LIVE MAP (ABOVE) ... SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1129 AM CDT Mon Jul 10 2023
Valid 101630Z - 111200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS
NORTHWEST KS AND SOUTHWEST NE...
...SUMMARY...
Scattered strong to severe thunderstorms and a couple of organizing
storm clusters may pose a risk for large to very large hail and
severe wind gusts across parts of the Upper Midwest into Great
Plains this afternoon into tonight.
...Upper Midwest into Central Plains...
Morning satellite imagery show several low-amplitude shortwave
troughs moving through the northern periphery of the upper ridging
extending from the southern High Plains into the northern Rockies.
One of these shortwaves is moving into central SD, with continued
southeastward motion towards the Mid MO Valley anticipated. In
addition to this approaching shortwave trough, a cold front
stretches from western SD eastward through southern MN and northern
WI and then back northeastward across Upper MI. This boundary is
expected to push gradually southward throughout the day, moving
across much of SD, southern MN, and northern/central WI.
Convergence along this boundary is expected to result in
thunderstorm development during the late afternoon across southern
MN and northern/central WI. Low 60s dewpoints are already in place
in this area, with additional moisture advection helping to offset
mixing throughout the day. As such, low 60s will likely still be in
place later this afternoon, helping to support moderate buoyancy
amid late afternoon temperatures in the upper 80s/low 90s. This
region will also be on the southern edge of the stronger
northwesterly flow aloft around the cyclone centered over northern
Ontario. These environmental conditions should support robust
updrafts along the front. Hail is possible with the initial
development, but low-level lapse rates will likely support
outflow-dominant storm structures, with upscale growth into one or
more linear segment anticipated quickly. These convective lines are
then expected to shift southward into more of central WI northern IA
during the evening before dissipating amid nocturnal stabilization.
Farther west (from the Mid MO Valley into NE), thunderstorms are
expected to develop ahead of the primary frontal zone along a
sharpening pre-frontal trough, with low-level convergence along the
trough augmented by ascent attendant the approaching shortwave.
Afternoon dewpoints along this trough will likely be in the mid 60s,
supporting strong buoyancy amid steep mid-level lapse rates and
surface temperatures in the low 90s. Robust shear will be in place
as well, as strong southerly surface winds veer to northwesterly
aloft. This environment should support supercells capable of large
to very large hail and strong outflow. Some upscale growth is
possible, with the resulting convective line moving south into
southern NE.
Another shortwave trough is moving into western CO, which is
expected to aid in the development of thunderstorms along the lee
trough in eastern CO, where the environment will be similar to that
over NE. Initial supercells capable of large to very large hail and
strong downdrafts are anticipated, before potential upscale growth
in this area as well. Interaction between these more
eastward-progressing storms and then more southward-progressing
storms in NE is likely. The latest guidance suggests this
interaction will lead to the development of a robust MCS capable of
significant wind gusts.
...Southern High Plains...
Afternoon thunderstorm development is anticipated across the higher
terrain before then moving into the moderately unstable airmass
downstream across eastern NM and west TX. The airmass across west TX
will be characterized by greater low-level moisture/instability,
supporting more robust updrafts and an increasing risk of a few
severe storms. Large hail and damaging winds will be possible.
These storms may persist for a few hours and spread into southwest
OK before weakening.
...Central MT...
A few strong to severe storms are possible across the region where
modest destabilization and shear will be in place ahead of a lead
short wave trough progressing into the northern Rockies. Initial
development is anticipated across the higher terrain before then
spreading into more of south-central Montana later this afternoon
into tonight.
..Mosier/Weinman.. 07/10/2023
Read more CHECK UPDATE ZOOM GRAPHIC
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