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TWISTEX Status Message: June 24, 2008 - END OF SEASON

June 24, 2008 – 5:38 pm

All:

Current Location: Lakewood, CO

The TWISTEX field program has been terminated for the season.

12z model data suggests that the current shortwave over SD/ND will scour out most of the moisture in the Dakotas leaving dry conditions for western SD/NE where the best dynamics are located.

On Thursday evening, models show the shortwave still in MT with the shortwave moving quickly through ND and MN during the early part of the day on Friday, which is out of phase with the best surface dynamics (what little existed).

After Thursday, a strong ridge of high pressure sets up across the intermountain states which is very typical of a summertime pattern.

Thus based on the current forecast, TWISTEX will terminate effective today, although Samaras will continue to look for storms that could generate large hail through the summer for data collection as time permits.

The Principle Investigators of the program (Bruce Lee, Cathy Finley, Tim Samaras) would like to thank everyone for their tireless efforts for this very successful season. The project has collected data from several  tornadoes including tornado core measurements.  The collected data has resulted in the generation of three abstract submissions for the upcoming SLS conference in October so far.

We also would like to thank the coordination efforts of Robin Tanamachi and Howie Bluestein from Oklahoma University during the latter part of the season.

ISU:

Would like to coordinate off-line to get the instrumentation racks back to Bruce/Cathy and to return the rental cars to MSP this Friday/Saturday if possible.  Please email/contact Bruce/Cathy/myself for coordination.

Target today:

None

Target tomorrow:

None

Future:

April 2009

Thanks,

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TWISTEX Status Message: June 23, 2008

June 23, 2008 – 10:22 am

All:

Current Location: Lakewood, CO

There are hints of possible operations for Wednesday and Thursday of this week.  Although not the greatest opportunitites, we are carefully evaluating these as a possible trip.  Small 500 mb flow disturbances appear to be riding along the zonal flow with reasonable moisture in place for the Dakotas.  The big negatives is that these are in areas where the road network isn’t the best (western Dakotas), and probable forced lifting by suggested coldfront.

If we decide to move forward with operations, we (the Denver group) will depart Wednesday morning for a target somewhere in western South Dakota.  Teams from MN and IA would plan accordingly.
General feeling at the moment is to NOT pursue the last field trip due to cost/benefit ratio.

If we decide NOT to move forward with this last trip, then TWISTEX will terminate for the year.

Equipment status:

Photogrammetric probes: Up
HITPR probes: Up
3D in-situ probe: In prep
High speed photography: Up
Sonde: Not participating this trip
Balloon Radiosonde: In prep
Mobile mesonet stations: Operational
Hail collection: Up

Target today:

None

Target tomorrow:

None

Future:

6/23 12z data shows small waves within the 500 mb zonal flow with adequate moisture.  Will make a go, no-go decision either this afternoon or tomorrow morning.

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TWISTEX Status Message: June 19, 2008

June 19, 2008 – 8:27 am

All:

Current Location:  Lakewood, CO

Currently the TWISTEX project is currently down, and will likely remain
down until the current ridge breaks down.  Seems like a summertime pattern has set in at the moment with northwest flow generating nightly MCS complexes that are racing southeast across the midwest.

At the moment, it appears that the long range forecast is giving some hope for late next week.

TWISTEX project will remain active through the end of June but may end
on June 25 if the forecast shows ridging through the end of the month, and next week’s possibility evaporate.

All team members:

Thanks for getting all of the receipts to me.  Reimbursements are on the way.  If TWISTEX officially closes by mid next week, we’ll need to make arrangements to get the MSP MM vehicle instrumentation returned to Bruce/Cathy and the vehicles turned in to MSP airport by the end of the month.

Equipment status:

Photogrammetric probes:                 Up
HITPR probes:                           Up
3D in-situ probe:                       In prep
High speed photography:                 Up
Sonde:                                  Not participating this trip
Balloon Radiosonde:                     In prep
Mobile mesonet stations:                Operational
Hail collection:                        Up

Target today:

None

Target tomorrow:

None

Future:

6/19 0z GFS shows a ridge now through next week with some possibilities maybe late next week.  Pending future model data, TWISTEX may terminate on June 25.

