LIVE MAP (ABOVE) ... SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1130 AM CDT Sat Jul 08 2023
Valid 081630Z - 091200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE FRONT
RANGE ACROSS THE TX/OK PANHANDLES AND INTO OK...AND 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 Oklahoma. 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...
A moist air mass is already in place across the Front Range, with
recent surface observations sampling upper 50s to low 60s dewpoints.
Southeasterly low-level flow will help maintain this moist air mass
throughout the day. Steep mid-level lapse rates are in place atop
this low-level moisture, with recent mesoanalysis estimate max 2-6
km AGL lapse rates around 8 to 8.5 deg C per km.
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
combine with moderate to strong buoyancy to support supercells
capable of all severe hazards, including very large hail greater
than 2" in diameter and a tornado or two.
These supercells will likely persist into the evening, when a
strengthening low-level jet should help promote upscale growth into
one or more linear clusters. The resulting convective lines are
then expected to progress southeastward across the TX/OK Panhandles
into OK overnight and into Sunday morning. Some potential for
significant wind gusts exists with these clusters, but uncertainty
regarding overall evolution (mostly the strength of the rear-inflow
jet) and most likely location for significant gusts precludes
delineating any areas in this outlook.
...Mid-South Vicinity...
Surface observations show mid-70s dewpoints are already in place
across the region, downstream of an MCV related to last night's
thunderstorms across OK. As discussed in recently issued MCD #1461,
greater thunderstorm strength and coverage is possible as the MCV
continues eastward and interacts with the destabilizing air mass
over the Mid-South. 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...
Surface analysis places a pair of weak lows over southern Lower MI
and western IN. A weak cold front extends between these two lows,
and extends back farther southwestward from the western IN low. An
area of showers and thunderstorms currently ongoing ahead of this
front over western OH. Expectation is for this ongoing activity to
continue eastward while gradually weakening over the next few hours.
Associated cloud cover may temper daytime heating across IN and OH,
but there should be a window for some limited
heating/destabilization between the early cloudiness and the
approaching cold front. 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/Supinie.. 07/08/2023
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