Mesoscale Discussion 1466

Issued

Aug 10, 2021, 3:40 PM MST (22:40 UTC)

Expired

Aug 10, 2021, 5:45 PM MST

In force

2 hr

Issued by

the Storm Prediction Center

Concerning

Severe potential...watch unlikely

Chance of a watch

20%

County La Paz County, AZ

The Las Vegas radar (KESX), 158 km from the middle of the area, began a volume at 22:37 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

005 
ACUS11 KWNS 102241
SWOMCD
SPC MCD 102240 
AZZ000-CAZ000-110045-

Mesoscale Discussion 1466
NWS Storm Prediction Center Norman OK
0540 PM CDT Tue Aug 10 2021

Areas affected...Parts of northwest/west central Arizona into
southeastern California

Concerning...Severe potential...Watch unlikely 

Valid 102240Z - 110045Z

Probability of Watch Issuance...20 percent

SUMMARY...A large cluster of thunderstorms may continue to develop
during the next hour or two across parts of northwestern Arizona,
before spreading southwestward across the Lake Havasu vicinity and
adjacent portions of the Colorado Valley by 6-8 PM PDT, accompanied
by strong, potentially damaging wind gusts.  It is not yet clear
that a severe weather watch is needed, but trends will continue to
be monitored.

DISCUSSION...Clusters of developing thunderstorm activity have
generated a number of substantive west/southwestward propagating
surface cold pools across the plateau region of northwestern Arizona
into western portions of the Mogollon Rim.  This has been aided by
the downward transfer of momentum associated with 10-15 kt easterly
wind fields around 500 mb.  Similar magnitude southwesterly flow
further aloft is allowing for anvil cloud cover and precipitation to
advect to the northeast, and not interfere with the weak westerly
and southwesterly low-level inflow.

Although wind fields and shear are generally weak, latest
observational data suggest that further convective development along
intersecting outflow boundaries will continue during the next couple
of hours.  It appears that this could contribute to one
consolidating cluster roughly centered south/southeast of Kingman. 
Thereafter, activity should continue a southwestward propagation
into and across the lower Colorado Valley, including the Lake Havasu
vicinity and areas to the south, where a relatively moist, hot
(surface temps at or above 100F) and deeply mixed boundary layer
will be increasing conducive to the potential for severe surface
gusts through 01-03Z.

..Kerr/Edwards.. 08/10/2021

...Please see www.spc.noaa.gov for graphic product...

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

LAT...LON   34471531 35331419 34751377 34701301 33781374 33421441
            33811522 34471531

Mesoscale Discussions in Arizona, 2021Every mesoscale discussion in 2021

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.