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Ominous, spiral-like storm base over northern Roanoke/Roanoke County

There appeared to be some weak rotation in the thunderstorm cell that passed over northern Roanoke County on one of the radar Web sites I sometimes consult, and this photo, shot from the Roanoke Times roof garden looking north, seems to show a spiral-like cloud formation. It was a high-based cloud structure and any rotation with it was very weak, certainly no threat to spin anything at ground level.

The National Weather Service in Blacksburg has received a report of trees down one-half mile west of the Roanoke Regional Airport, in the Loch Haven area. I observed winds gusting no higher than 50 mph, which kicked up some dust in downtown Roanoke, and we got very little rain downtown. The storm appeared to break up into two or three small but intense cells as it came over the valley, and some of these little cells may have been new storms that fired along outflow winds that were kicked out by previous storms. The most significant report of damage turned into the National Weather Service in Blacksburg so far was a report of numerous trees down in Pembroke in Giles County, which may have been the result of a microburst.

An anvil cloud on the storm after it passed through the Roanoke Valley

A couple more photos are linked: (1) The rain core of the storm with Fort Lewis Mountain to the left (this would have been about the time the wind damage was reported, and in the same general direction as this photo was taken); (2) an airplane coming in for a landing at Roanoke Regional Airport, silhouetted by storm clouds (there were two landings and a takeoff as I observed this storm passing not far from the airport); and (3) about 90 minutes later, the backsheared anvil cloud of the storm moving eastward. Backshearing often indicates strong updrafts.

Please let me know with a comment below or an email to me if you had any kind of significant wind damage, hail or any other interesting weather observations.

UPDATE FRIDAY 6/2, 4:40 P.M.: Scott Martin sent two photos (linked in blue within this update) of wind damage at Smith Mountain Lake. He said about 10 trees were blown down by straight-line winds on Thursday.

ADDED FRIDAY 6/27, 10:45 A.M.: In the extended entry below, Thursday's severe weather reports turned into the National Weather Service in Blacksburg.

PRELIMINARY LOCAL STORM REPORTS
NATIONAL WEATHER SERVICE BLACKSBURG VA
THU JUN 26 2008

..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..

1039 PM HAIL INDEPENDENCE 36.62N 81.15W
06/26/2008 E0.75 INCH GRAYSON VA PUBLIC

1039 PM TSTM WND GST INDEPENDENCE 36.62N 81.15W
06/26/2008 E58.00 MPH GRAYSON VA PUBLIC

0640 PM TSTM WND DMG GRETNA 36.95N 79.37W
06/26/2008 PITTSYLVANIA VA COUNTY OFFICIAL

TREES AND POWER LINES DOWN

0750 PM HAIL 6 SW CHRISTIANSBURG 37.08N 80.48W
06/26/2008 E0.88 INCH MONTGOMERY VA FIRE DEPT/RESCUE

NEAR RINER FIRE DEPARTMENT

0730 PM HAIL NATHALIE 36.93N 78.95W
06/26/2008 E0.75 INCH HALIFAX VA PUBLIC

0721 PM HAIL 8 SSW BROOKNEAL 36.94N 79.02W
06/26/2008 E0.88 INCH HALIFAX VA PUBLIC

NICKLE HAIL IN REPUBLICAN GROVE FROM 719PM TO 721PM

0708 PM HAIL 3 SE GRETNA 36.92N 79.33W
06/26/2008 E0.75 INCH PITTSYLVANIA VA PUBLIC

0636 PM TSTM WND DMG BASSETT 36.77N 79.98W
06/26/2008 HENRY VA TRAINED SPOTTER

TREES DOWN

0620 PM TSTM WND DMG PENHOOK 36.98N 79.63W
06/26/2008 FRANKLIN VA EMERGENCY MNGR

TREES DOWN NEAR TOWN

0500 PM TSTM WND DMG ROANOKE AIRPORT 37.33N 79.98W
06/26/2008 ROANOKE VA LAW ENFORCEMENT

SEVERAL TREES DOWN IN THE LOCH HAVEN AND BRADSHAW AREA
ABOUT A HALF MILE WEST OF THE AIRPORT.

0353 PM TSTM WND DMG PEMBROKE 37.32N 80.64W
06/26/2008 GILES VA TRAINED SPOTTER

NUMEROUS TREES DOWN. POSSIBLE MICROBURST. 3/4 INCH HAIL.

0341 PM HAIL PEARISBURG 37.32N 80.73W
06/26/2008 E0.88 INCH GILES VA PUBLIC

0340 PM HAIL PEARISBURG 37.32N 80.73W
06/26/2008 E0.75 INCH GILES VA TRAINED SPOTTER