LIVE MAP (ABOVE) ... SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0749 AM CDT Sat Jul 08 2023
Valid 081300Z - 091200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE FRONT
RANGE INTO THE SOUTHERN PLAINS...AND IN THE MID-SOUTH VICINITY...
...SUMMARY...
Scattered strong to severe thunderstorms, and one or two organized
thunderstorm clusters, are possible east of the Front Range and
Sangre de Cristo Mountains through the Texas and Oklahoma Panhandles
and Red River Valley vicinity. Additional strong to severe
thunderstorm development is possible across parts of the lower
Mississippi into Ohio Valleys.
...Front Range of the Central Rockies into TX Panhandle and OK...
Southeasterly low-level flow is expected to help maintain the moist
air mass already in place throughout the Front Range today.
Additionally, prevailing westerly flow aloft will help maintain the
steep mid-level lapse rates already in place, with the resulting
combination of low-level moisture and steep mid-level lapse rates
contributing to strong buoyancy this afternoon.
Convective initiation appears most likely first across the high
terrain of north-central CO (and maybe adjacent southern WY), with
these storms then moving into the destabilizing air mass across the
Front Range. Long hodographs, created by moderate low-level
southeasterlies veering to moderate northwesterlies aloft, will
support supercells capable of all severe hazards, including very
large hail greater than 2" in diameter.
These supercells are expected to progress gradually southeastward
into more of the central and southern High Plains during the
evening. Thereafter, a strengthening low-level jet and associated
warm-air advection may result in the development of one or more
organizing storms clusters. The resulting convective lines are then
expected to progress southeastward across the
Texas/Oklahoma Panhandles into OK overnight and into Sunday morning.
Strong to severe gusts may accompany any convective lines that do
develop.
...Mid-South Vicinity...
Surface observations already show 70s dewpoints across much of the
Mid-South vicinity this morning, with some mid-70s dewpoints across
AR and northern LA. A vorticity maximum, left over from the cluster
of storms overnight convection, is currently moving across eastern
OK. Scattered to widespread thunderstorm development is anticipated
across the region as the vorticity maximum continues eastward,
interacting the moist and diurnally destabilized air mass in place.
Mid-level flow throughout the region will be generally modest,
contributing to a predominantly multicellular mode. Even so, some
localized enhancement of the flow is possible near the vorticity
maximum, resulting in the potential for a few more organized
updrafts. Storm mergers could also help briefly augment overall
updraft strength. These factors, combined with ample moisture and
steep low-level lapse rates, result in the potential for a few
water-loaded downbursts.
...Middle/Upper OH Valley...
Early morning surface analysis places a low over southern IL, near
an area of showers and thunderstorms currently ongoing from
central/southern IL into central IN. Expectation is for this ongoing
activity to continue eastward through the middle OH Valley, with the
associated cloud cover tempering daytime heating across IN and OH.
The surface low may lag behind these warm-air advection showers, and
there should be a window for some limited heating/destabilization
between the early cloudiness and the approaching low from OH
southwestward into KY. Instability will still be modest, but this
region will be on the southern periphery of the cyclonic flow
covering eastern Canada, leading to slightly enhanced westerly flow
aloft. The resulting combination of instability and shear could
support a few stronger storms or bowing segments capable of damaging
gusts.
..Mosier/Leitman.. 07/08/2023
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