# How big does a lake have to be to have its own Sea Breeze?

How big does a body of water need to have a sea breeze? Is there a chart on sea breezes wind speed that include lakes?

Could a circular lake create enough sea breeze to create a wind vortex in the center of the lake? https://worldbuilding.stackexchange.com/questions/108896/could-a-city-be-built-out-of-balloons

• Great question. Lake Breezes are quite common... with the Great Lakes and Lake Okeechobee both commonly impactful. But often see lake breezes even on much small lakes such as Lake Apopka in Florida, and even boundaries come off rivers occasionally. Basically any temperature gradient can cause some sort of circulation, it's just whether it's its strong enough to impact clouds and such to be noted. Remind me in a couple months when it's warmer (and thus can be regularly seen in FL), and will try to delete this and write up an answer using some imagery/models showing them :) Apr 15 '18 at 21:50
• @JeopardyTempest - looking forward to your mesoscale model output. But looking at Lake Apopka - en.wikipedia.org/wiki/Lake_Apopka it is no small lake at least in my view of the world. Apr 16 '18 at 0:55
• @gansub, true, true, I get spoiled by the land of large lakes. It's the 5th largest in Florida, and only 6% the size of Lake Okeechobee... so I still call it "much smaller" :-p Apr 16 '18 at 4:04
• The temperature of the lake will also be important and that will depend on thermal mass, depth, and circulation within the lake. The characteristics and heating of the land also make a difference. To make things even more complicated the effects will be superimposed on the regional weather, which could either enhance or counteract the effect. Oct 29 '18 at 23:28
• (I didn't forget btw! And did save a few pertinent images this summer. Not sure I'll be able to perfectly answer all your interests, but hoping I can at least put something together eventually... just been busy/distracted/dealing with things like computer issues recently :-) ) Feb 21 '19 at 10:06

Lake breezes(similar to sea breezes) are fundamentally a feature of mesoscale meteorology and the peer reviewed reference Small Lake Daytime Breezes: Some Observational and Conceptual Evaluations details both the observational studies of lake breezes and the conceptual understanding behind the formation of the lake breeze.

Since OP's question is

How big does a body of water need to have a sea breeze?

The answer according to this book Climate in a small area which is one of the references in the first reference is that lake breezes have been observed in lakes with a width of about 4 kms(Lake Suwa, Japan ) and a width of 10 kms (Lake Constance, Switzerland). The lake breeze reached a speed of 2 m $$s^{-1}$$ in the case of Lake Suwa and slightly greater speed in the case of Lake Constance. But because both of these lakes are orographic lakes the presence of thermally induced upslope flows (diurnal heating and consequent upslope flows during the day) can interfere with the formation of lake breeze.

Further observational studies carried much later for the following lakes Lake El Dorado , Lake Okeechobee, Lake Winnipeg and Lake Eufaula have reported lake breeze speed values in the range of 2-4 m $$s^{-1}$$. One must remember that these lakes are much larger in size but in essence the numbers capture the range of the lake breeze values. These observations had been obtained as a result of measurements carried out over a period of few months and over different weather conditions.

The upper range for the lake breeze is around 6 m $$s^{-1}$$ and any lake having a width of less than 2 km is likely to have an undetectable lake breeze.

So the physics behind the lake breeze formation in essence is similar to the physics behind the sea breeze formation. A pressure gradient(density gradient) is created between the land and the lake and this gradient is primarily established in the lower troposphere. Greater the inland sensible heat flux greater the value of the pressure gradient.

The following URL shows satellite images of different stages of formation of a lake breeze during the day - Lake Breeze Satellite Imagery

In regards to the second question I believe steam devils are mesoscale vortices that have been observed to form over lakes. These vortices are no more than 50-200 meters wide and can develop in the absence of any major synoptic scale forcing. But the surface area of the lakes have to be in the range of Great Lakes of North America in order for the strong surface heat fluxes to play a role in mesoscale vortex development. The following peer reviewed reference provides observational and modeling studies of steam devils- Mesoscale spiral vortex embedded within a lake

• Great answer. Steam Devils are interesting. Does the lake breeze vortex when the wind meets in the middle over a smaller lake? Can it keep an idle vessel in the middle of the lake or a blimp over the center of the lake? The vortex maybe very wide and 5+mph and not visible.
– Muze
Feb 17 '19 at 18:52
• @Muze - I am not sure whether I understood your question. But IMHO steam devils are simply not possible in smaller lakes. For smaller lakes with favorable synoptic scale forcing you can have external vortices move in over the lake. Feb 18 '19 at 0:30
• yes. they would not get steam Devils it would be something completely different. I don't know if there is a name for it yet. I'm just saying smaller lakes that have a lake breeze then what happens when that llake breeze meets in the middle?
– Muze
Feb 18 '19 at 1:13
• @Muze - What do you mean when you write - lake breeze meets in the middle ? A lake breeze moves from water to land. Smaller lakes simply do not have the capacity to produce a vortex. Synoptic scale systems can create a lot of disturbance when it moves into the middle of the lake. But that uses energy from "outside" the lake. Feb 18 '19 at 1:22
• @Muze at night it is called land breeze. Lake breeze can move only direction from water to land. Feb 18 '19 at 2:11