ACUS02 KWNS 140604
SWODY2
SPC AC 140603

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
0103 AM CDT Sun Jul 14 2024

Valid 151200Z - 161200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE UPPER
MIDWEST INTO PORTIONS OF THE MID MISSISSIPPI VALLEY AND UPPER GREAT
LAKES...

...SUMMARY...
Strong to severe thunderstorms are possible from the Upper Midwest
into the Mid Mississippi Valley and Upper Great Lakes region on
Monday. Isolated severe thunderstorms are also possible across the
central Plains as well as south-central/southeast Arizona.

...Synopsis...
Upper ridging is forecast to persist across the southern CONUS on
Monday, while upper troughing extends across central Canada. A belt
of enhanced, broadly cyclonic upper flow will exist between these
two areas, extending across much of the northern CONUS. Several
shortwave troughs are expected to progress through this corridor,
with the most prominent wave extending from southern Manitoba
southward across the Dakotas early Monday. This shortwave is
forecast to progress eastward/east-southeastward across the Upper
Midwest, Upper Great Lakes, and southern/eastern Ontario. Another
shortwave trough, likely augmented by Sunday night's thunderstorms
over the Mid MS Valley, is expected to extend from Lower MI into the
Middle OH Valley early Monday night. This shortwave is then expected
to continue eastward through the Upper OH Valley and
Northeast/northern Mid-Atlantic during the day. Lastly, there is
some chance another shortwave trough progresses through the northern
periphery of the Southwest upper ridging, emerging into the central
Plains and continuing eastward in the Mid MS Valley. Guidance varies
on the amplitude and speed of this shortwave, which limits forecast
confidence on its potential evolution and impacts.

The surface pattern will be convoluted by several areas of
antecedent convection, particularly from the Upper Midwest into the
Mid MS and OH Valleys where storm outflow appears most likely.
General expectation is for warm front to extend eastward from a
surface low near the SD/NE/IA border intersection along the MN/IA
border vicinity into southern WI. This front will likely extend
eastward across the northern portions of the OH Valley, but with a
more stationary character. A cold front attendant to the
Manitoba/Dakotas shortwave is expected push southward across the
Dakotas and into NE and southeastward across the Upper Midwest. By
00Z this front will likely extend from a low over northwest Ontario
southwestward to another low over north-central KS.

...Upper MS Valley into the Middle OH Valley and Lower MI...
Thunderstorms will likely be ongoing ahead of the cold front across
the Upper MS Valley early Monday morning. These early storms are
expected to be elevated, but should trend towards becoming more
surface based as they progress southeastward and the airmass
destabilizes. The strength of the buoyancy within the downstream
airmass will depend on the evolution of Sunday night's storms, with
at least some potential for some cooler and drier conditions.
However, consensus among the guidance is for low 70s dewpoints and
strong buoyancy during the afternoon. These thermodynamic
conditions, coupled with moderate vertical shear, would support
strong to severe thunderstorms. All severe hazards would be possible
within any more cellular storms, but a linear mode is expected to
dominant, with some potential for the development of an organized
MCS. Damaging gusts will be the primary risk across this region.

...Upper OH Valley into the northern Mid-Atlantic...
Afternoon/early evening thunderstorms are possible from
the Upper OH Valley into the Northeast as the modest, convectively
augmented shortwave trough interacts with the warm and moist airmass
over the region. Shear will likely be modest, mitigating the
potential for organized storms. However, moderate buoyancy and steep
low-level lapse rates will support to the potential for strong
downbursts with the more robust storms.

...Central High Plains into the Central Plains...
Some of the guidance, particularly the CAMs, has trended towards
more storm development across the central High Plains during the
late afternoon/early evening. The modest shortwave trough
progressing through the northern periphery of the upper ridge
mentioned in the synopsis appears to be the impetus for these
storms, providing the large-scale ascent needed for initiation. High
cloud bases and steep low-level lapse rates will support strong
outflow, with some cold-pool amalgamation and the development of an
organized MCS possible. Uncertainty regarding storm coverage and
location of greatest severe potential precludes higher probabilities
with this outlook.

...South-Central/Southeast AZ...
Modest easterly mid-level flow is expected across the region, which
will be located on the western periphery of the upper ridge.
Afternoon thunderstorm development is anticipated over the high
terrain, with storms then moving westward off into lower elevations.
A few strong gusts are possible as these storms move into the
well-mixed airmass over the lower elevations.

..Mosier.. 07/14/2024

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