UPDATE 11:10 PM, 7/3: Hot as a firecracker with some stormy fireworks possible through July 4th and beyond
Wednesday’s Weather Journal column: Looking at where Friday’s events fit in local weather history
UPDATE 11:10 PM, 7/3: Happy Fourth of July everyone! Happy 236th Birthday, America! A special salute to all the utility linemen, our local workers and those from other states who are residing in our area this holiday getting our power back on. Similar weather on Wednesday — hot, highs ranging from upper 80s west of Roanoke to mid 90s Roanoke Valley south and east. Afternoon pop-up storms, some of which could be strong to locally severe, as happened Tuesday. And we’ll keep an eye on developments to our northwest to see if a strong storm cluster forms and slides southeast at us again — it is a possibility, and more of a chance Wednesday than later in the week. Looks like we’re going to warm up again, with some 100-degree readings possible Thursday and Friday, before what could be a substantial cooldown early next week. Hope to get a more extensive post on future weather developments up in the near future. END UPDATE
UPDATE 12:30 PM, 7/3: At this time, it appears more typical summer pop-up storms will be the order of the afternoon, though some could become locally severe (while others, locally, get nothing). More organized convection is possible this evening if activity from the west in Kentucky organizes and moves our way, or sends out outflow breezes that trigger new storms. The storm clusters near the Great Lakes are likely to stay well north of our area today. END UPDATE
Hot days will be the constant through the remainder of this holiday week — lots of highs in the 90s. The high that caused the extreme heat is starting to weaken and shift west away from us, but it’s not positioned where it can help funnel in much cooler air. We continue in a northwest flow aloft, which raises the specter any day of storm clusters forming in the Ohio Valley and moving southeastward, like Friday night’s derecho and Sunday night/early Monday’s bow echo in the New River Valley and south (which for some locations was worse than the bigger derecho was). 
There has been some indication that it might happen again Tuesday night (a storm cluster, not necessarily a derecho), but model signals are not certain. Storms may also form west of the Appalachians in Kentucky with a lingering moisture axis, and east of the mountains with a “lee trough,” a weak area of surface low pressure that often forms in the summer months. It’s kind of a watch-and-see mode on radar where storms develop Tuesday and Wednesday, the Fourth of July. The Hydrometeorological Prediction Center is certain enough in storms developing over our area to put the region in .25-.50 rain Tuesday night through Wednesday night. That would probably mean a few spots getting 1-2 inches in storms, and other spots getting much less, even nothing for some.
July 2, 2012 - 11:12 PM
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Tonight, the arrowhead of Minnesota, northern Wisconsin and the upper peninsula of Michigan are experience a bow-echo storm system with 60-80 mph winds. This one is not expected to drop far enough south to affect us.
We were out of town for the Fri. event but the one Sun. night/actually Mon. morning was just about the most intense lightning storm I’ve ever seen. For a period of maybe five minutes there were multiple flashes per second, with much less frequent thunder booms. We’re on the continental divide near Blacksburg.
Kevin, it seems I am reading about more bow echo storms this summer. I know I have heard Jim Cantori (of the TWC) talked about them but they always seemed smaller in size. Why are we having so many of them? What has developed to cause so many? and last quesiton – are they more common in other areas of the country? world?
I’ll be traveling to North Carolina this evening. I know what to expect when in NC: hot, humid days, thunderous evening, and more of the same. That’s the only thing I’d would be dreading about the visit in NC.
Anybody know if Minnesota suffered any damages and power outages due to the derecho? Also, I saw that Dan tweeted a link to Brad who said there was a massive derecho last year that affected a lot of North Carolina. I could not recall it at all.
Derechos/bow echoes (a derecho is a bow echo that continues for an extended distance and time) are certainly nothing new. They happen just about every summer, and some in spring too. Strong speed shear — where winds are blowing from generally the same direction aloft, but at much different speeds — contributes to their development. They also tend for form in extra abundance around the “ring of fire” — the loop of convection that develops around a summer heat dome.
Reasons they seem to be more prominent this summer: (1) a very bad one has occurred in our region and the DC metro area, so they’re getting extra attention; (2) we have a very pronounced heat dome that hasn’t expanded over the entire Northeast, so the “ring of fire” is farther south and east than it sometimes is; (3) May and June have had an extreme lack of tornadoes in the U.S., historically, so other severe thunderstorm types are getting more notice. Some research suggests May had the least tornadoes nationally in 60+ years.
One extreme derecho I’m familiar with hit Memphis, Tenn., on July 22, 2003, in the morning hours. It had winds of over 100 mph — even stronger than the one that hit us — and pretty much paralyzed the city for a few days — including power outages in extreme summer heat. Local residents were very angry that event was pretty much ignored by the national media. They dubbed it “Hurricane Elvis.”
