John Monteverdi (left) and Thom Trimble

2010 Chase Vehicle

2010 Chase Vehicle -- Dodge Journey

Chase 2010 Extended Diary

Note: This has been such an active trip that I have not had time to update this diary. Please check our blog, linked to just below.

See Instant Update Blog

A daily, preal time, blog will still be produced this year. This was running as an experiment this year, and it was very successful. Since Scott Landolt will be with Vortex2 this year during our normal chase time together, Cameron Redwine will be joining me when Thom leaves.

Updated May 26, 2010 10:16 AM


Research Purpose and Outlook for the Trip

John Monteverdi

Research Purpose

The mission is to (a) document tornadic thunderstorms; (b) document supercell thunderstorms in general; and (c) get lightning shots. The first two are very rare to relatively rare. Perhaps 1 in every thousand thunderstorms worldwide is a supercell, and of all supercells, less than 15% produce mesocyclone-tornadoes ("Wizard of Oz" type tornadoes).

The first two depend on some aspects of the large scale weather pattern that mostly involve the evolution of the wind patterns at jet stream levels and the presence of low level moisture/instability. The Great Plains is climatologically favored for the juxtaposition of favorable low, mid and upper level patterns favorable for tornadic supercells, on average, the last two weeks of May and the first two weeks of June.

Since I am a synoptic meteorologist interested in weather pattern analysis and forecasting, the chief purpose I have is to understand how the ingredients that produce tornadic supercells and supercells in general come together in the weather patterns that occur during the period of our chase. The challenge for me as a meteorologist is to forecast these patterns in advance and to put myself and my chase partner in a position to view a tornado and/or a supercell. Clearly, if we manage to do that, I have made a successful forecast.

This is important because there are indeed weather patterns that occur in California that produce tornadic supercell thunderstorms. While these patterns are relatively infrequent, they do occur. In order to hone my skills in anticipating these patterns, though, I need to put myself in an environment in which forecasting "tries" at anticipating them occur frequently. Hence, these trips to the Great Plains.

The results of these trips are measurable in the form of publications on tornadic storms in the Great Plains and in California. Also important, is the transfer of the knowledge I acquire into the classes I teach, particularly, Meteorology 302 (The Violent Atmosphere and Ocean, Meteorology 503 (Weather Analysis and Forecasting II), and, most significantly, Meteorology 515/815 (Analysis and Prediction of Severe Storms).

Outlook for the Trip

The main issue is whether the tendency for El Niño influenced-active flow over the subtropics will continue to invigorate the subtropical branch of the jet flow. It has been doing so all spring, but the medium range models have not been indicating this, and have been suggesting, generally, an unfavorable pattern for chasing. That's the model view....the ensemble view (the model plus a bunch of other tries with slightly different observations) do show such breakthroughs. We are waiting with baited breath.....

 


May 19

Forecast/Tentative Target Blog

TARGET: Northwest Oklahoma

As of Noon PDT 5.18/10, the pattern appears to be setting up for tornadic supercells ahead of the dry line that should extend north-south parallel to the Oklahoma-Tx Panhandle border and along and south of a warm frontal boundary stretched along Interstate 40. Thom and I arrive din Denver around 9:45 AM, and were planning to try to make a run for that area. We thought we would be able to make it to the Woodward-Gage region or even Elk-City Sayre by convective initiation or shortly thereafter, if there are no road problems (construction etc) even though it's a very long drive.

Speaking of drives, this is our rental car. We upgraded to a mid-size SUV for safety and comfort. It's a Dodge Jericho, and it drives well at speed, and gets reasonably good gas mileage....19 miles per gallon over 348 miles at 80 mph or so.

Meteorology

The best CAPE and shear combination for tornadic storms was set up for the Clinton-Taloga area. It was a long shot....we figured we MIGHT be able to make 590 miles to get to the Clinton-Taloga area, and then if and only if the storms did not fire early and stayed back west.

As it is, the storms DID fire early, and were along I35 before we got to the Oklahoma border about 150 miles west of that at around 7PM. You can see the winds had all veered around west of Oklahoma City by 21 UTC (that's 4PM local time). Faced with still doing a "stern chase" to storms movisng away from us, we called it a day, and pulled back to overnight in Dodge City KS.

Turns out that there was enough vertical shear and low level instability to generate a class of storms called "low topped" supercells in western KS. We arrived in Dodge City to the sound of tornado sirens, and an interesting looking sky near sunset, with a low hanging base with inflow fingers. Too dark for pictures. Here's a radar plot.

