SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1230 PM CDT Sun May 07 2023
Valid 081200Z - 091200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE LOWER
MISSOURI VALLEY ACROSS THE OHIO VALLEY...
...SUMMARY...
Scattered severe storms are most probable from the mid Mississippi
Valley into the Ohio Valley, with damaging winds and hail. Sporadic
severe storms cannot be ruled out anywhere from Texas to the
Appalachians.
...Synopsis...
A low-predictability weather pattern will exist on Monday, with a
belt of modest midlevel flow from the central Plains across the OH
Valley, and a large area of instability from the southern Plains to
the OH and TN Valleys. Of primary focus will be a midlevel wave
positioned from IA into northern IL Monday morning. This feature is
forecast to move east/southeast across the OH Valley states,
providing enhanced wind speeds and deep layer shear. A weak surface
low will also track from IL to WV with the associated midlevel wave,
and this corridor will be the main focus for potential damaging
winds and hail. A cold front will extend southwestward from the low,
from southern MO into OK, with a very moist and unstable air mass to
the south. In addition, a dryline will stretch from northwest TX
southward toward the Big Bend.
Elsewhere, a shortwave trough will affect parts of northern CA and
NV into OR and ID, providing cool air aloft, weak instability and
scattered afternoon thunderstorms. Locally gusty winds or small
hail may occur.
...Lower MO/Mid MS/OH Valleys...
The initiation of severe potential may be tied to the position of
early day storms over the IA/IL/MO area Monday morning. These storms
and associated outflow may persist throughout the morning with an
increasing severe wind risk as the air mass becomes very unstable.
Forecast soundings show steep midlevel lapse rates and sufficient
midlevel flow to produce an MCS producing wind damage. However, if
the early morning storms have not produced much outflow, then
afternoon development may be cellular initially, producing large
hail and perhaps a tornado given effective SRH over 200 m2/s2 ahead
of the low. In summary, nearly all modes of severe will be possible
from eastern MO into OH and KY, primarily with damaging wind and
large hail. While predictability is low, the potential for a
concentrated corridor of wind damage could develop, necessitating
higher probabilities in later updates.
...AR into OK and parts of western TX...
The boundary moving out of MO into AR, extending west into OK, will
likely provide a focus for diurnal development, as heating of a
moist air mass results in 3000-4000 J/kg MUCAPE. Westerly flow aloft
at this latitude will be generally weak, but low-level convergence
may be enough to initiate scattered clusters of storms along this
front from afternoon through evening. Some of the stronger storms
will likely produce large hail or locally damaging gusts. Farther
south along the dryline into TX, strong heating will totally erode
the capping inversion, and at least isolated thunderstorms are
expected, producing localized strong gusts or hail.
..Jewell.. 05/07/2023
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