729
ACUS48 KWNS 010857
SWOD48
SPC AC 010855
DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0355 AM CDT MON JUN 01 2026
VALID 041200Z - 091200Z
..DISCUSSION
..THURSDAY/DAY 4 TO SATURDAY/DAY 6
AT MID-LEVELS, A TROUGH IS FORECAST TO MOVE ACROSS THE WESTERN U.S.
ON THURSDAY, AS A SUBTLE LEAD SHORTWAVE TROUGH MOVES INTO THE
CENTRAL AND NORTHERN HIGH PLAINS. AT THE SURFACE, A BROAD AREA OF
MODERATE INSTABILITY IS FORECAST TO BE IN PLACE ACROSS MUCH OF
NEBRASKA AND SOUTH DAKOTA BY AFTERNOON. SCATTERED THUNDERSTORMS ARE
EXPECTED TO DEVELOP AHEAD OF THE SHORTWAVE TROUGH IN THE CENTRAL AND
NORTHERN HIGH PLAINS, WITH THESE STORMS MOVING EASTWARD ACROSS
WESTERN NEBRASKA AND WESTERN SOUTH DAKOTA DURING THE AFTERNOON AND
EVENING. THE INSTABILITY ALONG WITH MODERATE TO STRONG DEEP-LAYER
SHEAR IS EXPECTED TO SUPPORT SEVERE THUNDERSTORM DEVELOPMENT.
SUPERCELLS WITH LARGE HAIL AND SEVERE WIND GUSTS WILL BE POSSIBLE.
AN ISOLATED TORNADO THREAT MAY ALSO DEVELOP.
THE MID-LEVEL SHORTWAVE TROUGH IS FORECAST TO MOVE EASTWARD ACROSS
THE NORTHERN PLAINS ON FRIDAY AND INTO THE UPPER MISSISSIPPI VALLEY
ON SATURDAY. DURING THIS TIME, A SEVERE THREAT WILL BE POSSIBLE EACH
AFTERNOON AHEAD OF THE SHORTWAVE TROUGH IN A MOIST AND UNSTABLE
AIRMASS. A MORE ISOLATED SEVERE THREAT MAY DEVELOP SOUTHWARD INTO
THE CENTRAL PLAINS AND LOWER TO MID MISSOURI VALLEY. FOR THESE TWO
DAYS, SPATIAL UNCERTAINTY IS SUBSTANTIAL CONCERNING THE EXACT
LOCATION OF WHERE THE SEVERE THREAT WILL BE GREATEST.
..SUNDAY/DAY 7 AND MONDAY/DAY 8
FROM SUNDAY INTO MONDAY, A BROAD CORRIDOR OF MOIST AIR IS EXPECTED
TO BE IN PLACE OVER THE GREAT PLAINS. MODERATE TO STRONG INSTABILITY
APPEARS LIKELY TO DEVELOP ACROSS PARTS OF THIS AIRMASS EACH
AFTERNOON. MODEL FORECASTS SUGGEST THAT DEEP-LAYER SHEAR WILL REMAIN
RELATIVELY WEAK OVER MOST OF THE GREAT PLAINS. ALTHOUGH AN ISOLATED
SEVERE THREAT WOULD BE POSSIBLE IN SOME AREAS, UNCERTAINTY
CONCERNING THE MID-LEVEL PATTERN AND THE RESULTANT DEEP-LAYER SHEAR
IS CONSIDERABLE AT THIS TIME.
..BROYLES.. 06/01/2026
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