RAIN or shine

Rain or Shine Report for January 23
Lake, Dow approach milestone lows

The big news in South Florida is the Lake’s return back toward the 10 ft mean sea level mark.

It’s still hovering an inch or two above 10, but it’s still at its lowest January mark on record. The Lake’s current level is almost 2 ft lower than January of last year. Looking back to last year, it wasn’t until much later in the dry season — early April — that Lake stage dropped below 10 ft, and it took an additional 12 weeks after that before it bottomed out at its all-time low of 8.8 ft msl.

That puts us around over two months ahead of last year’s drop.

Looking back, this is the first consecutive Summer and Fall on record that Lake stage did not rise above 11 ft. Back during the 2001 drought, Lake stage rose above 11 ft in early August, and shot up to 14 ft by late September 2001.

This year the Lake only rose above 10 in early October, and appears poised to drop back below the mark 4 months later, if not a week or two before.

Why so much emphasis on the Lake?

Lake stage is as close as we have to a universal hydrologic index in south Florida. In that way its not unlike the financial worlds Dow Jones Industrial Index. The Dow doesn’t tell you everything you need to know about the stock market or the economy — and to be sure other indices are more comprehensive — but the Dow rings a historical and cultural chord that resonates among both professionals and the public.

So too does the Lake: for its history, its central role in south Florida’s water pie, and as a barometer for gaging the state of the water cycle. Other indices are probably more comprehensive, but Lake level rings a bell that stakeholders and the public pay attention to.

Similar to the Lake, the Dow approach (and plunged below) a milestone low this week — the 12000 mark — which it first rose above back in late 2006.

Wall Street has its Bull and Bear. South Florida’s water cycle has its Hare and Tortoise.
But the two are reversed.

The rise of The Dow is gradual, inching up in a very incremental fashion, but when the Dow falls, it can do so precipitously and quickly.

Compare that to the rise of The Lake.

The Lake’s rise can be rapid and dramatic, increasing several feet in a week or two span in response to summer deluges and inflows from the Kissimmee — during which The Hare sprints ahead of The Tortoise in the annual water cycle race.

By contrast, the fall of The Lake is very gradual — moving down incrementally inch by inch –over the course of months — in response to the more constant (but less dramatic) tug of the sun through evaporation — during which The Tortoise slowly gains ground (and passes) the sleeping Hare.

But hold the press.

Blustery weather overtook south Florida this weekend — signaling surprise, and presumably temporary, dry season visit from The Hare (rainfall). That’s only a momentary setback to the Tortoise (evaporation), which should start to kick in for its annual sprint to the end of the dry season sometime in early February.

Central Florida received the most rain from this system, a good portion of which dropped in the Upper Kissimmee, which in turn feeds down towards the Lake. That could help sustain Kissimmee River flows farther into the dry season.

The National Weather Service shows spots in central Florida where over 5 inches fell over the past 7 days, but the representative total appears to be closer to 2-3 inches. Still, that’s a sizeable event considering we’re in the middle of our annual dry season, several seasons into a multi-year drought, and that a La Nina is in play.
Ft Myers and Lake Okeechobee received around an inch of rain in comparison, with amounts progressively diminishing towards the southeast.

I was on Key Largo for the weekend.

It was blustery, and cooler than normal, but only a sprinkling at most.

To be honest, with that rain falling in the early AM hours, I had initially assumed that the rain was an artifact of Miami’s famed morning showers, caused by the Gulf Stream convergence of nightime land breeze hitting head on with the easterly inflow of Trade Winds spinning off the Atlantic’s Bermuda High.

After a quick glance at the radar I could see it was part of a larger regional system.

And one that presumable will give a boost to flows and flow duration in the Kissimmee, which in turn may feed some additional water into the Lake.
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The Lake’s drop back below 10 is near, but still hovers on the horizon for now.

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