447
ACUS02 KWNS 130517
SWODY2
SPC AC 130515
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1215 AM CDT TUE OCT 13 2026
VALID 141200Z - 151200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE SOUTHERN PLAINS INTO THE OZARK PLATEAU...AND IN PARTS OF THE
UPPER OHIO VALLEY AND MID-ATLANTIC...
..SUMMARY
ISOLATED SEVERE THUNDERSTORMS CAPABLE OF MAINLY DAMAGING WIND GUSTS
ARE POSSIBLE ACROSS PORTIONS OF THE SOUTHERN PLAINS INTO THE OZARK
PLATEAU, AND IN THE PARTS OF THE UPPER OHIO VALLEY AND MID-ATLANTIC
WEDNESDAY AFTERNOON AND EVENING.
..SYNOPSIS
AN UPPER LOW CENTERED NEAR THE FOUR CORNERS WEDNESDAY MORNING IS
FORECAST TO GRADUALLY WEAKEN WHILE PROGRESSING INTO THE CENTRAL HIGH
PLAINS BY EARLY THURSDAY. WITHIN THE SOUTHEAST PERIPHERY OF THE LOW,
A VORTICITY MAXIMUM IS EXPECTED TO ADVANCE FROM THE SOUTHERN ROCKIES
INTO THE CENTRAL HIGH PLAINS IN TANDEM WITH A 50-60 KT JET STREAK IN
THE MID LEVELS. ELSEWHERE, A SERIES OF VORTICITY MAXIMA (SOME OF
CONVECTIVE ORIGIN) ARE FORECAST TO TRANSLATE FROM THE MID-MS VALLEY
TO THE SOUTHERN MID-ATLANTIC. AT THE SURFACE, A COLD FRONT WILL MOVE
SOUTH THROUGH THE MID-ATLANTIC, OH AND MID-MS VALLEYS, AND INTO
PORTIONS OF THE SOUTHERN PLAINS. THE WESTERN SEGMENT OF THE FRONT
OVER THE SOUTHERN PLAINS MAY EVENTUALLY STALL AND PERHAPS RETREAT
NORTH WEDNESDAY NIGHT IN RESPONSE TO FALLING PRESSURES OVER THE
CENTRAL PLAINS.
..SOUTHERN PLAINS INTO THE OZARK PLATEAU
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO BE ONGOING AT 12Z
WEDNESDAY, ALONG AND AHEAD OF THE COLD FRONT, AIDED BY MODEST WARM
ADVECTION AND MOISTURE TRANSPORT ALONG A WEAKENING NOCTURNAL
LOW-LEVEL JET. THE PRESENCE OF A SEASONABLY MOIST (E.G., DEWPOINTS
IN THE MID 60S TO MID 70S F) AND AT LEAST MARGINALLY UNSTABLE AIR
MASS WILL LIKELY SUPPORT THE CONTINUATION OF SHOWERS AND
THUNDERSTORMS THROUGH THE DAY IN SOME AREAS. ON THE SOUTHERN FRINGE
OF ANY MORE PERSISTENT CLOUDS AND PRECIPITATION, STRONGER HEATING
MAY CONTRIBUTE TO CORRIDORS OF MODERATE INSTABILITY BY AFTERNOON
WHERE MLCAPE MAY APPROACH 1500-2000 J/KG. THAT DESTABILIZATION
PROCESS WILL COINCIDE WITH STRENGTHENING VERTICAL SHEAR AND FORCING
FOR ASCENT PRECEDING THE SOUTHERN ROCKIES DISTURBANCE, YIELDING AN
ENVIRONMENT SUPPORTIVE OF ISOLATED STRONG TO SEVERE STORMS DURING
THE AFTERNOON AND EVENING. DAMAGING WIND GUSTS APPEAR TO BE THE
PRIMARY HAZARD WITH THE BEST POTENTIAL FOR A FEW OCCURRENCES OF
SEVERE HAIL BEING IN SOUTHWEST TX.
..UPPER OHIO VALLEY INTO THE MID-ATLANTIC
DAYTIME HEATING COMBINED WITH BOUNDARY-LAYER DEWPOINTS IN THE MID
60S TO LOW 70S F IS EXPECTED TO CONTRIBUTE TO POCKETS OF MODERATE
INSTABILITY WITH MLCAPE APPROACHING 1000-1250 J/KG BY MID-LATE
AFTERNOON AHEAD OF THE COLD FRONT. AIDED BY FORCING FOR ASCENT
PRECEDING THE SERIES OF VORTICITY MAXIMA APPROACHING FROM THE WEST,
THUNDERSTORMS ARE EXPECTED TO DEVELOP AND SUBSEQUENTLY INCREASE IN
AREAL COVERAGE ALONG THE FRONT AT THAT TIME. STEEPENING LOW-LEVEL
LAPSE RATES COUPLED WITH STRENGTHENING WEST-SOUTHWESTERLY WINDS WITH
HEIGHT (YIELDING UP TO 35-40 KT OF DEEP-LAYER SHEAR) APPEAR
SUPPORTIVE OF ISOLATED SEVERE STORMS CAPABLE OF DAMAGING WIND GUSTS
INTO EVENING.
..MEAD.. 10/13/2026
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