Mesoscale Discussion 320

Issued

Mar 24, 2017, 6:03 PM CDT (23:03 UTC)

Expired

Mar 24, 2017, 7:00 PM CDT

In force

57 min

Issued by

the Storm Prediction Center

Chance of a watch

60%

The Houston radar (KHGX), 169 km from the middle of the area, began a volume at 23:03 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.

• Tornado Watch 80Mar 24, 7:05 PM CDT
• Tornado Watch 82Mar 24, 9:20 PM CDT

521 
ACUS11 KWNS 242303
SWOMCD
SPC MCD 242303 
TXZ000-250000-

Mesoscale Discussion 0320
NWS Storm Prediction Center Norman OK
0603 PM CDT Fri Mar 24 2017

Areas affected...east-central into eastern TX

Concerning...Severe potential...Watch possible 

Valid 242303Z - 250000Z

Probability of Watch Issuance...60 percent

SUMMARY...A tornado watch may be needed by 7-8pm CDT.  Hail and wind
will be the primary severe hazards but the potential development of
low-level mesocyclones later this evening may pose an isolated
tornado risk.

DISCUSSION...Visible satellite imagery shows bands of convection
within a broad shield of stratocumulus from the upper coast of TX
north-northeastward into the ArkLaTex.  Surface temperatures have
warmed into the lower-middle 70s with a narrow corridor of mid-upper
60s degree F dewpoints near CLL and only near 60 F near and
northeast of UTS.  As a result, a gradient of buoyancy (1000 J/kg
MLCAPE to less than 500 J/kg) currently exists from southwest to
northeast across the discussion area.

Water vapor imagery indicates another mid-level vorticity lobe over
the TX Hill Country will pivot east-northeast across the region
later this evening.  Upward vertical motion will correspondingly
increase this evening and aid in leading to a gradual
intensification of storms concurrent with a modest increase in
low-level moisture.  A wind profile supportive of supercells will
favor at least some hail/wind risk with the stronger/sustained
updrafts.  A tornado threat may also develop as temperature-dewpoint
spreads decrease this evening.  Sizable hodographs as indicated in
forecast soundings would favor a tendency for the stronger and more
discrete updrafts to acquire some low-level rotation but a
veer-back-veer signature in the hodograph may modulate an otherwise
greater risk for a few tornadoes.

..Smith/Thompson.. 03/24/2017

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

ATTN...WFO...LCH...SHV...HGX...FWD...EWX...

LAT...LON   30139686 32229569 32399465 31789397 30839430 30249489
            29869670 30139686

Mesoscale Discussions in Texas, 2017Every mesoscale discussion in 2017

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.