Sea surface temperatures across much of the Gulf of Mexico are in the mid to upper 80s, and that warmth is adding to a hot August along the Gulf Coast. For people near the shore, the water is helping hold overnight temperatures up instead of letting the air cool quickly.
Much of the water is warmer than normal for this point in August. Water heats and cools more slowly than land, so the Gulf keeps its heat longer after sunset while inland areas lose heat more efficiently overnight.
August warmth along Gulf Coast
That difference shows up in the daily temperature range. Along the immediate coast, highs tend to stay a little lower than inland locations, but lows stay warmer because the Gulf keeps sending humid air back toward shore. During August, that can leave little relief before daytime heat builds again the following day.
One person feeling that pattern is a resident in MOBILE, Ala., where warm nights matter most when the air has already stayed hot through the evening. The same setup also affects the central Gulf Coast, where coastal areas can stay warmer overnight than communities a little farther inland.
For readers using the reef habitat story on Alabama's M60 Tanks as a comparison, the water’s slow response to heat is part of why coastal conditions can change less between day and night than they do farther inland.
Warm Gulf and hurricane season
The warm Gulf also matters as the Atlantic hurricane season moves toward its climatological peak. Tropical systems draw heat and moisture from warm ocean water, so unusually warm sea surface temperatures can provide additional energy for a developing storm.
That does not mean a tropical storm or hurricane will form or intensify on warm water alone. Wind shear, atmospheric moisture and the structure of a tropical disturbance still shape what happens next, and those conditions can either limit development or let a storm tap the ocean heat available in the Gulf.
Persistent ocean heat can also affect marine life below the surface. Warmer water holds less dissolved oxygen, fish and other mobile species may move toward cooler water, and corals can bleach if heat stress lasts too long.