 


 

May 20

Forecast/Tentative Target Blog

TARGET: Possible Night Lightning in NW KS--Goodland

This is mostly setting us up for a possibly active two or three days in the north-central Plains. We thiink that the upslope area of northeast CO/NW KS/sw Nebraska looks interesting tomorrow. W

Meanwhile, we upgraded from a full sized car to a mid size SUV. This drives great in the rain, and also gets reasonable gas mileage. Here's a picture of our Chase Vehicle, a Dodge Jericho mid-size SUV. Be sure to check out the other side of the story at Chasing Storks.

Meteorology

We started in Dodge City today and will reevaluate our destination for tonight based upon the 12 and 18 UTC run of the models.

Anyway, there will probably be some lightning photography opportunities this evening up in ne Colorado/nw KS, so we will probably head up that way today, and then the next two days look great.

Tomorrow this same area, northwest into northeast Colorado could have tornadic supercells. We reevaluated the risk area again in the afternoon and still think that north-central Nebraska will be our goal for Saturday, and that the potential exists locally here for some interesting weather tomorrow. You can see the forecast CAPE and dew point tongues curling into this area and then northwestward in the forecast under pretty remarkable 0-6 km shear for this area. Here's the forecast NAM sounding and hodograph for Goodland tomorrow. That looks tornadic, if it verifies.

Then there is a huge discrepency betweem the SPC outlook for Saturday and the 0000 UTC NAM. The latter has a potential for strong tornadic supercels for north-central Nebraska, but SPC has the risk way up in the Dakotas. Still two days off....so a lot can change. But here's the forecast CAPE fromt the NAM and from the GFS. Both are targetting the area around Oneill to Valentine.....

 

 

 

 


May 21

 

Forecast/Tentative Target Blog

TARGET:

 

Meteorology

 

Pictures (and less Meteorology)

 

 


 

May 22: Tornado Near Aberdeen, South Dakota

AberdeenTornado Hook

 

Forecast/Tentative Target Blog

TARGET: Central South Dakota:

Surface convergence should occur into a low pressure area in west-central South Dakota. Although there will be a triple point near Pierre in late afternoon, the issue is the strong capping inversion. Above that inversion, the sbCAPE would be enormous. So we decided to move with Scott Landolt's group to the area east of the Black Hills. One scenario had convective initiation on the mountains, then drifted northeastward towards the deeper moisture.

Meteorology

The morning surface chart showed a forming circulation in west-central South Dakota. A cold front, dry line, warm front triple point wass setting up near Pierre, with clearing south of the warm front. Afternoon forecasts had a tongue of high dew points curling into north-central South Dakota, with explosive CAPE values (on the high end of what we've seen in our chases.) The issue was the strong morning capping inversion that the models suggested would disappear by afternoon. Above that capping inversion could be found CAPE values consistent with updrafts >100 mph, and storm tops to 60000 feet. If the inversion failed to be eradicated (largely dependent on the evolution of the surface dew point fields), then we'd be looking at blue skies. SPC had highlighted the area for a relatively large risk of tornadoes.

We drove north from Chadron, Nebraska, to Rapid City, and picked up some sandwiches, and moved east to Wall, SD. That little move almost proved fatal. We had decidedd to use Interstate 90 to move quickly the 200 miles into the inflow air curling northward tthrough central South Dakota. The roads that moved northeastward to the triple point area north of Pierre were farm-market roads or a few state and federal highways on which the speed limit was 65 mph or less. While we were at Wall, however, explosive development occurred over north-central SD...and we were limited by the northbound options.

As we drove south of Pierre, the first tornado warnings were issued. Ultimately, this storm became cyclic and a repetitive tornado producer as we were driving northward to it. Fortunately, the storm still had an amazing aspect on radar as we came up to it, with a large bulbous hook, even on Mobile ThreatNet (which has composite radar, rather single tilts). As we approached the storm, it was obvious that it was a major supercell, with large curving inflow bands, and a hard, flat, rain free base. The storm cycled several times as we watched it, with new areas of rotation and rear flank downdraft notches very obvious. Much of the storm was wrapped in rain, but nevertheless, we noted several funnels, possibly tornadoes. Finally, during one of its cycles, the storm developed a rear flank downdraft yet again, and produced a tornado to our west.

