Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
786 ACUS02 KWNS 220555 SWODY2 SPC AC 220554 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1254 AM CDT Sat Jun 22 2024 Valid 231200Z - 241200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF PA/NY INTO VT/NH...WESTERN MA...NORTHWEST CT...EXTREME WESTERN ME... ...SUMMARY... Scattered damaging winds and a few tornadoes are possible across parts of the Northeast on Sunday. ...Northeast... A Slight Risk has been added for parts of the Northeast on Sunday, with potential for scattered damaging winds and a few tornadoes during the afternoon and early evening. Guidance still varies regarding the amplitude of embedded shortwaves moving through a large-scale upper trough from the Great Lakes into the Northeast on Sunday, which in turn results in uncertainty regarding the strength/track of a related surface low. In general, potential for rather strong low/midlevel flow to overspread a moderately unstable environment remains evident across much of the Northeast. Scattered thunderstorm development will be possible by afternoon, both along and in advance of the cold front. Organized cells/clusters will be possible, including the potential for a few supercells. A zone of relatively backed surface winds may persist through the day from central/eastern NY into parts of NH/VT/western MA, in closer proximity to the surface warm front. Locally enhanced low-level shear/SRH and sufficient deep-layer shear will support some potential for tornadic supercells across this area. Otherwise, scattered damaging winds will be possible with both frontal and prefrontal convection across the broader region during the afternoon and evening, before an expected weakening trend by later Sunday night. ...OH/TN Valley vicinity... The cold front trailing from the New England system will move across parts of the Ohio Valley during the afternoon and evening. Thunderstorm development will be possible along/ahead of the front, within a moderately unstable and modestly sheared environment. A few stronger cells or small clusters will be possible within this regime, with a threat of locally damaging wind. Some convection may spread into parts of northern MS/AL Sunday night, though the potential severity of any nocturnal convection in this area remains uncertain. ...Eastern MT into northwest ND... A shortwave trough is forecast to move east-northeastward from the Pacific Northwest into parts of BC/AB by Sunday evening. A deepening surface cyclone will accompany this shortwave, with a cold front trailing southward into parts of MT. Low-level southeasterly flow will transport modest low-level moisture into parts of eastern MT, resulting in the potential for moderate destabilization. Deep-layer shear will be favorable for organized convection, but large-scale ascent attendant to the shortwave trough may tend to remain north of the international border. Development of a strong/severe storm or two across eastern MT cannot be ruled out by early evening, which would then potentially spread into northwest ND Sunday night. A Marginal Risk has been added for this conditional scenario. ..Dean.. 06/22/2024 $$