Alert archive / Arizona / Mesoscale Discussions in 2021
Mesoscale Discussion 1227
The Storm Prediction Center issued this mesoscale discussion at Jul 9, 2021, 10:21 PM MST for Maricopa County, Pinal County, Arizona. It was in force for 54 min.
The area
The outline as issued.
The facts
- Issued
- Jul 9, 2021, 10:21 PM MST (05:21 UTC)
- Expired
- Jul 9, 2021, 11:15 PM MST
- In force
- 54 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 20%
Counties Maricopa County, AZ, Pinal County, AZ
The radar
The Phoenix radar (KIWA), 83 km from the middle of the area, began a volume at 05:23 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
Phoenix, AZ (KPSR), launched 00:00Z, 5.4 hours before the alert went out and 79 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
- 1011 J/kg
- Mixed-layer CIN
- -182 J/kg
- Mixed-layer LCL
- 3280 m above ground
- 0-6 km bulk shear
- 34 kt
- 0-1 km storm-relative helicity
- -35 m²/s²
- 0-3 km storm-relative helicity
- 54 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
The text
As transmitted.
765
ACUS11 KWNS 100521
SWOMCD
SPC MCD 100521
AZZ000-100615-
Mesoscale Discussion 1227
NWS Storm Prediction Center Norman OK
1221 AM CDT Sat Jul 10 2021
Areas affected...South-central Arizona
Concerning...Severe potential...Watch unlikely
Valid 100521Z - 100615Z
Probability of Watch Issuance...20 percent
SUMMARY...A cluster of thunderstorms moving into the southern
portions of the Phoenix metro area will pose a risk of
damaging/severe wind gusts for the next 1-2 hours. Due to limited
temporal/areal threat, a watch is not anticipated.
DISCUSSION...A cluster of thunderstorms that formed earlier this
evening over the Mogollon Rim and Gila mountains has intensified
rapidly in the last 30-45 minutes. The outflow associated with
these storms is now moving southwestward over 40 knots toward and
south of the southern portions of the Phoenix metro area.
Temperatures ahead of the storms remain in the low 100s, and
forecast soundings show sufficient CAPE to maintain storms for
another 1-2 hours. VAD profiles from IWA and PHX TDWR show 20+
knots of southeasterly low-level inflow, and 20-30 knots of
northwesterly mid-level winds. This is resulting in considerable
inflow/convergence along the leading edge of convection to maintain
intensity. Locally damaging wind gusts are the main threat.
..Hart.. 07/10/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...TWC...PSR...
LAT...LON 33071329 33521227 33441129 32901098 32311120 32061223
32151298 32521334 33071329SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 10, 2:48 PM MST | Mesoscale Discussion | SPC | Cochise, Gila, Graham, Pinal | 117 min |
| Jul 10, 4:52 PM MST | Severe Thunderstorm Watch | SPC | Gila, Maricopa, Pima, Pinal | 7 hr |
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.