955
ACUS02 KWNS 011729
SWODY2
SPC AC 011727
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1227 PM CDT WED JUL 01 2026
VALID 021200Z - 031200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE NORTHERN
PLAINS INTO PARTS OF THE UPPER GREAT LAKES AND MIDWEST AND OVER THE
SOUTHERN APPALACHIANS...
..SUMMARY
STRONG TO SEVERE STORMS WILL BE POSSIBLE FROM THE NORTHERN PLAINS
INTO THE MIDWEST AND GREAT LAKES REGIONS, AS WELL AS ACROSS THE
SOUTHERN APPALACHIANS ON THURSDAY. ISOLATED STRONG TO SEVERE STORMS
MAY ALSO OCCUR IN THE TENNESSEE VALLEY, CENTRAL HIGH PLAINS, AND
PARTS OF THE NORTHEAST.
..SYNOPSIS
WITHIN THE PERIPHERY OF AN UPPER HIGH CENTERED OVER THE TN VALLEY
AND CUMBERLAND PLATEAU, A NUMBER OF WEAK MID-LEVEL PERTURBATIONS
(SOME OF CONVECTIVE ORIGIN) WILL PROGRESS THROUGH THE NORTHERN AND
CENTRAL PLAINS, GREAT LAKES, AND NORTHEAST. AT THE SURFACE, A LEE
CYCLONE WILL PERSIST OVER EASTERN MT OR THE WESTERN DAKOTAS WITH AN
ASSOCIATED STATIONARY OR WARM FRONT EXTENDING EAST THROUGH CENTRAL
MN INTO NORTHERN OR CENTRAL WI. THE SPECIFIC LOCATION OF THAT
BOUNDARY ACROSS MN AND WI WILL BE DICTATED BY THE EXTENT OF
CONVECTIVE OUTFLOW GENERATED BY STORMS OCCURRING TONIGHT.
..NORTHERN HIGH PLAINS INTO THE GREAT LAKES AND MIDWEST
THERE IS CONSIDERABLE SPREAD IN 12Z GUIDANCE WITH RESPECT TO
FINE-SCALE DETAILS OF STORM EVOLUTION DURING THE FORECAST PERIOD.
HOWEVER, THOSE DATA INDICATE A COUPLE POTENTIAL SCENARIOS THAT MAY
UNFOLD. THE FIRST ONE APPEARS TO BE ASSOCIATED WITH AN MCV
ORIGINATING FROM CENTRAL HIGH PLAINS CONVECTION THIS AFTERNOON INTO
TONIGHT, WHICH WILL MOVE THROUGH THE MID MO VALLEY THURSDAY MORNING.
FORECAST SOUNDINGS SUGGEST INITIAL STORMS MAY BE SLIGHTLY ELEVATED
AND ROOTED WITHIN A MODERATE TO STRONGLY UNSTABLE ENVIRONMENT, WHICH
WILL COINCIDE WITH A ZONE OF ENHANCED MID-LEVEL FLOW ACCOMPANYING
THE MCV. AS SUCH, THE EARLY-DAY STORMS MAY POSE A LARGE HAIL AND
DAMAGING WIND RISK WITH THE POTENTIAL FOR THAT ACTIVITY TO GROW
UPSCALE INTO A SEVERE-WIND-PRODUCING MCS THAT TRACKS THROUGH IA INTO
SOUTHERN MN, WI, AND PERHAPS NORTHERN IL DURING THE DAY. ADDITIONAL
AFTERNOON AND EVENING STORMS CAPABLE OF LARGE HAIL AND DAMAGING
WINDS ARE POSSIBLE DOWNSTREAM FROM THE POTENTIAL MCS, ALONG THE
OUTFLOW-MODULATED STATIONARY FRONT IN MN AND WI.
