068
ACUS03 KWNS 120731
SWODY3
SPC AC 120730
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0230 AM CDT SUN JUL 12 2026
VALID 141200Z - 151200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS NORTHERN
NEW ENGLAND...
..SUMMARY
SEVERE THUNDERSTORMS WILL BE POSSIBLE DURING THE AFTERNOON AND
EVENING ACROSS PORTIONS OF NEW ENGLAND ON TUESDAY. ADDITIONAL
STRONG-TO-SEVERE THUNDERSTORMS WILL BE POSSIBLE ACROSS PARTS OF
WESTERN AND CENTRAL MONTANA.
.. SYNOPSIS
AN EXPANSIVE MID-LEVEL RIDGE CENTERED OVER THE NORTH-CENTRAL US WILL
BEGIN TO RETROGRADE ON TUESDAY AS A STRONG SHORT-WAVE TROUGH DIGS
SOUTHEAST OUT OF CANADA TOWARD NEW ENGLAND. AS THE RIDGE BUILDS
WEST, THE MID-LEVEL HEIGHT GRADIENT WILL INCREASE ACROSS THE
NORTHWESTERN US AS A SEASONABLY STRONG MID-LEVEL TROUGH/CLOSED LOW
REMAINS ANCHORED OFF THE WASHINGTON/OREGON COASTS.
.. NEW ENGLAND
THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS PORTIONS OF QUEBEC ON
TUESDAY AFTERNOON AS A STRONG MID-LEVEL TROUGH AND ATTENDANT SURFACE
COLD FRONT MOVE ACROSS THE REGION. AHEAD OF THIS COLD FRONT,
SOUTHWESTERLY SURFACE WINDS WILL TRANSPORT IN RICH BOUNDARY LAYER
MOISTURE, WHICH WILL COMBINE WITH DIURNAL HEATING TO SUPPORT MUCAPE
IN THE 1500-2500 J/KG RANGE. STRONG VERTICAL SHEAR (ON THE ORDER OF
50-60 KNOTS) WILL OVERSPREAD THE REGION DURING THE AFTERNOON AND
EVENING, WHICH WILL SUPPORT ONE OR MORE CLUSTERS OF SEVERE
THUNDERSTORMS MOVING FROM QUEBEC INTO AND ACROSS PORTIONS OF NEW
ENGLAND DURING THE LATE AFTERNOON, EVENING, AND EARLY MORNING HOURS.
ALL SEVERE HAZARDS WILL BE POSSIBLE WITH ANY SUSTAINED THUNDERSTORM.
ONE MITIGATING FACTOR FOR A MORE SIGNIFICANT SEVERE WEATHER EVENT
WILL BE THE TIMING OF THE STORMS. AT THIS TIME, IT APPEARS
THUNDERSTORMS WILL BE MOVING ACROSS NEW ENGLAND WELL AFTER PEAK
HEATING AND INTO THE OVERNIGHT. SHOULD THE TIMING OF STORMS BE
EARLIER THAN CURRENTLY EXPECTED, GREATER COVERAGE OF THUNDERSTORMS
MAY RESULT AND HIGHER SEVERE PROBABILITIES WOULD BE WARRANTED.
.. PORTIONS OF WESTERN AND CENTRAL MONTANA
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS THE HIGHER
TERRAIN OF SOUTHWEST MONTANA DURING THE AFTERNOON ON TUESDAY.
SURFACE MOISTURE WILL BE BETTER (SURFACE DEWPOINTS IN THE 50FS) THAN
IN PREVIOUS DAYS, WHICH SHOULD SUPPORT GREATER AFTERNOON BUOYANCY
AND IN TURN STRONGER THUNDERSTORM UPDRAFTS. STRONG
SOUTH-SOUTHWESTERLY MID-LEVEL FLOW IN BETWEEN THE TROUGH TO THE WEST
AND RIDGE TO THE EAST WILL SUPPORT THUNDERSTORM ORGANIZATION AND
SOME SEVERE POTENTIAL AS SOME OF THE STORMS MOVE NORTHEAST OFF THE
HIGHER TERRAIN.
..MARSH.. 07/12/2026
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