Severe Storm Outlook Narrative (AC)
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000
ACUS11 KWNS 211855
SWOMCD
SPC MCD 211854
TXZ000-212130-

Mesoscale Discussion 0276
NWS Storm Prediction Center Norman OK
0154 PM CDT Thu Mar 21 2024

Areas affected...Parts of north and central Texas

Concerning...Severe potential...Watch unlikely

Valid 211854Z - 212130Z

Probability of Watch Issuance...20 percent

SUMMARY...Strong to severe thunderstorm development is expected over
the next couple hours. Isolated large hail and locally severe gusts
are the primary concerns. A watch is not currently expected.

DISCUSSION...Boundary-layer cumulus is gradually deepening in the
vicinity of a mesoscale low over northwest TX, where steep low-level
lapse rates are impinging on middle/upper 50s surface dewpoints.
Isolated convective initiation is underway in this area of focused
mesoscale ascent. Farther south, cumulus is more shallow along the
dryline (owing to weak low-level convergence), though deepening
cumulus is developing west of the dryline in a
well-mixed/destabilizing boundary layer. Aided by gradually
strengthening DCVA preceding a midlevel shortwave trough crossing
west TX, initial thunderstorms will develop/intensify along/south of
the mesoscale low, where low-level convergence is maximized. Around
35 kt of effective shear (characterized by a mostly straight
hodograph) will support initially discrete cells, with an isolated
hail risk (potentially up to 1.5 inches with the stronger storms)
and locally strong/severe gusts. Farther south, thunderstorms should
evolve out of the steep low-level lapse rate plume, with a similar
risk of isolated hail and slightly greater severe-wind risk, given
the steeper low-level lapse rates and stronger deep-layer shear.

With time, these storms should increase in coverage and spread
eastward, as the large-scale ascent continues to overspread the
region. This will promote localized upscale growth into several
loosely organized clusters, though the strongest deep-layer shear
may be displaced to the south of this activity -- potentially
limiting convective organization and favoring outflow dominant
storms. Nevertheless, strong to severe gusts (generally 50-60 mph)
will become the main concern, though isolated large hail will remain
possible with the more discrete activity. Current thinking is that
the severe hail/wind risk may remain too isolated/marginal for a
watch, though convective trends will be monitored through the
afternoon.

..Weinman/Goss.. 03/21/2024

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

ATTN...WFO...FWD...OUN...EWX...SJT...LUB...

LAT...LON   29909915 29939967 30149991 30600021 31770040 32650038
            33380016 33839983 34029939 34089897 34029836 33799780
            33399747 32239759 30449798 29959857 29909915



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