SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0300 PM CDT Tue May 10 2022
Valid 102000Z - 111200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PORTIONS
OF NORTHWEST TEXAS AND SOUTHWEST OKLAHOMA...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR MUCH OF
SOUTHERN AND CENTRAL WISCONSIN INTO SOUTHERN PARTS OF THE UPPER
PENINSULA OF MICHIGAN...
...SUMMARY...
Scattered severe thunderstorms are likely over parts of the southern
High Plains beginning late this afternoon through this evening.
Very large hail, isolated severe gusts and a tornado threat are
forecast this afternoon and evening over parts of Wisconsin and
vicinity.
...Discussion...
Only minor changes were made to the previous convective outlook.
They are listed as follows:
1) Removed low tornado probabilities near the immediate Wisconsin
lakeshore of Lake Michigan. Likewise adjusted the significant hail
probabilities to be removed from the immediate coast.
2) Added a small 5-percent tornado probability near the TX Big Bend.
A very moist airmass and adequate deep-layer shear for supercells
(at least early in the convective lifecycle) will seemingly support
a 2-3 hour window of tornado potential with a cyclonically rotating
supercell.
..Smith.. 05/10/2022
.PREV DISCUSSION... /ISSUED 1135 AM CDT Tue May 10 2022/
...Synopsis...
Expansive upper ridging is currently in place from the western Gulf
of Mexico into southern Quebec, while upper troughing extends from
Alberta southwestward into central CA. The upper ridging is forecast
to build westward/northwestward into more of the southern/central
Plains and Upper MS Valley today, while an upper low embedded within
the western CONUS troughing moves from central CA into the Great
Basin. Strong southwesterly mid-level flow will persist between
these two features, helping to advect a strong elevated mixed layer
over a large part of the Plains and MS Valley.
Current surface analysis places a low over northeast KS, with a
stationary boundary extending northeastward across central IA to
another weak low in central WI. A cold front also extends
southwestward from this low across southwest KS and into the western
OK Panhandle before arcing back northwestward into central CO. A
dryline is also apparent, extending from the northeast KS low
southwestward into southeast NM before transitioning more southward
across Far West TX. The stationary boundary in WI and dryline in TX
will both be areas of focus for severe thunderstorms today.
...Southern High Plains...
A very moist air mass is already in place across the region east of
the dryline, with dewpoints ranging from mid 60s near LBB to the
upper 60s at MAF and FST. Strong heating is anticipated today across
this air mass, with afternoon temperatures in the upper 80s/low 90s,
contributing to very strong buoyancy and limited convective
inhibition. A weak shortwave trough evident in water vapor imagery
moving out of northern Mexico is expected to interact with this
unstable and uncapped air mass, providing the impetus for numerous
thunderstorms.
Initial development is expected across West TX/Pecos River vicinity,
where a few storms may be strong enough to produce very large hail.
Weak deep-layer vertical shear, abundant low-level moisture, and
steep low-level lapse rates will promote outflow dominant storm
structures. Upscale growth into one or more convective lines appears
likely as cold pool amalgamate, with the resulting lines propagating
northeastward. Severe wind gusts with, some downdrafts potentially
reaching 65-kt significant criteria, should accompany this activity.
...WI and vicinity...
Mid 60s dewpoints are already in place across much of central and
southern WI, in the vicinity of the stationary front mentioned in
synopsis. Some further increase in low-level moisture is anticipated
throughout the day, with strong diurnal heating also expected. Very
strong buoyancy will be in place this afternoon in the vicinity of
the stationary boundary and weak surface low forecast to move along
the front during the afternoon.
Surface convergence in proximity to this low and stationary boundary
will be the main stimulant for thunderstorm development today, with
large-scale ascent absent amid background height rises. Even so, at
least scattered thunderstorm coverage appears likely, amid an
environment supportive of supercells. All severe hazards would be
possible with these supercells, including very large hail and a
tornado or two.
Uncertainty remains as to the potential for upscale growth of
convection across the region, and the potential for any such
activity to coalesce cold pools enough to transition to a
forward-propagating complex. Low wind probabilities were extended
eastward/southeastward across Lake Michigan into western Lower MI
and/or northern IL to account for this potential.
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