MD 2017 CONCERNING SEVERE POTENTIAL…WATCH POSSIBLE FOR SOUTHEAST CA…SOUTHWEST AZ…EXTREME SOUTHERN NV
Mesoscale Discussion 2017
NWS Storm Prediction Center Norman OK
0109 PM CDT Sun Aug 20 2023
Areas affected…Southeast CA…Southwest AZ…extreme southern NV
Concerning…Severe potential…Watch possible
Valid 201809Z – 202015Z
Probability of Watch Issuance…40 percent
SUMMARY…A couple tornadoes are possible this afternoon as T.C.
Hilary moves north-northwestward. Tornado Watch issuance is
possible.
DISCUSSION…Tropical Storm Hilary is quickly moving
north-northwestward near the Baja California coast late this
morning. While Hilary will continue to weaken through the day,
strong low/midlevel flow associated with the broader circulation has
already spread into parts of southern CA/AZ, and will move into a
larger portion of southeast CA into western AZ with time. 0-1 km SRH
of 200-300 m2/s2 (as noted on recent VWPs from KYUX and also from
objective mesoanalyses) will be supportive of low-level rotation
with any deeper convection to the east/northeast of Hilary’s track.
Uncertainty remains regarding the coverage of deep convection within
the favorable low-level shear regime. Convective banding may remain
somewhat muted in closer proximity to Hilary’s center as the surface
circulation continues to decay, and widespread cloudiness will tend
to limit destabilization. The greatest relative threat may
materialize along and west of the lower CO River Valley, where
richer low-level moisture will be in place and somewhat greater
heating/destabilization is underway along the eastern periphery of
the strongest low-level flow/shear. One or more arcs of deeper
convection may evolve with time across this region, with embedded
transient supercells and a couple of tornadoes possible. Tornado
Watch issuance is possible, depending on short-term observational
trends regarding destabilization and convective evolution.
..Dean/Grams.. 08/20/2023
…Please see www.spc.noaa.gov for graphic product…
ATTN…WFO…PSR…VEF…SGX…
LAT…LON 32621629 33721664 34891669 35301623 35511564 35351458
34231421 32791410 32171410 32361496 32621629
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