SPC MD 1200

MD 1200 CONCERNING SEVERE POTENTIAL...SEVERE THUNDERSTORM WATCH LIKELY FOR OK...NORTH TX...TX PANHANDLE

Mesoscale Discussion 1200
NWS Storm Prediction Center Norman OK
0321 PM CDT Fri Jun 30 2017

Areas affected...OK...North TX...TX Panhandle

Concerning...Severe potential...Severe Thunderstorm Watch likely 

Valid 302021Z - 302215Z

Probability of Watch Issuance...95 percent

SUMMARY...Scattered strong/severe thunderstorm development is
expected across portions of Oklahoma and west/north Texas later this
afternoon. Severe thunderstorm watch issuance is likely by 21-22Z.

DISCUSSION...The primary outflow boundary from the earlier MCS that
moved across much of northern OK is now draped along the Red River,
with a secondary boundary in place further north from northwest AR
into central/northern OK. To the south of the southern boundary,
strong heating is underway within a very moist environment, and
MLCAPE has increased into the 2500-4000 J/kg range per recent
mesoanalyses. Substantial airmass recovery appears to be underway
between the two boundaries, with dewpoints increasing to near 70 F,
though the character of the cumulus field suggests that significant
inhibition remains across portions of central/eastern OK. 

With time, continued heating and erosion of inhibition will allow
thunderstorm development, with initial development most likely
across portions of southwest OK and western north TX, where the
strongest heating is occurring, and perhaps into central OK in the
vicinity of the northern boundary. The initial mode will likely be
primarily discrete, with sufficient deep-layer shear for supercells.

Very steep midlevel lapse rates and strong buoyancy will support a
threat of potentially very large hail. A brief tornado also cannot
be ruled out with any supercell that interacts with any of the
pre-existing boundaries, though weak low-level flow should otherwise
limit the coverage of the tornado risk. A substantial increase in
storm coverage by early evening will allow for some upscale growth,
with an increasing threat of damaging winds spreading eastward with
time.

..Dean/Hart.. 06/30/2017

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

ATTN...WFO...SHV...TSA...FWD...OUN...LUB...AMA...

LAT...LON   35240012 35589998 35859889 35919718 35949557 35719499
            35589459 34969456 33799452 33649573 33619782 33619934
            33809995 34080034 34770023 35240012 

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