Watching the Skies

The National Weather Service in Fort Worth put together a storm summary for the very active weather pattern from June 10 through June 14, including the Tornadoes in Denton County that prompted the warning for Frisco. I didn’t realize there was actually tornado damage reported in The Colony too, the only areas I heard of damage was from Roanoke, Trophy Club and Flower Mound. The Colony is Frisco’s western neighbor and only 3 miles away from downtown Frisco! At this time it appears that three separate tornado touchdowns occurred, the strongest being eF-1 in Flower Mound.

…SUMMARY OF STORM IMPACTS FROM JUNE 10 THROUGH JUNE 14…

AN UNUSUALLY ACTIVE SERIES OF SEVERE WEATHER EVENTS…EVEN BY NORTH
TEXAS STANDARDS…IMPACTED THE AREA FROM THE LATE AFTERNOON OF JUNE
10 THROUGH THE EARLY MORNING HOURS OF JUNE 14. BASED ON RADAR
DATA…STORM SPOTTER REPORTS…AND COORDINATION WITH LOCAL
OFFICIALS…HERE IS A BRIEF PRELIMINARY SUMMARY OF THE STORM IMPACTS.

JUNE 10…
A CLUSTER OF SEVERE STORMS DEVELOPED OVER WEST CENTRAL TEXAS AND
MOVED EAST. THE STORMS ORGANIZED INTO A BOW ECHO JUST WEST OF THE
DALLAS-FORT WORTH METROPLEX AND PRODUCED EXTREMELY STRONG WINDS.
NUMEROUS 70-80 MPH WIND GUSTS OCCURRED ACROSS NORTHERN PARKER…
SOUTHERN WISE…NORTHERN TARRANT…SOUTHERN DENTON…NORTHERN
DALLAS…AND SOUTHERN COLLIN COUNTIES. WIND GUSTS IN EXCESS OF 60
MPH OCCURRED ACROSS MUCH OF THE REMAINDER OF THE METROPLEX.

WITHIN THE BROAD AREA OF DAMAGING WINDS…AT LEAST THREE BRIEF
TORNADOES OCCURRED. SPOTTERS OBSERVED THE TORNADOES FROM ROANOKE TO
TROPHY CLUB AT APPROXIMATELY 640 PM…IN FLOWER MOUND AT ROUGHLY 650
PM…AND IN THE COLONY-HEBRON AT ROUGHLY 705 PM. THE ROANOKE AND
COLONY TORNADOES WILL LIKELY BE RATED EF-0…WHILE THE FLOWER MOUND
TORNADO WILL LIKELY WARRANT AN EF-1 RATING. FURTHER INVESTIGATION
MAY REVEAL ADDITIONAL BRIEF TORNADOES WITHIN THE DAMAGE SWATH.

JUNE 11…
THE STORMS FROM THE EVENING OF JUNE 10 LEFT BEHIND AN AREA OF
RAIN-COOLED AIR. THE BOUNDARY BETWEEN THE RAIN-COOLED AIR AND THE
WARM HUMID AIR SAGGED TO THE SOUTH OF THE I-20 CORRIDOR. WARM MOIST
AIR WAS FORCED UP AND OVER THE BOUNDARY…RESULTING IN A NEARLY
CONTINUOUS STREAM OF THUNDERSTORMS DURING THE MORNING AND EARLY
AFTERNOON OF JUNE 11. MORE THAN THREE INCHES OF RAIN FELL FROM JACK
COUNTY SOUTHEAST TO HENDERSON COUNTY. THE HEAVIEST RAIN FELL FROM
NORTHERN TARRANT TO KAUFMAN COUNTY…WITH MORE THAN EIGHT INCHES
ACROSS MUCH OF DALLAS COUNTY. THE RESULTING HEAVY RAIN CAUSED
WIDESPREAD FLOODING IN THE AREA.

A SEPARATE CLUSTER OF SEVERE THUNDERSTORMS DEVELOPED WEST OF THE
HEAVY RAIN AREA…FROM EASTLAND COUNTY SOUTHWARD. LARGE HAIL FELL
FROM NEAR CISCO TO NORTH OF LAMPASAS…WITH THE HAIL REACHING
BASEBALL SIZE IN LAMPASAS COUNTY.

