589
ACUS01 KWNS 150534
SWODY1
SPC AC 150532
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1232 AM CDT THU OCT 15 2026
VALID 151200Z - 161200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE MID
MISSISSIPPI VALLEY INTO THE OHIO VALLEY...AND OVER PARTS OF THE
SOUTHERN PLAINS...
..SUMMARY
THUNDERSTORMS WITH ISOLATED SEVERE WIND GUSTS AND PERHAPS A TORNADO
OR TWO ARE POSSIBLE TODAY ACROSS PARTS OF THE MID MISSISSIPPI AND
OHIO VALLEYS. ADDITIONAL STORMS WITH ISOLATED SEVERE WIND GUSTS WILL
BE POSSIBLE IN PARTS OF THE SOUTHERN PLAINS.
..MID MISSISSIPPI AND OHIO VALLEYS
AT MID-LEVELS, A RIDGE WILL MOVE EASTWARD TODAY INTO THE NORTHEAST,
AS A LARGE-SCALE TROUGH MOVES INTO THE GREAT PLAINS. AHEAD OF THE
TROUGH, A SURFACE LOW WILL TRACK NORTHEASTWARD FROM THE MID
MISSISSIPPI VALLEY INTO THE SOUTHWESTERN GREAT LAKES. AHEAD OF THE
SURFACE LOW, A WARM FRONT WILL MOVE NORTHWARD THROUGH THE OHIO
VALLEY. TO THE SOUTH OF THE WARM FRONT, SURFACE DEWPOINTS WILL BE IN
THE UPPER 60S AND LOWER 70S F. THIS WILL ENABLE AN AXIS OF
INSTABILITY TO DEVELOP BY AFTERNOON, WITH MLCAPE LIKELY PEAKING
AROUND 1000 J/KG. AHEAD OF THE TROUGH, A MID-LEVEL JET WILL
OVERSPREAD THE WARM SECTOR DURING THE AFTERNOON. THIS WILL CREATE
MODERATE DEEP-LAYER SHEAR OVER MUCH OF THE OHIO VALLEY, WHICH WILL
SUPPORT ISOLATED SUPERCELL DEVELOPMENT. IN ADDITION, RAP FORECAST
SOUNDINGS IN THE OHIO VALLEY BY MID AFTERNOON HAVE 0-3 KM
STORM-RELATIVE HELICITY IN THE 200 TO 250 M2/S2 RANGE SUGGESTING
THAT A TORNADO OR TWO WILL BE POSSIBLE. SHORT LINE SEGMENTS CAPABLE
OF ISOLATED SEVERE WIND GUSTS WILL ALSO BE POSSIBLE. POOR LAPSE
RATES WILL BE THE MAIN LIMITING FACTOR FOR A GREATER SEVERE THREAT
COVERAGE AND MAGNITUDE.
..SOUTHERN PLAINS
AN UPPER-LEVEL TROUGH WILL MOVE INTO THE GREAT PLAINS TODAY, AS
MID-LEVEL FLOW REMAINS SOUTHWESTERLY AHEAD OF THE TROUGH. AT THE
SURFACE, A COLD FRONT WILL ADVANCE SOUTHWARD ACROSS THE SOUTHERN
PLAINS, WITH THE FRONT LOCATED FROM WEST-CENTRAL TEXAS INTO
SOUTHEAST OKLAHOMA BY AFTERNOON. ALTHOUGH LARGE-SCALE ASCENT WILL BE
WEAK, LOW-LEVEL CONVERGENCE ALONG AND NEAR THE FRONT WILL RESULT IN
THUNDERSTORM DEVELOPMENT. STORMS WILL MOVE EAST-SOUTHEASTWARD ACROSS
A NARROW CORRIDOR OF INSTABILITY, WHERE MLCAPE IS FORECAST TO PEAK
IN THE 1000 TO 1500 J/KG RANGE. AS LOW-LEVEL LAPSE RATES STEEPEN IN
THE AFTERNOON, ISOLATED SEVERE WIND GUSTS WILL BE POSSIBLE WITH
MULTICELLS. HOWEVER, DEEP-LAYER SHEAR WILL BE MARGINAL FOR ORGANIZED
CONVECTION, AND POOR LAPSE RATES WILL BE A MAJOR LIMITING FACTOR.
..BROYLES/CHALMERS.. 10/15/2026
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