Does Colder Water Mean Better Thermals??

In Chicago in the Summer we can count on North winds bringing the air getting cooled and becoming denser from the cold lake water as it comes on shore. This air expands and rises from the heat of the city. As it does it creates a strong on shore thermal flow that picks up around 5 pm and runs till the sun sets around 7 pm. My question as a relative newbie comes from the record cold temps that have produced record cold water. Do some of the "old hands" on this forum think the colder water will lead to better thermals when the sun returns and the land heats up again? If so, what wind directions produce the best thermals? Do the thermals kick in late in the day? Afternoon? All day?

On Lake Michigan the thermals work anywhere when we have cold water about 50 and hot land. The northern lake with a very cold pool of water gets great summertime thermals on S and SW winds that the heat of the land pulls on shore in the afternoon. This makes for great consistent kiting in great fresh water which few outside the region really know about.

On the East coast of Florida I've ridden the late afternoon thermal winds that come on shore in Cocoa and Jupiter. I wonder if we get anything like that around Tampa Bay?

Regards,
Tim

[Steve-O]

We get some seabreezes here in the spring for sure. Usually N to NW.

It helps to have windflow already in the air from a passing front. A NE wind in the am helps to create a N to NW seabreeze in the pm.

Bright sunny days are the best IMO. If its overcast, that pretty much kills the effect.

Some have noted a 25 degree plus temperature change from the morning low to the afternoon high also is a helpful factor.

It is yet to be seen if this unusually cold water we have will have any effect on better seabreezes. We will get them regardless, the question is will we have more of them than normal due to the cold water in the gulf.

Have to wait and see.

Scott has been following the wind around here as long as anyone and I am sure will have some helpful info on the subject.

[Unimog Bob]

I think a couple guys are overlooking something, or assuming...
When the sun returns and the land heats up, so will the water (pretty quickly) is my bet. The Gulf is pretty shallow. I don't think we will have a huge degree of separation b/n the Gulf temp. and afternoon highs for very many weeks. (Not anything like 60 or 65 vs. 85 or 90, anyway).

I have seen the Gulf temp change as much as 15 degrees in 3 days (near shore in our area).

Other than that, I use to pay very close attention to the weather patterns around here and I have noticed a particular pattern to sea breezes along St. Pete Beach. It can get a little hard to describe, but I think the afternoon sea breezes have more to due with high pressure system(s) and where it is sitting (to our west is great... not over the east coast), - and believe it or not- tides seem to influence them as well (at least close to PaG). Sounds crazy, but a strong outgoing tide seems to amp up the sea breeze. High pressure seems to cause an early a.m. NE flow, followed by a possible afternoon s.b.

Also, the typical sea breeze turns on like a frickin' switch - literally 5 knots or 0 knots NE straight to 20 NW in less than 5 minutes. It's pretty awesome to watch it from it's beginning.
They turn off almost as fast and average 2.5 hours in time. So, I usually start driving to the beach when the Skyway sensor says "Zero" (no, I am not joking) if the other variables I observe that day fit my "model". Most of our beach sensors either suck or update AFTER the sea breeze is over... so... you have to anticipate them or get a call early or sumtin.
If you wait til a sensor says "it's blowing" to leave, you will probably get there at the tail end of it.

S.b.s don't happen every day, btw, even during a good season. If I had to guess, maybe 10 out of 30 days.

It's also very common for s.b.s to come in waves of three days. So, if it blows one day good, the next is a good bet (around the same time).
It use to be that March was our premier s.b. month.. the last 3 years or so, April has been the best, up until maybe late May or until it's starts raining in the afternoons.

Who knows what will happen. This area has a HIGH degree of variance with wind/weather, is one thing I have noticed. It's pretty ridiculous and I would never bet on squat around here weatherwise more than 2 days in advance.

Bob,

Thanks for thoughts on sea breezes and thermals which makes sense to me. I had overlooked the fact of the relatively shallow depth of the Gulf. Lake Michigan's average depth of over 200 feet keeps the core temp of the deep water at 40F. This means that the wind can blow the warmer surface water away and the cold water will well up in its place. The Northern part of the lake stays cold 50F to 60F making it great for thermal flows on shore all summer.

Looking ahead, I hope we can continue this dialogue on sea breezes. Maybe you could post up when you think them likely as the season progresses. Or send a windy text. I generally watch the meters before going, but as you say in your post I could miss some sessions following this routine. Am used to more predictable thermals on Lake Michigan and in Corpus.

