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TWISTEX fielding status: June 29, 2007: Program end

All:

Returned from Devils Lake, North Dakota on Tuesday, June 26th.  Storm did not initiate the day before in North Dakota.

ISU team stopped through Minnesota to return the mobile mesonet equipment to Bruce Lee/Cathy Finley, and returned to Ames on Tuesday. Students will drive to Colorado on Sunday to return the vehicles.

TWISTEX 2007 will officially end today.  Good results were attained this year with an in-situ measurement of a weak tornado in April, and near-field measurements of a tornado collected on May 23rd. Unfortunately, June was painfully quiet for TWISTEX.

There might be some opportunities through the summer which we may participate in a spot chase to collect hail/tornado data depending on availability.

I would like to express my thanks to the following contributing individuals that participated with TWISTEX this year:

Bruce Lee
Cathy Finley
Carl Young
Tony Laubach
Pat Porter
Jon Davies
Matt Biddle
Carsten Peter
Jason Patton
Chris Karstens
Chris Conoan
Jayson Prentice
Adam Clark
Scott Lincoln
Sara Schmidt
Justin Gehrts
Andrew Ansorge
Verne Carlson
Jon Van de Grift
Paul Samaras

And the following contributers:

Iowa State University, Dr. Partha Sarkar, Dr. Bill Gallus
National Geographic Society
__________________, Dr. Kevin Housen

Also, I wish to express my gratitude to Bruce Lee and Cathy Finley for their tireless preparation and data collection using their mobile mesonet systems.

This summer, I will be working once again on a project to capture a naturally produced lightning strike using ultra-high speed photography. One of the many purposes is to study and visualize the attachment process of the stepped leader/return stroke/dart leader to the ground. We will also be taking RF spectrum data to match stepped leader/return stroke RF frequency distribution as a function of time.

I will have a similar email update for this program that will start in a few weeks.  For those of you who wish to be updated on this program, please respond to this email, and I will add you to the list.  For those who were on the list last year, there is no need to respond, you are already added.

Until next year!

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TWISTEX fielding status: June 25, 2007

 All:

Current location:  Miles City, Montana

Targeted supercel that developed north of Billings last night.  Storm was tornado warned for over an hour.  Classic shape, no tornadoes observed.  Photographed lightning for several hours.

Cold front will sweep through North Dakota today.  Plan is to get northeast of the surface low in reasonable backed winds.  Model data shows best area northeast of Bismark around Devils Lake or even close to the international border by late evening.  Capping will be an issue today, but believe that storms will initiate.

Target of Devils Lake by 4 PM CDT

After today, prospects for storms are grim..

Equipment status:

Photogrammetric probes:          Up
HITPR probes:                    Up
3D in-situ probe:                Up
vehicle.
High speed photography:            Up
system
mounts.
Mobile mesonet stations:          UP,
Hail collection/protection:        Up

Target today:

Devils Lake by 4 PM

Target tomorrow:

None

Time of departure:

8 AM CDT from Miles City

Next update is tomorrow morning.

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TWISTEX fielding status: June 22, 2007

 All:

Current location:  Lakewood, CO

Very concerned about the mid level temperatures for the next several days.  So concerned that the cost/benefit ratio of making the trip to the Dakotas this weekend is slim at the moment.

Activity the past few days under northwest flow has generated no ‘targetable’ tornadoes.  Some brief touchdowns were noted, as well as several tornado watches.

If any TWISTEX participant(s)see something that I’m missing, please email me to discuss.

Equipment status:

Photogrammetric probes:          Up
HITPR probes:                    Up
3D in-situ probe:                Up
vehicle.
High speed photography:            Up
system
mounts.
Mobile mesonet stations:          UP,
Hail collection/protection:        Up

Target today:

None

Target tomorrow:

None

Time of departure:

None

Next update is tomorrow morning.

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TWISTEX fielding status: June 20, 2007

 All:

Current location:  Lakewood, CO

Northwest flow will prevail over the midwest the next several days, thus providing a chance of severe in South Dakota and Iowa for today and Thursday.  Northwest flow are often poor tornado producers, thus TWISTEX will stand down until this weekend where another system will skirt through the northern plains.

Chris karstens:  Thanks for the forecast thoughts for tomorrow.  I think there is too much uncertainty with the potential event tomorrow with the forecasted overnight MCS in NW flow that makes me a bit nervous about real tornado potential.  With that said, being that TWISTEX won’t be participating tomorrow, IA may have a good NW flow tornado outbreak tomorrow.

Please note that we may travel to Manitoba for the next trip.  Again, no passports are required, just your drivers license.

Equipment status:

Photogrammetric probes:          Up
HITPR probes:                    Up
3D in-situ probe:                Up
vehicle.
High speed photography:            Up
system
mounts.
Mobile mesonet stations:          UP,
Hail collection/protection:        Up

Target today:

None

Target tomorrow:

None

Time of departure:

None

Next update is tomorrow morning.

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TWISTEX fielding status: June 19, 2007

 All:

Current location:  Lakewood, CO

Teams back from two day trip into the Dakotas.

June 16:

Chased developing storms west of the black hills into Wyoming.  Storms were mainly outflfow dominant as they crossed into South Dakota near Sturgis.  Collected some good cloud-ground lightning strikes.  Stayed in Pierre for the evening.  Had a tire blowout on M2 enroute to Pierre. Replaced tire the next morning.

June 17:

Target was Jamestown, North Dakota.  Tried to target the warm from aligned over I-94 by noon on Sunday.  As the warm front drifted north, several convergance boundaries collided, but no early storm initiation along the front.

