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Dallas derecho

Posted: Thu Jun 11, 2009 12:57 am
by cheezyWXguy
Anyone in Dallas, how did the storm go for you? Here we had a gust officially clocked at 78mph, some possibly higher. Lots of trees down and I think I spotted the circulation which was causing so much hype in the Flower Mound/North Dallas area. This storm was practically a carbon copy of last year's storm.

Re: Dallas derecho

Posted: Thu Jun 11, 2009 11:23 am
by zaqxsw75050
I was inside school during the storm so I missed the action. I saw some damage though around the Arlington area and I think there is an apartment fire cause by lightning near Brown and 360.

The rainfall amount is just incredible. 4-6 inches have fallen and more on the way.

Re: Dallas derecho

Posted: Thu Jun 11, 2009 8:39 pm
by Aslkahuna
FWIW, I see nothing on radar to suggest a Derecho-a typical run of the mill severe thunderstorm complex yes, but not a Derecho which has some very special features.

Steve

Re: Dallas derecho

Posted: Fri Jun 12, 2009 7:22 am
by Ed Mahmoud
How does a QLCS with embedded LEWPS/bowing segments and brief tornadic spin-ups, with a fair amount of straight line wind damage differ from a true derecho?

Posted: Fri Jun 12, 2009 7:30 am
by brunota2003
doesn't a derecho travel for hundreds or thousands of miles, lasting a day or more, while stretched over a considerable distance?

Posted: Fri Jun 12, 2009 8:54 am
by senorpepr
Well, if you can only qualify the event as being in Dallas, it definitely doesn't meet the criteria of being long-living nor widespread like a derecho.


According to the National Weather Service criterion, a derecho is classified as a band of storms that have winds of at least 50 knots (58 mil/hr or 93 km/hr) along the entire span of the derecho, which occurs over a time span of at least 6 hours.

Re:

Posted: Sat Jun 13, 2009 1:34 pm
by cheezyWXguy
senorpepr wrote:Well, if you can only qualify the event as being in Dallas, it definitely doesn't meet the criteria of being long-living nor widespread like a derecho.


According to the National Weather Service criterion, a derecho is classified as a band of storms that have winds of at least 50 knots (58 mil/hr or 93 km/hr) along the entire span of the derecho, which occurs over a time span of at least 6 hours.

that qualifies it. Dallas referred to the general metroplex, or NTX area. I was talking to people in the metroplex, because that's where I live and I was wondering of other people's accounts of the storm. But the storm was very large, very wide, produced winds in excess of 80mph and lasted most of the day traveling from near abilene into the mississippi area before collapsing completely.

Re: Dallas derecho

Posted: Sat Jun 13, 2009 10:56 pm
by Aslkahuna
I believe that we are talking about two different storm complexes because the one I saw in the Dallas area when I answered the post was clearly not a Derecho while a later event clearly was.

Steve

Re: Dallas derecho

Posted: Sat Jun 13, 2009 11:18 pm
by Aslkahuna
Looking at the storm reports for June 11th and 12th, I find that on both days the severe storms that developed in N Central TX moved S-SW and did not track very far. The Derecho of the 12th developed in NE OK and bowed out across AR/TN before ultimately dissipating in northern MS. The Texas storms do not appear to meet the requirements for a Derecho and I don't believe that SPC referred to them as such.

Steve

Re: Dallas derecho

Posted: Sun Jun 14, 2009 12:31 am
by cheezyWXguy
Aslkahuna wrote:Looking at the storm reports for June 11th and 12th, I find that on both days the severe storms that developed in N Central TX moved S-SW and did not track very far. The Derecho of the 12th developed in NE OK and bowed out across AR/TN before ultimately dissipating in northern MS. The Texas storms do not appear to meet the requirements for a Derecho and I don't believe that SPC referred to them as such.

Steve

It was on the tenth. Neither storm on the 11 or 12 made it to the dfw area.

Re: Dallas derecho

Posted: Sun Jun 14, 2009 6:27 am
by Dionne
Well folks, whatever the event is being called....one thing is for certain, it really played havoc with air travel through DFW. When we finally had a window to get out......it was still stormy enough to cancel the beverage service. Climbing through 21K we encountered some of the heaviest rain I can remember in 50+ years of air travel. It's no wonder Dallas flooded.

Re: Dallas derecho

Posted: Sun Jun 14, 2009 1:05 pm
by mcallum177
Hello all, new to this forum...short time lurker on the tropical forums. I would say that what we got was a derecho, it lasted from west texas all the way into the arklatex region...or several hours.

