Seasonal fluctuations in water temperatures are common and often extreme here in southern Ocean County, NJ. Water temperatures may plummet over the course of a couple of tidal cycles. This past week July 18th, 2024 we woke to frigid water temps. My watch was reading 56 degrees early Thursday morning.
Why does this happen you may wonder. The answer is fairly simple but science is involved in the explanation so I'll do my best to keep it short and sweet.
Summer here in southern Ocean County is a time when we have southerly trade winds. They may shift from the South East to the South West. These southerly trades at times blow at near gale force causing upwelling in the ocean.
Upwelling is a process where colder deeper waters replace warmer surface waters. This happens most quickly when the winds are South East and strong. Most recently the winds were blowing hard out of the South East and caused the ocean temperature to plummet to 56 degrees.
In the northern hemisphere surface currents move 20 to 40 degrees to the right of wind direction. Here in Seaside Park those strong South East winds move all our warm coastal waters offshore and leave us with the cold bottom water.
Within 36 hours of the cold drop in water temperatures the ocean now has peaked back up at 70 degrees. That's at 14 degree temperature swing! Now how did that happen you may ask.
While South East winds cause upwelling, North East winds do the opposite and pile up all the warm surface water along the coast. Voila! Warm surf conditions!
In conclusion, just remember Southerly winds will cool the ocean and North East winds will warm the ocean. This explanation is specifically for Seaside Park and locally adjacent coastal waters. The stronger the winds the more drastic the results.
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