As for where they’re most common, like most severe weather, it tends to favor the central U.S. I remember watching a derecho cross Kansas and Oklahoma a week or two ago and commenting on how it would be awful to have a lot of power outages during severe heat.
Question – is it possible for something similar to a derecho to form during winter? I’m asking because if it’s possible to have “thundersnow” during a winter storm, then it may be plausible there would be an extreme wind shear during a winter storm.
Looks like some nasty storms moving into Ohio and Pennsylvania tracking to the southeast toward Virginia! Does any sort of future cast have these storms coming into the Charlottesville area? Looks like current track is moving directly at us or maybe a hair north of us. Kevin, where do you see these storms going?
I think that stuff is going to stay well north, Jared.
Trevor: There was something of a “snow derecho” nature in central Illinois a few years ago. Severe thunderstorm warnings were even issued for 60 mph winds and blinding snow squalls. I think that was an Arctic front pushing into a relatively milder (but still cold) air mass.
CCFP shows small area in Wstrn NC and SWVA
possibly active in next 3 or 4 hours.
Looks like it would bear watching the area
west of PSK. Satellite shows a few cloud buildups starting
to blossom.
I hope it won’t affect my travel along I-77, 74, 52, and 40 this evening.
We only got .02 out of the storm Sunday night. Good thing, I wasn’t going out to turn off my generator. Currently it’s raining in Goodview and the temp has dropped from 94.8(today’s high) to 77.4 in less than an hour. We’ve received .08 inches of rain so far (3:27pm)
Nice line of thunderstorms now
from Northern Botertourt County
to just south of Waynesboro..around
Wintergreen or so…
mostly scattered south of that..
Hope that overall it cools the area
for you folks tonight.
Weyers Cave just dropped to 83F as
thunderstorm passed.
I just looked at the 6-10 day CPC map, and my wife is going to be one very happy camper when we go to Mass. and New Hampshire next week. ***If the CPC map “verifies,” of course, which KM and the Captain have both talked about. New England and eastern swath of NY state are in the 40% chance of being cooler than normal!!! Yippee!! Of course that means this COLC whose bod is used to consistent temps in the 90s will have to bundle up during the mornings. Several times when NG and I have gone to New England, they have their hottest week of the summer. And once in mid-June of 1993 or 1994, we were in a ski chalet in the White Mntns with no AC (they told us they never need it … 3000 feet elevation in the northern half of NH), and it was in the mid and upper 90s THE ENTIRE WEEK. It was dreadful.
Oh, BTW, the outlook for SW Virginia is the neutral zone, which will feel cool after these past 6 days.
On the 8-14 day, the southern half of the nation (except for Calif.) and the entire eastern seaboard will be again in the neutral zone. So maybe after a rough start July won’t end up being that bad. The NW corner of the nation is going to roast. I bet the PNA thing is very positive during the next week or two. Ridge in the west and a trough (well, at least not a ridge) in the east.
We just got power back after Friday night’s Derecho event. This may have already been discussed, so please forgive me. Kevin – How in the world do we have a “once in a lifetime” wind event on Friday night, and it was not even forecasted? The NWS mentioned NOTHING about historically high winds for Friday night (81 mph at Roanoke, must have been near an all time high gust). Seems like an incredible disservice to the public! A 30% chance of storms was forecasted, but that is forecasted nearly every summer evening. I hope someone at the NWS has been held accountable for this. By the way, hats off to the folks at Appalachian Power!
Nice cluster formed up and heading into Wytheville area..
moving generally toward Pulaski (PSK)..
Nice tops on it…to 55000ft…im sure ther folks there are getting
a good drenching..will see how long that one holds together.
Theres no consistant movement to various clusters from
the Southside through SWVA.
Lost power this afternoon for about 3 hours. Hoping that some rain will come and cool us down – or even a breeze would be nice.
Roanoke high of 97 was a record for July 3. Previous record 96 in 1966. Just a fluke on the calendar that it had never been hotter on this date.
Mike: Don’t have all answers for you on that. Some mention of MCS from Ohio Valley in forecast discussions that day and previous days.
I do have to mention that “derecho” was mentioned by name on this blog at 9:50 am on Friday!
Kevin…now might be a good time to differentiate a
Derecho and a Haboob.
Neither easy to say…and neither much fun.
Mike, I should point out, in all fairness, that there was more than 2 hours lead time on a severe thunderstorm watch Friday night that specifically mentioned 80+ mph winds, and 30-45 minutes lead time on severe thunderstorm warnings issued for large blocks of counties specifically mentioning 70+ mph winds.
Following Joe’s suggestion: A “haboob” is a wall of dense dust, often thousands of feet high, kicked up and lifted by thunderstorm outflow winds. Phoenix seems to have a couple or three of these each summer during monsoon season.
