Big Rain Days

Fay brings Big Rain Days to all of Florida

Rain Or Shine Report for August 21st

TS Fay gave south Florida a coveted Big Rain Day! … actually, make that plural: Big Rain Days.

And when its done we may very well be able to chalk up a few Big Rain Days for all of Florida.

Call Fay a thirst quencher for a formerly drought parched peninsula state.
Big Rain Day is not my term:

It was coined over in the South Florida Water Management District’s meteorology shop, by Eric Swartz and Geoff Shaughnessy.

But as soon as I heard them say it, it made immediate sense.

It was somewhat of a watershed moment in my life as a hydrologist.

So often I find myself “locked in the numbers”, trying to describe hydrologic processes in decimal accuracy, with a carefully calibrated calculus of how the storm relates back in time to the parade of storms that came before.

The beauty of the Big Rain Day is that it breaks outside of that box – and calls it just like it is.

A Big Rain Day is whenever you get lots of rain really fast and spread across most of the region. The District’s meteorologists draw the meteorological line in the sky at 1 inch of District-wide daily rainfall.

Anything above that is a Big Rain Day.

If you’ve ever been caught out in the rain during a sudden down pour then you know exactly what I mean. Back in my younger years, during the summer break from school, I worked as a mason tender for Wayne Carter Construction in the bucolic countryside of Baltimore County Maryland and would be periodically confronted with a battle against time associated with the sudden appearance of a late afternoon thunder heads rising out of the pea-soup humidity. A mad scramble ensued to use up the “mud” (mortar), clean the mixer, cover the bricks, and load up the vehicles before the sky broke loose. Most of the time we would beat those clouds, but I remember a time or two when in the rush around to get it all done, the pitter patter of a few lone drops gave way to an accelerating downpour that fell from the sky in buckets. That was mirrored by my accelerating pace to get it all done and then a slow decelerating realization that there was no longer a reason to run: I was already as wet as a body could get wet – soaking wet to the bone.

Metaphorically, that’s sort of like the Big Rain Day.

Was it 3 inches, or 6, or was it 9, was it 12?

How about the +20 inches they are talking about in parts of Northeast Florida!

Actually, that could qualify as a RBRD:
A Really Big Rain Day!

I’ll have to check with the District meteorologist on that one.
But a Big Rain Day is a Big Rain Day.

Eric and Geoff point out that our annual rainfall totals are sort of dependent on them, and that our tendency to descend into drought mode is often an artifact of not getting them. That makes BRDs a critical cog in our water cycle wagon. But it’s a careful balance, too many and we’re back up in flood mode.
And in flat Florida, the rains that Fay is dropping — especially in the northeast part of the state — are causing floods of great severity. Fay could be crowned the rain maker of rain makers when its finally crosses (or should we say crawls) its way past the finish line into the history books of Florida storms.

As for the exact numbers, a storm like this is so big that it takes time for it to soak in – both literally and figuratively. I’ll have more to say on the storm in the upcoming days. That will give us a chance to get a better look how far water levels jump.

That’s also my way of buying time. Way back when I started this journal I developed the routine of updating my data sets every Monday. Storms that arrive on Monday and Tuesday, especially big game changers like Fay, sort of put a monkey wrench in the works of my weekly data update routine.

But in closing, I would like to hand out a Gold Medal to Lake Okeechobee.

The Lake rose from 11 to 12 ft in record breaking time: only needing 2 weeks to do so. It was only on August 6th that the Lake rose back above the 11 ft mark. That’s pretty amazing considering it took 73 weeks to break back up above 11.

The previous record holder was 1982 when the Lake did the same 11 to 12 ft jump in 3 weeks.

The water cycle never ceases to amaze.

And remember: the books are still open on Fay. And that includes south Florida, not just the north Florida and the panhandle. That means the rainfall numbers will continue to climb through the end of the week before we close the books on Fay.

And to think hurricane season is still a couple weeks away from its mid September peak!

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