Alert archive / Arizona / Mesoscale Discussions in 2021
Mesoscale Discussion 1342
The Storm Prediction Center issued this mesoscale discussion at Jul 24, 2021, 1:01 PM MST for 4 counties in Arizona; McKinley County, San Juan County, New Mexico; Kane County, Washington County, Utah. It was in force for 119 min.
The area
The outline as issued.
The facts
- Issued
- Jul 24, 2021, 1:01 PM MST (20:01 UTC)
- Expired
- Jul 24, 2021, 3:00 PM MST
- In force
- 119 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 20%
Counties Apache County, AZ, Coconino County, AZ, Mohave County, AZ, Navajo County, AZ, McKinley County, NM, San Juan County, NM, Kane County, UT, Washington County, UT
The radar
The Flagstaff radar (KFSX), 175 km from the middle of the area, began a volume at 20:03 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, 8.0 hours before the alert went out and 119 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1053 m above ground
- 0-6 km bulk shear
- 21 kt
- 0-1 km storm-relative helicity
- 13 m²/s²
- 0-3 km storm-relative helicity
- -9 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
702
ACUS11 KWNS 242001
SWOMCD
SPC MCD 242001
NMZ000-COZ000-UTZ000-AZZ000-NVZ000-242200-
Mesoscale Discussion 1342
NWS Storm Prediction Center Norman OK
0301 PM CDT Sat Jul 24 2021
Areas affected...Four Corners into southern Nevada
Concerning...Severe potential...Watch unlikely
Valid 242001Z - 242200Z
Probability of Watch Issuance...20 percent
SUMMARY...Several clusters of thunderstorms across northern New
Mexico and southern Utah have recently shown signs of
intensification. These storms and additional development may pose a
risk for damaging winds or small hail this afternoon and evening.
DISCUSSION...Within a monsoonal flow regime beneath a weak upper
low, strong diurnal heating and weak ascent have allowed several
clusters of thunderstorms to become established over portions of the
Southwest in the last couple of hours. As heating and orographic
ascent continue, additional thunderstorm development appears likely.
Within the high PWAT airmass, SPC mesoanalysis indicates 500-1000
J/kg of MLCAPE has developed. While thermodynamics are favorable for
robust updrafts, a blocking ridge of high pressure in the mid levels
should limit flow aloft and resulting vertical shear to below 25
kts. A multicellular storm mode is expected with the stronger storms
capable of damaging wind gusts and small hail. A locally greater
risk of damaging wind gusts may develop if storm outflows are able
to evolve into small clusters as suggested by some hi-res guidance.
However, given the low predictability and expected limited severe
threat, a watch is unlikely at this time.
..Lyons/Hart.. 07/24/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...ABQ...GJT...FGZ...SLC...VEF...
LAT...LON 36521526 37381456 37601320 37611229 37571105 37230966
37010892 36630819 36250784 35800784 35230798 34800888
34740966 34721061 34851193 35021295 35191412 36521526Nearby
Mesoscale Discussions in Arizona, 2021Mesoscale Discussions in New Mexico, 2021Mesoscale Discussions in Utah, 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.