Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1130 AM CDT Sat Jul 11 2026
Valid 111630Z - 121200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM OKLAHOMA INTO
THE LOWER MISSISSIPPI VALLEY/TENNESSEE VALLEY AND SOUTHEAST...AND
ACROSS SOUTHERN ARIZONA...
...SUMMARY...
Thunderstorms capable of producing scattered severe/damaging winds
will be possible this afternoon and evening from parts of the
southern Plains eastward into the lower Mississippi Valley and
Southeast. Scattered severe wind gusts are possible over southern
Arizona late this afternoon through the evening.
...Southern Plains/Ozarks into the Tennessee Valley/Southeast and
Mid-Atlantic...
Weak mid-level troughing with multiple embedded and convectively
enhanced vorticity maxima (i.e., several MCVs evident in radar
mosaic/satellite imagery) will advance slowly eastward across the
mid MS Valley into the lower OH Valley/Midwest and TN Valley and
southern Appalachians. A developing thunderstorm cluster over the
Upstate of SC will likely move east towards the Carolina coast later
today. Ahead of this cluster, strong heating with temperatures
warming into the 90s with lower to mid 70s F dewpoints will result
in a moderately unstable airmass. Westerly low-level flow will
imply the wind risk will likely overspread the coast.
Isolated damaging winds may also occur farther north along/near a
weak synoptic front, but less instability is forecast with northward
extent into the OH Valley and Mid-Atlantic.
Farther west, several clusters may evolve across the Mid South with
damaging gusts the primary severe hazard. Visible-satellite imagery
shows an MCV over northwest OK moving east. The airmass south of a
stalled frontal zone will undergo strong heating via clear skies
through mid afternoon. Short-term model guidance (HREF, HRRR-RRFS
time-lagged ensemble) show scattered storms developing across
north-central OK by 21-23 UTC. A well-mixed boundary layer will
support strong evaporatively cooled downdrafts capable of severe
gusts with the more intense single and multicells. Have expanded
the Slight Risk to account for this increased confidence in a severe
threat across central OK.
...Southern Arizona...
With a mid-level anticyclone centered over the Four Corners, a weak
easterly mid-level flow regime is present today across the Sonoran
Desert. Very strong heating will result in a deeply mixed boundary
layer and this was depicted on the 12 UTC Phoenix raob, with an
accompanying 11.6 g/kg lowest 100-mb mean mixing ratio. Forecast
soundings show 20-kt easterly flow in the mid levels atop weak
westerly surface flow. Very steep low- to mid-level lapse rates and
inverted-V thermodynamic profiles will strongly favor evaporatively
cooled downdrafts with the more intense cores. Severe gusts 60-80
mph appear likely with the stronger microbursts. This activity will
likely transition from a few cells into an outflow-dominant cluster
during the evening and coincide with a greater prevalence of severe
gusts. Isolated hail may also occur with the stronger cores.
..Smith/Chalmers.. 07/11/2026
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