I suppose a derecho — a long-lasting bow echo with continuously damaging thunderstorm outflow winds — could cause a haboob. We had an unusual amount of blowing dust around here on Friday night. But if we start having haboobs in western Virginia, we’ve already got some big problems going on.
My power back on @ 9:30 tonight thanks to a crew from Missouri. With all the trees down in my area from the Sunday morning storm I’m actually surprised its on this fast.
This is Trevar in Cave Spring, not to be confused with Trevor, who I believe is in NC tonight. Kevin, I think we had as close to a haboob as we could come Friday night, I suspect if we had a true haboob it would be because we have had a serious drought. Anyway, I left Lowes on 220 south Friday night around the time the storm was coming through. When I looked down the road I thought that I was seeing an impressive wall of rain headed our way. It turned out to be the debris kicked up by the wind, not rain.
Here’s a haboob:
http://tinyurl.com/7vmm66x
This is from Egypt.
If we had a true haboob, it would mean we had gone beyond drought into near-desertification.
I think what also caught people off guard Friday was it was clear skies until within about 30 minutes of the event and then you had to be looking to the NW to see it coming…but if you did look it would have grabbed your attention as you could clearly see the clouds looking very turbulent and almost rolling over themselves. I was discussing the clouds with family when we heard the roar come over Read MT and just barely made it inside.
The warnings were there early enough along with numerous damage reports out of SE Ohio and WV, but TV like WSLS focused more on the Olympic trials versus breaking in to a LIVE EXTENDED weather discussion/warning which is always the tough call in the eyes of the public.
We are at the edge of it Kevin..
many evenings we say West Texas
is being dropped on us.
Lots of times you can see it in the sunset,,
Theres just enough vegetation west of here to
keep it fairly benign. But there times rain drops
filled with dust pock the cars..and many times u just
get the earthy smell.
Heres one in Phoenix almost exactly a year ago.
This is all desert dust..at the end u can see it enveloping
Phoenix Sky Harbor Airport and the arena where the Suns play.
http://www.youtube.com/watch?v=8W4Cx44XKZ4
Just awakened from a nap and took the dog out. I have a question: Who stole the moon? It should be up there somewhere. It is full, FYI, but the Klingons must have cloaked it.
Regarding the forecast for the Friday storm…between following this blog, Jamey Singleton, and looking at radar and conditions in the Ohio Valley beforehand, I had a suspicion such a storm complex could move in before the clock struck noon. By later in the afternoon as the complex took shape and aim on the region, I began letting friends and family know what might be coming. By 7 I was securing our property, and by 8 I was hunkered down inside when the storm warnings were being posted. We were eating a late dinner around 9 when the storm finally hit.
Last sentence of the thread at the top of these comments: “That would probably mean a few spots getting 1-2 inches in storms, and other spots getting much less, even nothing for some.” Last four words are for me. HPC could have drawn in a tiny white circle around my neighborhood … 71* here as I head down the road to DVGC. HAPPY 4TH OF JULY, EVERYONE!!
Arrived to work this morning at 6 AM and the temperature was 81! I mean the temperature cant even dip below 80 at night, what gives? Anyhow calling for temperatures the next 3 days at 103, 102 and 104, give me a break. I guess try and survive until this insanity is gone, which I hope is next week from all indications! Anymore insight on next week Kevin? Not sure which is going to give out first, me or the greens at the golf course LOL!
Thanks Kevin for clarifying about a derecho and a haboob. It is good to learn something new every day. Happy 4th to you and everyone out in blog land.
Pattern is changing substantially next week. The heat dome is relocating to the West — it’s already shifting west, though it will expand more firmly over us next 3 days. The Hudson Bay vortex, a giant swirl of cool air that is common during our coldest winter periods, is forming. And a cold front is sinking south in response to all this over the weekend/early next week. Fronts always meet resistance moving south in midsummer, so it won’t zoom through, and it will be a focus for thunderstorms as it moves south. But as of now it appears it will get to almost the Gulf Coast, and we could be in line for some sub-90 high temperatures next week.
One thing that is different now than last week is the upper-level steering flow is weaker. So we’re less likely to see fast-moving storm complexes, but rather, slower storms dumping very heavy rain on small areas, and a few “microbursts” of high wind.
Added a link to my Weather Journal column about where the derecho fits into our local weather history:
http://www.roanoke.com/weather/wb/311152
Low of 70 this morning in Goodview. We ended up with .68 inches from two different storms yesterday. We definitely needed that.
On Friday, the wife and I have just walked in the house from shopping at Kroger, and 30 seconds later, the wind kicked up something fierce. I immediately went back outside to check on things. My eyes was assaulted by dusts. I sincerely hope we don’t have the hobo storm.