A storm did form near Devil’s Lake, but on the north side of the warm front.  Being that it was the only storm in the area, we decided to have a look.  Outdoor temperatures were in the high 60s, while the dewpoint was high as well, creating a dewpoint depression of only 2-3 degrees. Because of this, the team was literally chasing in fog.  In fact we saw no structure to the storm at all due to no visibility.  Only visual indications that a storm was approaching was using live radar, and we can see the sky light up due to lightning strikes.  Storm became tornado warned by late evening, as the mobile mesonet team sampled the storm for several hours.  By late evening, some of the fog lifted around the storm to a point where we could barely detect the RFD wrapping around.  We continued to give chase until 10 PM when we broke off and stayed in Grand Forks for the evening.  Later in the evening, the cold front generated massive thunderstorms that swept over North Dakota during the late evening/early morning causing more flash floods for the area.

June 18:

Cold front had blasted through most of the midwest, stalling over north Texas thus creating the deadly flood situation that claimed several lives.

All team members returned home.

Future:

Appears that there is one possible opportunity coming up on Saturday/Sunday/Monday that will be monitored for possible operations.

Thanks to all team members for their efforts over the weekend.  Spent long hours on the road.

Equipment status:

Photogrammetric probes:          Up
HITPR probes:                    Up
3D in-situ probe:                Up
vehicle.
High speed photography:            Up
system
mounts.
Mobile mesonet stations:          UP,
Hail collection/protection:        Up

Target today:

None

Target tomorrow:

None

Time of departure:

None

Next update is tomorrow morning.

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TWISTEX fielding status: June 16, 2007

 All:

Current location:  North Platte, Nebraska

Current plans are to meet in Murdo, South Dakota by 2 PM CDT today.  0z model suggest best combination of shear and cape appears to be in the western portion of South Dakota.  Once our teams are together, we’ll refine the forecast.

ISU:  Give me a call this morning to check in.

Equipment status:

Photogrammetric probes:          Up
HITPR probes:                    Up
3D in-situ probe:                Up
vehicle.
High speed photography:            Up
system
mounts.
Mobile mesonet stations:          UP,
Hail collection/protection:        Up

Target today:

Fairpoint to Wasta, South Dakota (to start)

Target tomorrow:

Undetermined, but likely western South Dakota.

Time of departure:
8:30 CDT

Next update is tomorrow morning.

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TWISTEX fielding status: June 13, 2007

 All:

Current location:  Lakewood, CO

Multi-cell storms expected in western Oklahoma and southwestern Kansas.
 Due to the weak mid-level winds, supercells will be the exception
rather than the rule today in this area.  If a supercell does initiate
in this area, there is a small chance of a tornado.

Unfortunately, this small chance does not warrant a mission to this area
today.

Looks quiet for the next couple of days, then the model data suggests an
active period starting Sunday through Monday or Tuesday.

TWISTEX is down for today, tomorrow, and Friday.

Equipment status:

Photogrammetric probes:          Up
HITPR probes:                    Up
3D in-situ probe:                Up
vehicle.
High speed photography:            Up
system
mounts.
Mobile mesonet stations:          UP,
Hail collection/protection:        Up

Target today:

None

Target tomorrow:

None

Time of departure:

None

Next update is tomorrow morning.

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TWISTEX fielding status: June 11, 2007

 All:

Current location:  Lakewood, CO

12z model data is not optimistic about tornadoes in the northern plains for Tuesday, Wednesday, and the balance of the week.  This is certainly unfortunate, as the program is coming down to the final three weeks of formal operation.

At the moment, TWISTEX is standing down for Tuesday due to poor surface features under the stronger 500 mb flow in the northern plains.  I would certainly listen to ideas if somebody sees something in the forecast that I’m missing.

Being that the model data has been struggling with the forecast each day, we will evaluate tomorrow and Wednesday, then once we see strong evidence that the ridge is settling in for the balance of the week, we’ll officially stand down until the next system comes aboard perhaps this weekend.

We might do a local chase in Colorado for hail, as it appears that some strong storms (likely line segments) may develop in eastern Colorado that would produce 1″ or larger hail.

Equipment status:

Photogrammetric probes:          Up
HITPR probes:                    Up
3D in-situ probe:                Up
vehicle.
High speed photography:            Up
system
mounts.
Mobile mesonet stations:          UP,
Hail collection/protection:        Up

Target today:

None

Target tomorrow:

None

Time of departure:

None

Next update is tomorrow morning.

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TWISTEX fielding status: June 9, 2007

 All:

Current location:  Lakewood, CO

Travel day yesterday back to Denver-arrived 1 AM Saturday.  ISU crew returned to Ames, and Bruce/Cathy returned home.

Looks like a quiet weekend ahead with possible operations early next week.  Monday operations are certainly possible, but the terrain and surface features are not supportive as suggested by this morning’s model runs.  Will evaluate tomorrow.

Looks like a summertime ridge settles in the midwest after Wednesday, with a possible disturbance after the 17th of June.

Congrats to Howie and his group for a great year, they have terminated operations for the season.  They have collected radar imagery of great storms using new technology for the first time.

Equipment status:

Photogrammetric probes:          Up
HITPR probes:                    Up
3D in-situ probe:                Up
vehicle.
High speed photography:            Up
system
mounts.
Mobile mesonet stations:          UP,
Hail collection/protection:        Up

Target today:

None

Target tomorrow:

None

Time of departure:

None

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TWISTEX fielding status: June 8, 2007

All:

Next update will be tomorrow morning.

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