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TWISTEX Status Message: June 17, 2008

June 17, 2008 – 7:53 am

All:

Current Location:  Lakewood, CO

Currently the TWISTEX project is currently down, and will likely remain
down until the current ridge breaks down.  GFS continues to show ridging through the weekend with some possibilities perhaps by mid next week.

TWISTEX project will remain active through the end of June but will end
if the forecast shows ridging through the end of the month.

All team members:

I would like to catch up on our financial status of the project-please give me your unpaid receipt totals as soon as possible if you haven’t done so already.

Equipment status:

Photogrammetric probes:                 Up
HITPR probes:                           Up
3D in-situ probe:                       In Prep
High speed photography:                 Up
Sonde:                                  Not participating this trip
Balloon Radiosonde:                     In prep
Mobile mesonet stations:                Operational
Hail collection:                        Up

Target today:

None

Target tomorrow (Wednesday):

None

Future:

6/17 0z GFS shows a ridge now through next week.  Will it ‘flip’ again to show opportunities for middle of next week?  Stay tuned–

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TWISTEX Status Message: June 14, 2008

June 14, 2008 – 8:11 am

All:

Current Location:  Lakewood, CO

Currently the TWISTEX project is currently down, and will likely remain down until the current ridge breaks down.  GFS shows some hope of operations in the northern plains/Canada by late next week.

TWISTEX project will remain active through the end of June but will end if the forecast shows ridging through the end of the month.

Equipment status:

Photogrammetric probes:         Up
HITPR probes:                       Up
3D in-situ probe:                     In Prep
High speed photography:         Up
Sonde:                                 Not participating this trip
Balloon Radiosonde:             In prep
Mobile mesonet stations:         Operational
Hail collection:                         Up

Target today:

None

Target tomorrow (Thursday):

None

Future:

0z GFS shows a ridge now through next week.  Will it ‘flip’ again to show opportunities for middle of next week?  Stay tuned–

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TWISTEX Status Message: June 12, 2008

June 12, 2008 – 9:59 am

All:

Current Location:  Lincoln, Nebraska

Yesterday, we intercepted a tornadic circulation approximately 100-150 meters from the mobile mesonets about 30 miles east of Lincoln late last night.  Circulation was buried within the line of convection, and was moving to the north at ~40 kts.  No in-situ deployments attempted.

Today a reasonable target seems to be in southeast Kansas.  Reasonable windfields and excellent moisture exists within a coldfront boundary which should become stationary by mid afternoon.  Issues include storm seeding, but we’ll target the southwestern most storm of the line, which should offer the best potential for tornadoes.

After today, its likely that TWISTEX will be down until mid-late next week where the GFS indicates the next system emerging in the northern plains.  Our program end date is the end of June.

Equipment status:

Photogrammetric probes:     Up
HITPR probes:                       Up
3D in-situ probe:                     In Prep
High speed photography:     Up
Sonde:                                 Not participating this trip
Balloon Radiosonde:             In prep
Mobile mesonet stations:         Operational
Hail collection:                         Up

Target today:

Southeast Kansas along the turnpike from Wichita to Topeka

Target tomorrow (Thursday):

Likely down until mid next week

Future:

12z GFS shows hope beginning Wednesday/Thursday of next week for the northern plains.
We’ll see.

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TWISTEX Status Message: June 11, 2008

June 11, 2008 – 12:05 pm

All:

(Note:  On new computer-old one crashed that had expanded email list)

Current Location:  Sioux City, Iowa

Yesterday, storms did not initiate along the warm front by dusk-used the day for travel.

Today is a complicated forecast.  Differing model solutions aid to the confusion, however it appears that there is a reasonable threat for hail/tornadoes in southeastern Nebraska today.  Issues today include ongoing morning convection in Iowa, and very stable atmosphere over southeastern Nebraska as shown on satellite.  Good moisture and upper dynamics are in place, but once again-the storm speeds are ~40 kts to the northeast, typical of early Spring.  Where are the REAL June storms?

