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000
ACUS02 KWNS 211714
SWODY2
SPC AC 211713

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1213 PM CDT Sun Apr 21 2024

Valid 221200Z - 231200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE
SOUTHEASTERN FLORIDA PENINSULA...

...SUMMARY...
Strong to locally severe thunderstorms, capable of marginally severe
wind gusts and hail, will be possible across the central and
southern Florida Peninsula on Monday.

...Synopsis...
A cold front currently draped across the southeastern states to the
northern Gulf will continue to slowly push south/southeast over the
next 24-48 hours. This feature should reach the central to southern
FL peninsula by mid-day Monday. Thunderstorms will likely be focused
along this boundary as it pushes towards far south FL by late Monday
evening. Across the Plains, more isolated thunderstorms will be
possible along a cold front and in the vicinity of a surface low
from northeast CO to the upper MS River Valley.

...South Florida...
Heating of a moist air mass currently in place across south FL,
combined with modest mid-level lapse rates, should support MLCAPE
values between 1000-1500 J/kg ahead of the approaching front.
Although low-level flow will be somewhat weak, winds aloft will be
sufficiently strong to support effective bulk wind differences on
the order of 30-40 knots. Elongated, nearly straight hodographs
should favor splitting cells with the potential for a couple of
right-moving supercells that will pose a large hail threat. However,
storm motions and deep-layer shear vectors should largely be along
the surface boundary, and weak inhibition may favor multiple
thunderstorms along the front by peak heating. These factors could
favor upscale growth of cells into clusters by late afternoon, which
may limit the supercell potential. Regardless, both
discrete/semi-discrete cells and/or more organized clusters should
pose a damaging wind threat given low-level lapse rates approaching
8 C/km by mid afternoon. Latest CAM guidance suggests the severe
threat is most likely to manifest across the southern portion of the
Marginal risk area - particularly in the Miami vicinity as the front
arrives by late afternoon. However, a few strong/severe storms will
be possible late morning further north.

...Eastern CO to northwest KS...
Dry conditions are prevalent across the Plains in the wake of the
recent frontal passage. However, modified mid-level Pacific moisture
associated with an approaching shortwave trough (currently over
portions of the Pacific Northwest) should overspread parts of the
central to northern High Plains by Monday afternoon. Modest
mid-level moisture atop a deep, well-mixed boundary layer may
support sufficient buoyancy for a few thunderstorms with an
attendant risk for dry downbursts along a weak surface cold front.
Strong to severe outflow gusts are possible based on the forecast
thermodynamic profiles, but do not appear to be probable based on
convective signals in latest guidance and discrepancies between
solutions regarding mid-level saturation (and resultant buoyancy).
Forecast trends will be monitored for the need for low-end,
wind-driven risk probabilities.

..Moore.. 04/21/2024

$$