638
ACUS02 KWNS 270639
SWODY2
SPC AC 270637
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1237 AM CST SAT DEC 27 2025
VALID 281200Z - 291200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN MO/AR TO THE
OH AND TN VALLEYS...
..SUMMARY
A LOW-PROBABILITY SEVERE THUNDERSTORM THREAT IS FORECAST FROM SUNDAY
AFTERNOON INTO SUNDAY NIGHT FROM MISSOURI-ARKANSAS INTO THE OHIO AND
TENNESSEE VALLEYS.
..MO/AR TO THE OH/TN VALLEYS
PHASING OF MULTIPLE SHORTWAVE IMPULSES WILL SUPPORT AMPLIFICATION OF
AN UPPER TROUGH, MAINLY ON SUNDAY NIGHT, AS IT PROGRESSES FROM THE
HIGH PLAINS TO THE GREAT LAKES. THIS WILL INDUCE DEEPENING OF A
SURFACE CYCLONE FROM THE LOWER MO VALLEY TOWARDS LAKE HURON.
ATTENDANT COLD FRONT WILL ACCELERATE SUNDAY NIGHT AS IT QUICKLY
SWEEPS EAST INTO THE UPPER OH VALLEY AND SOUTH INTO THE NORTHWEST
GULF BY 12Z MONDAY.
ISOLATED TO SCATTERED ELEVATED THUNDERSTORMS ARE MOST LIKELY ON
SUNDAY MORNING ACROSS PARTS OF THE MID-MS VALLEY TO THE SOUTHERN
GREAT LAKES WITHIN A STRENGTHENING LOW-LEVEL WARM CONVEYOR. IT IS
PLAUSIBLE THAT A FEW UPDRAFTS MIGHT WEAKLY ROTATE, BUT MEAGER
BUOYANCY ATOP THE STABLE SURFACE AND CLUSTER CONVECTIVE MODE APPEARS
SUPPORTIVE OF ONLY SMALL HAIL.
PRIMARY FORECAST CHALLENGE IS THE DEGREE OF SURFACE-BASED
DESTABILIZATION BY SUNDAY AFTERNOON, WHICH WILL LARGELY INFLUENCE
TORNADO AND SEVERE THUNDERSTORM WIND POTENTIAL. LATEST GUIDANCE
REMAINS SPLIT INTO TWO PATHS. THIS EVENING'S RRFS/RAP/HRRR/HRW-ARW
SUGGEST THAT A PLUME OF MEAGER BUOYANCY WITH MLCAPE UP TO 500 J/KG
SHOULD BECOME ESTABLISHED AHEAD OF A COLD FRONT ACROSS THE OZARKS TO
A PORTION OF THE MID-MS VALLEY NEAR THE SURFACE CYCLONE BY
AFTERNOON. MEANWHILE THE NAM AND HRW-NSSL INDICATE LITTLE TO NO
SURFACE-BASED BUOYANCY IN THE WARM-MOIST SECTOR ALONG THE FRONT.
GUIDANCE CONSENSUS DOES SUGGEST AT LEAST A LOW-TOPPED, THIN QLCS
SHOULD BECOME ESTABLISHED ALONG THE FRONT FROM IL/IN TOWARDS AR BY
EARLY EVENING.
THE PROGRESSIVE NATURE OF THE FRONT ALONG WITH THE PAUCITY OF
SURFACE-BASED INSTABILITY DOWNSTREAM RENDERS LARGE UNCERTAINTY IN
WHETHER LIGHTNING-PRODUCING CONVECTION WILL BE MAINTAINED SUNDAY
NIGHT ALONG THE FRONT. HOWEVER, KINEMATIC FIELDS WILL BECOME
INCREASINGLY IMPRESSIVE, WITH STRONG GUSTS LIKELY ACCOMPANYING
LOW-TOPPED CONVECTION ALONG THE FRONT. CAM CONSENSUS THOUGH IS FOR
CONVECTION TO WANE EARLY MORNING MONDAY AS INSTABILITY REMAINS
NEGLIGIBLE. AS SUCH, HAVE MAINTAINED THE PRIOR LEVEL 1-MRGL RISK FOR
WIND, WITH A SUBSET OF LOW TORNADO PROBABILITIES FROM MO TO IN.
..GRAMS.. 12/27/2025
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page