Mesoscale Discussion 0877
NWS Storm Prediction Center Norman OK
0600 PM CDT Sat May 27 2017
Areas affected...Portions of North Texas
Concerning...Severe potential...Watch possible
Valid 272300Z - 280030Z
Probability of Watch Issuance...40 percent
SUMMARY...Portions of north Texas are being monitored for
thunderstorm development. A substantial conditional (upon
development) severe risk exists and watch issuance is possible.
DISCUSSION...Towering cumulus have recently been noted near the Red
River across portions of north TX. While large-scale forcing is weak
at best across this area, continued convergence in the vicinity of a
diffuse dryline may result in storm development during the next 1-2
hours. Steep midlevel lapse rates atop a very warm and moist
boundary layer are resulting in extreme buoyancy, with MLCAPE likely
approaching 6000 J/kg in some areas. With moderately strong
southwesterly midlevel flow across the region, effective shear is
more than sufficient for supercells, and any storms that develop
will have a threat of giant hail and localized, but potentially
significant, wind gusts. While low-level flow, as sampled by area
VWPs, is not overly strong, some tornado threat would also exist
given the extreme CAPE environment and some expected intensification
of the low-level jet later this evening.
It is unclear how many storms, if any, will develop in the short
term across this area, but watch issuance may become necessary if
initiation appears imminent.
...Please see www.spc.noaa.gov for graphic product...
LAT...LON 33789869 33949857 34059824 33809741 33279722 32689758
32339810 32199899 32569939 33319886 33789869