985
ACUS03 KWNS 240708
SWODY3
SPC AC 240707
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0207 AM CDT FRI JUL 24 2026
VALID 261200Z - 271200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER THE UPPER
MISSISSIPPI VALLEY INTO UPPER MIDWEST...
..SUMMARY
SEVERE THUNDERSTORMS CAPABLE OF MAINLY LARGE HAIL AND DAMAGING WINDS
ARE POSSIBLE FROM THE UPPER MISSISSIPPI VALLEY AND GREAT LAKES INTO
PORTIONS OF THE OHIO AND MID MISSOURI VALLEYS ON SUNDAY AND SUNDAY
NIGHT.
..SYNOPSIS
ALONG THE PERIPHERY OF AN UPPER HIGH ANCHORED OVER THE CENTRAL AND
SOUTHERN PLAINS, A BELT OF ENHANCED MID-LEVEL WINDS WILL EXTEND FROM
THE PACIFIC NORTHWEST THROUGH SOUTH-CENTRAL CANADA INTO THE GREAT
LAKES. A SERIES OF PERTURBATIONS WILL BE EMBEDDED WITHIN THE
HIGHER-MOMENTUM FLOW REGIME, THE MOST NOTABLE BEING A DISTURBANCE
TRACKING THROUGH SOUTHERN PARTS OF SK AND MB INTO NORTHWEST ON AND
NORTHERN MN LATE SUNDAY NIGHT. A SURFACE LOW IS FORECAST TO FOLLOW
THAT SAME TRACK WITH AN ASSOCIATED TROUGH OR WEAK COOL FRONT
ADVANCING THROUGH THE NORTHERN PLAINS INTO THE UPPER MS VALLEY.
..UPPER MISSISSIPPI VALLEY INTO THE GREAT LAKES
BOUNDARY-LAYER DEWPOINTS IN THE 60S TO MID 70S WILL COINCIDE WITH AN
EASTWARD-EXPANDING EML PLUME AND ASSOCIATED CAP TO YIELD A FAIRLY
WIDESPREAD RESERVOIR OF MODERATE TO STRONG INSTABILITY ACROSS THE
REGION ON SUNDAY. THERE IS SOME MODEL SIGNAL FOR A SUBTLE MID-LEVEL
DISTURBANCE TO PROGRESS FROM THE NORTHERN PLAINS INTO THE UPPER
MIDWEST DURING THE DAY WITH AN ASSOCIATED BAND OF FORCING FOR ASCENT
POTENTIALLY SERVING AS A FOCUS FOR DIURNALLY ENHANCED THUNDERSTORM
DEVELOPMENT. HOWEVER, THE ABSENCE OF DISCERNIBLE SURFACE BOUNDARIES
AND THE RESIDUAL CAPPING LEADS TO UNCERTAINTY IN THE LOCATION AND
EXTENT OF DIURNALLY ENHANCED THUNDERSTORM DEVELOPMENT. NONETHELESS,
A CONDITIONAL SEVERE WEATHER THREAT WILL EXIST WITH ANY STORMS THAT
CAN BECOME ROOTED WITHIN THE BOUNDARY LAYER, GIVEN THE PRESENCE OF
35-50 KT DEEP-LAYER SHEAR.
MORE SUBSTANTIAL FORCING FOR ASCENT IS FORECAST SUNDAY EVENING INTO
NIGHT ACROSS THE UPPER MS VALLEY WITH THE APPROACH OF THE MID-LEVEL
WAVE MENTIONED IN THE SYNOPSIS. AT THAT TIME, THE SURFACE FRONT WILL
BE MOVING INTO THE AREA FROM THE WEST, POTENTIALLY SERVING AS A
FOCUS FOR THUNDERSTORM DEVELOPMENT. THE 00Z ECMWF IN PARTICULAR
DEPICTS A LARGE THUNDERSTORM COMPLEX DEVELOPING OVER THAT AREA WITH
A SUBSEQUENT SOUTHWARD MOVEMENT TOWARD THE MID MO VALLEY SUNDAY
NIGHT INTO EARLY MONDAY. A CORRIDOR OF ENHANCED DAMAGING WIND
POTENTIAL WOULD EXIST IN THAT SCENARIO; HOWEVER, CONFIDENCE IN SUCH
AN OCCURRENCE IS PRESENTLY TOO LOW TO INCLUDE HIGHER PROBABILITIES
AND A CONDITIONAL INTENSITY GROUP 1 CONTOUR.
..MEAD.. 07/24/2026
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