Alert archive / Arizona / Mesoscale Discussions in 2021

Mesoscale Discussion 1803

October 5, 2021Maricopa County, Arizona

The Storm Prediction Center issued this mesoscale discussion at Oct 5, 2021, 5:51 PM MST for Maricopa County, Arizona. It was in force for 54 min.

The area

The outline as issued.

The facts

Issued
Oct 5, 2021, 5:51 PM MST (00:51 UTC)
Expired
Oct 5, 2021, 6:45 PM MST
In force
54 min
Issued by
the Storm Prediction Center
Concerning
Severe thunderstorm watch 512

County Maricopa County, AZ

The radar

The Phoenix radar (KIWA), 90 km from the middle of the area, began a volume at 00:51 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 00:00Z, 0.9 hours before the alert went out and 201 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 00:00Z on 2021-10-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 00:00Z on 2021-10-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 16 square meters per square second.19395878Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
840 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
16 m²/s²
0-3 km storm-relative helicity
135 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

493 
ACUS11 KWNS 060051
SWOMCD
SPC MCD 060051 
AZZ000-060145-

Mesoscale Discussion 1803
NWS Storm Prediction Center Norman OK
0751 PM CDT Tue Oct 05 2021

Areas affected...portions of central Arizona.

Concerning...Severe Thunderstorm Watch 512...

Valid 060051Z - 060145Z

The severe weather threat for Severe Thunderstorm Watch 512
continues.

SUMMARY...Isolated supercells may pose a large hail/damaging wind
threat through the evening.

DISCUSSION...A supercell split in southwest Maricopa county with the
left split now in northwest Maricopa county and the right mover
approaching the south Phoenix/Tempe metro area. Sufficient airmass
recovery has occurred in this area with MLCAPE around 500 to 1000
J/kg per SPC mesoanalysis and the 00Z TUS RAOB. Enough residual
instability should remain in the Phoenix metro area to sustain this
supercell and an associated severe weather threat for the next 1 to
2 hours before a cooling boundary layer and increasing inhibition
should eventually result in storm weakening.

..Bentley.. 10/06/2021

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

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

LAT...LON   34051328 34401329 34361163 33431118 33011170 32911242
            32991285 33081310 33161314 34051328

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Oct 5, 5:45 PM MSTMesoscale DiscussionSPCApache, Greenlee90 min

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.