Regards,
Tim

[Unimog Bob]

Sure, I can make guesses about them in the future on occasion.
I don't have nearly as much free time these days as in the past though, so I may not being paying much attention. But if I think it might blow, I will make a windy text post.

The guesses will only apply to the area around PaG, because one more thing to mention is that with s.b.s - it might blow good at PaG and suck at TI (that's actually common) one day - also, sometimes it will blow pretty good at Cypress and not blow at the beach. This area really does have a lot of variability, both spatially and temporally. So "it's gonna sea breeze today" doesn't necessarily mean the whole coast.

When asked by out of towners or new riders about the Tampa Bay area, I have always referred to our area as potentially one of the BEST spots in the country to kite (we have SO many spots and every direction covered) - if ONLY we had consistent wind (which we have anything but). In other words, I don't think this area is that great for kiting, all things considered.
If it were, I wouldn't have wasted literally hundreds of hours tossing my brain with stupid "wind model guessing tricks" so that I could try to ride once a week when the wind popped up for 2 hours.
So many other things would probably be different as well. For example, we would most likely have a big school similar to Real's and probably have weekly races like in San Fran, is my guess. The wind is too "spotty" to schedule with confidence and frequency though.

Oh well... it just makes it a "special occasion" to have (good) wind, when it actually does blow.

(Scott)

Scott,

Thanks for your input on sea breezes which I think still fall into the category of thermally driven winds. Hope you don't mind me asking if you think Pass A Grille a better spot for thermal sea breezes than Treasure Island? Or is it just random? One day PAG better and the next TI better. Also do the sea breezes generally pick up at any special time like late in the day as they do around Chicago?

This may sound weird, but I think the rotation of the earth can effect sea breezes. At launches where the water sits east of the launch the water is cooling and the land is still absorbing the heat of the sun. Therefore the air over the water cools and the land stays warm increasing the cold vs. heat differential fueling the late afternoon/early evening thermal. This happens regularly in Chicago which sits on the west coast of Lake Michigan with water to the east. Likewise, have seen it happen in Cocoa and Jupiter as well as Rimini on the Adriatic on the west side of Italy. Unfortunately the water on our Gulf around Tampa Bay sits to the west and stays warm as the land cools. This negates a normal thermal pull with the land pulling the cooler air ashore heating it and making it rise to be replaced by more cool air pulled on shore.

Regards,
Tim

[Unimog Bob]

Imo, PaG almost always blows better than TI on NW s.b.s.
In general, our s.b.s don't happen before noon, because they are thermally driven events needing the land to heat up. 1pm - 2pm is most common as the "starting point".

The Coriolis effect seems like it might have a localized influence (who knows, doesn't seem crazy to me). I know it has a huge influence on global wind patterns, but can also affect smaller bodies, like the water in the toilet to spin one way in our part of the world vs. south of the equator. That's an interesting question (I think I will try to find info, out of curiosity )

If you have access to iKite's FX (or whatever it's called.. I don't pay for it), you can access the wind histories at sites and check out what it did in the past. That can be fairly interesting to look at - if you think the data you are looking at are accurate- and you can get a feel for when s.bs happened in past years at PaG.

[Unimog Bob]

I just talked with some guys in St. Augustine.
Apparently, really cold water can kill their SE winds along the beach.
Then, the wind picks up just a mile or so inland.

Same thing seems to happen here with our SWs (like this Sunday)

More stuff to ponder.

[Whitey]

Yeh what's up with that? Sunday up north flag at US 19 and Curlew was pegged as we passed it on the way to the beach, I mean smoking good, we were discussing what small kites we had in the truck thinking we did not have rigs small enough. Got to the beach and could not ride 8 to 10 kts all day drove home and the same flag is still cranking straight out. Then I hear the guys in at picnic had a great day. Don't recall that in the patterns around here. I have picked up on the summer seabreeze not being as strong due west of lake tarpon up here, been out in the boat and find good breeze at Anclote and good breeze at honeymoon but no good at three rooker area. Not enough asphalt to heat up and cause the effect I guess.

[Unimog Bob]

I have seen that same thing happen a lot this time of year over the years, with SW winds. I have some interesting stories regarding paragliding boats and people getting a certain height up.

Not for certain why, but here is my guess.

The water is SO cold... lol... it is chilling the air down at the surface and up a little bit, as well.
The warmer air (the air with wind) passes over this colder air, creating a wedge.

So, I think the wind is unfortunately up above a little higher than our kites. That's why Sam had much better wind with his kite up an extra "mile"

Go inland, and that wedge disappears and the winds blow good.

Just a guess.