829
ACUS03 KWNS 280732
SWODY3
SPC AC 280730
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0230 AM CDT MON SEP 28 2026
VALID 301200Z - 011200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE SOUTHERN PLAINS...
..SUMMARY
THUNDERSTORMS WITH LARGE HAIL, WIND DAMAGE AND PERHAPS A TORNADO OR
TWO WILL BE POSSIBLE ON WEDNESDAY AFTERNOON AND EVENING IN PARTS OF
WEST-CENTRAL AND NORTHWEST TEXAS INTO WESTERN AND CENTRAL OKLAHOMA.
ISOLATED SEVERE STORMS WILL ALSO BE POSSIBLE IN PARTS OF WESTERN AND
CENTRAL KANSAS INTO FAR SOUTHERN NEBRASKA.
..SOUTHERN PLAINS
AN UPPER-LEVEL LOW AND AN ASSOCIATED 50 TO 70 KNOT MID-LEVEL JET
WILL MOVE FROM THE SOUTHERN ROCKIES INTO THE SOUTHERN HIGH PLAINS ON
WEDNESDAY. A SURFACE LOW WILL MOVE EASTWARD INTO WESTERN KANSAS
DURING THE DAY, AS A DRYLINE SHARPENS FROM THE FAR EASTERN TEXAS
PANHANDLE SOUTHWARD INTO WEST TEXAS. TO THE EAST OF THE DRYLINE,
SURFACE DEWPOINTS WILL BE IN THE UPPER 60S AND LOWER 70S F, WHICH
WILL CONTRIBUTE TO A POCKET OF MODERATE INSTABILITY FROM WEST TEXAS
INTO SOUTHWEST OKLAHOMA BY AFTERNOON. AS LARGE-SCALE ASCENT
ASSOCIATED WITH THE APPROACHING SYSTEM OVERSPREADS THE DRYLINE,
THUNDERSTORMS WILL DEVELOP AND INCREASE IN COVERAGE IN THE MID TO
LATE AFTERNOON. A LINE OF STORMS IS EXPECTED TO ORGANIZE AND MOVE
EASTWARD ACROSS THE SOUTHERN PLAINS DURING THE LATE AFTERNOON AND
EVENING.
MODEL FORECASTS VARY CONCERNING THE EXACT POSITION OF THE STRONGEST
INSTABILITY ON WEDNESDAY. THE LATEST ECMWF SEEMS TO BE CLOSE TO
CONSENSUS, WITH MLCAPE INCREASING INTO THE 1000 TO 2000 J/KG RANGE
FROM EAST OF LUBBOCK TO NEAR LAWTON. THIS LOCATION WILL BE JUST TO
THE EAST OF THE MID-LEVEL JET, WHICH WILL PROVIDE DEEP-LAYER SHEAR
FAVORABLE FOR SEVERE THUNDERSTORM DEVELOPMENT. FORECAST SOUNDINGS AT
21Z NEAR THE FORECAST INSTABILITY AXIS HAVE 0-6 KM SHEAR AROUND 40
KNOTS, WHICH WILL SUPPORT SUPERCELLS WITH A THREAT OF WIND DAMAGE
AND HAIL. ALTHOUGH STORM DEVELOPMENT MAY INITIALLY BE DISCRETE, A
LINE IS EXPECTED TO FORM AS CONVECTIVE COVERAGE FILLS THE EAST OF
THE DRYLINE. THIS LINE WILL BE CAPABLE OF WIND DAMAGE. DURING THE
EARLY EVENING, 0-3 KM STORM-RELATIVE HELICITY IS FORECAST TO
INCREASE INTO THE 200 TO 250 M2/S2 RANGE, SUGGESTING THAT A TORNADO
THREAT WILL ALSO DEVELOP WITH EMBEDDED ROTATING STORMS IN THE LINE.
ANY SEVERE THREAT SHOULD PERSIST INTO THE MID TO LATE EVENING AS THE
LINE MOVES EASTWARD ACROSS CENTRAL OKLAHOMA AND CENTRAL TO SOUTHWEST
TEXAS.
..CENTRAL PLAINS
AT MID-LEVELS, DIVERGENT SOUTHWESTERLY FLOW WILL BE IN PLACE ACROSS
THE CENTRAL PLAINS ON WEDNESDAY. AT THE SURFACE, A LOW WILL MOVE
EASTWARD INTO WESTERN KANSAS WITH A DRYLINE EXTENDING SOUTHWARD FROM
THE LOW. SURFACE HEATING AND INCREASING LOW-LEVEL CONVERGENCE NEAR
THE DRYLINE SHOULD RESULT IN THUNDERSTORM DEVELOPMENT DURING THE
LATE AFTERNOON. AS THE EXIT REGION OF A MID-LEVEL JET OVERSPREADS
WESTERN KANSAS DURING THE DAY, DEEP-LAYER SHEAR WILL BECOME STRONG
ENOUGH TO SUPPORT ORGANIZED CONVECTION. STORMS ARE EXPECTED TO
INCREASE IN COVERAGE AND MOVE EASTWARD INTO CENTRAL KANSAS DURING
THE LATE AFTERNOON AND EARLY EVENING. ALTHOUGH LOW-LEVEL LAPSE RATES
ARE FORECAST TO BE POOR, MLCAPE AROUND 1000 J/KG WITH 50 KTS OF 0-6
KM SHEAR SHOULD SUPPORT AN ISOLATED SEVERE THREAT. SEVERE WIND GUSTS
AND HAIL WILL BE POSSIBLE WITH SUPERCELLS OR MULTICELLS, ESPECIALLY
AS LOW-LEVEL FLOW INCREASES DURING THE EARLY EVENING.
..BROYLES.. 09/28/2026
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