019
ACUS48 KWNS 160857
SWOD48
SPC AC 160856
DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0356 AM CDT SAT AUG 16 2025
VALID 191200Z - 241200Z
..DISCUSSION
..TUESDAY/DAY 4 AND WEDNESDAY/DAY 5
A MID-LEVEL RIDGE WILL BUILD ACROSS THE ROCKIES AND NORTHERN HIGH
PLAINS DURING THE MIDDLE PART OF THE WEEK. AT THE SURFACE, A FRONT
WILL ADVANCE SLOWLY SOUTHWARD INTO THE LOWER MISSOURI AND MID
MISSISSIPPI VALLEYS. A POST-FRONTAL AIRMASS WILL REMAIN OVER THE
UPPER MISSISSIPPI AND GREAT LAKES REGION. ON THE SOUTHERN AND
WESTERN PERIPHERY OF THIS AIRMASS, MODERATE INSTABILITY IS FORECAST
TO DEVELOP EACH AFTERNOON. LIMITED LARGE-SCALE ASCENT IS EXPECTED TO
KEEP CONVECTIVE COVERAGE ISOLATED. IN SPITE OF RELATIVELY WEAK
DEEP-LAYER SHEAR ALONG MUCH OF THE INSTABILITY CORRIDOR, STEEP LOW
TO MID-LEVEL LAPSE RATES WILL BE IN PLACE AND COULD BE ENOUGH FOR A
MARGINAL SEVERE THREAT IN AREAS THAT DESTABILIZE THE MOST.
..THURSDAY/DAY 6 AND SATURDAY/DAY 8
MID-LEVEL ZONAL FLOW IS FORECAST TO DEVELOP ON THURSDAY OVER MUCH OF
THE NORTH-CENTRAL AND NORTHWESTERN U.S., AS A RIDGE MOVES
SOUTHEASTWARD INTO THE WESTERN GREAT LAKES. A POCKET OF MODERATE
INSTABILITY IS FORECAST TO DEVELOP AHEAD OF A COLD FRONT ON THURSDAY
IN THE NORTHERN PLAINS. LIMITED LARGE-SCALE ASCENT SHOULD KEEP
CONVECTIVE COVERAGE ISOLATED. ALTHOUGH DEEP-LAYER SHEAR IS FORECAST
TO BE MODEST, ANY CELL THAT CAN DEVELOP AND PERSIST NEAR THE
STRONGER INSTABILITY IN THE LATE AFTERNOON AND EARLY EVENING COULD
OBTAIN AN ISOLATED SEVERE THREAT.
ON FRIDAY AN SATURDAY, A COLD FRONT IS FORECAST TO MOVE
SOUTHEASTWARD ACROSS THE NORTH-CENTRAL U.S. NEAR AND AHEAD OF THE
FRONT, ISOLATED THUNDERSTORMS WILL BE POSSIBLE EACH AFTERNOON FROM
THE UPPER MISSISSIPPI VALLEY INTO THE GREAT LAKES REGION. THE
COMBINATION OF INSTABILITY AND SHEAR COULD BE SUFFICIENT FOR AN
ISOLATED SEVERE THREAT. HOWEVER, CONSIDERABLE UNCERTAINTY EXISTS AT
THIS RANGE IN THE FORECAST.
..BROYLES.. 08/16/2025
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