LIVE MAP (ABOVE) ... SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0245 PM CDT Mon Aug 28 2023
Valid 282000Z - 291200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
ACROSS PORTIONS OF THE SOUTHEAST...
...SUMMARY...
Isolated storms capable of strong and gusty winds are possible
across the Southeast this afternoon.
...20Z Update...
...Southeast...
18Z soundings sampled a moist, moderately buoyant, and weakly
sheared environment across the region. This matches the overall
expectation outlined in the previous outlook (appended below), with
a predominantly disorganized multicellular storm mode anticipated.
Isolated water-loaded downbursts remain possible, particularly from
southern MS and across much of AL where the highest storm coverage
is anticipated.
...Central/Southern High Plains...
Convective initiation has already occurred across the high terrain,
with southeastward motion still expected to take these storms into
the High Plains. Mesoanalysis estimated effective bulk shear is
already 20 to 25 kt across the region, with some additional increase
anticipated throughout the afternoon. As such, some organization is
possible, with an attendant threat for a strong gust or two. Overall
coverage is still expected to remain too low for an outlook area.
..Mosier.. 08/28/2023
.PREV DISCUSSION... /ISSUED 1126 AM CDT Mon Aug 28 2023/
...Southeast this afternoon...
A weak midlevel trough persists from the northern Gulf of Mexico to
the southern Appalachians with multiple embedded vorticity maxima.
Vertical shear is very weak across the Southeast, and thermodynamic
profiles are less favorable for strong downdrafts compared to
previous days. Thus, scattered pulse-type storms are expected this
afternoon along a combination of a stalled synoptic front, weak
differential heating zones and local sea breeze circulations. The
wind-damage threat appears to be on the lower margins for an outlook
area, but will maintain the 5% area for the possibility of isolated
downbursts.
...Central/southern High Plains this afternoon/evening...
Similar to yesterday, a few storm clusters will form this afternoon
and move south-southeastward from southeast WY across eastern CO
into eastern NM through this evening. Effective bulk shear of 25-30
kt will support semi-organized storms, a few of which could produce
gusty outflow winds and small hail. However, the storms will be
relatively low topped for late summer and the severe threat appears
too marginal to add an outlook area.
...Tropical cyclone Idalia and FL...
Tropical storm Idalia is expected to become a hurricane later today
into tonight while moving northward toward the southeast Gulf of
Mexico (please refer to latest NHC advisories for additional
information). The stronger wind profiles and associated supercell
threat will likely be delayed in FL until Tuesday during the day, so
will not add any tornado probabilities in this update.
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