SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1220 PM CDT Tue Aug 13 2024
Valid 141200Z - 151200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF
EASTERN NE...WESTERN IA...NORTHEAST KS...NORTHWEST MO...
...SUMMARY...
Isolated to scattered severe thunderstorms are possible Wednesday
across parts of the northern/central Plains into the mid Missouri
Valley, with greater potential for large hail, damaging winds, and a
tornado or two across parts of northeast Kansas, eastern Nebraska,
western Iowa, and northwest Missouri.
...Eastern NE/northeast KS into parts of IA/MO/southern MN...
A mid/upper-level trough will move across the central/northern Great
Plains towards the upper Midwest on Wednesday. Multiple vorticity
maxima, and possibly one or more MCVs, will likely move through the
larger-scale trough. The surface pattern will be similarly complex,
with a general consensus for a consolidating surface low somewhere
across central NE/KS by afternoon. Outflow and cloudiness from
morning convection will influence the position of surface boundaries
later in the day. One surface boundary that will serve as an
effective warm front is forecast to move northward somewhere across
northeast KS/northwest MO into eastern NE/western IA, though its
position by afternoon/evening remains uncertain. A weak surface
trough/cold front will move across parts of the Dakotas into central
NE, with another surface trough potentially moving across
KS/southeast NE and intersecting the warm front.
Given the rather complex surface/upper-air pattern and influence of
morning convection, storm evolution remains rather uncertain
Wednesday afternoon and evening. From northeast KS/northwest MO into
southeast NE/southwest IA, at least isolated storm development will
be possible by late afternoon near the warm front and other surface
boundaries. Modestly enhanced southwesterly flow aloft will support
effective shear of 30-40 kt, and a couple of supercells could evolve
from initial development, with a threat of large hail and damaging
wind. Some tornado threat would also accompany any supercells near
the warm front, especially into the evening when some increase in
low-level flow and SRH is expected. With time, one or more
upscale-growing clusters may develop, with an attendant threat of
damaging gusts spreading eastward across parts of IA/MO.
...Dakotas into central NE...
A few strong to locally severe storms will be possible across parts
of the Dakotas into central NE. For the Dakotas, somewhat weaker
instability and deep-layer shear is expected compared to areas to
the south and east, but at least scattered storm development will be
possible in conjunction with the mid/upper-level trough. Depending
on the extent of heating/destabilization, isolated hail and
strong/damaging gusts will be possible.
Across central NE, instability and deep-layer shear may be somewhat
stronger, though confidence regarding storm coverage decreases with
southward extent. A conditional risk for hail and localized severe
gusts will accompany any stronger storm in this area.
...Far eastern ID/UT into WY...northern/eastern CO...western
KS...TX/OK Panhandles...
Another round of relatively high-based convection appears possible
Wednesday afternoon into the early evening from parts of eastern
ID/UT into WY and northwest CO. Sufficient instability and modest
westerly flow aloft could support a few stronger cells/clusters with
strong to locally severe outflow winds.
Isolated strong storms will also be possible from eastern CO into
western KS, and potentially into the OK/TX Panhandle region. While
this area will generally be displaced from stronger large-scale
ascent, relatively strong heating, weak to moderate buoyancy, and
modest deep-layer flow/shear could support a couple stronger
cells/clusters capable of isolated strong/severe gusts and hail.
...Parts of New England...
Isolated to widely scattered thunderstorms are possible Wednesday
afternoon across parts of New England, along the western periphery
of a midlevel low near the Canadian Maritimes. Deep-layer shear will
generally be weak, but cold temperatures aloft and unidirectional
northerly flow could support a few stronger southward-moving
cells/clusters, with small hail and locally gusty winds. Confidence
in a more organized severe threat is currently too low for
probabilities.
..Dean.. 08/13/2024
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