Severe Storm Outlook Narrative (AC)
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ACUS11 KWNS 181933
SPC MCD 181933

Mesoscale Discussion 0133
NWS Storm Prediction Center Norman OK
0233 PM CDT Sun Mar 18 2018

Areas affected...Western north Texas and far southwest/south-central

Concerning...Severe potential...Watch possible

Valid 181933Z - 182130Z

Probability of Watch Issuance...40 percent

SUMMARY...Isolated thunderstorms may develop across portions of
western north Texas and far southwest Oklahoma over the next several
hours. Any thunderstorm that develops should move generally east
toward the I-35 corridor, posing a risk for large hail and strong
winds, although a tornado or two will be possible with any sustained

DISCUSSION...Visible satellite imagery indicates thinning/clearing
clouds across western north Texas in the wake of morning
clouds/precipitation. Strong heating in the wake of the clouds has
allowed for cumulus development on the dryline near its intersection
with a weak surface front that extends northeast into southern
Oklahoma. Additional cumulus development is noted along the
aforementioned surface front as far northeast as far southwest

Current indications are that afternoon insolation will combine with
continued low-level moistening to allow for isolated thunderstorms
to develop out of these increasingly agitated cumulus fields over
the next several hours. Steep/steepening midlevel-lapse rates will
support most-unstable CAPE ranging from 1000-2500 J/kg at the same
time a strong mid-level jet moves across the region supporting
effective-layer shear on the order of 50-70 knots. This environment
will support a supercell threat with any thunderstorm that can
develop and become sustained. Large hail and strong winds will be
the primary threats initially. The tornado threat will slowly
increase this evening as the low-level jet increases and storms move
east into the better low-level moisture.

..Marsh/Guyer.. 03/18/2018

...Please see for graphic product...


LAT...LON   31759992 32640021 33929986 34509876 34489792 34379735
            33889705 32919684 32279704 31559760 31439896 31759992 is the U.S. government's official web portal to all federal, state and local government web resources and services.