331
ACUS01 KWNS 030602
SWODY1
SPC AC 030600

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0100 AM CDT Mon Jun 03 2024

Valid 031200Z - 041200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
THE SOUTHERN PLAINS...THE UPPER MIDWEST AND THE LOWER MISSISSIPPI
RIVER VALLEY...

...SUMMARY...
Strong to severe thunderstorms are possible from much of the
Mississippi Valley into the Ozark Plateau and southern Plains today.
A more concentrated area of severe thunderstorm risk may become
focused across southern Oklahoma into the ArkLaTex vicinity, where a
swath of damaging gusts is possible.

...Synopsis...
Within a weak and predominately zonal mid-level flow regime, a
complex series of mesoscale features will dictate the potential for
severe thunderstorms today and tonight. A subtle, convectively
enhanced shortwave trough currently over the mid Missouri Valley
will move into parts of the upper Midwest by early afternoon. A
second remnant MCS appears likely to be ongoing at the start of the
period over the southern/central Plains. The potential outflow from
this system may serve as a focus for secondary initiation later in
the afternoon across parts of TX and OK. Additional storms are also
possible along the dryline in Southwest TX.

...Upper Midwest and mid MS Valley...
Rich low-level moisture advection is expected to be ongoing with
southerly low-level flow across much of the Midwest ahead of the
remnant MCV early this morning. Some clearing should allow diurnal
heating to support moderate destabilization ahead of the MCV from
eastern IA into southern WI and far northern IL despite relatively
poor mid-level lapse rates. Weak convergence and some ascent from
the convectively enhanced shortwave should allow for scattered
thunderstorms to develop by early afternoon. Deep-layer shear
profiles are not particularly strong (20-30 kt), though some low and
mid-level enhancement from the MCV may be enough to support
organized multicells and a few transient supercells structures.
Damaging wind gusts, hail and a brief tornado or two will be
possible.

More isolated storms are also possible along a subtle wind shift/
surface pressure trough farther south across parts of eastern MO and
western IL. However, confidence in storm development here is low
owing to the potential disruption of diurnal heating from cloud
debris or remnant convection from the overnight central Plains MCS.
Still, a few instances of hail or damaging winds are possible should
an organized multicell cluster or two develop.

...Southern Plains to the ArkLaMs...
Short-term CAM and regional model guidance has come into fairly
strong agreement on the presence of an overnight MCS across parts of
the central Plains. By 12z convection will most likely be located
across parts of southern KS, to as far as northeast OK. Relatively
clear skies and strong low-level moisture advection (low to mid 70s
F surface dewpoints) will likely be in place ahead of the early
morning storms. This, along with numerous CAM solutions, suggests
intensification of this cluster is likely from late morning through
the early afternoon hours as it tracks east/southeastward into AR.
Despite modest forcing for ascent, a broad swath of moderate to
large buoyancy (3000+ J/kg of MLCAPE) and a fairly organized cold
pool may support storms farther east into parts of the lower MS
valley with a risk for damaging winds and hail into the evening
hours.

In the wake of the morning cluster of storms, a trailing outflow
boundary is likely to be located somewhere over the southern Plains
from central/southern OK into the Panhandle/western north TX. With
very rich low-level moisture moving in from central TX (mean W of
16-18 G/kg), modification of this outflow boundary may serve as a
focus for additional storm development through the afternoon and
evening hours ahead of a subtle shortwave trough embedded within the
mostly zonal flow. This appears especially likely where the boundary
could intersect with the dryline over parts of the eastern TX
Panhandle, far western OK and western north TX. Model soundings here
show very large buoyancy (4500-6000 J/kg of MLCAPE) and sufficient
deep-layer shear for supercells. Should storms form (pending the
location of the outflow) large buoyancy and sufficient shear would
support a risk for large to very large hail, damaging gusts and
potentially a couple of tornadoes. Eventual upscale growth into a
cluster or MCS may also support a risk for damaging winds downstream
into parts of central TX later into the evening.

...Southwest TX...
Along the southern portions of the dryline, very hot temperatures
95-105F are likely along with rich boundary-layer dewpoints in the
70s F. While large-scale ascent appears rather nebulous, the diurnal
dryline circulation and weak upslope flow may support isolated
thunderstorm development near the international border. While
modest, 25-30 kt of mid-level flow within the sub-tropical jet may
support some organization into isolated supercell structures. While
uncertain, a few instances of hail and damaging winds are possible.

..Lyons/Darrow.. 06/03/2024

$$