ACUS01 KWNS 171250
SWODY1
SPC AC 171248

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0748 AM CDT Sat Aug 17 2024

Valid 171300Z - 181200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR CENTRAL KENTUCKY INTO
SOUTHERN OHIO...UTAH...AND PARTS OF THE CASCADES OF OREGON AND WASHINGTON...

...SUMMARY...
Scattered severe thunderstorms are possible in parts of Kentucky and
the Ohio Valley mainly this afternoon into the early evening.
Scattered severe thunderstorms are also forecast for Utah and in the
vicinity of the Cascades of Oregon and Washington.  Wind and hail
are the primary threats.

...Lower Great Lakes into the central/southern Appalachians and OH
Valley...
A mid-level low and associated trough will slowly move east today
and reach the Upper OH Valley/Appalachians tonight as a mid-level
anticyclone remains centered over northeast NM.  High-level
diffluent flow will be noted across the OH Valley into the Mid South
and be favorable for scattered thunderstorms developing across much
of this region coincident with strong heating.  A front will
gradually shift east across the OH Valley with this boundary
becoming more diffuse in part related to convective outflow across
the Mid South/Ozarks.  Stronger mid-level flow aiding in storm
organization will primarily extend from the Great Smoky Mtns
northward into KY/OH/WV.  Organized multicells and transient
supercells are possible with scattered coverage of severe wind/hail
possible with these storms.  Observational trends of an MCV over
Middle TN moving eastward into the southern Appalachians and the 00z
MPAS-NSSL model run data, lend the possibility for a mesoscale
corridor of higher thunderstorm coverage and greater damaging-wind
potential for the western Carolinas and perhaps into central
portions of AL.  Limited confidence in this scenario precludes
higher severe probabilities at this time.

...Lower MS Valley into north TX...
Morning thunderstorms over the OK/AR border associated with
low-level WAA may continue into the midday with incipient outflow
progressively shunting additional storms/new development farther
west and south across eastern OK.  Model guidance indicates at least
isolated storms potentially developing within an east-west corridor
from MS westward into north/northwest TX later today.  Forecast
soundings indicate severe microbursts will be possible with the more
intense cores.  Have adjusted low-severe probabilities to trend
farther west/southwest based on this forecast scenario.

...Utah Region...
Water-vapor imagery this morning shows a northward-moving shortwave
trough over southern NV and extrapolation has this feature moving
into northern UT by mid afternoon.  Scattered to numerous
thunderstorms are forecast to begin developing by late morning and
spreading north-northeast within a strongly sheared environment.
Increasing cloud cover and some limit on the quality of lapse rates
will temper overall buoyancy.  However, some organization into small
clusters yielding severe gusts will be the primary threat with the
stronger storms.

...Western OR/Southwest WA...
Strong 500mb speed max will round the base of the offshore trough
and translate across northern CA into eastern OR by early evening.
Left exit region of this feature will aid UVV near the higher
terrain and cooling/moistening mid-levels will contribute to modest
buoyancy along the cyclonic side of the speed max. Forecast
soundings exhibit strongly sheared profiles and isolated supercells
are expected to develop, then spread north-northeast as a short-wave
trough ejects into southern WA. Hail/wind are possible with these
storms.

..Smith/Mosier.. 08/17/2024

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