4/6...another early season false alarm
Pics from my 4/6 chase can be found here. I played around Madill to Atoka where the struggling "showers" along the dryline finally erupted into some formidable cells in western Atoka county. At one point near Stringtown, north of Atoka, the storm threatened to spin up a tornado. A strong convergence point formed under an updraft with lots of motions and then some weak rotation and a hook. I'm not entirely sure, but as I was trying to get east if Stringtown on 43 through the "mountains", I swear I thought I saw a funnel cloud trying to form...could have been a look-alike. With fast storm motions, I didn't want to stop until I felt like I got far enough east with a good viewing point to film a tornado in case it produced one. When I did, the "magic" was gone. LOL! I would watch a couple of other strong convergence zones and some ominous swirling with this storm north of Daisy and Goss east of the Turnpike until I decided to finally give up and hit the turnpike towards home. I caught up to a new storm forming in Lamar county, TX and caught a few lighting shots. Note to self: Atoka is as far east as I'll ever chase again. :-)
Yet another "particularly dangerous situation" didn't unfold as expected by myself and many other people including the SPC. There were a few tornadic storms, but far fewer than had been anticipated. The early season for severe weather in the plains can be extremely fickle and difficult to forecast as demonstrated for the past several weeks. Too may things can happen to disrupt the delicate balance of moisture, instability and shear. The atmosphere doesn't have as long to recover from things that disrupt this balance...such as early morning convection or extensive cloudiness in addition to moisture return usually conisting of modified gulf air at best.
Yesterday looked like a significant outbreak in NE OK, E/SE KS, NW AR and MO. The powerful upper level dynamics were there to be certain. However, the instability was not. I think the whole event was squelched by extensive early to mid morning convection from NE TX into NE OK and W AR. These storms were intense and a few SVR was issued for them. The colder outflow from the strong elevated storms with the lingering cloud cover kept this entire region cooled and partially stabilized. All of the storms that fired later in the afternoon in E KS down into S OK were moving into less unstable airmass. There wasn't enough time for the atmosphere to recover nor was there a good, uncontaminated source region for the lower level winds to advect into the target area (theta-e advection).
In fact, watching the Weather Channel radar loop last night after getting home, all of the storms practically dissipated as they moved into Missouri...like a giant hand parting the Red Sea. So maybe there was some divine intervention for the ravaged residents of that state. A couple of storms did pop some TORs for NE OK and along the KS/OK border, but they didn't produce anything notable and soon fizzled out. I think here, the jet dynamics were the strongest and just barely overcome the instability deficits. Further north along the KS/NE border area, there were some more significant tornadoes very near the surface low/front under a cold core regime. Even here it looks like only one or two cells at most were spinnning them up. That's it.
So, to simplify, it simply appears to have been another case of strong, powerful dynamics and weak instability relative to the amount of shear. I almost forgot to add the dismal veering profiles south of the I-40/44 corridor. 850mb winds were SSW at best and mainly SW creating a nearly unidirectional profile.
Another note is from my rant yesterday about the dryline forecast. That sucker just barely eased by I-35 in TX around 00Z and even retreated after dark. In fact, it was still along the I-35 corridor south of I-40 well after 21Z. This has been a very common scenario with a strong, developing surface low in Nebraska for as long as I can remember. The old ETA had this problem too. Could it be that the dryline is mixing into a "deeper" boundary layer airmass related to surface elevation? It seems like simple physics to me as far as the volume of air to be mixed or "shoved". It always seems like the I-35 corridor seems to act like dampener on a dryline's eastward progression. I dunno.....practicing physics and meteorolgy without a license here. ;-) It's definitely a problem for the models though to be certain. Some young, aspiring met student out there should consider this for a master's thesis. If a comprehensive study has already been done on this subject, please let me know so that I don't sound like a doofus. :-)
Yet another "particularly dangerous situation" didn't unfold as expected by myself and many other people including the SPC. There were a few tornadic storms, but far fewer than had been anticipated. The early season for severe weather in the plains can be extremely fickle and difficult to forecast as demonstrated for the past several weeks. Too may things can happen to disrupt the delicate balance of moisture, instability and shear. The atmosphere doesn't have as long to recover from things that disrupt this balance...such as early morning convection or extensive cloudiness in addition to moisture return usually conisting of modified gulf air at best.
Yesterday looked like a significant outbreak in NE OK, E/SE KS, NW AR and MO. The powerful upper level dynamics were there to be certain. However, the instability was not. I think the whole event was squelched by extensive early to mid morning convection from NE TX into NE OK and W AR. These storms were intense and a few SVR was issued for them. The colder outflow from the strong elevated storms with the lingering cloud cover kept this entire region cooled and partially stabilized. All of the storms that fired later in the afternoon in E KS down into S OK were moving into less unstable airmass. There wasn't enough time for the atmosphere to recover nor was there a good, uncontaminated source region for the lower level winds to advect into the target area (theta-e advection).
In fact, watching the Weather Channel radar loop last night after getting home, all of the storms practically dissipated as they moved into Missouri...like a giant hand parting the Red Sea. So maybe there was some divine intervention for the ravaged residents of that state. A couple of storms did pop some TORs for NE OK and along the KS/OK border, but they didn't produce anything notable and soon fizzled out. I think here, the jet dynamics were the strongest and just barely overcome the instability deficits. Further north along the KS/NE border area, there were some more significant tornadoes very near the surface low/front under a cold core regime. Even here it looks like only one or two cells at most were spinnning them up. That's it.
So, to simplify, it simply appears to have been another case of strong, powerful dynamics and weak instability relative to the amount of shear. I almost forgot to add the dismal veering profiles south of the I-40/44 corridor. 850mb winds were SSW at best and mainly SW creating a nearly unidirectional profile.
Another note is from my rant yesterday about the dryline forecast. That sucker just barely eased by I-35 in TX around 00Z and even retreated after dark. In fact, it was still along the I-35 corridor south of I-40 well after 21Z. This has been a very common scenario with a strong, developing surface low in Nebraska for as long as I can remember. The old ETA had this problem too. Could it be that the dryline is mixing into a "deeper" boundary layer airmass related to surface elevation? It seems like simple physics to me as far as the volume of air to be mixed or "shoved". It always seems like the I-35 corridor seems to act like dampener on a dryline's eastward progression. I dunno.....practicing physics and meteorolgy without a license here. ;-) It's definitely a problem for the models though to be certain. Some young, aspiring met student out there should consider this for a master's thesis. If a comprehensive study has already been done on this subject, please let me know so that I don't sound like a doofus. :-)
posted by Steve Miller TX at 4/07/2006 10:31:00 AM
0 Comments:
Post a Comment
<< Home