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ACUS01 KWNS 081950

SWODY1

SPC AC 081949



Day 1 Convective Outlook  

NWS Storm Prediction Center Norman OK

0249 PM CDT Mon Apr 08 2024



Valid 082000Z - 091200Z



...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM THE TEXAS

SOUTH PLAINS AND BIG COUNTRY VICINITY EASTWARD TO NORTHWESTERN

LOUISIANA...



...SUMMARY...

Multiple rounds of severe thunderstorms are expected through tonight

across a large portion of the southern Plains and into the lower

Mississippi valley. Very large hail will likely be the main threat,

though a few tornadoes and severe gusts are also possible.



...Discussion...

With convection evolving largely as expected per prior outlooks, no

appreciable changes to outlook areas appear necessary at this time.



..Goss.. 04/08/2024



.PREV DISCUSSION... /ISSUED 1130 AM CDT Mon Apr 08 2024/



...Synopsis...

Primary feature of interest related to severe potential today is a

mid/upper-level trough digging over the Southwest. This feature will

slowly move eastward across northern Mexico and AZ/NM through the

period, while eventually evolving into a closed low. A broad zone of

enhanced southwesterly flow is present downstream across northern

Mexico into the southern Plains and lower/mid MS Valley. Rich

low-level moisture, with surface dewpoints in the mid/upper 60s to

low 70s, will continue to stream northward across much of TX through

the day in tandem with a modest southerly low-level jet. A weak

surface low analyzed over central OK this morning should develop

northeastward this afternoon into MO, with a trailing cold front

forecast to stall over parts of northwest TX into far southern OK.



...Coastal/East Texas into the Lower Mississippi Valley...

A broad warm sector is already in place this morning along and south

of an effective warm front. 12Z soundings from DRT/CRP show steep

mid-level lapse rates, but warm low-level temperatures and related

MLCIN. This, along with nebulous large-scale ascent, should act to

inhibit convection for at least a couple more hours across east TX.

But, continued filtered daytime heating and low-level moistening

associated with the modest southerly low-level jet should encourage

robust convective initiation along the northern extent of the

returning moisture by early this afternoon (around 18-20Z/1pm-3pm

CDT). With moderate instability and strong deep-layer shear, and

elongated/nearly straight hodographs at mid/upper levels, initial

supercell development will likely pose a threat for large to very

large (2+ inch) hail.



The tornado threat may initially be limited by modest low-level

winds/shear, but the chance for a few tornadoes will likely increase

through late afternoon and continue through tonight as a southerly

low-level jet gradually strengthens. Additional supercells and

clusters will likely spread eastward this evening and overnight

along/near the warm front. While some of this activity may be

slightly elevated, a continued threat for large to very large hail

and tornadoes should continue overnight with embedded supercells.

Severe/damaging winds may also occur with any cluster that can form.

Given increased confidence in multiple rounds of supercells

occurring, the Enhanced Risk for large/very large hail has been

expanded eastward to include more of north-central/northeast TX and

northwestern LA.



...Northwest into North-Central/Northeast Texas and Far Southern

Oklahoma...

Compared to locations farther east across TX, the northward return

of rich low-level moisture will be delayed until later this

afternoon and early evening. Still, strong daytime heating will

eventually erode the cap in the vicinity of a weak front and dryline

intersection across northwest TX. Ample deep-layer shear and steep

mid-level lapse rates will aid in multiple robust supercells capable

of producing very large to possible giant hail (2-4 inches)

initially. These supercells should eventually encounter greater

low-level moisture into north-central TX, with a continued threat

for very large hail and a few tornadoes. The potential for a

saturated temperature profile and neutral low-level lapse rates in

various forecast soundings overnight along/near the warm front

lowers confidence in a greater tornado threat. But, low-level shear

will increase through the night, especially towards the ArkLaTex

where an enhanced low-level jet should be focused. This activity may

eventually merge with the low-level warm advection convection across

the ArkLaTex late tonight, with messy modes possibly complicating

severe hail potential.



...West/Central Texas Late Tonight/Early Tuesday Morning...

Increasing forcing for ascent via stronger mid-level height falls

will overspread much of west/central Texas tonight. Continued

low-level moistening beneath steep mid-level lapse rates will foster

moderate to strong MUCAPE. Elongated hodographs with 60-kt effective

shear will promote supercells and mainly a risk for large to very

large hail across parts of the TX Hill Country. Southerly low-level

winds will also increase overnight and act to enhance initially

limited hodographs. If a cluster organizes overnight (06-12z), a

risk for severe wind gusts and perhaps a couple tornadoes could also

develop.



The dryline is expected to retreat westward across parts of west

Texas overnight with strong instability building back to near

Midland early Tuesday morning. As strong upper forcing overspreads

this region, at least isolated to scattered storms will probably

develop on the western periphery of a strongly unstable/sheared

environment.



$$