197
ACUS02 KWNS 200557
SWODY2
SPC AC 200556
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1256 AM CDT WED AUG 20 2025
VALID 211200Z - 221200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR THE
CENTRAL/EASTERN DAKOTAS INTO PARTS OF MINNESOTA...
..SUMMARY
AN ISOLATED SEVERE THREAT IS EXPECTED TO DEVELOP THURSDAY INTO
THURSDAY NIGHT OVER PARTS OF THE DAKOTAS INTO MINNESOTA, WITH SEVERE
GUSTS AND HAIL POSSIBLE.
..NORTHERN PLAINS INTO PARTS OF MN
A MID/UPPER-LEVEL SHORTWAVE TROUGH IS FORECAST TO EVOLVE INTO A
DEEP-LAYER CYCLONE AS IT MOVES EASTWARD ACROSS PARTS OF THE CANADIAN
PRAIRIES ON THURSDAY. A TRAILING COLD FRONT WILL MOVE THROUGH THE
DAKOTAS AND NORTHWEST MN, WITH A WEAK FRONTAL WAVE POTENTIALLY
DEVELOPING ACROSS SD. DIURNAL HEATING OF A RELATIVELY MOIST AIRMASS
WILL RESULT IN MODERATE TO LOCALLY STRONG DESTABILIZATION BY LATE
AFTERNOON.
AN EMBEDDED MID/UPPER-LEVEL SHORTWAVE TROUGH AND ASSOCIATED REMNANT
CONVECTION IS EXPECTED TO MOVE ACROSS MB/ND AND NORTHERN MN EARLY IN
THE DAY. IN THE WAKE OF THIS SHORTWAVE, LARGE-SCALE ASCENT IS
EXPECTED TO BE GENERALLY WEAK UNTIL LATER THURSDAY NIGHT, RESULTING
IN UNCERTAINTY REGARDING AFTERNOON/EVENING STORM DEVELOPMENT.
ISOLATED STORM DEVELOPMENT CANNOT BE RULED OUT NEAR THE FRONT, AND
POTENTIALLY NEAR THE WEAK SURFACE LOW ACROSS SD. AN INCREASE IN
STORM COVERAGE IS EXPECTED LATE THURSDAY NIGHT, AS SOMEWHAT STRONGER
MIDLEVEL HEIGHT FALLS AND UPPER-LEVEL DIFLUENCE OVERSPREAD THE
REGION.
THE STRONGEST MID/UPPER-LEVEL FLOW WILL TEND TO LAG BEHIND THE
FRONT, BUT DEEP-LAYER SHEAR WILL STILL BE SUFFICIENT FOR SOME STORM
ORGANIZATION, INCLUDING CONDITIONAL SUPERCELL POTENTIAL. THE
MARGINAL RISK HAS BEEN MAINTAINED WITH THIS OUTLOOK, BUT GREATER
SEVERE PROBABILITIES MAY EVENTUALLY BE NEEDED, DEPENDING ON TRENDS
REGARDING STORM COVERAGE AND TIMING FROM PARTS OF THE DAKOTAS INTO
NORTHWEST MN.
OTHER STRONG STORMS MAY DEVELOP THURSDAY NIGHT ACROSS PARTS OF THE
NORTHERN HIGH PLAINS, WITHIN A FAVORABLY SHEARED POST-FRONTAL
REGIME. SEVERE PROBABILITIES MAY EVENTUALLY NEED TO BE EXPANDED
WESTWARD, IF CONFIDENCE INCREASES IN A FAVORED POST-FRONTAL
CORRIDOR.
..COASTAL NC
THE CENTER OF HURRICANE ERIN IS FORECAST BY NHC TO REMAIN WELL
OFFSHORE OF COASTAL NC ON THURSDAY AS IT BEGINS MOVING
NORTHEASTWARD. HOWEVER, THE WESTERN PERIPHERY OF ERIN'S LARGE WIND
FIELD WILL RESULT IN RATHER STRONG DEEP-LAYER NORTHERLY FLOW ACROSS
THE OUTER BANKS AND VICINITY. IF MODEST DIURNAL HEATING CAN OCCUR,
THEN SHOWERS AND POSSIBLY A FEW WEAK STORMS MAY DEVELOP DURING THE
AFTERNOON, THOUGH IT IS UNCERTAIN IF ANY SUCH DEVELOPMENT WOULD BE
SUFFICIENTLY VIGOROUS TO SUPPORT CONVECTIVELY AUGMENTED GUSTS.
..PARTS OF THE SOUTHEAST/SOUTHERN APPALACHIANS
SCATTERED THUNDERSTORMS ARE FORECAST TO DEVELOP ACROSS PARTS OF THE
SOUTHEAST AND SOUTHERN APPALACHIANS VICINITY THURSDAY AFTERNOON.
DEEP-LAYER SHEAR WILL REMAIN QUITE WEAK, BUT NORTHERLY LOW-MIDLEVEL
FLOW MAY SUPPORT ONE OR MORE SOUTHWARD-MOVING CLUSTERS. POOR
MIDLEVEL LAPSE RATES WILL TEND TO LIMIT UPDRAFT INTENSITY, AND THE
ORGANIZED SEVERE THREAT APPEARS LOW, BUT LOCALIZED TREE DAMAGE COULD
ACCOMPANY THESE STORMS DURING THE AFTERNOON AND EARLY EVENING.
..ARIZONA
THUNDERSTORMS ARE EXPECTED TO DEVELOP THURSDAY AFTERNOON AND EVENING
ACROSS PARTS OF AZ, INITIALLY NEAR THE HIGHER TERRAIN. ISOLATED
STRONG GUSTS COULD ACCOMPANY THESE STORMS. WITH AN AMPLIFIED
UPPER-LEVEL RIDGE ANCHORED NEAR THE FOUR CORNERS, MIDLEVEL FLOW WILL
GENERALLY BE EASTERLY ACROSS CENTRAL/SOUTHERN AZ. THE EASTERLY
STEERING FLOW AND A VERY HOT AND WELL-MIXED ENVIRONMENT COULD
SUPPORT A THREAT OF STRONG OUTFLOW GUSTS INTO THE LOWER ELEVATIONS,
THOUGH IT IS UNCERTAIN IF STORM COVERAGE WILL BE SUFFICIENT FOR
LARGER-SCALE OUTFLOW DEVELOPMENT AND MORE THAN VERY ISOLATED
DAMAGING-WIND POTENTIAL.
..DEAN.. 08/20/2025
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