Alert archive / Texas / Mesoscale Discussions in 2021

Mesoscale Discussion 123

February 18, 2021Kinney County, Uvalde County, Texas

The Storm Prediction Center issued this mesoscale discussion at Feb 18, 2021, 12:51 PM CST for Kinney County, Uvalde County, Texas. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued
Feb 18, 2021, 12:51 PM CST (18:51 UTC)
Expired
Feb 18, 2021, 3:45 PM CST
In force
3 hr
Issued by
the Storm Prediction Center
Concerning
Heavy snow

Counties Kinney County, TX, Uvalde County, TX

The radar

The Laughlin AFB radar (KDFX), 22 km from the middle of the area, began a volume at 18:50 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

Midland Regional, TX (KMAF), launched 12:00Z, 6.9 hours before the alert went out and 332 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.

Skew-T log-pSkew-T log-p diagram, Midland Regional, TX at 12:00Z on 2021-02-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Midland Regional, TX at 12:00Z on 2021-02-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 112 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
600 m above ground
0-6 km bulk shear
83 kt
0-1 km storm-relative helicity
112 m²/s²
0-3 km storm-relative helicity
65 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

160 
ACUS11 KWNS 181851
SWOMCD
SPC MCD 181851 
TXZ000-182145-

Mesoscale Discussion 0123
NWS Storm Prediction Center Norman OK
1251 PM CST Thu Feb 18 2021

Areas affected...southern Val Verde ...Kinney...and Uvalde counties
in Texas

Concerning...Heavy snow 

Valid 181851Z - 182145Z

SUMMARY...A narrow band of heavy snow continues across southern Val
Verde, Kinney, and Uvalde counties in Texas. This band will
gradually weaken through the afternoon.

DISCUSSION...A band of heavy snow has become narrower, but heavy
snowfall rates remain within this corridor from Del Rio, Texas
eastward. Snowfall rates as high as 3 inches per hour have been
reported in Del Rio this morning. Frontogenesis has started to
weaken across the area, which is likely responsible for the
narrowing corridor of the heaviest snow rates. As frontogenesis
continues to weaken, snowfall rates will continue to lower, but 1+
inch per hour snowfall rates could persist through mid to late
afternoon beneath the heaviest portions of the band. The heaviest
snowfall rates will likely remain near Del Rio where significant
snowfall totals have already been reported.

..Bentley.. 02/18/2021

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

ATTN...WFO...EWX...

LAT...LON   29540126 29610096 29550029 29549999 29429976 29279974
            29149986 29080018 29100044 29200073 29220095 29260103
            29540126

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Feb 18, 10:07 AM CSTMesoscale DiscussionSPCBandera, Bexar, Comal, Guadalupe, Kendall, Kinney and 3 more2 hr

Nearby

Mesoscale Discussions in Texas, 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.