NOAA's Ocean Service kept its El Niño high-tide flooding warning live on Friday, with the CPC ENSO probabilities still putting the chance of El Niño emerging by July at roughly 82%. NOAA's monthly high-tide flooding outlook flags Sunday May 24 through Tuesday May 26 as the highest-tide window on the East Coast and central Gulf — covering Memorial Day weekend. [1][2]

The plain-English version of "El Niño sea-level multiplier": decades of slow sea-level rise have already left water lapping the top of seawalls in many U.S. coastal towns. An El Niño raises Pacific and Atlantic water levels another few inches by warming and pushing water against the eastern Pacific and the Atlantic seaboard. Add the two together and the same routine lunar high tide that used to wet a beach parking lot can now flood a sidewalk, a basement door, or a holiday boardwalk on a clear day with no storm anywhere on the radar. NOAA's William Sweet, who anchored the paper's May 21 brief, calls this the "second punch" after the first punch of accumulated rise. [3]

The Friday service rail: Florida, the Carolinas, and the central Gulf are the highest-probability streets to see saltwater this weekend. The hurricane outlook NOAA printed Wednesday at 8–14 named storms is a separate document; the tides arrive regardless of that number. [1][2]

-- DARA OSEI, London