A SECOND, HIGHER-CONFIDENCE SCENARIO IS FOR DIURNALLY ENHANCED
THUNDERSTORMS TO DEVELOP IN THE VICINITY OF THE LEE CYCLONE AND
SURFACE FRONT ACROSS THE WESTERN DAKOTAS, IN ADVANCE OF A SHORT-WAVE
TROUGH MOVING THROUGH EASTERN MT. FORECAST SOUNDINGS INDICATE THE
PRESENCE OF STEEP LAPSE RATES AND RESULTANT MODERATE INSTABILITY,
WHICH WILL COINCIDE WITH A VERTICALLY VEERING WIND PROFILE WITH
40-45 KT OF DEEP-LAYER SHEAR. THAT ENVIRONMENT WILL SUPPORT
SUPERCELLS AS THE INITIAL STORM MODE WITH THE PRIMARY HAZARD BEING
LARGE TO VERY LARGE HAIL. THE TORNADO THREAT IS EXPECTED TO BE
LIMITED BY RELATIVELY LARGE TEMPERATURE-DEWPOINT SPREADS, WHICH WILL
SUPPORT STRONGER COLD POOL DEVELOPMENT.
THE MODELS INDICATE THE INITIAL STORMS GROWING UPSCALE INTO ONE OR
MULTIPLE FORWARD-PROPAGATING MCSS ACROSS THE CENTRAL AND EASTERN
DAKOTAS INTO EASTERN PARTS OF THE MIDWEST THURSDAY EVENING INTO
NIGHT WITH THE POTENTIAL FOR CORRIDORS OF DAMAGING WINDS WITH
SIGNIFICANT GUSTS IN EXCESS OF 75 MPH. UNCERTAINTY IN THE SPECIFIC
TRACK OF THE MCS(S) PRECLUDES THE INCLUSION OF HIGHER WIND
PROBABILITIES AND A RELATED LEVEL 3/ENHANCED RISK.
..SOUTHERN APPALACHIANS INTO THE TENNESSEE VALLEY
MODERATE TO STRONG INSTABILITY IS FORECAST IN THE VICINITY OF THE
UPPER HIGH THURSDAY AFTERNOON. THERE IS A RELATIVELY CONSISTENT
SIGNAL IN 12Z GUIDANCE THAT STORMS WILL FORM ALONG THE HIGH TERRAIN
OF EAST TN, THE WESTERN CAROLINAS, AND NORTH GA WITH A SUBSEQUENT
WEST TO SOUTHWEST MOTION/PROPAGATION DURING THE AFTERNOON AND EARLY
EVENING HOURS. SIMILAR TO THE 12Z OBSERVED SOUNDINGS THIS MORNING,
THE FORECAST ENVIRONMENT INDICATES A BELT OF ENHANCED EASTERLY WINDS
IN THE 2-4 KM AGL LAYER, WHICH MAY SUPPORT COLD POOL ORGANIZATION
AND THE POTENTIAL FOR A MORE CONCENTRATED DAMAGING WIND THREAT.
..CENTRAL HIGH PLAINS
ISOLATED HIGH-BASED THUNDERSTORMS ARE POSSIBLE ALONG A LEE TROUGH
OVER FAR EASTERN CO INTO WESTERN KS THURSDAY AFTERNOON AND EVENING.
STEEP LOW/MID-LEVEL LAPSE RATES AND UP TO 30 KT OF DEEP-LAYER SHEAR
MAY CONTRIBUTE TO EPISODIC SUPERCELL STRUCTURES WITH AN ATTENDANT
RISK FOR LARGE HAIL AND SEVERE WIND GUSTS.
..NORTHEAST
IN THE ABSENCE OF A DISCERNIBLE SURFACE BOUNDARY, THE TIMING AND
EXTENT OF ANY THUNDERSTORM DEVELOPMENT REMAINS UNCERTAIN. THE MOST
LIKELY SCENARIO WILL BE FOR THUNDERSTORMS TO MOVE INTO THE REGION
FROM SOUTHERN QUEBEC OR SOUTHEAST ONTARIO THURSDAY AFTERNOON INTO
NIGHT. THE PRESENCE OF MODERATE TO STRONG INSTABILITY AND 30-40 KT
OF DEEP-LAYER SHEAR WILL BE SUPPORTIVE OF ORGANIZED STORM MODES WITH
THE PREDOMINANT HAZARD BEING DAMAGING WINDS. HIGHER WIND
PROBABILITIES AND A LEVEL 2/SLIGHT RISK MAY BECOME NECESSARY IN
LATER OUTLOOKS ONCE CONVECTIVE DETAILS BECOME MORE CERTAIN.
..MEAD.. 07/01/2026
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