Severe Storm Outlook Narrative (AC)
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ACUS03 KWNS 050731
SPC AC 050730

Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0230 AM CDT Mon Jun 05 2023

Valid 071200Z - 081200Z


Isolated strong to severe thunderstorms appear possible Wednesday
across parts of the interior Pacific Northwest, southern High
Plains, and South Carolina vicinity.

A quasi-omega blocking pattern will continue over the CONUS on
Wednesday, with a weak upper low over CA and the western Great
Basin, upper ridging over much of the Plains, and another upper
trough/low persisting over parts of the eastern states.

...Northern California into Oregon/Idaho/Western Montana...
Similar to Day 2/Tuesday, thunderstorms should initially develop
over the higher terrain of northern CA due to orographic influences
and weak ascent on the northern periphery of an upper low. With
seasonably cool temperatures aloft and modest deep-layer shear
forecast, some of these thunderstorms could produce marginally
severe hail. Additional convective development should occur farther
east into OR/ID and parts of western MT. While low-level moisture is
forecast to remain rather limited, sufficient instability to support
high-based thunderstorms is still forecast. 20-30 kt of effective
bulk shear should also provide modest updraft organization. Isolated
severe wind gusts should be the main threat with convective clusters
as they spread generally west-northwestward with time. Some hail
could also occur with initial development.

...Southern High Plains...
Thunderstorms should once again develop across the higher terrain of
central/eastern NM and west TX Wednesday afternoon. Although weak
upper ridging will persist, modestly enhanced mid/upper-level
westerly winds are forecast with southward extent across this region
in association with a sub-tropical jet. Deep-layer shear should
generally range around 20-30 kt, perhaps slightly weaker towards
CO/KS. Loosely organized thunderstorm clusters spreading eastward
Wednesday afternoon/evening may be capable of producing isolated
severe gusts as low-level lapse rates steepen through the day.
Occasional large hail also appears possible, especially across parts
of west TX where effective bulk shear may be slightly stronger.

...South Carolina Vicinity...
A weak surface trough/front should be draped across parts of the
Southeast. A seasonably moist low-level airmass will likely be in
place along/south of this boundary. Moderate instability should
develop in a narrow corridor across parts of GA into SC and far
southern/coastal NC by Wednesday afternoon. Stronger mid-level
westerly flow associated with an upper trough/low should gradually
overspread the warm sector through the day. Sufficient deep-layer
shear to support organized convection should be present, but weak
low-level convergence along the boundary casts some uncertainty
regarding thunderstorm coverage. Still, have opted to include low
severe probabilities where most guidance suggests robust convection
will develop.

..Gleason.. 06/05/2023

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