Mesoscale Discussion 1228
NWS Storm Prediction Center Norman OK
0630 PM CDT Fri Aug 03 2018
Areas affected...Far east Colorado...northwest Kansas...far
Concerning...Severe potential...Watch unlikely
Valid 032330Z - 040200Z
Probability of Watch Issuance...5 percent
SUMMARY...Scattered strong to occasionally severe storms may
continue to produce isolated damaging wind gusts and large hail
until after sunset. A WW issuance is not currently anticipated.
DISCUSSION...Pulse severe convection has initiated along a cold
front along the Colorado/Kansas border, in an ambient environment
characterized by around 1000-2000 J/Kg MLCAPE and 30 knots of
effective bulk shear. The ambient buoyancy is mainly driven by
surface heating and associated steep low-level lapse rates, which
are expected to wane at the onset of nocturnal cooling/boundary
layer stabilization, when storms are expected to begin weakening.
In the meantime, steep low-level lapse rates, combined with marginal
shear profiles, may support severe hail growth in some of the more
organized updrafts. The relatively drier, heated airmass in a
dry-adiabatic sfc-700 mb layer will also support strong evaporative
cooling with the more intense thunderstorm downdrafts, where
additional instances of severe wind gusts may occur.
Given the marginal and isolated nature of the severe threat, a WW
issuance is not expected at this time.
...Please see www.spc.noaa.gov for graphic product...
LAT...LON 38070307 39250240 40240239 40840180 41330130 41160072
40680053 39980067 39240093 38680158 38320203 38120234