WEATHERAmerica Newsletter, Saturday, May 4, 2024; SHORT RANGE OUTLOOK

[Larry Cosgrove]

SHORT RANGE OUTLOOK

(Through The Next 72 Hours)

 

Severe Weather (And Flooding Rain) Season At Its Peak....

METEOBLUE

TwisterData.Com (3)

University Of Wisconsin Weather Server (3)

UQAM Meteocentre (3)

College Of DuPage Weather Laboratory

In terms of tornado output nationally, the only bigger season was in 2011. While that year had absurdly high ongoing potential and twister strikes, this spring has a chance to catch up with severe weather occurrences via MCS formation and intense convection associated with surface low pressure and attendant frontal structures. The next ten days still look extremely active. But pay close attention to the subtle northward latitude shift that is going on.

The latest disturbance in the pipeline will sweep through the Pacific Northwest and likely dig into Wyoming or northern Colorado, moving along the vicinity of Interstate 70 and 80. Picking up a dry slot and pipeline of very moist and unstable air, the system will target a convective zone from N TX, OK, KS and NE. Many of the schemes are showing a "bolting" process where the low pressure and its fronts accelerate on Day 3. That would mean parts of Missouri, Arkansas, and Louisiana through the Ohio and Tennessee Valleys may have an outbreak of severe weather. I suspect that the Mid-Atlantic region will also be targeted as the warm sector could get into NY and MA. The rain/thunder event on Sunday may offer some intense activity for precipitation amounts and hail. But the midweek severe thunderstorm and tornado potential looks far more dangerous.

How Long Will The Disturbances Hold Off The Mexican Heat Ridge?

METEOBLUE

PivotalWeather.com (3)

ECMWF

If you look at the temperature spectrum across Mexico and Texas, you cannot escape the extreme heat presented along the Rio Grande Valley and points south. That is important for two aspects of the forecast. One is that the associated heat ridge complex will, sooner or later, begin its northward transition and bring some very brutal temperatures to the southern two-thirds of the U.S. The other issue is that the hot and dry regime will serve as an injection into the convergence associated with the storm moving rapidly out of the Pacific Northwest.

If current model guidance is correct, the storm sequence stretching back into Asia will keep moving across the lower 48 states through the middle of May. The passage of each impulse may draw some of the cTw values into the warm sector, which in turn enhances severe weather threats east of the Rocky Mountains. But as long as the disturbances keep moving across the same general area, the searing profiles of the Mexican domain cannot get above the Interstate 10 corridor. At some point in the extended range, cooling demand will shoot up from the Great Plains through the Dixie, Corn Belt, and Mid-Atlantic states. But not just yet!