ACUS01 KWNS 051624

SWODY1

SPC AC 051622



Day 1 Convective Outlook  

NWS Storm Prediction Center Norman OK

1122 AM CDT Sat Sep 05 2026



Valid 051630Z - 061200Z



...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF

THE CENTRAL APPALACHIANS INTO SOUTHERN VIRGINIA AND THE CAROLINAS...



...SUMMARY...

Strong to severe thunderstorms capable of producing scattered

damaging winds should occur this afternoon/evening across parts of

the central Appalachians into southern Virginia and the Carolinas.

Isolated large hail and severe winds may also occur over parts of

the northern/central Plains through tonight.



...Ohio Valley/Central Appalachians into the Mid-Atlantic and

Carolinas...

An earlier MCS across the OH Valley has weakened as it crossed/moved

eastward over the central Appalachians. The strongest remaining

convective segment is ongoing late this morning across parts of

southwest VA/northeast TN. Robust destabilization is expected to

continue this afternoon downstream of this activity across southern

VA into the Carolinas, with MLCAPE peaking around 2500-3500 J/kg

over central/eastern NC. This region will be on the southern

periphery of modestly enhanced mid-level west-northwesterly flow,

and sufficient deep-layer shear will be present to maintain some

convective organization.



Current expectations are for one or more thunderstorm clusters to

gradually increase in intensity this afternoon as they spread

eastward across southern VA and central/eastern NC, with some

uncertainty whether the ongoing convection will restrengthen, or if

new development will occur along its outflow. Regardless, latest

guidance and observational trends still suggest that a relatively

greater threat for damaging winds should exist this afternoon across

central/eastern NC and vicinity, where the greatest thunderstorm

coverage, maxima in MLCAPE/DCAPE, and steepened low-level lapse

rates are forecast. Have therefore introduced higher severe wind

probabilities (30% area) across this region. Isolated hail may also

occur with the strongest cores that can develop, although mid-level

lapse rates are expected to remain rather poor. Severe potential

should gradually wane this evening with the loss of daytime heating,

and as convection moves offshore.



Farther west, outflow from the morning thunderstorms may serve as a

focus for renewed thunderstorm development this afternoon from parts

of the OH Valley southeastward into the TN Valley. This region will

be displaced from the stronger flow aloft present over the

Mid-Atlantic/Northeast, with weak deep-layer shear expected. Still,

some risk for isolated damaging winds may exist with any loosely

organized cells/clusters that can develop given the presence of

moderate to locally strong instability. 



...Northern/Central Plains...

A highly amplified mid/upper-level ridge will remain anchored over

the central CONUS into south-central Canada through the period, with

generally neutral to weakly rising mid-level heights expected over

the northern/central Plains. Ongoing elevated cells across northern

ND may continue to pose an isolated severe hail threat in the short

term, but weakening low-level warm advection should tend to result

in a further decrease in intensity with this activity. Otherwise,

additional isolated to perhaps widely scattered high-based

thunderstorms may develop this afternoon along/east of a surface lee

trough over the northern/central Plains. While mid-level flow and

related effective bulk shear should remain weak, occasional severe

gusts may still occur with convective downdrafts given a well-mixed

boundary layer. Some risk for hail and gusty winds may also exist

with elevated convection that should eventually develop tonight into

early Sunday morning in a renewed/modest low-level warm advection

regime.



...Western Montana...

To the east of a closed mid-level low over WA/OR, a belt of enhanced

southwesterly mid/upper-level winds will extend across the northern

Rockies. Gradually increasing moisture and large-scale ascent aloft

associated with a weak/embedded shortwave trough are expected to

support an increase in isolated thunderstorms this

afternoon/evening. Lapse rates through low/mid levels will be steep

with strong deep-layer shear present, but modest low-level moisture

should limit MLCAPE to generally less than 500 J/kg. The potential

for severe wind gusts still appears too low to justify including 5%

wind probabilities at this time.



..Gleason/Thornton.. 09/05/2026



$$