Jeff Snyder
EF5
I dont know if I'm missing something that others are seeing, but moisture is the last of my worries. This year so far, tornadoes have formed when dewpoints have been in the mid 50s, and the tornadoes have been large.....Throw the dryline in the whole mess and it looks to be a very interesting day on SAT.
Brandon,
The problem is that, although we are seeing southeasterly flow in western TX now, the surface ridge on the eastern US is north enough that there is easterly flow across most of the central and norther Gulf. In essence, the position of the high is leading to the recirculation of drier continental air from the southeastern US, across the Gulf, then up into the Plains. So, we may be seeing low-mid 50s across areas of western TX now, but models continue to indicate that, despite southeasterly flow across much of the risk area, better Gulf moisture is unlikely to make it into the Plains by Saturday evening.
The 00z BRO and CRP soundings look pretty bad in terms of low-level moisture. Buoy 42002 east of CRP is observing a northly wind at ~20mph, with a Td of 66.6F (likely quite shallow). 00z soundings from Mexican locales in the southwestern Gulf (e.g. MMVR --> http://www.rap.ucar.edu/weather/upper/mmvr.gif ) show relatively deep northerly and northeasterly flow in the low-levels, another strike.
Pattern recognition indicates that confluent, mid-level flow associated with mid-level ridging over the Gulf and a deep trough off the southeastern US coast is often not favorable for the advection of rich Gulf moisture into the Plains. I'd much rather see the mid-level trough off the coast slide east faster, which would allow more ridging on southeast coast, and may allow for more favorable trajectories.
Per the latest 00z NAM, it looks like the trough will come through quite a way farther south and later than previous models outlined. Jeez, looking at the surface progs, some chasers may even target Tucumcari NM for Saturday. Of course, a slower solution shouldn't really surprise anyone, given the tendency for the NCEP models to be too fast / too far east with many of the dryline days this year so far (prime example being 2-28). With the slowdown, timing has now become an issue. Ah well, we certainly can't expect 72+ hour forecasts to verify perfectly within 50-75 miles and 1-3 hours.
EDIT: All this is NOT to say that Tds won't reach 60F in spots. There is the possibility that tds will verify higher than models are currently forecasting, and there's no way we can know for sure at this time. All that said, I think there is a better than 50% probability that we'll see widespread mid-50s Tds across western KS and areas northward, with widespread upper50s farther south. I've be pleasantly surprised, but surprised nonetheless, to see low-60F Tds widespread in the warm sector, with the way it currently looks. I hope I'm wrong, and I'll be the first to admit it if I am. Ah, the unpredictability of the atmosphere.
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