Valid 172000Z – 181200Z
…THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
NORTHERN AND WESTERN TEXAS…
…SUMMARY…
Scattered large hail and severe wind gusts are expected through
tonight from southwest to north-central Texas. A couple tornadoes
are also possible across western North Texas, mainly from late
afternoon to early evening.
…20z Update…
The Marginal risk area has been expanded south and east across
portions of northern/northeastern Texas based on latest surface
observations indicating the warm front has not progressed as far
northward as previously expected. Widespread cloud cover over OK and
the Red River vicinity, and eastward-progressing showers over
southwestern OK, will continue to limit heating the remainder of the
afternoon. Visible satellite shows areas of TCU closer to the warm
front, which extends southeastward from south of Lubbock to near
Stephenville to Palestine Texas. Upper forcing is weak across this
area for now, and initial thunderstorm development will depend on
strong diurnal heating. However, should storms develop, large hail
and strong wind gusts will be possible. For more details on ongoing
WW 52 across northwest Texas and possible downstream concerns,
reference forthcoming MCD 189.
Further west across western Texas, thunderstorms are expected to
develop in the next few hours. Supercells may initially develop
before some upscale growth occurs during the evening into tonight.
Reference MCD 188 for more details.
..Leitman.. 03/17/2020
.PREV DISCUSSION… /ISSUED 1129 AM CDT Tue Mar 17 2020/
…Southern High Plains…
Ongoing cluster of thunderstorms with a history of small to
marginally severe hail should persist eastward along and north of a
west/east-oriented warm front across north TX. Widespread stratus
north of the front will slow its northward progression at the
surface today. While surface heating should be gradual, as the
cluster impinges on a plume of mid 60s surface dew points emanating
from central TX through the Big Country, additional storm
development into the warm sector is possible. Low-level flow will be
modest, but sufficient veering with height near the surface front
could foster a risk for a couple tornadoes in addition to large hail
and isolated severe wind.
Farther west, additional thunderstorms may form in multiple rounds.
Isolated thunderstorms should develop in east-central NM off the
higher terrain and possibly south along the TX/NM border near the
surface trough during the mid to late afternoon. A greater
likelihood for scattered thunderstorms is anticipated during the
early evening across the Pecos Valley as large-scale ascent
increases with rapid approach of a low-amplitude shortwave impulse
from the Gulf of CA. 35-45 kt effective shear and steep mid-level
lapse rates will support a risk for large hail in the early
convective life-cycle. Storm-scale consolidation and upscale growth
into an eastward-progessing MCS appears probable this evening from
the Concho Valley/Edwards Plateau into the Big Country with a mixed
risk of severe wind and hail. The severe threat should wane during
the overnight owing to decreasing instability with eastern extent in
central TX.
$$