Severe weather risk 4/30 - 5/3

[Drz1111]

I was (thankfully?) in court most of yesterday afternoon and evening and couldn't armchair chase, but during recesses when I could peek, it sure looked like the upper flow down in OK and TX wasn't as orthogonal as you might've hoped (or had been forecast by the CAMs).  With initiation being so early and relatively little CIN I'm not sure anything was going to save yesterday from being messy unless there was near-perfect conditions upstairs to support discrete storms.

[bdgwx]

I noticed on more than one occasion that the RFD surges encroached too far into the inflow notch as I was virtual chasing from laptop at home.

[WhiteoutWX]

52 minutes ago, bdgwx said:

I noticed on more than one occasion that the RFD surges encroached too far into the inflow notch as I was virtual chasing from laptop at home.

I would guess the weak inflow winds were creating rather unbalanced RFDs in addition to limiting low level shear magnitude. 

I can say that visually the storms looked very outflow dominant.

[Quincy]

Southern Iowa could very well see a few tornadoes later this afternoon. The near-term setup has trended a bit more favorable.

Pros: Backed low-level flow, favorable low-level shear (mainly near the warm front), clearing skies upstream allowing for boundary layer thermodynamic recovery, dew-points still in the mid-60s near the IA/MO border (may even increase a bit), enhanced low-level vorticity near the surface low, relatively low LCLs.

Cons: Weakness in the wind field around 700mb, cell interaction, as CAMs show many storms in close proximity by 22-23z and a relatively narrow overlap of favorable CAPE/low-level shear. 

[cstrunk]

Watch message mentions a tornado or two are possible.

[Chinook]

May 1-2 verification based on storm report type (13z outlook of both days.) May 1st was very accurate.  The 10% tornado and 30% hail outlook contours on May 2 were not so great, but overall, not terrible.

[WhiteoutWX]

Northwest Oklahoma really stands out there with no reports at all. ^^

[nrgjeff]

No cell service so no (model dependent) chasers, lol. Just kidding! ^^

[Chinook]

I am not entirely sure what happened yesterday. Southern Missouri was a worked-over and low-CAPE atmosphere after the previous severe storms, which apparently prevented severe reports in all of Missouri. Some storms fired up in Iowa, but things were mainly non-severe, except for a cluster of tornadoes with a squall line. Not a whole lot was severe in Arkansas or Texas. Despite strong flow at 500mb, not too many severe storms were expected in AR/TX.

[Quincy]

54 minutes ago, Chinook said:

I am not entirely sure what happened yesterday. Southern Missouri was a worked-over and low-CAPE atmosphere after the previous severe storms, which apparently prevented severe reports in all of Missouri. Some storms fired up in Iowa, but things were mainly non-severe, except for a cluster of tornadoes with a squall line. Not a whole lot was severe in Arkansas or Texas. Despite strong flow at 500mb, not too many severe storms were expected in AR/TX.

The early day convection threw a wrench in everything. The timing of the ozarks/southern Plains squall line was too early for reintensification (weakened as the low level jet ramped down) and it effectively ruined the inflow environment from far eastern Kansas into Missouri. Mid-level wind fields were kind of junky in the Iowa vicinity, which limited updraft organization. Most of the discrete storms that developed some low-level rotation in Iowa were short lived and low-topped. 

Eastern Kansas would have been real interesting if low-level thermodynamics weren't trashed. There was almost enough boundary layer recovery, but only a few loosely organized cells managed to form. 

The mid-level wind fields were particularly bad across northern Missouri, where data suggested only 10-20 knots of 700mb flow was present during much of the afternoon. I'm guessing the earlier convection had some effect on the wind field.