264
ACUS02 KWNS 031729
SWODY2
SPC AC 031728

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1228 PM CDT Mon Jun 03 2024

Valid 041200Z - 051200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE MIDDLE
MISSOURI VALLEY...

...SUMMARY...
A large area of strong to severe storms are possible on Tuesday from
Oklahoma to the Tennessee Valley northward to the Upper Mississippi
Valley. An area of better organized severe potential is expected
across the Middle Missouri Valley where damaging gusts and large
hail will be possible.

...Synopsis...

An upper shortwave trough over the northern High Plains will become
negatively tilted as it pivots east to the Upper Midwest on Tuesday.
Vertical shear ahead of the trough will remain weak, with stronger
deep-layer flow confined to the back side of the trough. At the
surface, a cold front oriented north to south from the central
Dakotas into northwest KS Tuesday morning will shift east through
the period. By Wednesday morning the front is expected to be located
from Lake Michigan south/southwest to central OK and northwest TX,
though the southern extent of the boundary will be somewhat diffuse.
A couple of MCVs also are forecast. The first may be located in the
vicinity of the Ozarks, shifting east across the Mid-South and TN
Valley. Another MCV near the Mid-MS Valley may lift north/northeast
into WI. These features are dependent on convection in the Day
1/Monday period, so some uncertainty in exact location by Tuesday is
uncertain. Nevertheless, these features, along with the surface cold
front and northern upper trough will provide focus for strong to
severe storms across a broad area Tuesday.

...Middle Missouri to Upper Mississippi Valley...

A seasonally moist airmass will be in place ahead of the
eastward-advancing cold front. Heating into the 70s and 80s F will
aid in modest destabilization, with MLCAPE values from 1000-2000
J/kg.  Vertical shear will be marginal across the region, with
generally around 20-30 kt effective shear magnitudes expected.
Furthermore, deep-layer flow will be more meridional and parallel to
the surface boundary across MN. This may result in anafrontal type
convection along the boundary, especially across northern MN.
Nevertheless, a corridor of damaging wind and hail potential will
exist from the Mid-MO Valley into southeast/east-central MN where
stronger heating will result in a band of greater destabilization.

...Northern IL into WI...

Convection is expected to develop during the afternoon in response
to the northward moving MCV. A seasonally moist and unstable airmass
will be in place ahead of this feature across northern IL into WI.
Vertical shear is expected to be weak, though may be locally
enhanced near the MCV sufficiently to allow for at least briefly
strong to severe storms. Locally strong gusts and marginal hail will
be possible with this activity.

...Ozarks to Tennessee Valley...

Afternoon thunderstorms are possible as one or more convectively
enhanced vorticity maxima float across the region. A seasonally
moist and moderately unstable, but weakly sheared environment is
forecast. Some local enhancement to shear is possible near remnant
MCVs or outflow boundaries moving over the area. Isolated strong to
severe storms capable of strong gusts and marginal hail will be
possible through early evening.

...TX Panhandle into southern OK/north TX...

A somewhat conditional risk is expected across the TX Panhandle into
southwest OK Tuesday afternoon. Warm midlevel temperatures will
likely maintain capping. However, a weak surface low is forecast
over the southeast TX Panhandle/southwest OK vicinity. The surface
cold front will sag into central OK and the TX Panhandle, but a very
moist airmass ahead of this feature will allow moisture to wrap
around the weak surface low into the TX Panhandle. Low-level
convergence and cooling aloft may allow for a storm or two to
develop. If this occurs, large hail and damaging gusts are possible.
However, given uncertainty/conditionality only low (5 percent)
wind/hail probabilities are included.

Most guidance is in better agreement that another MCS may develop
near the cold front overnight and move across portions of
southern/eastern OK into north TX. This scenario is also uncertain,
but some wind/hail risk could accompany this activity if it
develops.

...Lower MS Valley...

A remnant MCS from the Day 1/Monday period may be ongoing Tuesday
morning near the ArkLaTex. Some guidance suggests this system will
continue or may reintensify as it shifts east/southeast along an
instability gradient over LA into southern MS. Vertical shear will
be weak, with little upper support for ascent. However, a very moist
and unstable airmass will be present. If a sufficient cold pool
and/or MCV exists, this could support continued thunderstorm
development into the afternoon. While this remains conditional, low
severe probabilities (5 percent) for wind have been introduced.

..Leitman.. 06/03/2024

$$