LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1132 PM CST Wed Jan 18 2023
Valid 191200Z - 201200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE OHIO VALLEY...
...SUMMARY...
Isolated to widely scattered severe gusts are possible from eastern
Indiana through central and northern Ohio on Thursday afternoon to
early evening.
...Ohio Valley...
Strong upper low currently located over the central Plains will
eject east into the OH Valley later Thursday as a 110kt 500mb speed
max translates across the TN Valley into the southern middle
Atlantic during the latter half of the period. Latest model guidance
suggests intense 12hr height falls, on the order of 210m, will
spread over the OH Valley during the day ahead of the approaching
short wave. Additionally, very steep mid-level lapse rates will
develop by mid day over IN/OH, with -30C temperature forecast at
500mb in the coldest part of the trough. This rapid adjustment will
result in thermodynamic profiles becoming more favorable for
convective development ahead of the front, especially with added
boundary layer heating. The northern plume of strongest
boundary-layer heating should extend across the southern half of
IN/OH, and forecast soundings indicate up to 500mb of surface-based
buoyancy will develop despite the overall poor PW values (~0.50-0.60
inch) and low surface dew points. Latest thinking is convection
should easily develop by early afternoon across eastern IN,
immediately ahead of the front, then spread downstream, aided by
very strong forcing. Wind profiles support organized updrafts and
potential supercells, but linear development is likely which should
favor wind with this activity. Forced line of convection should
spread across OH toward the PA border by early evening where
weakening is expected, partly due to cooler boundary layer
conditions and lower buoyancy.
..Darrow/Bentley.. 01/19/2023
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