Mesoscale Discussion 1785

Issued

Sep 26, 2021, 2:39 PM MST (21:39 UTC)

Expired

Sep 26, 2021, 4:15 PM MST

In force

96 min

Issued by

the Storm Prediction Center

Concerning

Severe potential...watch unlikely

Chance of a watch

5%

Counties Cochise County, AZ, Catron County, NM, Doña Ana County, NM, Grant County, NM, Hidalgo County, NM, Luna County, NM, Sierra County, NM, Socorro County, NM, Valencia County, NM

The El Paso radar (KEPZ), 161 km from the middle of the area, began a volume at 21:41 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.

898 
ACUS11 KWNS 262139
SWOMCD
SPC MCD 262139 
NMZ000-TXZ000-AZZ000-262315-

Mesoscale Discussion 1785
NWS Storm Prediction Center Norman OK
0439 PM CDT Sun Sep 26 2021

Areas affected...portions of southeastern Arizona and southwest New
Mexico

Concerning...Severe potential...Watch unlikely 

Valid 262139Z - 262315Z

Probability of Watch Issuance...5 percent

SUMMARY...Scattered thunderstorms across Arizona and New Mexico are
expected to continue this afternoon and evening. Recent radar trends
suggest some strengthening over the last hour with an increasing
risk for a few instances of damaging winds or hail with the
strongest storms. Given the relatively limited threat, a weather
watch is unlikely.

DISCUSSION...As of 2115 UTC, radar and satellite imagery showed
scattered to numerous thunderstorms ongoing across portions of
southern Arizona and western New Mexico. Associated with a weak
upper low moving out of the Gulf of California, these storms are
ongoing in a moderately unstable environment with around 1000 J/kg
of MLCAPE from SPC mesoanalysis. As lift from the trough and a 35 kt
mid-level jet streak continues to impinge on the monsoonal moisture
in place, continuation of the current storms and some additional
development appears likely. Deep-layer shear profiles are weak to
moderate (30-40 kts), but should continue to support a few organized
multicell clusters or weak supercells as mid-level southwesterlies
increase ahead of the jet. Given relatively steep lapse rates of 7
C/km in the low to mid levels, a few instances of damaging outflow
winds and severe hail appear likely into this evening. 

Latest model guidance and observational trends suggest peak severe
coverage will likely be reached over the next hour or two as ongoing
storms move through the area of maximum solar heating and favorable
boundary-layer moisture near the Arizona New Mexico border. As
convection shifts slowly to the east with time, a drier airmass and
increasing nocturnal inhibition should begin to diminish the severe
threat later this evening. Given the relatively narrow window and
expected isolated severe coverage, a weather watch appears
unnecessary.

..Lyons/Grams.. 09/26/2021

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

ATTN...WFO...ABQ...EPZ...TWC...

LAT...LON   31130806 31180969 31561027 32060992 32810939 33300914
            33920882 34660818 35060742 34980646 33780615 32640628
            31810666 31630704 31670809 31130806

Mesoscale Discussions in New Mexico, 2021Mesoscale Discussions in Arizona, 2021Every mesoscale discussion in 2021

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.