Mesoscale Discussion 2386
NWS Storm Prediction Center Norman OK
1135 AM CDT Wed Oct 21 2026
Areas affected...Northern and central Arizona into far southeastern
Nevada
Concerning...Severe potential...Tornado Watch likely
Valid 211635Z - 211830Z
Probability of Watch Issuance...80 percent
SUMMARY...The risk for supercells capable of producing a few
tornadoes, large hail, and severe wind gusts will continue
increasing into this afternoon. A Tornado Watch is likely.
DISCUSSION...Within a broad zone of warm/moist advection extending
across AZ, a couple of storms have intensified into supercells,
though this intensification has been mostly associated with
small-scale terrain enhancements thus far. Recent visible satellite
and radar data now show the genesis zone for deep convection south
of the Mogollon Rim, where the boundary layer is diurnally
destabilizing. Current thinking is that this activity will continue
tracking northward toward the aforementioned terrain features and
related enhancement to low-level shear profiles. This, combined with
a sheltered boundary layer with clockwise-curved low-level
hodographs (per VWP and mesoanalysis data) along/north of the Rim,
should promote an increase in supercells through the afternoon.
Given generally weak large-scale forcing for ascent,
discrete/semi-discrete supercells should persist, with an associated
risk for a few tornadoes, large hail, and locally severe gusts. A
Tornado Watch is likely for parts of central and northern AZ.
..Weinman/Mosier.. 10/21/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...FGZ...PSR...VEF...
LAT...LON 33751069 33901210 34121313 34441403 34831435 35341449
35931445 36511421 36691383 36751335 36651180 36091022
35670975 34860956 34100999 33751069
MOST PROBABLE PEAK TORNADO INTENSITY...85-110 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN
Source link