Mesoscale Discussion 498

Issued

May 3, 2021, 3:14 PM CDT (20:14 UTC)

Expired

May 3, 2021, 5:15 PM CDT

In force

2 hr

Issued by

the Storm Prediction Center

Concerning

Severe potential...tornado watch likely

Chance of a watch

95%

The Dallas/Ft Worth radar (KFWS), 81 km from the middle of the area, began a volume at 20:17 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.

• Tornado Watch 133May 3, 3:50 PM CDT
• Severe Thunderstorm Watch 134May 3, 6:35 PM CDT

239 
ACUS11 KWNS 032014
SWOMCD
SPC MCD 032014 
OKZ000-TXZ000-032215-

Mesoscale Discussion 0498
NWS Storm Prediction Center Norman OK
0314 PM CDT Mon May 03 2021

Areas affected...Northern Texas and southeast Oklahoma

Concerning...Severe potential...Tornado Watch likely 

Valid 032014Z - 032215Z

Probability of Watch Issuance...95 percent

SUMMARY...Strong to severe thunderstorms are expected to develop
across north Texas and south-central Oklahoma between 5-7 PM CDT.
These storms will pose a risk for large hail and a few tornadoes. A
watch is likely by 21 UTC.

DISCUSSION...Surface observations from north TX and southern OK
reveal a surface low northeast of Abilene, TX with a stalled cold
front draped to the southwest and a dryline extending to the south.
To the northeast of this low, a stationary front is noted across
southern to northeast OK. Recent GOES visible imagery shows a
shallow, but growing, cumulus field west of the DFW metro into
southeast OK east of the stationary boundary. A 19 UTC FWD sounding
shows considerable MLCIN remains in place, and should keep
convection at bay in the near term. However, continued diurnal
heating and increasing ascent over the region (due to the approach
of an upper-level wave from the west) will help erode lingering
inhibition by the 5-7 PM CDT time frame. Deep-layer shear is
forecast to increase as stronger flow associated with the synoptic
trough moves over the region, which will support initially discrete
cells along the dryline and stationary boundary. Steep mid-level
lapse rates noted in the 19 UTC FWD sounding and dewpoints
increasing into the upper 60s/low 70s will support MLCAPE values
near 3000-4000 J/kg. 

Consequently, severe hail appears likely and a few instances of
large (2+") hail are probable with any initial discrete storms. The
KFWS VWP recently observed around 100 m2/s2 0-1 km SRH, which may
support at least a low-end tornado threat across north TX. The
tornado threat will likely be higher along the Red River and
northward into south/southeast OK in the vicinity of the triple
point and along the stationary boundary where more backed low-level
winds are noted and environmental vertical vorticity is higher.
Although the potential for a few tornadoes exists with any initial
discrete convection, rapid upscale growth is possible within an hour
or two after initiation, and may limit the overall tornado
potential. Nonetheless, a tornado watch is likely by 21 UTC.

..Moore/Grams.. 05/03/2021

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

ATTN...WFO...SHV...TSA...FWD...OUN...SJT...

LAT...LON   32349878 33399800 34149751 34849731 35219655 35269553
            34959507 34309498 33569502 32899532 32439620 31919717
            31539805 31409867 31639898 32349878

Mesoscale Discussions in Texas, 2021Mesoscale Discussions in Oklahoma, 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.