We are now in NC, outside Greensboro, where we spent a night in a hotel. The only thing was our GPS didn’t work (receive signals), but the turn by turn text direction saved me some sanity. I did see fell trees along 77 but NC looked like it escape the derecho.
We’ll be traveling to my birth place, Goldsboro, to visit with relatives.
This is from Dave Tolleris’s wxrisk.com FB page…Infrared Satellite loop from last Friday’s Derecho event. Notice how the red/magenta kind of bubbles like a pot of stew. The white colors embedded in the magenta are cloud tops above 60000′ MSL. You can really notice the white as it came across Northern VA west of DC. Wow!
http://cimss.ssec.wisc.edu/goes/blog/wp-content/uploads/2012/06/120629-30_g13_ir_derecho_anim.gif
Happy Independence Day everyone!
You do a great job here Kevin. I rely on your commentary more than that of our local news weathermen and women. Nothing against them, but I like the whys with the whats. I like knowing the contibuting factors. I like the absolute lack of political bias in your posts. That is what a true newsman should always stive to be is apolitical. Just the facts and the science as it is understood absent results steered in order to win grants. You are a credit to your professions both journalist and scientist.
I was aware of the potential for dangerous weather on Friday, mostly because of Kevin’s blog here, so thank you Kevin! I do remember you mentioning derecho in that morning’s blog and although I was somewhat familiar with the term I did look it up. So I did watch the radar for the familiar bow echo shape of the storms and when I saw those developing I knew we had to batten down the hatches. The intensity and quick movement of the storm kind of took my by surprise though, mostly because we were on the southern curve of the “bow echo” formation, so the radar did not show the bright reds etc that are normally associated with the move violent storms. I really thought when I heard the roar coming down the valley (sounded like a couple of jet engines revving up!) that we were going to get hit by a tornado. The only thing I overlooked was a patio table that we had sitting on our property near where we do bonfires. Not much we can do about trees though. So yes, I was prepared for the most part.
I really am looking forward to winter. I’ll be honest, I’d rather endure power outages when it is cold than in this miserable heat. We had several trees go down so we are thinking it is a sign to put in a wood burning stove before winter gets here.
Happy 4th to all the weather blog folks and to you and yours Kevin! I hope everyone can enjoy they day at least in some part.
I was out of town and missed Friday’s weather happenings but was able to follow them through the Roanoke Times and your blog, in particular, from Long Island, NY. Came back Sunday evening just in time for one heck of a thunderstorm here in S.W. Montgomery County. Our area lost power from 9:00 Friday night until about 6 Tuesday night. Thanks for providing entertainment and information over the years.
Here is another reason why I adore playing golf at Draper Valley, and this one IS weather-related. Temp here at 6 AM … 71. Temp at DVGC at 7:10: 64. Temp when I drove away from Draper about 10:30 … 79. Temp in Christiansburg at New River Valley Mall about 12 … 82. Temp here in SW County when I got back about 1 PM …. 91. UGH!!
I strongly encourage fellow bloggers to click on the link above to Kevin’s Weather Journal article of today. Kevin, I think this weather event of Friday night has caused the most severe damage and caused the most hardship (especially in terms of the number of days involved) to the most number of people here in the Roanoke valley (at least the Roanoke valley, and perhaps all of SW Virginia) since I moved to this area in late 1997. Two other events caused more inconvenience to me personally, but that does not count. And I can categorically state that having no power now is MUCH MORE of a problem than not having it after the Feb 2008 windstorm in mid-winter. People can always bundle up, and a cold house does not cause food in the fridge or freezer to go bad, and at least before the last year or two I had always found it easier to sleep in a cold house than in a hot one.
I looked briefly at the AO, NAO, and PNA outlooks, including the history of the NAO. You folks who want a cold winter should not look at the history of the NAO over the past 3 or 4 months. Very positive in March and for part of April, I think, and almost entirely negative as far back as the middle of May. If this streak of negative NAO readings had started in December, we would have had another cold winter.
The NWS forecast graphics under my nameplate are out of whack. There is no widespread heavy rain expected. And no pictures to go with the forecast as of 5 p.m.
Also … it’s not 0 degrees at VT Airport … that automated instrument site has not been registering online since the derecho.
Fun lil storm here at Windy Gap. Knocked my in laws power back out after just getting back on 4 hours ago.
Less than an inch of rain and about pea sized hail. Good bit of wind again.
Couple of cells developed early this evening on east side of Roanoke Valley and tracked south. Small but intense cells, with some gusty winds as Amanda notes, and up to quarter-size hail. Most of Roanoke west of downtown/I-581/U.S. 220 was not directly affected, other than some cooling breezes that knocked airport temperature from 97 to 83.