UPDATE 6:40 PM: Bad news — there are some pretty heavy showers around. Good news — they’re small and tracking west to northwest (yes, odd direction) pretty rapidly, so no stalling or training is occurring. Latest radar linked here. END UPDATE
UPDATE 2 PM, 7/13: Heavy rain clustered in the Raleigh-Durham area of North Carolina is moving northwest. It is likely to affect Southside Virginia in the next couple of hours and may spread over more of Southwest Virginia after that. Click here for latest radar. END UPDATE
Something I should have posted Friday — Zach Crizer’s article (with a little input from a certain weather columnist) on the aftermath assessment of Wednesday’s flash flooding in north Roanoke.
The flash flood watch has been extended through this afternoon and tonight mainly for the counties along the Blue Ridge. Weak easterly to southeasterly winds will bring moisture back from the ocean, as a diffuse stationary front — the cold front that moved through early Friday — backs up to the west. As I write this at mid morning, this return flow, the influence of an upper-level low to our west and some remnants of what was once Tropical Storm Chantal are resulting in showers and bands of rain moving northward over central and eastern North Carolina, beginning to enter southern Virginia. As the day progresses, this activity is expected to develop and move westward and northwestward. Afternoon heating may cause a few stronger storms to develop. As in recent days, this is not likely to be a widespread heavy rain situation, but a very spotty one. On the whole, this is not a situation that would lead to a flash flood watch were we in a more typical July, but the pre-existing saturated soils have made it where amounts of rain as low as an inch in some spots will trigger flash flooding in the watch area.
Cross your fingers, Southwest Virginia. There are growing indications that the upper-level low is about to be bounced west rapidly — and odd situation in itself in the typically west-to-east upper flow over North America — as the persistent and seemingly impenetrable Bermuda high to our east expands west and southwest. As currently modeled, this may result in a rather rapid decrease in areal coverage of showers and storms the next few days as the moist flow is shunted west, perhaps beginning as early as Sunday. The upper-low is expected in fact to MOVE WEST AND SOUTHWEST ALL THE WAY FROM EASTERN KENTUCKY ACROSS THE SOUTHERN PLAINS TO THE DESERT SOUTHWEST by the middle of next week (linked series of maps from North American Model, 500 millibars, for this morning, Sunday evening and Tuesday evening), a situation I can remember no previous precedent for in my years of watching weather, and one that will spread MUCH-NEEDED RAIN into the drought-ridden Southern Plains and wildfire-battered regions of the Southern Rockies and Southwest while at least temporarily shutting off the faucet here. Daytime heating and surface moisture will always allow some chance of afternoon showers and storms, and there may be new cold frontal activity from the northwest mid to late next week to enhance showers, but perhaps we can at least keep new tropical soup from being poured into our bowl for a few days.