Subj : DAY1SVR: Day 1 Convective Outlook
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Mon Mar 20 2023 12:42:39

ACUS01 KWNS 201242
SWODY1
SPC AC 201241

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0741 AM CDT Mon Mar 20 2023

Valid 201300Z - 211200Z

....NO SEVERE THUNDERSTORM AREAS FORECAST...

....SUMMARY...
Severe thunderstorms are not expected today.

....Synopsis/Discussion...
In mid/upper levels, a zonal to broadly cyclonic pattern exists
across the CONUS, perturbed mainly by shortwave troughs over the
southern Appalachians and coastal OR/northwestern CA.  The eastern
trough will deamplify and move northeastward off the Mid-Atlantic
Coast around 00Z, while the western one also weakens, and moves
inland to southern ID and northern NV.  Well offshore, a cyclone is
apparent in moisture-channel imagery between 130W-140W and 40N-50N.
This vortex will dig southeastward, expand and intensify, while
approaching (but remaining offshore from) the CA Coast by the end of
the period.

Downstream from that cyclone, a series of small shortwaves and
vorticity maxima will traverse a lengthy fetch of broadly difluent
flow.  Associated cooling aloft and at least marginally suitable
low/middle-level moisture above the boundary layer will contribute
to isolated, episodic thunder potential over the Intermountain West
through tonight.  Low-level lee troughing and cyclogenesis are
expected to continue just east of the central/southern Rockies, with
a surface low moving eastward out of CO toward the GLD/MCK/IML
region by 12Z.

One of those mid/upper perturbations -- initially just off south-
central CA, will move rapidly eastward.  This feature should cross
northern NM around 06Z and reach parts of southwestern KS,
northwestern OK and the TX/OK Panhandles by 12Z.  Associated lift
and steepening of midlevel lapse rates, atop greater low/middle-
level moisture and lapse rates within a strengthening warm-advection
regime, will cause up to about 300 J/kg elevated MUCAPE to develop
in parts of central/eastern KS/OK.  Forecast soundings suggest the
buoyancy, though meager and rooted between 700-850 mb, can extend
into icing layers favorable for lightning production.  As such, at
least isolated thunderstorms should develop within a broader area of
showers overnight, especially after 06Z.  Moisture and instability
should be too weak for severe potential, however.

...Edwards/Broyles.. 03/20/2023

$$

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