ACUS01 KWNS 080549
SWODY1
SPC AC 080547

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1247 AM CDT Sun Sep 08 2024

Valid 081200Z - 091200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
The organized severe-thunderstorm threat is expected to be low on
Sunday.

...Synopsis and Discussion...
A mature mid-latitude cyclone, embedded within larger upper
troughing, is forecast to progress northeastward from southern
Quebec into northeastern Quebec. Another shortwave trough is
expected to move through the western portion of the parent upper
troughing, dropping across western Ontario and the Upper Great Lakes
Sunday evening into Monday morning. Isolated thunderstorms are
possible with this second wave late Sunday night into early Monday
morning. Evolution of these shortwaves will help maintain troughing
across much of the eastern CONUS throughout the period.

Farther west, upper ridging will gradually move eastward into the
Plains while a low-amplitude shortwave trough moves through the
Pacific Northwest and into the northern Rockies.

At the surface, expansive high pressure centered over the Mid MS
Valley will dominate the sensible weather from the Mid MS and OH
Valleys into much of the central and southern Plains. This should
keep any low-level moisture confined to the immediate Gulf Coast and
FL Peninsula. A stationary front will likely extend from a low over
the far western Gulf of Mexico northeastward through northern FL.
Thunderstorms are possible in the vicinity of this boundary
throughout the day, with the highest coverage expected over the
northern/central FL Peninsula. Abundant cloud cover will limit
heating across northern/central FL Peninsula, and lapse rates will
be poor. However, mid-level flow around 40 kt may support enough
vertical shear for a few more persistent/organized updrafts capable
of damaging gusts. Even so, severe coverage is expected to remain
less than 5%.

Afternoon thunderstorms are expected again from the central High
Plains into parts of the central/southern Rockies, Great Basin, and
Southwest. High-based character of these storms could result in a
few locally strong gusts. Isolated high-based thunderstorms are also
possible from the interior Pacific Northwest into the northern
Rockies as a shortwave trough progresses through the region. A few
strong gusts are possible with these storms as well. In both of
these areas, overall severe coverage is expected to remain less than
5%.

..Mosier/Lyons.. 09/08/2024

$$