SPC Jul 28, 2024 1730 UTC Day 2 Convective Outlook

[NorthGeorgiaWX]

SPC 1730Z Day 2 Outlook

Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1227 PM CDT Sun Jul 28 2024

Valid 291200Z - 301200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE NORTHERN PLAINS...

...SUMMARY...
Scattered strong to severe storms are possible in portions of the
Midwest and the northern Plains on Monday.

...Synopsis...
Upper ridging is expected to become established from the southern
Plains into the Gulf of Mexico on Monday, with modest upper
troughing across the Pacific Northwest and an upper low off the
coast of southern New England. Some enhanced westerly/northwesterly
flow aloft is anticipated between the Pacific Northwest trough and
the New England cyclone, extending from the northern Great Basin
into the Upper/Mid MS Valley. A pair of shortwave troughs will
likely be embedded within this stronger flow, a convectively
augmented shortwave expected to begin the period over the Mid MS
Valley and a low-amplitude wave expected to develop during the
afternoon over the northern High Plains. The convectively augmented
shortwave is forecast to continue southeastward across the middle OH
Valley throughout the day while the developing wave continues
eastward across the northern Plains.

A complex surface pattern will likely be in place early Monday, with
several areas of low pressure expected to be embedded within a broad
area of troughing extending from the Upper Midwest through the
central Plains. A moist airmass will exist east of the modest
surface trough extending between these lows.

...Northern Plains...
Scattered afternoon thunderstorm development appears probable as a
weak shortwave trough interacts with the deeply mixed and
destabilized airmass across the region. Low-level flow will be weak,
but moderate westerly mid-level flow atop these modest southerlies
will result in moderate vertical shear (i.e. effective bulk shear
around 40 kt), which should be sufficient for updraft organization
and a few supercells. Steep mid-level lapse rates will support the
potential for large to very large hail, particularly within the
earlier, more discrete storms. A transition to a more linear
character is possible during the evening as cold pools amalgamate.
Damaging gusts are the primary threat with line segments. The
severe-weather threat is expected to wane shortly after sunset given
increasing inhibition and the low-level jet being displaced well
southeast.

...Mid MS Valley into the Lower/Middle OH Valley...
Showers and thunderstorms will be likely be ongoing early Monday
morning, remnant from overnight development and supported by the
low-level jet (and associated warm-air advection). These storms will
likely dissipate throughout the morning as the low-level jet weaken,
but associated cloud cover and tempered heating could help support
the development of an effective warm front in the northern
IL/central IN/southern OH vicinity. Convergence along this boundary,
combined with ascent attendant to the convectively enhanced
shortwave trough/vorticity maximum expected to be progressing
southeastward throughout the region, will likely result in renewed
thunderstorm development during the afternoon and evening. Modest
vertical shear should result in predominantly multicellular mode,
but some stronger shear is possible closer to the vorticity maximum,
and the potential exists for a few more organized storms. Damaging
gusts are the primary hazard, but hail and even a brief tornado are
possible as well. Mesoscale details will strongly influence where
the greatest severe potential exists, precluding the confidence
needed to introduce higher severe probabilities across the region
with this outlook.

A few afternoon/evening storms are also possible farther north
across central/southern WI as a subtle shortwave trough moves across
the region. Weak shear should preclude storm organization, but a few
precipitation-loaded downbursts are possible.

..Mosier.. 07/28/2024

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