Alert archive / Arizona / Mesoscale Discussions in 2023
Mesoscale Discussion 2021
The Storm Prediction Center issued this mesoscale discussion at Aug 21, 2023, 12:58 PM MST for 5 counties in Arizona. It was in force for 3 hr.
The area
The outline as issued.
The facts
- Issued
- Aug 21, 2023, 12:58 PM MST (19:58 UTC)
- Expired
- Aug 21, 2023, 3:30 PM MST
- In force
- 3 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 20%
Counties Cochise County, AZ, Gila County, AZ, Graham County, AZ, Pinal County, AZ, Santa Cruz County, AZ
The radar
The Phoenix radar (KIWA), 118 km from the middle of the area, began a volume at 19:59 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
Tuscon, AZ (KTUS), launched 12:00Z, 8.0 hours before the alert went out and 118 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.
- Mixed-layer CAPE
- 414 J/kg
- Mixed-layer CIN
- -36 J/kg
- Mixed-layer LCL
- 1145 m above ground
- 0-6 km bulk shear
- 37 kt
- 0-1 km storm-relative helicity
- 31 m²/s²
- 0-3 km storm-relative helicity
- 93 m²/s²
- Significant tornado parameter
- 0.1
- Supercell composite
- 2.0
The text
As transmitted.
803
ACUS11 KWNS 211959
SWOMCD
SPC MCD 211958
AZZ000-212230-
Mesoscale Discussion 2021
NWS Storm Prediction Center Norman OK
0258 PM CDT Mon Aug 21 2023
Areas affected...Southeast/East-Central AZ
Concerning...Severe potential...Watch unlikely
Valid 211958Z - 212230Z
Probability of Watch Issuance...20 percent
SUMMARY...Thunderstorms capable of damaging gusts may develop across
east-central and southeast Arizona this afternoon.
DISCUSSION...Recent visible satellite imagery shows some deepening
cumulus across southeast/east-central AZ, between more widespread
cumulus over the higher terrain near the AZ/NM border and a more
persistent north/south oriented cloud band across central AZ.
This persistent cloudiness has tempered heating and destabilization
across central AZ thus far, but partly cloudy skies have allow
modest destabilization across south-central/southeast AZ. Further
destabilization is anticipated throughout the afternoon, and
moisture convergence along this differential heating zone is
expected to result in convective initiation. Strong low to mid-level
flow extends throughout this region as well, with recent
mesoanalysis estimating effective bulk shear from 35 to 45 kt. As
such, any storms that area able to deepen and persist could become
organized/supercellular with the potential to produce damaging
gusts. Overall coverage of strong to severe storms appears it will
remain isolated, likely precluding the need for a watch.
..Mosier/Grams.. 08/21/2023
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...TWC...FGZ...PSR...
LAT...LON 31411103 32831163 34271174 34881159 35241114 35111033
34540989 33500953 32700927 32180920 31470925 31340973
31411103SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 21, 12:47 PM MST | Mesoscale Discussion | SPC | Cochise, Gila, Graham, Pinal, Santa Cruz | 2 hr |
Nearby
Mesoscale Discussions in Arizona, 2023Every mesoscale discussion in 2023
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.