700
ACUS01 KWNS 272002
SWODY1
SPC AC 272000
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0300 PM CDT SAT JUN 27 2026
VALID 272000Z - 281200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS THE
NORTHERN HIGH PLAINS...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
TENNESSEE VALLEY TO THE CAROLINAS...
..SUMMARY
SEVERE THUNDERSTORMS ARE LIKELY TODAY ACROSS THE NORTHERN HIGH
PLAINS INCLUDING NORTHEAST WYOMING AND EASTERN MONTANA INTO THE
WESTERN DAKOTAS, WITH STORMS CAPABLE OF VERY LARGE HAIL, VERY STRONG
OUTFLOW WINDS (80+ MPH), AND TORNADOES LATE THIS AFTERNOON INTO
TONIGHT.
..20Z UPDATE
THE PREVIOUS FORECAST REMAINS ON TRACK, AND ONLY MINOR ADJUSTMENTS
WERE MADE WITH THIS UPDATE. THE ENH RISK WAS EXPANDED SLIGHTLY
SOUTHWESTWARD IN NORTHEASTERN WY, WHERE SEVERAL DISCRETE SUPERCELL
HAVE EVOLVED OFF THE BIGHORN MOUNTAINS -- POSING A RISK OF LARGE TO
VERY LARGE HAIL.
IN WESTERN ND, THE CIG1 TORNADO AREA WAS EXTENDED SLIGHTLY
NORTHWARD. CONTINUED DIURNAL HEATING AMID UPPER 60S DEWPOINTS WILL
YIELD MODERATE-STRONG SURFACE-BASED BUOYANCY AND MINIMAL INHIBITION.
BACKED SURFACE WINDS BENEATH STRENGTHENING FLOW ALOFT WILL
CONTRIBUTE TO FAVORABLY CURVED HODOGRAPHS. ANY STORMS THAT CAN FORM
OR MOVE INTO THIS ENVIRONMENT WILL CONDITIONALLY SUPPORT A STRONG
TORNADO.
FARTHER EAST, THE SLGT RISK WAS EXPANDED NORTHWARD IN THE LOWER OH
VALLEY. HERE, DIURNAL HEATING/DESTABILIZATION OF A VERY MOIST AIR
MASS (UPPER 70S DEWPOINTS) WILL CONTINUE TO SUPPORT LOOSELY
ORGANIZED THUNDERSTORM CLUSTERS CAPABLE OF PRODUCING WIDELY
SCATTERED DAMAGING WINDS THIS AFTERNOON.
..WEINMAN.. 06/27/2026
PREV DISCUSSION
/ISSUED 1142 AM CDT SAT JUN 27 2026/
..NORTHERN HIGH PLAINS THIS AFTERNOON INTO TONIGHT
A RATHER ACTIVE SEVERE-WEATHER SCENARIO IS ANTICIPATED REGIONALLY
LATER TODAY, INCLUDING THE POTENTIAL FOR INTENSE/LOCALLY SIGNIFICANT
SEVERE STORMS. A LEAD SHORTWAVE TROUGH/SPEED MAX WILL CONTINUE TO
APPROACH THROUGH LATE TODAY, WITH THE EXIT REGION OF A STRONG
UPPER-LEVEL JET OVERSPREADING THE REGION INCLUDING 50+ KT
SOUTHWESTERLIES ABOVE 5KM AGL. BOUNDARY-LAYER DEWPOINTS IN THE 60S F
WILL CONTINUE TO SPREAD NORTHWARD REGIONALLY, TO THE EAST OF A
DEEPENING SURFACE LOW ACROSS NORTHEAST WYOMING TOWARD THE FAR
WESTERN DAKOTAS, AND A SHARPENING LEE TROUGH/DRYLINE ACROSS A MORE
PREVALENT NORTH/SOUTH EXTENT OF THE HIGH PLAINS. THIS LOW-LEVEL
MOISTENING WILL OCCUR BENEATH A PLUME OF STEEP MID-LEVEL LAPSE RATES
EMANATING FROM THE GREAT BASIN AND NORTH-CENTRAL ROCKIES.
INITIAL SURFACE-BASED DEVELOPMENT IS EXPECTED NEAR THE SURFACE
LOW/TROUGH NEAR THE BIG HORN MOUNTAINS TOWARD THE
WYOMING/MONTANA/NORTH DAKOTA BORDER VICINITY. THE MATURING STRONGER
INITIAL STORMS WILL ALMOST CERTAINLY BE SUPERCELLULAR OWING TO
MODERATE TO LARGE CAPE AND A STRONG WIND FIELD. THE RISK FOR LARGE
TO VERY LARGE HAIL (2-3 INCHES IN DIAMETER) IS GREATEST NEAR THIS
AFOREMENTIONED BORDER REGION WHERE SUPERCELLS ARE FORECAST EARLY IN
THE CONVECTIVE LIFE CYCLE, ALTHOUGH ADDITIONAL/SOMEWHAT MORE
DISCRETE DEVELOPMENT WILL ALSO LIKELY OCCUR A BIT LATER FARTHER
SOUTHEASTWARD ACROSS NORTHWEST SOUTH DAKOTA.
