ACUS11 KWNS 220721
SWOMCD
SPC MCD 220721
AZZ000-220915-

Mesoscale Discussion 2395
NWS Storm Prediction Center Norman OK
0221 AM CDT Thu Oct 22 2026

Areas affected...parts of central Arizona

Concerning...Severe Thunderstorm Watch 690...

Valid 220721Z - 220915Z

The severe weather threat for Severe Thunderstorm Watch 690
continues.

SUMMARY...Scattered strong thunderstorm development remains possible
overnight. Although the potential for severe weather may currently
be at a relative minimum, it appears that this may increase again by
4-6 AM MST. A new severe weather watch may be needed, but it is not
certain whether this will be before WW 690 expires at 09Z, or a bit
later tonight.

DISCUSSION...There has been little change in the large-scale
environment through the evening into the overnight hours, downstream
of a notable mid-level trough and embedded low slowly migrating
inland of the southern California coast. Southerly low-level flow
is maintaining a seasonably moist boundary-layer across the lower
deserts into Mogollon Rim vicinity, which has been sufficient to
contribute to CAPE on the order of 500-1000+ J/kg beneath modestly
cool mid-level air. Beneath strong south to southwesterly flow in
the 500-300 mb layer, deep-layer shear remains conducive to
supercell development.

Forcing for ascent near and north of the Greater Phoenix area
continues to support renewed thunderstorm initiation, largely aided
by low-level warm advection and upslope flow into and across the
Mogollon Rim into Colorado Plateau. This is likely to continue
through the remainder of the night.

With the continued approach of the upstream trough axis and more
substantive mid-level height falls, along with perhaps some further strengthening of low-level flow/shear, latest model output
(including convection-allowing and related machine learning
guidance) suggests that the environment may once again become
increasingly conducive to supercells with potential to produce a
tornado or two, in addition to large hail, by 11-13Z, if not
earlier.

..Kerr.. 10/22/2026

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fjg!-zdmmdiOL9JKFH35Y6LV5g8odx7-kULFdwFuMfsutoA9pdAcR9zKyQdUR4E7-7OWipmDyykdkkThDIJS-CT2BBAIIH0$ for graphic product...

ATTN...WFO...FGZ...PSR...

LAT...LON 35361229 34911088 34031052 33191132 33351201 34431249
35361229

MOST PROBABLE PEAK TORNADO INTENSITY...85-110 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN
= = =
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--- scorpsmtpd
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