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Sunday was certainly not the storm day it could have been, with a strong cold front pressing in and an unseasonble southward dip in the jet stream, bringing both cold air and strong winds to the higher layers of the atmosphere. We were lacking some instability, as clouds held the temperatures down in many areas, and while it was pretty humid with dew points in the 60s, it could have been more sticky with dew points in the 70s. Still, a few decent storms managed to fire. If you look on the Storm Prediction Center's map of storm reports for Sunday, you will notice a blue dot and a green dot in Southwest Virginia. The blue dot is for a report of tree damage from wind near Callaway, while the green dot is for 3/4 inch hail near Penhook, both in Franklin County. I was out watching the storms Sunday afternoon, and shot this photo, looking west from Gretna, showing this same storm over eastern Franklin County as it approached northern Pittsylvania County. The storm, which showed weak rotation on radar at times, did have something of a layered, rounded structure, and spun out quite a few cloud-to-ground lightning strokes. If instability had been greater and moisture thicker, we might have seen serious stuff.

Don't be surprised if a few more storms develop today as unseasonably cold air flows in to many layers of the atmosphere above the surface, allowing any remnant moisture to bubble into it with daytime heating. With the freezing level so low, hail will be a possibility with any storm that develops today. The rest of the week looks mostly dry, and rather cool for this time of year, with some lows in the 50s by Tuesday morning.

Many ingredients for severe thunderstorms are in place today -- moisture, relatively strong winds aloft, and an approaching strong cold front to lift air upward. Heating, which provides instability as colder air moves in aloft, is a bit lacking right now, as clouds from last night's storm have blocked much of the sunlight. Temperatures are holding in the 70s in much of the Roanoke and New River valleys. Still, as the afternoon progresses, expect to see thunderstorms develop. South and east of us -- Southside Virginia, the Piedmont of Virginia and North Carolina -- may have the best shot at severe weather, where it is hotter, but I would not be surprised to see some storms fire along the cold front and move in late this afternoon. Also ... there's still a few hours for the sun to break out and get things cooking a little more.

Gust front over Roanoke shortly after noon

It was another pretty rough day of severe thunderstorms around Virginia, with numerous reports of wind damage, mostly to trees. The Roanoke Valley was twice under severe thunderstorm warnings, at midday and again nearly 4 hours later. Trees were reported blown down on Williamson Road near Hollins College and on Coyner Springs Road near U.S. 460 with the later storm. There were numerous other reports of wind damage in the area, and just a few reports of large hail. You can click here to scroll through the weather service reports, or visit this page to look at a map and listing of severe weather reports nationally.

It was an extremely rough day around Nebraska and Iowa, where the Omaha, Neb.-Council Bluffs, Iowa, was hammered by winds up to 100 mph and baseball-sized hail, causing widespread power outages and killing at least 2 when a tree fell on a car. This was caused by the same cold front that will be approaching us the next couple of days, plowing into hot, humid air. With this clash of air masses, lots of ouflow boundaries left from storms the last two days, a series of upper-level impulses moving ahead fo the cold front, and daytime heat and moisture bubbling into cooler air aloft, Saturday and Sunday appear likely to produce additional rounds of storms in our area.

With wind dynamics picking up above us, these storms may become more organized and severe weather may be more widespread throughout the East. Damaging winds and large hail appear to be the main threats, but I wouldn't be surprised to see some tornado reports, too.

Keep an eye on the sky this weekend.

Weather service radar, about 3 p.m.

The third very similar storm cluster in the last 24 hours appears to be headed through the New River and Roanoke valleys over the next hour or so. These storms, like those that moved through about 5 p.m. on Thursday and about noon today, pose primarily a threat of strong, gusty winds and some hail up to penny size.

I was out in the brunt of the midday storm and got some photos I will post later tonight.

A severe thunderstorm watch is in effect for most of Virginia until 8 p.m. as a moderately unstable air mass and some wind support aloft are firing storm clusters capable to strong winds and large hail.

Latest National Weather Service-Blacksburg radar.

National Weather Service radar about 11 a.m.

This may get to be a habit the next few days. A new cluster of storms, moving out of West Virginia, is headed eastward. If it maintains strength and keeps on its present trajectory, the southern edge of this line would scrape through Blacksburg and Roanoke during the next 30-90 minutes. The line is not severe presently, but the storms look pretty strong on radar. In Roanoke currently, it is starting to get warm, into the 80s, and the dew point is 65, which indicated a pretty moist atmosphere to support storms. Westerly winds, however, sometimes cause low-level drying that help diminish storms as they move east of the mountains. So it's a mixed report on whether these storms will be able to make it. With some upper-level support, there's a pretty good chance that at least some heavy showers, with a few bolts of lightning, will affect the Interstate 81 corridor from Roanoke to Lexington around noon or shortly thereafter. Some gusty winds or even hail can't be ruled out.

Latest National Weather Service-Blacksburg radar

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.

Read more »

One thunderstorm this afternoon, now moving into Montgomery County, has put down some pretty big hail, up to .88 inch in diameter, and some strong winds that have caused some damage in Giles County. If this storm holds together, it may affect the Roanoke Valley after 5 p.m. A severe thunderstorm warning now includes the southwestern corner of Roanoke County. Blacksburg should be feeling the effects before then, perhaps even right now.

As always, please leave a comment or email me if you experience any significant weather.

Photo caption: National Weather Service radar at 4:20 p.m.

Wednesday's high in Roanoke reached 90, the first 90-degree high in nine days, and it'll probably be similarly hot today. Humidity is also building, with the dew point getting close to 60 again. The combination of heat and humidity will start to trigger a few afternoon thundrestorms today and Friday. The bigger threat of storms will occur over the weekend as a cold front approaches. The Storm Prediction Center has placed our area in a slight risk of severe weather for Saturday.

After widespread morning lows in the 50s, temperatures will likely rebound to about 90 degrees in the Roanoke Valley on Wednesday afternoon. Very dry air has established itself in the area after the weekend front, and this allows for rapid cooling and warming of the air compared to more humid conditions. We could see the low 90s on Thursday and Friday as humidity also slowly builds. After our June 4-10 heat wave, it's only managed to hit 90 in Roanoke twice in the two weeks since. Our last 90-degree day was on June 16.

The weekend deserves a little attention for severe thunderstorm potential, as an approaching cold front accompanied by some upper-level cold air and wind dynamics will be moving into building heat and humidity. It's a long way off with a lot of details to work out. Several warm to hot, dry days are likely between now and then.

If you've been outside much today, you've probably noticed how dry the air feels. That lack of humidity is the reason storms have not been able to develop in most of Southwest Virginia too. The dew point at Roanoke as of 6 p.m. was 50 degrees. Sunday's storms wrung out a lot of moisture and kicked out some outflow winds that pushed a lot of the moisture eastward. Also, westerly winds today have been blowing downslope, drying them out. Storms have developed as close as the Greensboro area and some of Southside Virginia near Danville, where moisture is thicker. Also, storms have developed in West Virginia where cold air aloft is creating greater instability and there are better wind dynamics aloft for storms to become organized. There is some chance a few of these storms could drift into the area later tonight, but with such dry air in place, it's doubtful that we'll get much out of them.

Drier air looks to hang around a few days, with little chance of rain or thunderstorms until late in the week.