Plan is to depart hotel by 11 AM CDT and head south on I-29 towards Omaha.  Likely move into Nebraska by mid-late afternoon based on afternoon observations.

Equipment status:

Photogrammetric probes:     Up
HITPR probes:                       Up
3D in-situ probe:                     In Prep
High speed photography:     Up
Sonde:                                 Not participating this trip
Balloon Radiosonde:             In prep
Mobile mesonet stations:         Operational
Hail collection:                         Up

Target today:

Southeast Nebraska-hopefully in front of the crashing cold front

Target tomorrow (Thursday):

Unknown-maybe northern Illinois?

Future:

Likely we will go down starting on Friday until the ridge passes.  GFS gives some hope for the northern plains sometime by mid next week.

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TWISTEX Status Update: June 10, 2008

June 10, 2008 – 8:59 am

All:

Current location:  Teams en-route to potential target today along warm front in southeastern, SD near Neb border.

“A Tale of Two Models”

Based on the 12Z runs, RUC paints an optimistic picture for good moisture return right up to warm front and convective initiation by 22Z. Storms fire within about an hour’s drive west of Yankton. Given good directional shear and excellent CAPE, this would be an excellent recipe for supercells with some tornado potential.  The NAM paints just the opposite picture with no quality moisture return by 00Z and no convection along front during daylight hours.  We’ll see which model wins.  While RUC seems a bit optimistic, NAM’s Nebraska moisture prog looks too dry.  We have to hope that local source evaporation/evapotranspiration will get the Tds up near the RUC estimate.  Models do not do well with these sfc moisture fluxes.  So, while there is still large bust potential, at least there remains a few threads of hope.

M1 and M2 will tentatively meet at Yankton around 2:30 PM.  We will coordinate a meeting with Probe/M3 as they get closer to where we think target area will be.

Wednesday setup still remains about the same.  We think the sfc reflection of the upper-level dynamics may be underdone on the NAM, which may provide a bit better flow backing from southern/southwestern MN into northwestern/western IA.  Our location today puts us in good shape to get positioned early for Weds.
There may be mesoscale boundaries from noctural convection to make the setup a bit more complex.

Equipment status:

Photogrammetric probes:                  Up
HITPR probes:                            Up
3D in-situ probe:                        In Prep
High speed photography:                  Up
Sonde:                                   Not participating this trip
Balloon Radiosonde:                      In prep
Mobile mesonet stations:                 Operational
Hail collection:                         Up

Target today:

Warm front in southeastern SD near Neb border just east of stout lid.

Target tomorrow (Weds):

SW MN, NW IA, W IA: we’ll be largely dependent upon orientation of boundaries after nocturnal and AM convection clears the region.

Target Thursday:

Unclear at this time.  Will evaluate details on Weds.

Future:

With low-amplitude ridging progged to settle in over central NA after this wave, the project may be down for awhile.  The big caveat to this forecast is that the larger-scale forcing has reliably reestablished the southwest flow pattern this spring, so confidence in this extended ridge is not high.

Thanks,

Bruce

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TWISTEX Status Message: June 9, 2008

June 9, 2008 – 11:34 am

All:

Current location:  Teams in Denver, Ames and Grand Rapids.

Denver-based and Grand Rapids-based TWISTEX teams will be using today as a positioning day for potential operations on Tuesday.   The ISU team should be able to reach the initial meeting site with ease on Tuesday.  The emerging wave appears slightly more progressive on today’s 12Z NAM and GFS runs.  Big question is still moisture return.  If moisture makes it back as NAM believes it will (this solution has been alternating back and forth every 12 hours), then a target region along/near the warm front just east of the stout capping area should be viable for supercells with some tornadic potential.  GFS is much less optimistic about moisture return, so while it too suggests convective initiation in this area, GFS holds off development until sometime after 00Z.  If a few storms do go up along warm front, the likely storm motion could keep them in the front zone for an extended duration.

Given the moisture return issues, this forecast has considerable bust potential; however, with the dynamics likely shifting out of the region by Thursday, we have decided to give Tuesday a chance.  As of right now, eastern NE/western IA are the most likely targets for Wednesday operations, so Tuesday could set us up geographically for a hopefully short distance positioning leg on Wednesday morning.  Obviously, the Wednesday target could change considerably given the location of small amplitude jet streaks rotating around the main upper-level low and with any residual mesoscale boundaries.

