021
ACUS01 KWNS 271640
SWODY1
SPC AC 271637
DAY 1 CONVECTIVE OUTLOOK CORR 1
NWS STORM PREDICTION CENTER NORMAN OK
1137 AM CDT SUN SEP 27 2026
VALID 271630Z - 281200Z
..NO SEVERE THUNDERSTORM AREAS FORECAST
CORRECTED TO REMOVE DUPLICATE TSTM AREA IN NEW ENGLAND
..SUMMARY
ORGANIZED SEVERE STORMS ARE NOT EXPECTED THROUGH EARLY MONDAY.
..SYNOPSIS
AN OCCLUDED CYCLONE WILL SLOWLY WEAKEN NEAR THE NORTHERN
MID-ATLANTIC COAST, WITH LINGERING POTENTIAL FOR ELEVATED CONVECTION
AND ISOLATED LIGHTNING FLASHES TO ITS NORTHEAST ACROSS SOUTHEAST NEW
ENGLAND. FARTHER WEST, WEAK RIDGING ALOFT WILL EXTEND FROM THE
SOUTHERN HIGH PLAINS TOWARD MN. A FEW THUNDERSTORMS WILL BE
POSSIBLE LATE THIS AFTERNOON/EVENING ALONG A DIFFUSE SURFACE
BOUNDARY FROM NORTH TX INTO SOUTHERN OK. THE STRONGEST STORMS MAY
PRODUCE GUSTY OUTFLOW WINDS GIVEN STEEP LOW-LEVEL LAPSE RATES WITH
AFTERNOON MIXING, BUT THE SEVERE THREAT APPEARS TOO LOW TO JUSTIFY
ADDING SEVERE-WIND PROBABILITIES.
SLIGHTLY ELEVATED CONVECTION IS ONGOING ACROSS CENTRAL SD IN A ZONE
OF WEAK LOW-LEVEL FRONTOGENESIS, COINCIDENT WITH MIDLEVEL LAPSE
RATES NEAR 8 C/KM AND MUCAPE CLOSE TO 1000 J/KG. DEEP-LAYER
VERTICAL SHEAR IS ON THE LOWER MARGINS FOR STORM ORGANIZATION, BUT
IT APPEARS THIS CONVECTION HAS ALREADY PEAKED. ADDITIONAL ELEVATED
THUNDERSTORMS ARE EXPECTED OVERNIGHT FROM WESTERN SD INTO ND AS
LOW-LEVEL WARM ADVECTION INCREASES IN ASSOCIATION WITH EMBEDDED
SPEED MAXIMA DOWNSTREAM FROM A MIDLEVEL TROUGH MOVING ACROSS CA/NV.
WHILE AN ISOLATED HAIL REPORT COULD OCCUR OVERNIGHT AS FAR NORTHEAST
AS SOUTHWEST ND, THE OVERALL THREAT IS LOW AND WHEN COMBINED WITH
THE QUESTIONABLE THREAT FOR DIURNAL CONVECTION ACROSS THE CENTRAL
HIGH PLAINS, THE MRGL AREA HAS BEEN REMOVED.
..THOMPSON/CHALMERS.. 09/27/2026
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