DAY48SVR: Day6 Severe Ris
From
Mike Powell@618:250/1 to
All on Tue Mar 25 08:01:00 2025
ACUS48 KWNS 250911
SWOD48
SPC AC 250909
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0409 AM CDT Tue Mar 25 2025
Valid 281200Z - 021200Z
...DISCUSSION...
Medium-range models appear to be in reasonably good agreement into
the Day 7 period (Monday March 31), with respect to
evolution/progression of large-scale features.
Day 4/Friday, a southern-stream trough is forecast to continue
moving slowly eastward across the south-central states, reaching the
lower Mississippi Valley Saturday morning. Showers and
thunderstorms will accompany this feature, but the lack of robust
CAPE/shear likely to be associated with this feature suggests that
severe potential should remain subdued.
Farther north, weak disturbances moving through anticyclonic flow
aloft across the Upper Midwest/Upper Great Lakes/Ohio Valley will
likely combine with warm advection near the northward-advancing warm
front to support areas of deep convection, with some potential for
hail. Risk however appears too low to warrant an areal inclusion.
Saturday (Day 5), an upper trough will continue advancing across the
Rockies. However, models forecast the main surface low to remain
over the eastern Colorado vicinity into the evening hours, with a
capped warm sector residing across eastern Kansas/Oklahoma/Texas and
the Ozarks area (i.e. yesterday's Day 6 outlook area) in a zone of
subsidence in the wake of the slow-moving southern-stream trough.
As such, storm initiation now appears likely to remain largely
hindered through Sunday morning.
The primary severe risk appears likely to evolve Sunday/Day 6, from Missouri/Arkansas/northern Louisiana, spreading eastward through the
day, and eventually approaching the west slopes of the Appalachians.
As the western U.S. upper trough emerges into the Plains,
supporting deepening of surface low pressure, a moist warm sector
will destabilize through the day, likely yielding storm development
initially west of the Mississippi Valley, and then spreading
eastward through the evening. The favorable thermodynamic
environment will combine with strong/veering flow through the middle troposphere, suggesting of severe storms including supercells, and
attendant, all-hazards severe potential.
By Monday, models begin to diverge with respect to speed of
surface-frontal advancement east of the Appalachians. Still, enough destabilization should occur east and southeast of the front to
allow storms to spread across the Southeast, along with attendant
severe risk.
Tuesday, model differences continue to increase, with the front
residing off the Atlantic and Gulf Coasts per the GFS, while
lingering over parts of the Southeast and the Gulf Coast region per
the ECMWF. Given the uncertainty/predictability issues, no risk
areas will be included.
..Goss.. 03/25/2025
$$
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