Ramblings of a Graduate Student

Yesterday was a travel day for the armada as they headed north from Yukon, OK to Wichita, KS.  The thinking was that since severe thunderstorms would be possible anywhere from the Texas panhandle northeast through northern Missouri, staying in Wichita would provide the best opportunity to cover the entire risk area.  Unfortunately, Mother Nature didn’t show her hand this morning and provided us with a difficult forecast.  The armada’s choices were

1. Head northeast toward Emporia, KS / Kansas City, MO where there were better winds in the middle portion of the atmosphere and the possiblity of an outflow boundary from morning convection (which VORTEX I found can aid tornado development).
2. Stay in Wichita until late in the day and hope something develops nearby.
3. Head west toward SW KS / NW OK / northern OK & TX panhandles.  This area might have a brief opportunity for decent mid-level winds, east or southeast surface winds, and discrete storms.

The initial consensus was to head northeast toward Kansas City, however a few people (myself included) thought it would be better to go west toward the Texas panhandle.  Becuase of this, the armada decided to wait until 11AM to make a decisions, which is a delay of about an hour.

At 11AM the decision was made to head to Enid, OK, which is southwest of Wichita, but in the same general vicinity.  The armada convened in Enid around 2PM and then waited for thunderstorms to develop – which happened around 4PM in Kansas.  Additionally, an isolated supercell thunderstorm developed in the NE TX panhandle, where the cold front and dryline intersected.  (This thunderstorm went on to produce several brief, weak tornadoes.)

The thunderstorms in Kansas were developing southwest along the cold front and so the armada spent most of the afternoon waiting for the thunderstorms to come to them.  While they were waiting, the storm in the TX panhandle occurred and additional tornado warnings were issued for the Wichita, KS vicinity.  (Ironic, I know!)  By the time the thunderstorms reached the armada they were “gusting out” meaning that the rain cooled air was pushing out ahead of the storm, robbing it of the warm, moist air needed to sustain itself.  Along the leading edge of this gust front, things that resemble tornadoes often develop.  These are not true tornadoes (which occur with updrafts), but rather “gustnadoes”  (because they occur on the leading edge of the downdraft, which is known as the gust front).  One of these gustnado-like structures developed very near one of the mobile mesonets, which reported a brief funnel cloud.  However it never came in contact with the ground and was never really a serious threat.

All in all, today was a good day in terms of learning.  The armada was able to deploy and collect coordinated data, even though it wasn’t exciting.  (The next step will be to collect coordinated data on an exciting storm!)  The armada called it quits after the storms passed them and headed to their hotels.  Tomorrow, through at least the first part of the week looks to be “down” days because of the strong high pressure building over the central portion of the US.  This will limit severe weather chances for the forseeable future.  However, the armada is not taking it easy.  Tomorrow they will head to a new portion of the central plains and do “practice” for the next several days, in hopes that they become a well oiled machine for what appears like operations in South Dakota or North Dakota around mid-week.

Well today was the first day of real operations.  The armada spent the night in Clinton, OK in preparation of a chase today in either SW Kansas or the southern TX panhandle.  During our 9AM conference call, we decided that the chance of severe thunderstorms developing in SW Kansas was pretty slim (due to a strong cap, or warm air aloft).  Thus, we targest an area NE of Lubbock, TX and SW of Childress, TX.   A big concern we had was a lack of shear (change of wind speed and direction with height) which would tend to cause thunderstorms to be “multi-cellular” and not the “supercell” storms that produce the majority of tornadoes.  However, after two days of not seeing anything, the armada decided to at least go see a thunderstorm.

The armada departed Clinton, OK around 10:30 AM with an initial target of Shamrock, TX, when an update would be provided.  Stopping there would give the armada a chance to head south, if needed, or continue on toward Amarillo where they could take the interstate to Lubbock.  On the way to Shamrock, the FC (field coordinator) made the call to head on to Amarillo and then head south via I27.   The armada arrived in Tulia, TX by early afternoon, where they spent most of the afternoon waiting for the atmosphere to decide what it wanted to do.  (Note, the Texas Tech group actually played a game of whiffle ball to pass the time!)

Thunderstorms began developing to the west of Lubbock around 4PM in a region of very dry low-level air.  This is bad for tornadoes.  Tornadoes need warm, moist air at the surface because this air is unstable and wants to rise.  A tornado, afterall, is nothing but a rapidly, rotating column of rising air extending out of a thunderstorm.  Additionally, similar to how sweating when you are outside is designed to keep you cool, rain falling into dry air causes the temperature to fall.  This rain cooled air then accelerates away from the thunderstorm causing the thunderstorm to become “elevated” above the cool air and reduces the chance of tornadoes.  Well the first storm that developed did just this.  It quickly became elevated and “gusted out”.

To the southeast of this initial storm (east, northeast of Lubbock) a cluster of new thunderstorms developed in an area of slightly better moisture.  The armada was faced with a very tough decision: Go after the elevated, but better looking storm to the north, or take a chance on the weaker storm in a region of slightly better moisture.  The armada waited as long as they could to make a decision…even moving east from Tulia to Silverton, TX…but ultimately waited a little too long.  They tried to head north to the initially better looking storm, only to get hit with the cold air coming out from this storm.  Meanwhile, the storm to the southeast began to look  a lot better.  The armada then tried to catch back up to the eastern storm, but essentially was playing catch up the entire time.  In fact, in addition to playing catch up, the armada spent a considerable amount of time dodging storms that were developing all around them that began producing hail.  I should also mention that our communication systems do not work very well in this part of the country.  Cell phones were having a hard time keeping signal, and the canyons made it difficult for our line-of-sight radio signals to make it to the appropriate personnel.

Eventually the armada made it to the city where they were spending the night (have to read tomorrow to find out where!) and decided that even though a nearby storm was looking “interesting” they would end operations for the night due to everyone being exhausted from a long day and night was falling.

Here in the VOC, we spent most of the day preparing forecasts for today’s operations and planning for tomorrow’s operation.  It appears now that the armada will be operating somewhere in western Oklahoma in hopes that a storm can develop along the southern edge of what is feared to be a pretty strong squall line.  Model forecast fields indicate the presence of extreme instability in Oklahoma, so very large hail will be a very big concern.  Depending on the evolution of tonight’s thunderstorms, there might be a small tornado risk in this area as well.

We’ll see what happens!