ACUS02 KWNS 180429
SWODY2
SPC AC 180428
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1128 PM CDT Sun Mar 17 2024
Valid 191200Z - 201200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
The risk for severe thunderstorms appears negligible across the
U.S., Tuesday through Tuesday night.
...Synopsis...
Models continue to suggest that a high may become at least a bit
better established near/southwest of the Gulf of Alaska vicinity
during this period, within amplified split flow emanating from the
western mid-latitude Pacific. Downstream, as the blocking inland of
the U.S. Pacific coast continues to break down, the remnant
Southwestern low is forecast to elongate east-northeast of the lower
Colorado Valley, toward the southern Rockies.
To the east of this regime, confluent flow will generally be
maintained to the east of the Rockies, as another vigorous short
wave trough digs across the international border into the Upper
Midwest/Great Lakes region. It appears that this will be
accompanied by a reinforcing low-level cold intrusion, as far south
as the Ohio and lower Missouri Valleys by 12Z Wednesday, and
contribute to the maintenance of broad mid-level troughing east of
the Mississippi Valley through the western Atlantic. At the same
time, models indicate that upper ridging may build east-northeast of
the subtropical latitudes, into portions of the southern Great
Plains and Gulf Coast states.
In the wake of the mid-level troughing, the boundary-layer across
all but southwestern portions of the Gulf Basin will likely have
been stabilized by an initial intrusion of cool/dry air by early
Tuesday. While a developing southerly low-level return flow may
contribute to low-level moistening as far north as Deep South Texas
by late Tuesday night, this will likely be preceded by the advection
of a pronounced warm layer (centered around 700 mb) east of the Rio
Grande river through much of central and southern Texas.
...Deep South Texas...
At least some model output (perhaps most notably the NAM and ECMWF)
continues to suggest that a developing area of mid-level ascent,
aided by warm advection near the leading edge of the warm air
emerging from the Mexican Plateau, may contribute to weak
destabilization and elevated convection, some of which could become
capable of producing lightning early Tuesday.
...Colorado Plateau into southern Rockies...
Beneath the mid-level cold pool (including 500 mb temperatures still
around or below -20 to -22C) slowly shifting eastward across the
region, destabilization aided by daytime heating probably will be
sufficient to contribute to scattered weak afternoon and evening
thunderstorm activity.
...California...
Convective potential for Tuesday remains unclear beneath the
weakening mid/upper ridging across the Sierra Nevada, and the
residual cyclonic flow across parts of the Transverse and Peninsular
Ranges of southern California. However, most model output suggests
that destabilization supportive of isolated to widely scattered weak
thunderstorm activity is possible, generally focused along the
higher terrain.
..Kerr.. 03/18/2024
$$
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