Pictures (and less Meteorology)

As we drove north towards the Aberdeen supercell, we noted stout towers arrayed from south to north into the main updraft area...this was the evolving flanking line. About this time the storm had the best look on radar as we approached it. The closer we got, the more ferocious the storm appeared, with mid-level inflow bands, a striated, layered base, and transient funnel like features. We approached the east flank, and the wall cloud appeared ragged, yet had some funnel like features. At one point, the base evolved into a horseshoe, with an obvious rear flank downdraft, and a couple of appendages where you'd expect a tornado to form. Finally, during one of the reorganizational cycles, the base developed strong rotation, and we could see a wedge funnel develop in the rain. This funnel was in exactly the position you'd expect for an eastward moving supercell, on the western arm of the horseshoe base, separated by a rear flank downdraft clear slot.

Shortly after this, the area began to fill in with other thunderstorms, forming a discontinuous line all the way into Nebraska. As we drove south, we passed underneath a roiled base, that clearly had some shear funnels in it (lookiing straight up). To the west of the road, was the very impressive tiered base of the forming line.

We overnighted in O'Neill, Nebraska.

 

 

 

 

May 23: Tornado near Oakley, Kansas

Forecast/Tentative Target Blog

TARGET: NW Kansas

 

Meteorology

To appear soon.

Pictures (and less Meteorology)

 

 


May 24: Supercells Early/Squall Line Late

Radar

 

Forecast/Tentative Target Blog

TARGET: Northwest Nebraska/south-central South Dakota:

There is a volatile pattern setting up for fast moving supercells in South
Dakota, and perhaps northwest Nebraska. We are on the way....form Goodland.

Hodographs favor fast motions, but also a few tornadoes....with some strong and violent.

Meteorology

....and we should have stuck with our target. But storms erupting ahead of the cold front in western Nebraska were supercells and were producing tornadoes early on. So we attempted to get along that line and wait for the rapidly moving storms to train up the boundary to us.

One in particular near Alliance (see radar) had a history of producing TVS (tornado vortex signatures) and was intermittently tornado warned by the NWS. However, by the time we got in position, the whole area erupted into a rapidly moving squall line. Outflows from neighboring storms crashed through our storm and it became non-supercellular and absorbed into the line.

If we had left at 7AM we may have made it to our target in time to see South Dakota tornadoes at 1PM. That's about 6 hours earlier than tornadoes normally form. But them's the breaks...

 

 


May 25:

Forecast/Tentative Target Blog

TARGET: SE Colorado/Oklahoma Panhandle

Our preliminary target is southeastern Colorado and the Oklahoma Panhandle. We have departed Sterling CO and are southbound, after a run to the track (Thom) and a run to the gym (John) for workouts.

The front along which yesterday's squall line developed has stalled out along the Colorado-Oklahoma border. A new disturbance in the upper air moving from New Mexico is developing a low in northestern New Mexico. Around this low, easterly or southeasterly winds are bringing Gulf moisture into that area under moderate mid level winds.

This should create a favorable wind shear environment for a few supercells, and the low level shear is also moderate, suggesting a risk of tornadoes. We're hoping for a more sucessful day than yesterday.

Meteorology

 

Pictures (and less Meteorology)

 

 


 

May 26:

Forecast/Tentative Target Blog

TARGET:

 

Meteorology

 

Pictures (and less Meteorology)

 

 

 


May 27:

Forecast/Tentative Target Blog

TARGET:

 

Meteorology

 

Pictures (and less Meteorology)

 

 


May 28:

Forecast/Tentative Target Blog

TARGET:

 

Meteorology

 

Pictures (and less Meteorology)

 

 


 


May 29:

 

Forecast/Tentative Target Blog

TARGET:

 

Meteorology

 

Pictures (and less Meteorology)

 

 


May 30:

Forecast/Tentative Target Blog

TARGET:

 

Meteorology

 

Pictures (and less Meteorology)

 

 



May 31:

Forecast/Tentative Target Blog

TARGET:

 

Meteorology

 

Pictures (and less Meteorology)

 

 


June 1:

Forecast/Tentative Target Blog

TARGET:

 

Meteorology

 

Pictures (and less Meteorology)

 

 


June 2:

Forecast/Tentative Target Blog

TARGET:

 

Meteorology

 

Pictures (and less Meteorology)

 

 


June 3:

Forecast/Tentative Target Blog

TARGET:

 

Meteorology

 

Pictures (and less Meteorology)