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ACUS01 KWNS 090547

SWODY1

SPC AC 090545



Day 1 Convective Outlook  

NWS Storm Prediction Center Norman OK

1245 AM CDT Tue Apr 09 2024



Valid 091200Z - 101200Z



...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS

CENTRAL/EAST TEXAS INTO LOUISIANA...



...SUMMARY...

Severe thunderstorms are forecast today across much of Texas into

the Lower Mississippi River Valley. Several tornadoes, a couple of

which could be strong, significant large hail, and damaging winds

are are expected.



...TX to Lower MS Valley...



Upper low has sagged to near the AZ/international border early this

morning. As a 90+kt 500mb speed max translates through the base of

this feature, the low should then eject east early in the period.

Latest model guidance suggests the upper low will advance into far

west TX by 18z as the speed max approaches the Big Bend. Left-exit

region will encourage renewed deep convection across southeast NM

into the TX South Plains early as very steep mid-level lapse rates,

and large-scale ascent, aid buoyancy within a strongly diffluent

high-level flow regime. NAM forecast soundings at the start of the

period exhibit substantial MUCAPE across this region. 1km lifted

parcel will yield roughly 2500 J/kg. Very large hail may accompany

any supercells that evolve with this elevated activity.



Downstream, strongest, and most focused, LLJ will extend across the

northwestern Gulf Basin into the Arklatex region. Considerable

amount of convection has developed along the Red River, across

southern AR/northern LA into central MS early this morning. It seems

reasonable that the LLJ will maintain a complex corridor of deep

convection across this region, driven in large part by warm

advection. Models maintain LLJ across east TX into southern AR most

of the period. As a result, episodic bouts of deep convection should

be noted across this region. While warm advection will prove

instrumental in convection today, strong boundary-layer heating is

expected across northeast Mexico into the TX side of the Rio Grande

Valley. Surface parcels should easily reach their convective

temperatures and isolated thunderstorms may develop near the dry

line. During the evening, large-scale height falls will spread east

and convection may experience upscale growth within a strongly

sheared environment.



Multiple convective scenarios, along with the influence of ongoing

storms, will likely result in a complex evolution, including

isolated supercells, clusters, and possible line segments late.

Strong shear favors the potential for a few strong tornadoes, along

with very large hail.



...Lower Great Lakes...



Southern influence of a strong short-wave trough will glance

northern OH into western NY. Boundary-layer heating is expected to

contribute to modest instability by mid afternoon as surface

temperatures warm through the mid 60s to near 70F. Ample deep-layer

shear will exist for a few robust storms capable of generating gusty

winds and perhaps isolated severe hail. Greatest risk will be with

convection that develops along the front as it eases southeast into

this region.



..Darrow/Bentley.. 04/09/2024



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