SPC Jul 2, 2025 1300 UTC Day 1 Convective Outlook

SPC 1300Z Day 1 Outlook

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

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