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000
ACUS01 KWNS 231624
SWODY1
SPC AC 231623

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1123 AM CDT Tue Apr 23 2024

Valid 231630Z - 241200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR NORTHWEST
TEXAS...

...SUMMARY...
Isolated severe thunderstorms capable of producing large hail
(potentially 2+ inch diameter) and gusts to 65 mph will be possible
this afternoon and evening across northwest Texas.

...Northwest TX...
Visible satellite imagery and surface analysis this morning indicate
the initial stage of moisture return is occurring across the
southern Great Plains in the wake of a frontal intrusion into the
Gulf a few days ago.  A mid-level ridge will increasingly become
established across the central/southern Rockies and adjacent High
Plains as a Great Lakes disturbance gradually becomes more displaced
from the region.  An associated cold front will move southward
across KS/OK before eventually stalling tonight across southeast OK
and northwest TX.  Weak lee cyclogenesis will aid in maintaining a
southerly low-level fetch across central into west TX as strong
heating results in a sharpening dryline by late afternoon.  Isolated
thunderstorm development will be most probable near the triple point
20-22Z.  Steep lapse rates coupled with adequate moisture (1500-2000
J/kg MLCAPE) and veering flow beneath moderate westerlies, will
support an initial supercell mode.  Isolated very large hail of
2-2.5 inches in diameter will be the main threat, along with a few
55-65 mph gusts.

...Northern IL/southeast WI/Lower MI late this afternoon/evening...
Have not changed the existing outlook for this region due primarily
to consistency in model data and the forecast conceptual model not
deviating.  Water-vapor imagery this morning shows a mid-level
trough over the Upper Midwest and this will continue southeast into
the central Great Lakes by mid evening.  An associated surface
trough will likewise move southeastward, and this trough will be
preceded by a band of rain with minimal buoyancy.  Behind the rain
band, surface heating with steepening low-level lapse rates and
cooling midlevel temperatures will support weak surface-based
buoyancy just ahead of a secondary frontal surge.  Some low-topped
convection will be possible late this afternoon through late evening
from northern IL/southeast WI into Lower MI.  The stronger storms
could yield a localized marginal hail/damaging wind threat.

..Smith/Moore.. 04/23/2024

$$