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ACUS02 KWNS 041731

SWODY2

SPC AC 041730



Day 2 Convective Outlook  

NWS Storm Prediction Center Norman OK

1230 PM CDT Sat May 04 2024



Valid 051200Z - 061200Z



...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE TEXAS

HILL COUNTRY INTO THE MIDDLE TEXAS COASTAL PLAIN...



...SUMMARY...

Strong to severe thunderstorms may occur Sunday across parts of the

southern Plains into the ArkLaTex and Mid-South, and separately over

portions of Ohio into western Pennsylvania. Highest severe

thunderstorm potential is expected from the Texas Hill Country into

the Middle Texas Coastal Plain.



...Synopsis...

A southern-stream shortwave trough, likely enhanced somewhat by

widespread thunderstorms Saturday night, is expected to begin the

period extended from central OK through southeast TX. This shortwave

is forecast to make steady northeastward progress throughout the

day, reaching the Lower OH Valley by late Sunday night/early Monday

morning. A separate north-stream shortwave trough will likely will

move across Ontario and western Quebec, with an attendant surface

low moving just ahead of this wave. An associated cold front will

extend southwestward from this low, and is expected to progress

eastward across the OH Valley throughout the day. Southern portion

of this front (i.e. from the Mid-South into central TX) will remain

largely stationary throughout the day, before then transitioning to

a warm front amid strengthening return flow overnight. 



Farther west, a deep upper cyclone is forecast to progress eastward

across the Great Basin before devolving into more of an open wave as

it moves through the central Rockies and into the central High

Plains. Strong mid-level flow will accompany this system, spreading

eastward and reaching the southern/central High Plains by early

Monday morning.



...Southern Plains into the ArkLaTex and Mid-South...

Showers and thunderstorms will likely be ongoing from eastern OK

into central and southeast TX at the start of the period early

Sunday morning, although with varying convective modes.  A more

linear, modestly organized convective line may be ongoing across

southeast TX, remnant from Saturday night/early Sunday morning

activity across central TX. Gradually decreasing buoyancy should

lead to gradual weakening of this line as it moves into

west-central/southwest LA. Even so, given the potentially organized

character to the line, some damaging gust will still be possible.



A more multicellular mode is anticipated throughout the day from

eastern OK into the Arklatex and Mid-South, supported by persistent

forcing for ascent and modest buoyancy. A few stronger updrafts

capable of hail are possible, with some limited potential for a few

bowing segments capable of damaging gusts as well.



Farther west, an outflow boundary is expected to extend westward

from this decaying convective line, likely from the middle TX

Coastal Plain through the Hill Country into the Edwards Plateau.

This boundary will likely provide the focus for addition

thunderstorm activity during afternoon. Ample low-level moisture,

strong buoyancy, and moderate deep-layer shear support the potential

for supercells with any discrete development. Large hail is primary

hazard with initial development, but some trend towards upscale

growth is likely, with the resulting convective line tracking along

the outflow boundary. Mesoscale nature of this scenario does lead to

some uncertainty, particularly on the location of the outflow

boundary, but guidance is consistent enough to delineate higher

probabilities from the TX Hill Country into the Middle TX Coastal

Plain.



...Ohio into Western Pennsylvania...

As mentioned in the synopsis, a weak front is forecast to move

eastward across the OH Valley Sunday. Modest destabilization should

occur ahead of this front across OH and western PA, contributing to

the potential for isolated to scattered thunderstorms along and

ahead of this boundary. Deep-layer shear of 20-30 kt should support

marginal updraft organization, with occasionally strong to damaging

gusts as these storms spread east-southeastward across parts of OH

into western PA and vicinity Sunday afternoon and early evening.

This activity should gradually weaken through the evening across PA

as it encounters a less unstable airmass.



...Northern High Plains...

Despite limited low-level moisture and scant buoyancy, increasing

mid-level moisture and strengthening large-scale forcing for ascent

ahead of the Great Basin shortwave is forecast to support the

development of isolated thunderstorms late Sunday evening. Given the

high storm bases and strengthening mid/upper flow, a few strong

gusts are possible. Even so, the overall severe threat appears too

limited to include low severe probabilities with this outlook.



..Mosier.. 05/04/2024



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