I live in Plano and on my side of town we did not get the main blast so to speak. Here is a weather station chart from wunderground at Preston and Legacy.

Image



Image

Re: Dallas derecho

Posted: Sun Jun 14, 2009 2:23 pm
by cheezyWXguy
mcallum177 wrote:Hello all, new to this forum...short time lurker on the tropical forums. I would say that what we got was a derecho, it lasted from west texas all the way into the arklatex region...or several hours.

I live in Plano and on my side of town we did not get the main blast so to speak. Here is a weather station chart from wunderground at Preston and Legacy.

Image



Image

Thats weird...I live in Plano also, and the winds were definitely well over 70mph here, and there was report at some school in plano of a 78mph wind gust. What part of plano do you live in?

EDIT: nvm I see that's from the preston and legacy area, which is pretty close to frisco, right? I live near parker, and there were trees down everywhere, and I know there were some places that lost power for over a day in the area.

Posted: Sun Jun 14, 2009 3:29 pm
by mcallum177
I live by hedgecoxe and independence..no significant tree damage in my area.


one of those is from legacy+preston
and one is from somewhere in the colony

Re:

Posted: Sun Jun 14, 2009 6:45 pm
by cheezyWXguy
mcallum177 wrote:I live by hedgecoxe and independence..no significant tree damage in my area.


one of those is from legacy+preston
and one is from somewhere in the colony

ah, ok. looks like the colony got spared the worst, but the station at legacy and preston had winds sustained over 75mph with several gusts to 100 if Im reading that right...

Re: Dallas derecho

Posted: Sun Jun 14, 2009 7:36 pm
by Aslkahuna
Looking at the reports for June 10th it looks marginal for a full blown Derecho-the question being did SPC or NWS call it that. I see three different swaths of activity and neither really tightly concentrated like a Derecho would be. You can get extreme winds out of the thunderstorm and still not have a Derecho. I once saw 100 mph winds at Dugway UT and it was clearly not a Derecho and we get hurricane force wind gusts every year out of monsoon thunderstorms here in AZ and I know of few examples where they would meet Derecho criteria. Derechos by their nature are actually fairly rare occurring only a few times per year Countrywide. They also seem more common in NW Flow Severe situations than with SW flow. However, if you want it to be a Derecho go right ahead.

Steve

Re: Dallas derecho

Posted: Sun Jun 14, 2009 11:16 pm
by cheezyWXguy
Aslkahuna wrote:Looking at the reports for June 10th it looks marginal for a full blown Derecho-the question being did SPC or NWS call it that. I see three different swaths of activity and neither really tightly concentrated like a Derecho would be. You can get extreme winds out of the thunderstorm and still not have a Derecho. I once saw 100 mph winds at Dugway UT and it was clearly not a Derecho and we get hurricane force wind gusts every year out of monsoon thunderstorms here in AZ and I know of few examples where they would meet Derecho criteria. Derechos by their nature are actually fairly rare occurring only a few times per year Countrywide. They also seem more common in NW Flow Severe situations than with SW flow. However, if you want it to be a Derecho go right ahead.

Steve

lol you're just gonna give me this one, huh? I'm just wondering, if that's not a derecho, what is? could you give me some sort of criteria? Because what you mentioned earlier seems to fit, but apparently I'm wrong. I don't wanna come off as more persistent to defend myself than actually find out what is right, so if you could describe this, I'd be grateful.

Here's a radar archive of that day, if it helps at all...
http://radblast-sf.wunderground.com/cgi ... height=480

Posted: Mon Jun 15, 2009 12:37 am
by mcallum177
According to wikipedia sustained winds of over 58mph...there were several spotters on the ham frequency that were reporting gusts over 60-70. I couldn't see the whole gust front cloud from my backyard view but it definitely looked like the one on the wikipedia page, and we could see the clouds rolling up and down very fast, it was so cool 8-)


How long does the NWS take to publish storm reports on the Storm Events Index page? It hasn't been updated since may.

Posted: Mon Jun 15, 2009 7:38 pm
by brunota2003
I'm surprised this page has not been mentioned:

http://www.spc.noaa.gov/misc/AbtDerecho ... ofacts.htm

Re: Dallas derecho

Posted: Tue Jun 16, 2009 12:33 am
by vbhoutex
Thanks! Great info for everyone!