re: Wednesday weather thread: MS, AL, LA, TN, Enhanced for MS, AL, TN

Can Western Kentucky catch a break for a while? Last weather thread I thought I was saying goodbye.

It’s gonna be 66 tomorrow here. 69 degrees on New Years Eve. Usually it’s freezing cold that day. Gonna be alot of people out that night.

SPC upgrades tomorrow (Wednesday) to an Enhanced Risk for parts of AR,MS,AL, and TN. Slight risk also expanded.

quote:

---

Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1152 PM CST Tue Dec 28 2021

Valid 291200Z - 301200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM EASTERN ARKANSAS INTO PARTS OF NORTHERN MISSISSIPPI AND ALABAMA AND INTO SOUTHERN TENNESSEE...

...SUMMARY... Severe thunderstorms are forecast from parts of the lower Mississippi Valley into the Tennessee Valley. Damaging wind gusts, a few tornadoes, and hail are possible during the afternoon and evening.

...Synopsis... An expansive area of strong southwest flow aloft will stretch from Mexico into the Northeast, with a low-amplitude shortwave trough over the central Plains during the day. This wave will cross the MS River during the evening, with the bulk of the height falls north of the OH River. However, 60-70 kt midlevel wind speeds will exist as far south as the TN Valley.

At the surface, low pressure will develop near the ArkLaTex, with a trough extending eastward into TN and KY during the evening. A front will remain nearly stationary, from central AR into northern TN. Southwesterly low-level winds will maintain mid to upper 60s F dewpoints south of this boundary, with 70s F across LA, southern MS and AL. Southwest 850 mb winds will increase to 40 kt, enhancing lift from warm advection during the afternoon and evening across MS, AL and TN. A dryline will also extend from the ArkLaTex southwestward toward I-35 in TX, moving slowly east during the evening.

...Lower MS Valley into the TN Valley... Storms are expected to initiate during the afternoon from southern AR into northern MS related to the warm advection regime. SRH is forecast to increase to around 200 m2/s2, with effective deep-layer shear up to 60 kt. This will favor supercells moving east/northeast, and a few tornadoes will be possible. Long hodographs may also favor hail. Convection is expected to increase in coverage as it interacts with the stationary front, with mixed storm modes possibly developing with damaging winds also possible. The severe risk may extend east toward the southern Appalachians as the veered 850 mb winds aid moisture advection. While instability will be weaker farther east into GA and the western Carolinas, strong shear may yield an isolated tornado or damaging gusts.

Elsewhere, it is more uncertain how much convection will occur across the warm sector including much of AL and western GA, but any areas of storms that can develop there overnight could pose a severe risk.

..Jewell/Moore.. 12/29/2021

CLICK TO GET WUUS01 PTSDY1 PRODUCT

NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z

---

Great, the enhanced area is basically a circle drawn around me

The enhanced risk has now been expanded eastward a bit, and a hatched area has been added to the 10% tornado probabilities:

Tors love surface boundaries, like lets say the outflow boundary left behind by morning convection.

quote:

---

Tors love surface boundaries, like lets say the outflow boundary left behind by morning convection.

---

Let's say they don't like them just for today, deal?

Y'all can check out the wX app if you want an app that combines alot of stuff that normally takes multiple websites. It is called just wX and is on iOS and Android.

It will be particularly helpful with MCD discussions during an event because it has a share option that automatically shares the discussion you're looking at. It has all active warnings/discussions live. It beats even following NWS offices on Twitter.

As I have looked at this, I feel Northern MS and NW Alabama is the target zone today. Gotta watch the small scale features at this point such as any boundary lines from some of the early rain and such but hopefully some of the trigger mechanisms don't come together. That's my hope for this system today. My gut tells me it's not going to be THAT bad but we shall see.

This area, outside of the Enhanced Risk area, is looking concerning.


The Northern mode starts to get messier from that point on with the SW trailing edge of the system over the Arklamiss to the NE being in the clear and co-located with 3,000 SB CAPE and good Bulk Shear. Those storms could also be on or near a boundary laid down by morning convection. Anything discrete there will likely be a problem.

You can see that area starting to clear out some:


With no rain in the past few hours and winds picking up out of the SSW at around 20mph+ at the Greenville obs site.