Alert archive / Arizona / Mesoscale Discussions in 2021

Mesoscale Discussion 1528

August 15, 2021Mohave County, Yavapai County, Arizona

The Storm Prediction Center issued this mesoscale discussion at Aug 15, 2021, 1:41 PM MST for Mohave County, Yavapai County, Arizona. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Aug 15, 2021, 1:41 PM MST (20:41 UTC)
Expired
Aug 15, 2021, 3:45 PM MST
In force
2 hr
Issued by
the Storm Prediction Center
Concerning
Severe potential...watch unlikely
Chance of a watch
20%

Counties Mohave County, AZ, Yavapai County, AZ

The radar

The Flagstaff radar (KFSX), 166 km from the middle of the area, began a volume at 20:40 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.

The nearest sounding before it

Flgstf/Belemont, AZ (KFGZ), launched 12:00Z, 8.7 hours before the alert went out and 112 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Flgstf/Belemont, AZ at 12:00Z on 2021-08-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 9 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Flgstf/Belemont, AZ at 12:00Z on 2021-08-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 41 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
9 J/kg
Mixed-layer CIN
-172 J/kg
Mixed-layer LCL
2026 m above ground
0-6 km bulk shear
13 kt
0-1 km storm-relative helicity
41 m²/s²
0-3 km storm-relative helicity
73 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

387 
ACUS11 KWNS 152041
SWOMCD
SPC MCD 152041 
AZZ000-152245-

Mesoscale Discussion 1528
NWS Storm Prediction Center Norman OK
0341 PM CDT Sun Aug 15 2021

Areas affected...Western Arizona

Concerning...Severe potential...Watch unlikely 

Valid 152041Z - 152245Z

Probability of Watch Issuance...20 percent

SUMMARY...Isolated to scattered thunderstorms will continue to
gradually develop through the late afternoon and evening hours.
Severe downburst winds will be possible, but storm coverage will
likely remain too sparse to warrant a watch issuance.

DISCUSSION...Regional radar/satellite imagery and lightning data
indicate that robust convective initiation is underway across parts
of north-central AZ. Storms developing off the heated terrain are
currently in a modestly supportive environment (featuring around 500
J/kg MLCAPE), but are forecast to propagate into western AZ where
better low-level moisture is supporting upwards of 1500 J/kg MLCAPE.
Weak deep-layer shear and minimal forcing for ascent will favor
isolated, disorganized storms, but steep low-level lapse rates
(8-9.5 C/km per mesoanalysis estimates) will support the potential
for severe downburst winds. Given the isolated nature of this
threat, a watch is not expected at this time.

..Moore/Hart.. 08/15/2021

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

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

LAT...LON   34111382 34661440 35521441 35851373 36131274 35801193
            35081138 34601136 34201210 34021296 34111382

Nearby

Mesoscale Discussions in Arizona, 2021Every mesoscale discussion in 2021

Sources

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.