Mesoscale Discussion 867

Issued

Jun 7, 2021, 9:36 AM CDT (14:36 UTC)

Expired

Jun 7, 2021, 12:00 PM CDT

In force

2 hr

Issued by

the Storm Prediction Center

Concerning

Severe potential...watch possible

Chance of a watch

60%

The Dallas/Ft Worth radar (KFWS), 159 km from the middle of the area, began a volume at 14:38 UTC, the scan nearest the moment this went out.

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• Severe Thunderstorm Watch 242Jun 7, 12:30 PM CDT

761 
ACUS11 KWNS 071436
SWOMCD
SPC MCD 071436 
TXZ000-071700-

Mesoscale Discussion 0867
NWS Storm Prediction Center Norman OK
0936 AM CDT Mon Jun 07 2021

Areas affected...east-central and east TX

Concerning...Severe potential...Watch possible 

Valid 071436Z - 071700Z

Probability of Watch Issuance...60 percent

SUMMARY...The risk for severe gusts and wind damage will probably
focus near and south of I-20 through mid afternoon as an MCS moves
east-southeast towards the Sabine River.  The expected rejuvenation
of storm intensity with an associated severe threat will seemingly
coincide with surface temperatures warming into the low-mid 80s deg
F (around midday).

DISCUSSION...Radar mosaic this morning shows an MCS with an
associated MCV over north-central TX moving east-southeast across
the I-35 corridor.  Surface temperatures to the east of the
thunderstorm complex as of 930am, have warmed into the upper 70s to
near 80 deg F with mid 70s dewpoints.  Model guidance shows the
gradual weakening of a LLJ this morning (currently 30-35 kt over
east-central TX) but 25-kt southerly 850 mb flow is forecast to
remain over east TX through the early afternoon---maintaining a
moist conveyer.  The 7am Shreveport and Lake Charles, LA raobs
showed a very moist boundary layer with 16-18 g/kg lowest 100 mb
mean mixing ratios and 2500-3500 J/kg MLCAPE.  Additional heating
during the morning into the early afternoon will result in a very
unstable airmass across east TX on the southern periphery of the
mid-level low over the Ozark Plateau.  Current thinking is a severe
thunderstorm watch will likely be needed by the midday hours but
timing of issuance will coincide with radar trends.  Forecast
soundings suggest thunderstorm intensification in terms of a wind
damage threat will probably coincide with surface temperatures
warming into the mid 80s.  This warming would equate to the need for
a watch in the 11am-1pm timeframe.  

A risk for wind damage may also accompany storm activity on the
northern periphery of the MCS on if storms develop a warm advection
wing and surging portion of the line subsequently move east along
the differential heating boundary/effective warm front.

..Smith/Guyer.. 06/07/2021

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

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

LAT...LON   32599690 32539429 31989408 31409422 30919470 31269775
            31819778 32599690

Mesoscale Discussions in Texas, 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.