


Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
609 ACUS02 KWNS 131732 SWODY2 SPC AC 131731 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1231 PM CDT Sun Jul 13 2025 Valid 141200Z - 151200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM SOUTHERN NEW ENGLAND TO THE MID ATLANTIC AND THE NORTHERN ROCKIES/PLAINS... ...SUMMARY... Isolated strong to severe thunderstorms are possible across portions of the northern Plains/Rockies and across the Mid Atlantic and Southern New England Monday. ...Mid Atlantic to southern New England... Weak troughing at the northern periphery of the subtropical ridge will shift northward across parts of the Northeast Monday. At the surface, a wind shift/weak front will move from the eastern Great Lakes into the upper OH/St Lawrence Valley by early afternoon. A very warm and humid air mass is in place east of the front with dewpoints in the 70s F expected. Despite some lingering cloud cover, diurnal heating should support moderate destabilization over much of the Northeast. Widespread thunderstorm activity is expected along and ahead of the surface boundary from northern VA into southern NY. Slight enhancement of the flow aloft to near 20 kt from the approaching shortwave could be enough to foster some longer-lived clusters with damaging gust potential from northern VA into southern NY. Elsewhere across the East, confidence in storm coverage/damaging wind potential is lower, but any stronger storms will remain cable of damaging outflow gusts from heavily water-loaded downdrafts. ...Northern Rockies and Plains... An upper trough, forecast to emanate from southern Canada, will move eastward over the northern Rockies/Plains Monday and Monday night. Ascent from this feature will overspread a weak cold front and lee trough/low, that will serve as a focus for scattered thunderstorms through afternoon and evening. Along the southern fringes of enhanced westerly flow aloft, a mix of multicells and transient supercells is expected. Modest surface moisture and deep boundary-layer mixing will support moderate buoyancy atop inverted-v structures favorable for damaging gusts and some hail with storms from northern WY into the western Dakotas. Late in the evening and into the overnight hours, low-level warm advection and continued ascent from the upper trough are expected to intensify along and north of the cold front from eastern MT into ND. A belt of strong mid-level flow (35-50 kt) will overlap with elevated destabilization north of the front. While not overly robust, sufficient buoyancy (MUCAPE ~1000 J/kg) and elongated hodographs should support a few organized elevated storms (including supercell structures) capable of isolated hail. ...Southeast States... A seasonably warm and moist air mass will again reside across much of the southeastern US beneath broad subtropical ridging aloft. Scattered to numerous storms expected Monday afternoon and evening amid strong diurnal heating and weak background ascent. With PWATs near or exceeding two inches and moderate buoyancy, a few stronger thunderstorm clusters may develop. With weak vertical shear below 15 kt, organized storms on a widespread basis are not expected. Still, sporadic damaging gusts from wet microbursts are possible. ..Lyons.. 07/13/2025 $$