Some Severe Weather This Weekend?
A few model runs have stirred many a chaser from their summer slumber. I've actually looked at the models in more detail for the first time since June. However, everything is focused on the Minnesota and NW Iowa area for Saturday. Even then, meager instabilities and strong linear forcing looks more like a squall up there...and certainly a world away for this chaser. I really don't care. LOL!! Then, some severe possibilities for Missouri and possibly NE OK and N AR on Sunday where a right entrance jet region juxtaposed over the frontal boundary and meager instabilities.
The big problem is that the lower levels of the atmosphere have cooled faster than the mid levels. This is typical for fall and why it is so hard to get a good setup as instabilities are too often meager at best. The mid levels are warmed up by all of the "warm season" convection and longer heating. I first learned of this back in 1998 from a presentation by Dr. Doswell. However, we also benefit from having "bath water" sea surface temperatures in the GOM basin and a deep tropical airmass always poised to race northward.
Right now, the -5C line at 500mb sits right across Texas. With surface temps in the 80's and lower 90's, there just isn't much in the way of lapse rates and instabilities possible with that kind of profile. We'll have to have a deep trough move alot further southward to even get us down into the -10C range or better.
There is just enough though for some marginally severe thunderstorms to form along the front. In fact, enough low-level forcing and lift will exist with the front along with ample moisture and mid level dynamics associated with the right entrance region of mid and upper jets to produce a pretty decent rain event from Missouri into Texas on Sunday as depicted by the NAM. However, as mentioned above, anything "severe" will be marginal at best. Yawn. I'll keep an eye on things though as the event approaches. I've learned to never be arrogant with mother nature. ;-)
However, the upper air pattern looks to remain fairly active and dynamic for the next couple of weeks. The GFS and ECMWF are beginning to show some prety interesting trends regarding the latter part of next week into next weekend. If the GFS has the right idea, and I have little reason right now to dismiss it, then a more legitimate "chaseable" scenario unfolds with a sharp and vigorous trough diving into the southern Rockies and into the southern and central plains. The GFS seems to be having a bias towards digging troughs too much in the past few weeks....something to keep in mind. As of now, it's just something to keep an eye on. With gas prices plummeting right now, it certainly makes those long chase trips more appealing. :-)
Could this be an early sign of the new El Nino pattern that is beginning to establish itself? We'll see. It would be nice to have a couple of chase opportunities this fall. I'd be just peachy with alot of rainfall. There are plans around North Texas to move into a Stage 4 drought contingency plan soon. More on that in another blog rambling. ;-)
The big problem is that the lower levels of the atmosphere have cooled faster than the mid levels. This is typical for fall and why it is so hard to get a good setup as instabilities are too often meager at best. The mid levels are warmed up by all of the "warm season" convection and longer heating. I first learned of this back in 1998 from a presentation by Dr. Doswell. However, we also benefit from having "bath water" sea surface temperatures in the GOM basin and a deep tropical airmass always poised to race northward.
Right now, the -5C line at 500mb sits right across Texas. With surface temps in the 80's and lower 90's, there just isn't much in the way of lapse rates and instabilities possible with that kind of profile. We'll have to have a deep trough move alot further southward to even get us down into the -10C range or better.
There is just enough though for some marginally severe thunderstorms to form along the front. In fact, enough low-level forcing and lift will exist with the front along with ample moisture and mid level dynamics associated with the right entrance region of mid and upper jets to produce a pretty decent rain event from Missouri into Texas on Sunday as depicted by the NAM. However, as mentioned above, anything "severe" will be marginal at best. Yawn. I'll keep an eye on things though as the event approaches. I've learned to never be arrogant with mother nature. ;-)
However, the upper air pattern looks to remain fairly active and dynamic for the next couple of weeks. The GFS and ECMWF are beginning to show some prety interesting trends regarding the latter part of next week into next weekend. If the GFS has the right idea, and I have little reason right now to dismiss it, then a more legitimate "chaseable" scenario unfolds with a sharp and vigorous trough diving into the southern Rockies and into the southern and central plains. The GFS seems to be having a bias towards digging troughs too much in the past few weeks....something to keep in mind. As of now, it's just something to keep an eye on. With gas prices plummeting right now, it certainly makes those long chase trips more appealing. :-)
Could this be an early sign of the new El Nino pattern that is beginning to establish itself? We'll see. It would be nice to have a couple of chase opportunities this fall. I'd be just peachy with alot of rainfall. There are plans around North Texas to move into a Stage 4 drought contingency plan soon. More on that in another blog rambling. ;-)
posted by Steve Miller TX at 9/14/2006 11:52:00 AM
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