JUNE 12…
A SUPERCELL THUNDERSTORM DEVELOPED OVER NORTHERN JACK COUNTY AND
MOVED SOUTH-SOUTHEAST. THE STORM PRODUCED AT LEAST TWO CONFIRMED
TORNADOES…WINDS IN EXCESS OF 70 MPH…AND HAIL LARGER THAN
BASEBALLS. THE TORNADOES WERE APPROXIMATELY 5 MILES SOUTH OF
JACKSBORO JUST BEFORE 530 PM…AND JUST WEST OF PERRIN AT AROUND 550
PM. DAMAGE TO OUTBUILDINGS AND ROOFS RESULTED…AND THESE WILL
LIKELY BE RATED AS EF-1.

AS THE STORM MOVED THROUGH WESTERN PARKER COUNTY…POSSIBLE
TORNADOES IMPACTED AREAS NEAR THE COMMUNITY OF COOL…AND TO THE
SOUTHWEST OF WEATHERFORD. THE STORM UPROOTED TREES AND DESTROYED
STORAGE BUILDINGS IN THESE LOCATIONS. THE STORM CONTINUED PRODUCING
LARGE HAIL AND SEVERE WINDS INTO JOHNSON…HOOD…AND BOSQUE
COUNTIES.

TO THE SOUTHWEST…A CLUSTER OF SEVERE STORMS MOVED INTO COMANCHE
AND MILLS COUNTIES. HAIL UP TO NICKEL SIZE WAS REPORTED WITH THESE
STORMS.

JUNE 13-14…
A COMPLEX OF THUNDERSTORMS MOVED THROUGH WEST CENTRAL TEXAS ON THE
EVENING OF JUNE 13. THE STORMS MOVED INTO YOUNG AND MONTAGUE
COUNTIES BEFORE WEAKENING. DAMAGING WINDS IN EXCESS OF 70 MPH MOVED
THROUGH THE NOCONA AREA SHORTLY AFTER MIDNIGHT JUNE 14. A LARGE
TREE WAS BLOWN DOWN WEST OF NOCONA…AND ROOF DAMAGE OCCURRED IN
NOCONA.

YOUR NATIONAL WEATHER SERVICE WILL CONTINUE INVESTIGATING THE
IMPACTS FROM THIS SERIES OF SIGNIFICANT THUNDERSTORM EVENTS.
ADDITIONAL DETAILS AND INFORMATION WILL BE PROVIDED IN UPDATED
STATEMENTS AND POSTED TO OUR WEBSITE. FOR THE LATEST INFORMATION…
VISIT /LOWER CASE/ WWW.WEATHER.GOV/FORTWORTH

Hey everyone, looks like most of the day Saturday will be clear to partly cloudy skies and hot. At this time a Moderate severe storm risk has been issued for areas including the Texas panhandle and western Oklahoma.

Current forecasts call for severe thunderstorms to develop from the Texas panhandle down to near Wichita Falls TX, then evolve into an MCS (storm complex) and push down twards the northern parts of the metroplex this evening.

While areas north of I-20 does have slight chances for thunderstorms during the afternoon, most likely we will remain sunny and dry until the evening when the storm complex pushes through. Atmospheric conditions this evening may be supportive for a bow echo type of storm to develop. A bow echo is the same type of storm that impacted us on Wednesday, prompting the tornado warning for Frisco. If weather forecasts continue to indicate this type of event, I will likely send out further updates on this later.

