574
ACUS01 KWNS 221623
SWODY1
SPC AC 221621
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1121 AM CDT WED JUL 22 2026
VALID 221630Z - 231200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS
AFTERNOON/EVENING FOR MAINE AND THE MID-ATLANTIC...
..SUMMARY
SCATTERED STORMS ARE EXPECTED ACROSS THE CAROLINAS AND SOUTHERN
MID-ATLANTIC, AS WELL AS NEW ENGLAND THIS AFTERNOON AND EARLY
EVENING, WITH DAMAGING WINDS AS THE PRIMARY CONCERN. ISOLATED STRONG
TO SEVERE WIND GUSTS ARE ALSO POSSIBLE IN THE CENTRAL HIGH PLAINS,
SOUTHEAST TEXAS AND CENTRAL OREGON, WHERE ISOLATED LARGE HAIL WILL
ALSO BE POSSIBLE.
..NORTHERN NEW ENGLAND THIS AFTERNOON
PER WATER VAPOR IMAGERY AND MORNING UPPER AIR OBSERVATIONS, A
PRONOUNCED MIDLEVEL TROUGH WILL PROGRESS EAST-NORTHEASTWARD FROM
PA/NY/SAINT LAWRENCE VALLEY TOWARD NEW ENGLAND THROUGH THIS
AFTERNOON. AN ASSOCIATED SURFACE COLD FRONT WILL LIKEWISE MOVE
EASTWARD AND PROVIDE A FOCUS FOR THUNDERSTORM DEVELOPMENT BY EARLY
AFTERNOON INTO MAINE. A FEW CLOUD BREAKS DEVELOPING FROM
WEST-TO-EAST THROUGH THE AFTERNOON WILL ALLOW SURFACE TEMPERATURES
TO WARM INTO THE 70S WITH BOUNDARY-LAYER DEWPOINTS IN THE MID 60S,
RESULTING IN MLCAPE IN THE 1000-1500 J/KG RANGE. DEEP-LAYER,
SOUTH-SOUTHWESTERLY SHEAR WILL BE SUFFICIENT FOR A MIX OF CLUSTERS
AND SUPERCELLS WITH A PRIMARY THREAT FOR OCCASIONAL WIND DAMAGE.
..MID-ATLANTIC THIS AFTERNOON/EVENING
A PRE-FRONTAL BAND OF CONVECTION IS ONGOING ACROSS SOUTHERN VA, WITH
A NARROW ZONE OF STRONGER SURFACE HEATING/DESTABILIZATION TO THE
NORTH OF THE THICKER CLOUDS FROM NORTHERN VA INTO MD/DE IN ADVANCE
OF A COLD FRONT MOVING ACROSS PA. THE SOUTHERN FRINGE OF THE
STRONGER (35-50 KT) MIDLEVEL FLOW EXTENDS TO NEAR THE VA/NC BORDER
ON THE SOUTH SIDE OF THE THICKER CLOUD BAND. THE ONGOING CONVECTION
IS LIKELY PERSIST THROUGH THE AFTERNOON WHILE SPREADING SLOWLY
SOUTHWARD. MIDLEVEL LAPSE RATES WILL REMAIN POOR, BUT DEEP-LAYER
VERTICAL SHEAR WILL BE SUFFICIENT FOR EMBEDDED/ORGANIZED STORMS WITH
OCCASIONAL WIND DAMAGE. LOW-LEVEL SHEAR WILL BE MARGINALLY
FAVORABLE FOR ROTATING STORMS AND PERHAPS AN ISOLATED TORNADO.
..SOUTHEAST TX LATE THIS AFTERNOON THROUGH LATE EVENING
STRONG SURFACE HEATING IS UNDERWAY WITH A GENERAL CONFLUENCE ZONE
NEAR THE TX/LA BORDER WELL TO THE WEST OF HIGHLY-SHEARED TROPICAL
STORM BERTHA. AS BERTHA CONTINUES WESTWARD, THIS CONFLUENCE ZONE
SHOULD SUPPORT THUNDERSTORM DEVELOPMENT INTO SOUTHEAST TX LATE THIS
AFTERNOON. STEERING FLOW FROM THE NORTHEAST AT ~35 KT WILL FAVOR
STORM CLUSTERS MOVING SOUTHWESTWARD INTO A HOT, DEEPLY MIXED
BOUNDARY LAYER WHERE BUOYANCY WILL BE SUFFICIENT TO MAINTAIN THE
STORM CLUSTERS INTO LATE EVENING. A FEW STRONG-SEVERE OUTFLOW GUSTS
WILL BE THE MAIN THREATS.
..NORTHEAST CO AND VICINITY THIS AFTERNOON/EVENING
LOW-LEVEL UPSLOPE FLOW ON THE COOL SIDE OF A SURFACE FRONT, COMBINED
WITH WEAK PERTURBATIONS ROTATING AROUND THE NORTHWEST PERIPHERY OF
THE SOUTHERN PLAINS MIDLEVEL HIGH, WILL SUPPORT AFTERNOON
THUNDERSTORM DEVELOPMENT OVER THE FOOTHILLS. THE STORMS WILL SPREAD
EAST-SOUTHEASTWARD ONTO THE PLAINS, WITH A TENDENCY FOR CLUSTERING
WITH THE POTENTIAL FOR ISOLATED SEVERE OUTFLOW GUSTS.
..OR THIS AFTERNOON/EVENING
ALONG THE NORTHWEST EDGE OF THE MONSOONAL MOISTURE PLUME, A MIDLEVEL
SHORTWAVE TROUGH WILL MOVE NORTHWARD FROM NORTHERN CA INTO OR. WEAK
FORCING FOR ASCENT COMBINED WITH DAYTIME HEATING OVER THE HIGHER
TERRAIN WILL SUPPORT SCATTERED THUNDERSTORMS LATER THIS
AFTERNOON/EVENING FROM THE CASCADES INTO CENTRAL OR. AN ENVIRONMENT
WITH MLCAPE OF 500-1000 J/KG, STEEPENING LOW-LEVEL LAPSE RATES AND
EFFECTIVE BULK SHEAR NEAR 25 KT WILL SUPPORT ISOLATED STRONG OUTFLOW
GUSTS AND MARGINALLY SEVERE HAIL.
..THOMPSON/CHALMERS.. 07/22/2026
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