A FEW TORNADOES ARE ALSO POSSIBLE PARTICULARLY IN THE MORE
MOISTURE-RICH ENVIRONMENT NEAR THE SURFACE TRIPLE POINT, BUT
RELATIVELY LARGE TEMPERATURE-DEWPOINT SPREADS AND A TRANSITION TO
UPSCALE GROWTH MAY TEMPER THE TORNADO THREAT, PARTICULARLY WITH
NORTHWARD EXTENT EITHER SIDE OF THE MONTANA/NORTH DAKOTA BORDER
VICINITY. AS MORE STORMS DEVELOP LEADING TO STORM MERGERS AND
COALESCING OUTFLOW, A LINEAR CLUSTER WILL LIKELY DEVELOP INTO A
MATURING/ACCELERATING BOW ECHO INTO WESTERN NORTH DAKOTA THIS
EVENING, WITH SIGNIFICANT/INTENSE THUNDERSTORM WINDS (80+ MPH)
POSSIBLE.
SEVERE STORMS WILL LIKELY DEVELOP EASTWARD TONIGHT ACROSS THE
DAKOTAS, AND PRIOR TO THAT, DIURNALLY ENHANCED, BUT MORE ISOLATED
INTENSE, DEVELOPMENT IS PLAUSIBLE AS FAR SOUTH AS WESTERN NEBRASKA
WITH LARGE HAIL AND DAMAGING WINDS.
..NORTHERN INTERMOUNTAIN WEST INCLUDING NORTHERN UT/WESTERN WY
INFLUENCED BY A LEAD SHORTWAVE TROUGH/SPEED MAX ASSOCIATED WITH THE
PROMINENT UPPER-LEVEL TROUGH CENTERED OVER THE PACIFIC NORTHWEST,
STRONG TO LOCALLY SEVERE THUNDERSTORM POTENTIAL WILL PROBABLY EXIST
EARLY TODAY. THE PROLIFICALLY STRONG WIND FIELD AND MODEST
DESTABILIZATION WILL TEND TO FOCUS TODAY ACROSS NORTHERN UTAH,
SOUTHEAST IDAHO INTO WESTERN WYOMING, INCLUDING THE STAR VALLEY
VICINITY. SEVERE-CALIBER WIND GUSTS AND SOME HAIL MAY OCCUR.
..MID-SOUTH/TENNESSEE/SOUTHERN KENTUCKY TO NORTH CAROLINA
MULTIPLE MCVS, INCLUDING ACROSS FAR SOUTH-CENTRAL MISSOURI AND
SOUTHEAST KANSAS AT MIDDAY, WILL INFLUENCE THE REGION AS THEY
PROGRESS EAST-SOUTHWARD GENERALLY TOWARD KENTUCKY AND TENNESSEE.
RELATED FLOW ENHANCEMENT IS EVIDENT IN REGIONAL WSR-88D VWP DATA,
AND PARTICULARLY IN THE 12Z LAMONT, OK OBSERVED SOUNDING (40+ KT
4-9KM AGL). SEE MESOSCALE DISCUSSION 1346 FOR ADDITIONAL SHORT-TERM
DETAILS.
THESE MCVS WILL INFLUENCE AND SEMI-FOCUS THUNDERSTORM DEVELOPMENT
WITHIN A MOIST AND INCREASINGLY UNSTABLE BOUNDARY LAYER FROM THE
SOUTHEAST MISSOURI/NORTHEAST ARKANSAS BORDER VICINITY INTO KENTUCKY
AND TENNESSEE. THIS INCLUDES THE POSSIBILITY OF SOME SUPERCELLS AND
WELL-ORGANIZED CLUSTERS IN THE PRESENCE OF 35-40 KT EFFECTIVE SHEAR.
POCKETS OF WIND DAMAGE WILL BE THE MOST COMMON RISK, BUT SOME
TORNADO POTENTIAL WILL EXIST AS WELL. ADDITIONAL SEVERE STORMS
CAPABLE OF WIND DAMAGE ARE ALSO EXPECTED FARTHER EASTWARD INTO THE
CAROLINAS THIS AFTERNOON THROUGH AROUND MID-EVENING.
..TEXAS PANHANDLE/WEST TEXAS LATE THIS AFTERNOON/EVENING
THOUGH FORCING FOR ASCENT WILL BE WEAK AT BEST THIS FAR SOUTH,
STRONG SURFACE HEATING/MIXING ALONG THE LEE TROUGH/DRYLINE COULD
SUPPORT HIGH-BASED THUNDERSTORM DEVELOPMENT LATE THIS AFTERNOON.
INVERTED-V PROFILES WILL FAVOR THE POTENTIAL FOR ISOLATED SEVERE
OUTFLOW GUSTS OF 60-75 MPH.
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