|Monday, April 30, 2007 - 5:22AM EDT
May 5-10 looking good
And here comes May!
The western trough showing up for later this weekend is looking better with each model run. Southwest Kansas looks to be in the sweet spot for Sunday per the latest GFS forecast as of 00z today. (00z is 00:00 UTC, or Coordinated Universal Time).
Take a look at these three model output images for Sunday afternoon. Again, we're talking six days out, so this may change a little. But you can't ask for a better-looking picture here for storm observers. First of all, the front end of a strong 500mb trough is moving over the Plains, providing excellent mid and upper-level wind fields for supercells.
Second, abundant moisture, pulled north from the Gulf of Mexico, should be in place providing ample fuel for storms and helping the dryline become well-defined. Look at the widespread 65F dewpoints and large areas of 70F dewpoints over the Plains, as well as the sharp dryline in western OK, KS and the Texas panhandle.
Last but not least, a nice surface low pressure should be in place across the high Plains, providing low-level shear and backed surface winds, all juxtaposed with the mid-and upper-level winds and good low-level moisture. A classic tornado setup!
In observing, there's always a challenge. Despite this upcoming system being within our long-planned for May standby period, some of us still have work/scheduling issues that may interfere with our ability to make this series of expedition days. Tornadoes look like a definite lock for Sunday through Tuesday, maybe for more days afterward.
As a result, I may look at going on yet another 'pre-expedition' weather expedition like the one we just returned from, meaning that we'll end up having three trips out west rather than two. This is similar to 2004, when we had multiple active patterns that necessitated three round trips to the Plains to catch all the action. For now, I'll give May 1-10 back the probabilites I removed earlier, to reflect the possibility that all of us will end up being able to make this upcoming event.
Based on the current outlook, this probability table charts the chance of our trip starting on a particular date:
|2007 Weather Expedition - Departure Date Probability as of April 30|