Plans are as follows:

Probe/M3 will set out for an overnight stay in North Platte.

M1 will hopefully make it to some overnight location along I-29 around Watertown, SD.

M2, please tentatively plan on meeting M1 in Yankton, SD at 2 PM on Tuesday.  This meeting site could change based on the morning runs.   We need to swap out vehicles tomorrow so you can get back into the car with the nice XM radio and we can get back into our vehicle with the electronics we need.

M2, please email me your cell phone numbers so we can touch base tomorrow morning.  We can be reached on our cell number at 218-929-0155.

Once M1 and M2 are organized, we will coordinate a meeting location with Probe/M3 in a refined target area (assuming there is one).

Equipment status:

Photogrammetric probes:                 Up
HITPR probes:                                   Up
3D in-situ probe:                               In Prep
High speed photography:                  Up
Sonde:                                  Not participating this trip
Balloon Radiosonde:                             In prep
Mobile mesonet stations:                Operational
Hail collection:                                Up

Target today:

None – positioning day

Target tomorrow (Tuesday):

Likely along warm front in southeastern SD, just east of stout lid.

Target Wednesday:

Dynamics and moist convective forcing will be considerably stronger on Weds.  Although subject to major changes, as of now, eastern NE/western IA appear to offer the most favorable conditions for tornadic supercells.

Future:

Thursday looks to have only modest potential for operations at present but given model reliability of late, any decision on Thursday will have to wait until Weds evening.

With low-amplitude ridging progged to settle in over central NA after this wave, the project may be down for awhile.  The big caveat to this forecast is that the larger-scale forcing has reliably reestablished the southwest flow pattern this spring, so confidence in this extended ridge is not high.

Thanks,

Bruce

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TWISTEX Fielding Status: June 8, 2008

June 8, 2008 – 1:02 pm

All:

Current location:  A portion of TWISTEX overnighted in OMA.

Although Tim had laptop crash issues, he conveyed to me this morning that while operational opportunities yesterday were not easy to come by, at least there was one tornado within two miles of their hotel in OMA after dark.

TWISTEX will be down today with the ISU team back in Ames and the Colorado teams traveling back home.

NAM and GFS + GEFS all have substantial wave coming out in the Tues-Thurs time period; however, significant model differences on timing and details preclude much confidence in specifics at this point.  Some serious capping is evident in all model solutions.  It is noteable that the models have been overdoing cap strength this spring.  Big question for Tuesday operations is if quality moisture can make it back to the warm front area.  If that were the case, than operations east of the surface low along the warm front near the central SD/NE border could emerge as the target.  Wednesday’s dynamics are stronger and setup could be quite favorable for operations but model phase differences are large.  At this point a target northeast of surface low along the stationary front someplace between northern KS and eastern/southeastern NE could be viable.  Again, with significant model run-to-run changes in the placement and timing of the jet max coming out, I don’t have great confidence in specific placement of the surface features by Weds.

Stay tuned for an update either this evening or Monday AM from Tim on firmed up deployment plans for this week.

M1 and possibly M2 (depending upon target) should stand by for predeployment on Monday for potential Tuesday operations.

Equipment status:

Photogrammetric probes:          Up
HITPR probes:                    Up
3D in-situ probe:                In Prep
High speed photography:          Up
R/C Radiosonde drop plane:       First test flight completed
Balloon Radiosonde:              In prep
Mobile mesonet stations:         M2 station is now operational (M1 team to rejoin effort this week)
Hail collection:                 Up

Target today:

None

Target tomorrow (Mon):

None, but some teams like M1 and possibly M2 may need to pre-position for Tuesday if progs hold that moisture can make it back for Tuesday operations.  Watch for an update status message this evening or Monday AM.

Future:

With low-amplitude ridging progged to settle in over middle NA after this wave, the project may be down for awhile.  The big caveat to this forecast is that the larger-scale forcing has reliably reestablished the southwest flow pattern this spring.

Thanks,

Bruce

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