634
ACUS02 KWNS 210517
SWODY2
SPC AC 210515

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1215 AM CDT Tue Jul 21 2026

Valid 221200Z - 231200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
SOUTHERN MID-ATLANTIC...

...SUMMARY...
Isolated severe thunderstorms will pose a risk for damaging wind
gusts across parts of the southern Mid-Atlantic. Additional
thunderstorms are expected northward across New England, some of
which could produce locally strong wind gusts.

...Mid-Atlantic into New England...

Several shortwave impulses are forecast to move through large-scale
upper troughing across the Northeast on Wednesday. Relatively strong
deep-layer winds for mid/late July are forecast, characterized by
500 mb southerly flow around 45-60 kt, 35-55 kt at 700 mb, and 25-35
kt at 850 mb. At the surface, low pressure will lift northeast
across Quebec, with a surface trough extending southward into the
Mid-Atlantic. A cold front is forecast to be located from eastern NY
to the central Appalachians and the TN Valley Wednesday morning. The
northern extent of the front will be rather progressive as it moves
across New England and the northern Mid-Atlantic through the
afternoon and evening. The southern extent of the front will more
slowly sag south/southeast across VA/NC. Ahead of the front,
southerly low-level flow will maintain a seasonally moist airmass
beneath the moderately strong deep-layer wind fields.

While the boundary layer will be moist, strong heating will be
limited due to cloud cover and poor lapse rates. This will limit
instability, especially with northward extent into New England.
Nevertheless, sufficient instability coupled with the stronger
deep-layer flow will support organized clusters capable of wind
damage. The greatest risk will be focused across the southern
Mid-Atlantic where instability will be greatest (1000-1500 J/kg
MLCAPE).

..Leitman.. 07/21/2026

$$