Now as a side note, these severe weather events occurring the first two weeks of June is somewhat uncharacteristic for this area and certainly was not anticipated in long range climatological computer models. This June had the markings of being a very hot and very dry month, but Dallas received 8+ inches of rain in 24 hours this week, and multiple tornado reports have been received from all around north Texas including a few last night near Mineral Wells just 68 miles west of Frisco. Sunday and Monday also have severe weather threats for areas to our north and west but do not include the DFW metroplex at this time. I believe a major contributing factor to this pattern of severe weather is the southern branch of the jet stream is parked pretty far south for this time of year. Currently the jet stream sits across the 4 corners states, through Kansas and Oklahoma, into Illinois. This southern branch of the jet stream may be partially responsible for keeping moisture return from the gulf in the southern and central plains, keeping a fairly persistent stationary front parked right along the Texas/Oklahoma border, and overall seems to be retaining a very mid-spring type of weather pattern. Its almost as if the unseasonable high pressure ridge that kept most severe weather from forming during my storm chasing trip in May, is now indirectly responsible for this unseasonably late severe weather pattern in the southern and central plains.

Wow, amazing day! Tornado warned storm plowed through the area just 4 miles south of Frisco after 7pm bringing widespread high wind reports and some tornado damage to areas just west of Frisco. I took the liberty to take screen shots of the storm as it moved through the area, and draw a storm track on a Google map so you can see just how close we came. But first, a brief history and timeline. The timeline is relevant to storm events reported near Frisco and not a complete list.

• 4:30pm I notice a cluster of supercells merging into a large storm complex near Abilene TX about 130 miles west of Frisco.
• 5:00pm this storm appears to have evolved into a severe line of storms looking like a bow echo. This storm is in a favorable environment and at current speed will reach Frisco by 7:30pm
• 6:04pm Tornado Warning is issued for Denton county, does not include Frisco yet but the storm’s track is still set to move very close to Frisco.
• 6:40pm Tornado is spotted on the ground in Roanoke, 22 miles WSW of Frisco. Spotted by Amateur Radio operators.
• 6:43pm Tornado Warning is issued for Denton, Collin, Tarrant, Dallas and Rockwall counties. This includes Frisco and The Colony.
• 6:50pm Tornado spotted by retired NWS employee, brief touchdown in Flower Mound, 15 miles WSW of Frisco.
• 6:53pm Tornado ripped roof off and collapsed wall to apartment building in Flower Mound, 15 miles WSW of Frisco.
• 6:56pm Tornado sirens finally start to sound for Frisco, note the 13 minute discrepency. This is EXACTLY why I tell everyone not to trust the sirens.
• 7:00pm I get out of work, the storm is now less than 8 miles away from Frisco,
• 7:05pm I drive one mile west along Warren Pkwy. At the intersection of Warren & Legacy I observe power flashes on the horizon about 3 miles to my WSW. At this time I turn around and head back home, 1.5 miles away.
• 7:12pm I arrive at home just as the very high winds and rains hit. Sirens are still going off.
• 7:14pm The strongest rotation made a last minute right turn and passes 4 miles south of Frisco, into Plano. The sirens stop at this time.
• 7:14pm 72 MPH wind gust observed at Frisco Fire Station on Main Street and Preston Road.
• 7:19pm 78 MPH wind gust observed at a school in Plano, near Independance and Spring Creek.

Allow me to reiterate how close this storm was. The storm’s center of circulation passed only 4 miles south of the T-Mobile site in Frisco (where I was at the time). At the time the tornado warning was issued for Frisco, the storms current track took it within 1/2 mile of the T-Mobile site in Frisco. Below is a Google map I just made demonstrating this.

The red circles indicate tornado sightings and tornado damage reports. The red line indicates the path of the storm’s center of circulation. The blue line indicates the storms projected path when the tornado warning was issued for Frisco. The purple circle shows where the T-Mobile building is, and where I was at the time. As you can see… this was a close call. If the storm had maintained its current track and not turned right in Lewisville, Frisco could have been hit head on.

Above is a radar snap from 7:09pm CDT, when the storm’s center of circulation was at its closest to Frisco. Left side is standard precipitation and the right is base velocity. You can see a weak reflectivity couplet that is unfortnately a tad obscured by the large yellow warning box. The yellow and red icons indicate areas of wind damage, and tornado reports respectively.

At this time, some damage reports in Frisco have come in according to Fox News KDFW. Some homeowners had their fences blown down, satelite dishes blown off their houses and windows broken. Another reports states at least three seperate 18-wheeler trucks blown off the road and tipped over due to high winds, mostly around Fort Worth. The Denton County Sherrifs Office reported a minor explosion at a gas station due to the weather. Across the metroplex, a whopping 260,000 homes are reported without power.

