Alert archive / Arizona / Mesoscale Discussions in 2021
Mesoscale Discussion 1260
The Storm Prediction Center issued this mesoscale discussion at Jul 11, 2021, 3:59 PM MST for Gila County, Yavapai County, Arizona. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 11, 2021, 3:59 PM MST (22:59 UTC)
- Expired
- Jul 11, 2021, 6:00 PM MST
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 20%
Counties Gila County, AZ, Yavapai County, AZ
The radar
The Flagstaff radar (KFSX), 100 km from the middle of the area, began a volume at 23:01 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, 11.0 hours before the alert went out and 48 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
- 197 J/kg
- Mixed-layer CIN
- -303 J/kg
- Mixed-layer LCL
- 2378 m above ground
- 0-6 km bulk shear
- 13 kt
- 0-1 km storm-relative helicity
- 128 m²/s²
- 0-3 km storm-relative helicity
- 126 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
433
ACUS11 KWNS 112259
SWOMCD
SPC MCD 112259
AZZ000-120100-
Mesoscale Discussion 1260
NWS Storm Prediction Center Norman OK
0559 PM CDT Sun Jul 11 2021
Areas affected...Northwest/Central AZ
Concerning...Severe potential...Watch unlikely
Valid 112259Z - 120100Z
Probability of Watch Issuance...20 percent
SUMMARY...A few strong to severe storms are possible from northwest
into central AZ over the next few hours. Limited severe coverage is
expected to preclude the need for a watch.
DISCUSSION...Thunderstorms continue to develop along the higher
terrain stretching from northwest AZ eastward/southeastward into
central AZ. The boundary layer is deeply mixed and modest mid-level
moisture coupled with this deep mixing is fostering marginal
buoyancy. Thus far, individual updrafts have been relatively
short-lived, likely as a result of dry air entrainment and lack of
stronger vertical shear for updraft organization. Cell merger over
central Yavapai County has resulted in a robust updraft, but most of
the ongoing storms only show modest cores.
Strong to severe storms may occasionally occur for the next few
hours, predominantly as a result of cell mergers, but the overall
air mass appears less conducive for developing into the Lower
Deserts than yesterday. As such, the forecast of limited severe
coverage is expected to preclude the need for a watch.
..Mosier/Thompson.. 07/11/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...FGZ...PSR...VEF...
LAT...LON 36141374 36301309 35261205 34090990 33451027 33631101
34531376 36141374SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 10, 6:55 PM MST | Mesoscale Discussion | SPC | Gila, Graham, Maricopa, Pima, Pinal, Santa Cruz | 2 hr |
| Jul 11, 1:23 PM MST | Severe Thunderstorm Watch | SPC | Cochise, Graham, Greenlee | 8 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.