ACUS01 KWNS 021251

SWODY1

SPC AC 021250



Day 1 Convective Outlook  

NWS Storm Prediction Center Norman OK

0750 AM CDT Wed Jul 02 2025



Valid 021300Z - 031200Z



...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR CENTRAL INTO

NORTHERN PORTIONS OF MONTANA...



...SUMMARY...

Scattered severe thunderstorm gusts are possible across Montana this

afternoon into the evening.  Isolated severe thunderstorms may occur

today across parts of the Great Basin and Upper Midwest/Great Lakes.



...Northern Rockies/High Plains...

Water-vapor imagery shows a mid- to upper-level trough/low centered

over CA with downstream upper ridging centered over the

north-central Rockies and adjacent northern High Plains.  Modest

mid- to high-level west-southwesterly 500-250 mb flow (20-50 kt) is

forecast to remain across the northern Rockies and plains per model

data.  Surface observations this morning show 40s to lower 50s deg F

dewpoints over MT.  Strong heating will contribute to weak to

moderate buoyancy over the plains (500-1250 J/kg MLCAPE) and very

steep lapse rates from the surface into the mid levels.  Orographic

ascent will likely lead to isolated to scattered storms developing

by mid afternoon initially over southern MT and other

terrain-favored locales.  This activity is forecast to spread

north/northeast during the late afternoon/evening.  Thunderstorm

coverage will probably increase by the early evening in the form of

a few clusters and perhaps linearly oriented outflow surges. 

Evaporative cooling will facilitate efficient downdrafts and severe

gusts (60-70 mph) with the stronger cores. 



...Great Basin...

Modestly enhanced southerly flow will be present today over parts of

the Great Basin in association with a decaying/weak upper trough/low

over CA and the western Great Basin.  Scattered thunderstorms should

spread northward across these areas this afternoon/evening, with

isolated severe wind gusts possible.



...Upper Midwest/Great Lakes...

As upper ridging builds over the Plains today, a shortwave trough

over Ontario will dig southeastward and provide glancing large-scale

ascent over parts of the Upper Midwest and Great Lakes.  Model

guidance varies considerably on storm coverage, which is likely

related to capping concerns especially with westward extent into the

SD/IA/southwest MN vicinity.  Nonetheless, a seasonably

moist low-level airmass is expected to remain over most of these

regions, and daytime heating will likely aid in the development of

moderate to strong instability along/south of a front. Some

enhancement to the mid/upper-level west-northwesterly flow should

support sufficient deep-layer shear for organized thunderstorms with

an attendant hail/wind risk with the stronger storms.



...Eastern North Carolina...

Weak upper troughing will advance eastward today across the southern

Mid-Atlantic and Carolinas as a surface cold front likewise moves

slowly east-southeastward across these areas. Poor lapse rates aloft

will likely limit updraft strength, and deep-layer shear is also

expected to remain weak. While thunderstorms should develop through

the afternoon along/ahead of the front across eastern NC and

vicinity, the potential for damaging winds continues to appear to be

too limited for low probabilities.



..Smith/Broyles.. 07/02/2025



$$