Now we will wait and see what the NWS in Fort Worth states after they conduct their damage surveys, before we officially declare this as a tornado. Considering the numerous spotter reports, storm damage reports, and the radar velocity couplet, there is a good chance this will be classified as a tornado event. I will publish updates to this once the storm damage survey is released.

Hey folks, this will be relatively short as I have been very busy at work today. We have a very severe storm approaching from the west, which appears to be a bow echo type of storm (bow echo is large scale storm usually derived from a cluster of supercells, these produce very strong winds). Currently the storm is 66 miles west, moving east at 31 knots. This puts an ETA to Frisco by about 7:30pm to 7:45pm. Currently this storm is producing radar indicated winds of 65mph and two TVS (tornadic vortex signatures, essentially a radar indicated tornado). Considering the storms speed and structure, and the environment its moving in to, this storm is likely to retain its severity as it moves into our area so plan accordingly. This storm is also producing large hail, radar indicates a whopping 4.85 inches which is larger than grapefruit!

I will send updates as the storm gets closer, but plan on severe storm warnings to be issued as this storm approaches.

Well, after an exhausting 34 hours of driving in 54 hours time, I am back home. I used Thursday to travel back from Kearney Nebraska to Frisco Texas. Looking at the upcoming weather forecasts, looks like I am not missing much. I read a cool blog entry where the VORTEX2 team actually intercepted a supercell near Alliance Nebraska, basically where I was. Below is a link to their blog post about their chase day.

http://tornadoscientists.blogspot.com/2009/05/surprise-supercell-intercept.html

Now let me give you a synopsis of my chase day… I left Kearney Nebraska and headed for Alliance. This seemed to be the convergence area that all the chasers picked as I passed at least two separate chase tours and numerous independent chasers.  I got to Alliance around 2:30pm, gave me plenty of time to spare so I could get some food and check data to verify my location was good. Saw some cumulus puffs forming, and storm anvils to my distant west.

Middle of nowhere, Nebraska.

Storms 100 miles west in Wyoming.

I waited until about 3:30pm when a storm storm was about to pass through Angora. I shot south along US 385 till I found a spot just to the north of Bridgeport and just hung out for a few minutes. I got hailed on with pea sized hail for a minute, before the storm moved on to the north east. The storm was still strong but not severe as it moved into an area with absolutely no road network to chase with. After the heaviest rain passed, I traveled north again to a rural unpaved road along 385 then sat and watched it for a good 30 minutes as it moved away. I actually saw the TIV along the side of the road with other support vehicles around it, following the same storm as me! Other chasers actually stopped right next to me and we watched a large coal freight train move by and contemplated our other storm options. We decided after 30 or so minutes to shoot back to Alliance and pull a wait and see maneuver.

Trying to blast south and catch up with the storm.

Heavy rains just before the pea sized hail.

Watching the rain and hail move into an area with no roads.

Waiting with other chasers, contemplating our next move.

Watching the heavy freight train roll by.

I pulled into Alliance shortly after 4pm, and noticed a severe storm in extreme north west Nebraska, about a hour drive north. This storm had good looking winds on it and looked like a miniature bow echo for a short while so after maybe 5 minutes of waiting in Alliance, I abandoned the other chasers and headed north towards Chadron. As far as I could tell, this severe storm was sitting in a better environment so I figured this storm would be a shoe in for me. Well about 15 miles before I reached Chadron, the storm had lost its severity and was no longer severe warned. I found a nice pull off with a beautiful wide open field to stop and watch the storm roll in. The storm still had a general shape of a bow echo and I was sitting right on the southern part of it, hoping to catch some strong winds. I caught a few neat pics of a gust front ahead of the storm, and wind gusts up to 35mph with my handheld anemometer.

Blasting north twards Chadron trying to catch up with this beast.

15 miles south of Chadron, waiting to see what the storm does next.

Still south of Chadron watching the approaching gust front.

