375
ACUS02 KWNS 091738
SWODY2
SPC AC 091737
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1237 PM CDT SUN AUG 09 2026
VALID 101200Z - 111200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ROUGHLY FROM
ILLINOIS EASTWARD INTO PENNSYLVANIA...
..SUMMARY
THUNDERSTORMS WITH SEVERE WIND GUSTS WILL BE POSSIBLE MONDAY
AFTERNOON AND EVENING FROM NORTHERN ILLINOIS EASTWARD INTO WESTERN
PENNSYLVANIA. ISOLATED SEVERE GUSTS AND HAIL WILL ALSO BE POSSIBLE
FROM PARTS OF THE CENTRAL AND NORTHERN PLAINS INTO THE MIDWEST, WITH
SCATTERED STRONG STORMS OVER SOUTHERN ARIZONA.
..FROM NORTHERN IL EASTWARD INTO PA
A LEADING SHORTWAVE TROUGH MAY SUPPORT EARLY DAY THUNDERSTORMS OVER
PORTIONS OF NY AND PA, THOUGH PROBABLY NOT IMMEDIATELY SEVERE. SOME
CHANCE EXISTS FOR RE-DEVELOPMENT FROM SOUTHERN NEW ENGLAND INTO NJ
DURING THE AFTERNOON AS A SURFACE TROUGH DEVELOPS, AND AT LEAST
ISOLATED SEVERE ACTIVITY IS POSSIBLE. ADDITIONAL AFTERNOON STORMS
MAY DEVELOP ACROSS THE REMAINDER OF NY AND PA AS INSTABILITY
DEVELOPS BEHIND THE INITIAL WAVE WITH AREAS OF STRONG GUSTS AND
MARGINAL HAIL.
WHILE ISOLATED WIND/HAIL MAY OCCUR DURING THE EARLY TO MID AFTERNOON
AS THE AIR MASS BECOMES UNCAPPED, A GREATER COVERAGE OF SEVERE
STORMS IS EXPECTED DURING THE LATE AFTERNOON AND INTO THE EVENING
FROM SOUTHERN WI/IL INTO IN AND OH. HERE, A LARGE AREA OF STRONG
INSTABILITY WILL DEVELOP, WITH A PERSISTENT/DEEPENING BOUNDARY LAYER
THETA-E PLUME OUT OF THE SOUTHWEST. THE HIGH PWAT, RELATIVELY STEEP
MIDLEVEL LAPSE RATES, AND DEEP LAYER SHEAR OF 40-50 KT WILL SUPPORT
SUPERCELL DEVELOPMENT, WITH POSSIBLE BOWING STRUCTURES WITH TIME.
LARGE HAIL, PERHAPS AN ISOLATED TORNADO, AND DAMAGING WINDS WILL BE
POSSIBLE.
..NORTHERN PLAINS
SOUTHEAST SURFACE WINDS WILL MAINTAIN 60S F DEWPOINTS INTO NE AND SD
DURING THE AFTERNOON AS STRONG HEATING OCCURS NEAR A SURFACE TROUGH
OVER THE HIGH PLAINS/BLACK HILLS. THIS WILL OCCUR BENEATH MODERATE
WESTERLY FLOW ALOFT, WHICH WILL ELONGATE HODOGRAPHS AND PRODUCE
FAVORABLE DEEP-LAYER SHEAR FOR LONG-LIVED CELLS OR BOWS. STORM
COVERAGE IS UNCERTAIN, BUT THE CONDITIONAL RISK FOR LARGE DAMAGING
HAIL AND WIND IS HIGH. AT LEAST ISOLATED CELLS ARE EXPECTED TO FORM
NEAR THE BLACK HILLS AND INTO WESTERN NE WHERE HEATING WILL BE
STRONG, WITH PERHAPS GREATER STORM CHANCES INCREASING AFTER 00Z INTO
THE CENTRAL DAKOTAS WITH THE AID OF A MODEST NOCTURNAL LOW-LEVEL
JET.
..SOUTHERN AZ
SUBSTANTIAL MOISTURE WILL REMAIN OVER THE AREA MONDAY, WITH PWAT
OVER 1.25" AND AREAS OF 60S F DEWPOINTS. WESTERLY SURFACE WINDS ARE
FORECAST TO DEVELOP DURING THE AFTERNOON OVER SOUTHERN AZ, WHICH
WHEN COMBINED WITH THE DEEP EASTERLIES ALOFT, WILL SUPPORT
WESTWARD-PROPAGATING CELLS. STORMS SHOULD FORM NEAR THE RIM AND OVER
THE HIGHER TERRAIN OF SOUTHEAST AZ, WITH LOCALLY SEVERE GUSTS AS
ACTIVITY MOVES ACROSS THE LOWLANDS. A STORM OR TWO COULD POTENTIALLY
PRODUCE SMALL HAIL AS WELL AS DEEP-LAYER EFFECTIVE SHEAR WILL BE
OVER 30 KT.
..JEWELL.. 08/09/2026
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page