DAY1 Enhanced Risk Cen US
From
Dumas Walker@21:1/175 to
All on Wednesday, October 30, 2024 08:04:00
ACUS01 KWNS 301251
SWODY1
SPC AC 301250
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0750 AM CDT Wed Oct 30 2024
Valid 301300Z - 311200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR PORTIONS
EASTERN KANSAS...NORTHEAST OKLAHOMA...AND NORTHWEST MISSOURI...
...SUMMARY...
Severe thunderstorms capable of producing large hail, damaging wind
gusts, and a few tornadoes, are expected today into tonight across
the middle Missouri Valley and central/southern Plains, including
parts of eastern Kansas and Oklahoma into Missouri.
...Lower Missouri Valley/South-Central Plains...
A relatively active severe-weather day is expected regionally,
especially late this afternoon into evening, including some southern
Plains areas in which there hasn't been severe-weather potential in
over a month.
The lead portion of an upper-level trough centered over the
central/southern Rockies this morning will eject northeastward over
the central Plains toward broader parts of the Upper Midwest and
Corn Belt. A surface wave will evolve across the eastern Texas Panhandle/northwest Oklahoma vicinity. From this low, an east/southeastward-moving cold front will extend across Kansas into Iowa/Minnesota and eventually Wisconsin/western Missouri by this
evening, with this front overtaking a dryline across the southern
High Plains.
Some severe-weather potential may increase as early as late morning
into midday near the cold front across central Kansas into southeast
Nebraska and Iowa, with a likely increase in surface-rooted
convection and greater severe potential by mid/late afternoon as the
front approaches east-central/northeast Kansas and northwest
Missouri/southern Iowa. Pre-convective MLCAPE values should reach
500-1250 J/kg within this corridor, with very strong deep-layer
southwesterly winds supporting 40-50 kt effective shear and fast east-northeastward storm motions, which will largely parallel the
front and its east-southeastward motion. Some severe hail will be
possible during the day, but damaging winds and some tornado
potential will be more prevalent into late afternoon and evening as
a QLCS evolves with embedded bowing segments and potential
mesovortices.
Farther south, in closer proximity to the surface wave, somewhat
more discrete thunderstorm development is expected across south-central/east-central Kansas including the I-35/135 corridors
and north-central Oklahoma, with prospects for even more isolated
initial supercellular development by around sunset southward into central/southern Oklahoma and North Texas. Surface temperatures in
the upper 70s F, combined with mid 60s F dewpoints, will contribute
to 1500-2000 J/kg MLCAPE by peak heating. Storms that develop/mature
in this environment will likely be supercells in the presence of 45+
effective shear, highlighted by a dramatic strengthening (50-65 kt)
of 2-3 km AGL (surface-700 mb) southwesterly winds toward/after
sunset. Storm mergers will result in squall line development over
time, with a longer duration of more discrete development with
southward extent across Oklahoma. A few tornadoes are plausible
regionally, and a strong tornado or two could occur, particularly
within a couple of hours of sunset. The severe threat should
transition to more of a damaging wind threat as the squall line
matures, although line-embedded QLCS tornadoes will remain possible
this evening, and possibly overnight.
...Southeast Texas...
There is some potential that a few stronger/potentially rotating
storms could materialize today across the region within a very moist
and confluent low-level flow regime. This would be as low-level
lapse rates diurnally steepen coincident with a moderate degree of
low-level hodograph length and curvature. Modest-strength winds
above 2km AGL should limit the sustainability and intensity for any showers/thunderstorms that may exhibit rotating characteristics, and
the overall severe potential should remain limited.
..Guyer/Leitman.. 10/30/2024
$$
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