoke Valley. END UPDATE
UPDATE 7AM: Franklin County is now also included in the flash flood warning as a band of heavy rain continues to affect the U.S. 220 corridor from Martinsville to Rocky Mount to the Roanoke Valley. There are reports of creeks out of their banks in Martinsville and Bassett. Rainfall rates have reached 1/2 inch an hour at Roanoke Regional Airport, with some even higher rates reported southward along the Blue Ridge. The circulation of a low-pressure system can be seen in north-central North Carolina on a National Weather Service-Blacksburg radar loop and it appears this low’s northward track will continue to push bands of heavy rain across the U.S. 220 corridor/Blue Ridge area for the next 2 or 3 hours before there will be some slacking of the precipitation. END UPDATE
UPDATE 5AM: Heavy rain is lining up along the U.S. 220 corridor from the Greensboro/Winston-Salem area of North Carolina north to Roanoke and just to the north. Rainfall rates of around 1/2 inch per hour with occasionally as much as 1 inch per hour — perhaps locally 2 inches per hour, briefly — are possible in this corridor for the next few hours. Flash flood warnings have been issued in the Triad area of North Carolina ,with law enforcement reporting flooding, north toward Henry County in Virginia, where about 3 inches of rain has been reported in the last three hours. Greensboro received about 3/4 an inch between 3 and 4 a.m. Some moderate to locally heavy rain is also working west into the New River Valley. Interstate 77 remains approximately the line between significant rain and little rain, with the edge of the rain area located about 10 miles west of I-77 early this morning. You can continue to watch the progress of the rain on National Weather Service-Blacksburg radar, linked here. END UPDATE
With the edge of the moderate to heavy rain extending from Lynchburg to Martinsville to Mount Airy, N.C, and moving northwest, it appears most of Southwest Virginia will experience significant rainfall overnight from an atmospheric setup involving an upper-level low to our southwest, a long plume of tropical moisture from the Caribbean, a washed-out minimal tropical storm, a stalled front to our east, and a developing low pressure system along the coast incorporating elements of each of the above. Rainfall amounts are still a bit hard to discern, judging by differing forecasts and computer models, but it would appear at this time that Interstate 77 will roughly be the dividing line between moderate to heavy rainfall amounts of at least a half-inch to the east and lighter showers to the west overnight. A flash flood watch remains in effect until early Thursday evening for counties along a Stuart to Roanoke to Lexington line and eastward, with 2-4 inch rainfall amounts expected generally east of this line. Don’t be surprised if some places west of this line get more than 2 inches and some places to the east get less, as the movement of invidual rain bands and just plain ol’ inaccuracies in computer modeling could vary the amounts somewhat. There could be some localized flooding issues, but mostly this is going to be another welcome rain to build on the early week rain in easing long-term dryness.
A mostly dry and cool weekend — borderline cold by Sunday morning — looks to be on tap. Yet another upper-level low diving southeastward could bring showers back to the forecast by early next week, but it’s probably not going to have the same vein of tropical moisture to tap into as this week’s systems have.