Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0253 PM CDT Sat Oct 31 2026
Valid 312000Z - 011200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Organized severe thunderstorms are not forecast through tonight.
...20z Update...
Broad/diffluent southwesterly flow aloft continues to overspread the
Southwest. Visible satellite shows high clouds entering the region,
with filtered insolation resulting in some destabilization (200-300
J/kg MLCAPE) and cumulus development amid a moist boundary layer
across portions of southern AZ and across southern NV. Despite ample
shear that will increase throughout the remainder of the day, the
notably weak instability (perhaps peaking near 500 J/kg) will limit
the severe potential with any thunderstorm activity. Nonetheless,
general thunderstorm potential has been extended into parts of
southern NV.
Otherwise, the previous forecast remains on track. See the
discussion below for more details.
..Karstens.. 10/31/2026
.PREV DISCUSSION... /ISSUED 1126 AM CDT Sat Oct 31 2026/
...Synopsis and Discussion...
Downstream of weak mid-level troughing, isolated to scattered
thunderstorms will be possible through tonight across parts of the
lower MS Valley into the FL Panhandle and Peninsula as low-level
moisture gradually advances northward across these regions. Limited
overlap of sufficient instability and deep-layer shear to support
organized updrafts should preclude severe thunderstorms across these
areas.
Across the western CONUS, isolated convection appears possible
through the period across parts of central CA into the northern
Great Basin, and portions of southern/central AZ. Southwesterly
mid-level flow is forecast to strengthen across both of these
regions as upper troughing amplifies over the West Coast and as a
mid/upper-level subtropical jet overspreads the Southwest. However,
weak instability and modest mid-level lapse rates will likely hinder
severe thunderstorm potential through early Sunday morning.
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