SPC MD 865

MD 0865 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PARTS OF NORTHERN MAINE Mesoscale Discussion 0865 NWS Storm Prediction Center Norman OK 0523 PM CDT Tue May 26 2026 Areas affected...parts of northern Maine Concerning...Severe potential...Watch unlikely Valid 262223Z - 270100Z Probability of Watch Issuance...5 percent SUMMARY...A line of thunderstorms may progress across the international border by around 8 PM EDT, with continuing potential for a few strong gusts before weakening further thereafter. DISCUSSION...The most prominent thunderstorm activity, within a pre-frontal convective band now advancing to the southeast of the St. Lawrence Valley, appears to be propagating a bit slower and to the right of the 50-60 kt deep-layer westerly ambient mean flow, but still around 40 kt. With this continuing motion, storms are on pace to progress across the international border, coincident with a broad area of lower pressure to the south of the primary surface cyclone, between 23-00Z. Latest mesoanalysis suggests that the modestly deep mixed boundary layer ahead of activity may remain sufficiently unstable to support convection capable of producing a few strong surface gusts into portions of northern Maine, before storms weaken further with diminishing severe weather potential thereafter. ..Kerr/Thompson.. 05/26/2026 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...CAR...GYX... LAT...LON 46337223 46647119 46907038 47116938 46486815 45816994 45777058 46337223 MOST PROBABLE PEAK WIND GUST...55-70 MPH Read more