927
ACUS03 KWNS 130818
SWODY3
SPC AC 130817
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0217 AM CST THU NOV 13 2025
VALID 151200Z - 161200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN THE UPPER OH
VALLEY VICINITY...
..SUMMARY
ISOLATED DAMAGING WINDS ARE POSSIBLE DURING THE LATE AFTERNOON TO
EVENING SATURDAY ACROSS THE UPPER OHIO VALLEY VICINITY.
..UPPER OH VALLEY TO THE MID-ATLANTIC STATES
AMPLIFICATION OF A LARGE-SCALE UPPER TROUGH APPEARS PROBABLE FROM
THE CANADIAN PRAIRIES ACROSS THE GREAT LAKES TOWARDS THE NORTHEAST
THROUGH EARLY SUNDAY. THIS WILL INDUCE A DEEPENING SURFACE CYCLONE
FROM LAKE SUPERIOR/NORTHERN ON TOWARDS NEW ENGLAND. TRAILING TO ITS
SOUTHWEST WILL BE A SHARPENING COLD FRONT THAT SHOULD ACCELERATE
SOUTHEASTWARD. WITH ONLY MODIFIED BOUNDARY-LAYER MOISTURE RETURN
(EMANATING FROM EAST TX AND LA) AHEAD OF THE FRONT, MLCAPE SHOULD BE
QUITE LIMITED AND SPATIALLY CONFINED TO THE OH VICINITY. BUT
INTENSIFYING TROPOSPHERIC WIND PROFILES, COUPLED WITH THE INCREASING
LARGE-SCALE ASCENT ALONG THE FRONT, ARE CONCERNING FOR A CONDITIONAL
THREAT OF AT LEAST DAMAGING WINDS WHERE SURFACE-BASED CONVECTION CAN
DEVELOP. GUIDANCE CONSENSUS SUGGESTS THIS MAY OCCUR TOWARDS LATE
AFTERNOON AND ESPECIALLY INTO THE EVENING ACROSS THE UPPER OH
VALLEY. EAST OF THE APPALACHIANS, DEVELOPMENT OF SURFACE-BASED
INSTABILITY APPEARS UNLIKELY SATURDAY NIGHT, ALTHOUGH ELEVATED
CONVECTION MAY PERSIST TOWARDS PARTS OF THE COASTAL MID-ATLANTIC.
..SOUTHWEST
THE DRIFTING UPPER LOW OFF THE SOUTHERN CA COAST SHOULD EVOLVE BACK
INTO AN OPEN TROUGH THAT ACCELERATES NORTHEASTWARD BY 12Z SUNDAY.
THIS WILL LEAD TO THE MID-LEVEL COLD CORE FINALLY MOVING INLAND,
AIDING IN STEEPENING OF LAPSE RATES. THE LOW-LEVEL WARM CONVEYOR
WILL LIKEWISE SHIFT EAST ACROSS THE LOWER CO VALLEY AND MOJAVE
DESERT. THIS SETUP WILL SUPPORT A BROADENING OF ISOLATED THUNDER
POTENTIAL FROM SOUTHERN CA INTO WESTERN AZ AND FAR SOUTHERN NV BY
SATURDAY NIGHT.
..GRAMS.. 11/13/2025
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