A one in a million lightning shot during the day. This is using a Canon Powershot SD1000 with a 1/60 exposure time, and I captured lightning! WOW.

At this time, I noticed the remnants of the storm that I was originally chasing had actually become severe and looked supercellular, DOH! The storm was 70 miles to my ESE, moving east at about 30 mph. By this time it was 6pm and assuming all goes well I would intercept this storm at 8pm at the earliest. I decided to shoot south to Alliance again, then take state road 2 east as fast as I could. I anticipated on arriving in Thedford Nebraska as the storm was arriving, right around sunset.  While driving south on 385 towards Alliance, I got some more pea sized hail which slowed my travel down. I passed two more VORTEX2 vehicles which appeared to be part of the mobile mesonet. Then as I was driving state road 2 through the rural sand hills, a line of storms formed along the cold front directly in front of me. This was unexpected! I saw some very low level clouds forming below the general cloud deck which appeared to be a shelf cloud! This line of developing storms was occurring behind the severe warned supercell I was intending on catching, but directly in front of me. It was pretty to watch but the storms happened to be moving about the same speed as me since I was not able to get in front of these storms easily. For a brief moment I thought I saw a funnel cloud forming out of the shelf cloud about 3 miles to my south east, but the road took be behind some tall hills and by the time I emerged, there was no trace of the funnel. I drove through about 20 miles of white out condition rains which dropped my speed to 40mph and basically left me stuck right in the worst of this storm as we were traveling about the same speed. I finally emerged from the rain near Whitman Nebraska and saw the leading edge of this shelf cloud as it started to collapse. I continued to drive east towards Thedford but by the time I arrived, the supercell storm was no longer severe and had moved out of Thedford. About this time the sun had just set, so I decided to call it a day. I prepared for another 3 hour drive back towards Kearney for the night.

Shelf cloud starting to develop a few short miles infront of me.

A possible funnel cloud emerging from the shelf cloud? Sorry for the blur, its dark, and I am driving 70mph trying to get ahead of this.

Very heavy rains infront of me, this is the leading edge of the storm front, just behind the shelf cloud.

Finally ahead of the storm front, the shelf cloud has collapsed. This is the end of my chase day.

All in all, I am happy that I picked the same target area as the professionals with VORTEX2 and other chasers. However I did not pick the right individual storms it appears. At the time that I made my decision they were the strongest storms in the area. If the original storm I had picked hadn’t moved into an area with no roads, then I’d have stayed on that storm until it became the supercell. I also learned that I will no longer use an integrated data card for my cellular data service. The connection drops when you switch roaming data providers and does not reconncet. Next time I will tether to a BlackBerry so I don’t have that issue again. Also 14 hours of driving does not work well for me when driving solo. Next time I will keep it to 12 or less. I got a few good pictures but nothing amazing. I will not put my telephoto lense on the DSLR camera anymore either, capturing the entire storm is more important than capturing telephoto detail.

You can view the rest of my gallery here: http://watchingtheskies.com/?page_id=33&album=4&gallery=29

Here is a blog entry made by the CIMSS Satellite Blog folks on today’s extremely powerful derecho event in the mid-west. At one point, the storm looked like a hurricane from both the radar and satellite views with an incredible comma shape precip echo on radar that nearly wrapped around the entire storm and traverse banding spreading out from the upper layers of the storm. See one of my previous posts for a screenshot of radar reflectivity earlier.

http://cimss.ssec.wisc.edu/goes/blog/archives/2534

At 18:25 GMT a wind speed of 106mph was measured in Illinois and hail up to 2.75 inches measured in Missouri at 14:34 GMT. Now THAT is an incredible derecho!

Today I captured this absolutely amazing looking bow echo storm that transformed into a, well quite frankly I have no idea what you would consider this. This looks more like a major rain wrap around a low pressure system, or even to a degree like a hurricane. Take a look at this crazy storm. This thing could still be considered a derecho event too as it was putting out very impressive winds, several tornado reports and hail.

UPDATE: So apparently this is could be called a comma shaped bow echo, generally considered to be the last stage in evolution of a bow echo storm.  I haven’t seen anything like it before, looks incredible to me.