The NOAA Ocean Service coastal-flood map is still lit on Sunday morning of Memorial Day weekend, and the Mid-Atlantic cold-and-wet forecast is sitting on top of it. The Pacific El Niño signal that has kept the National Hurricane Center's Atlantic tropical-weather outlook at zero disturbances for an eighth straight day is the same signal pushing extra inches of saltwater onto Carolinas, Mid-Atlantic, and Northeast curbs at high tide. The two readings are still true on the same forecast map. [1][2]

Saturday's brief on the El Niño multiplier into the holiday tide carried the framing north from Miami Beach; the Sunday update is the operational data point. Charleston's Sunday tide gauge runs at 8:42 a.m. and 9:06 p.m.; Cape May runs at 9:14 a.m. and 9:38 p.m.; Sandy Hook 26 minutes earlier. The NOAA Coastal Inundation Dashboard is reading "minor" coastal-flood thresholds active along the Carolinas through New Jersey, with elevated baselines extending into Maine where NWS Caribou has confirmed rain starting Sunday night and continuing into Memorial Day. The high tide is the schedule. The rain is the weather. The multiplier is the reason both are happening on the same Sunday morning. [1][3]

In plain English: a strong Pacific El Niño tears apart the wind fields that would let Atlantic hurricanes spin up, which is why the basin's tropical map is empty in late May. The same signal lifts a few extra inches of water onto American coasts at routine high tide, even with no storm in the sky. For a Memorial Day Sunday cookout in Cape May or Charleston, the consequential forecast is not the rain percentage. It is the tide table. The street that floods at 9 a.m. with no storm offshore is the El Niño multiplier in print. [2][3]

-- DARA OSEI, London