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View Full Version : Lake Breeze and severe storms in IL, IN, MI, OH



tom hanlon
06-02-2007, 08:17 AM
This thread http://www.stormtrack.org/forum/showthread.php?t=12728
regarding severe weather June 1, 2007 discusses the lake breeze interaction as the storm enters the Chicago area.

I chased in and around Bay City and Bad Axe MI a few years back and the Storms got tornadic as they hit the last 10 to 20 miles before the lake.

One poster, I forget who exactly had a signature that was something like.
"disable the cook county (IL) convective deflector"

I have watched storms in OH get a little more active as they interact in a glancing direction with the Lake Breeze.

Florida seems to get some Ocean breeze CU activity.

I grew up about 1 mile from Lake Erie and the weather was often strikingly ominous in appearance as clouds and storms would come in with very low bases off of the Lake.


All of the above threads and references seem to have something to do with Lake Breeze and it's effects.

So now that I am interested in Severe Storms, how do I predict forecast or otherwise understand Lake Breeze Severe weather interaction ?

My current mode is to just prepare for things to change as a storm interacts with the Lake breeze. Some get more severe some die out.


Needless to say just knowing that things might change is not the most helpful tidbit of information.

So if someone could answer the following questions it would be great.

What is it about the lake breeze that affects storms ?

Does the "lake front" generate some much needed spin ?

Does the humidity bring the cloud bases lower ?

Does the front provide some lift as a focus for initiation ?

Supposing the lake Breeze "front" lies straight East to West. Is it more likely to enhance a storm with motion roughly parallel or roughly perpendicular to the "lake breeze front" ?

Are there some guidelines for predicting the effects ?

How do I find the Lake Breeze? Sometimes it is obvious on Satellite. Sometimes it is obvious from reported observations. Most of the time it is so subtle that it is hard to locate.

Any pointers to papers or research on this topic would also be helpful.


--
Tom Hanlon

Scott Olson
06-02-2007, 08:30 PM
'So now that I am interested in Severe Storms, how do I predict forecast or otherwise understand Lake Breeze Severe weather interaction ? "

Tom, such interactions can be quite uncertain. There were a couple older threads where the possibility of a sea breeze boundary as a hinderance or enhancement for severe storms was discussed. Whether it can be an ehancement is certainly releated to the amount of forcing and the amount of instability on the cool side. As you suggest, the orientation would also be important, ideally you would want the boundary to be streamwise to the low level inflow vector. The answer to each of your questions is it can provide a source of vorticity, intiation and provide an area of lower LCL's. However the increasingly stable air and possibility of linear forcing can be an impediment. Interaction with cold front's and outflow appear to usually provide enough focus for intiation, though they can do so completely on there own. The development of small scale circulations on the boundary seems to be fairly common, which could help intiate storms or provide an area for landspout development.

Some reading:
http://ams.confex.com/ams/pdfpapers/81527.pdf
http://ams.allenpress.com/perlserv/?request=get-abstract&doi=10.1175%2F1520-0434%282003%29018%3C0795%3ALBISOA%3E2.0.CO%3B2

Hope that helps Tom,
Scott.

Adam Lucio
06-04-2007, 04:44 PM
Living in Chicago all my life i can say Lake Michigan kills more storms than it does intensify, but i have seen it happen where a storm interacts with a lake breeze, often times it results in a brief land-spout type tornado, the biggest and most obvious cause would be the added shear created by the lake breeze, tho im not totaly educated on the subject myself. This happened recently actually, i think may 16th was the date? not too sure. but a SVR storm was moving SE outa wisconsin, hit the breeze and spun up a brief landspout that ripped the roof off a store and damaged some trees.

and i totaly agree with that signature "kill the convective deflector" haha, will county gets everything!

rdale
06-04-2007, 05:20 PM
One thing to realize is that it'd be pretty tough for a lake breeze to have a major impact on "real" storms for a few reasons -- primarily that you won't have a lake breeze on a dynamic weather day. You need to have light winds (especially at low levels) so by default if winds are light you won't have major storms. NWS Gaylord has done a lot of research (I don't think any office gets lake breezes from so many angles!) so you might check their website for some info - Bruce Smith has made a few presentations on the subject and they all have been quite educational.

Jeremy Lemanski
06-04-2007, 06:33 PM
This thread http://www.stormtrack.org/forum/showthread.php?t=12728
regarding severe weather June 1, 2007 discusses the lake breeze interaction as the storm enters the Chicago area.

I chased in and around Bay City and Bad Axe MI a few years back and the Storms got tornadic as they hit the last 10 to 20 miles before the lake.

One poster, I forget who exactly had a signature that was something like.
"disable the cook county (IL) convective deflector"

I have watched storms in OH get a little more active as they interact in a glancing direction with the Lake Breeze.

Florida seems to get some Ocean breeze CU activity.

I grew up about 1 mile from Lake Erie and the weather was often strikingly ominous in appearance as clouds and storms would come in with very low bases off of the Lake.


All of the above threads and references seem to have something to do with Lake Breeze and it's effects.

So now that I am interested in Severe Storms, how do I predict forecast or otherwise understand Lake Breeze Severe weather interaction ?

My current mode is to just prepare for things to change as a storm interacts with the Lake breeze. Some get more severe some die out.


Needless to say just knowing that things might change is not the most helpful tidbit of information.

So if someone could answer the following questions it would be great.

What is it about the lake breeze that affects storms ?

Does the "lake front" generate some much needed spin ?

Does the humidity bring the cloud bases lower ?

Does the front provide some lift as a focus for initiation ?

Supposing the lake Breeze "front" lies straight East to West. Is it more likely to enhance a storm with motion roughly parallel or roughly perpendicular to the "lake breeze front" ?

Are there some guidelines for predicting the effects ?

How do I find the Lake Breeze? Sometimes it is obvious on Satellite. Sometimes it is obvious from reported observations. Most of the time it is so subtle that it is hard to locate.

Any pointers to papers or research on this topic would also be helpful.


--
Tom Hanlon


In reference to the area around here, thumb of michigan, the past couple years that tornadoes have occured near the lakeshore, june of 04 and may 2000, the supercell storms did drop a tornado within 5 miles of the lakeshore. There was a SE wind at the lakeshore, compared to South or SW winds here at bad axe, 17 miles inland. However, both of those storms were riding a warm front which was hung up around the area. The lakes, early in the year the effect is greater, tend to slow the progress of warm fronts as they move through.

Take June 13th 04, the warm front had moved through bad axe hours before the supercell which would drop a tornado near harbor beach on the lakeshore occured. However, if my memory is correct, the wind never shifted near the lakeshore, as the 50 degree water slowed the warm front and it was located somewhere near the shoreline. I guess you could call it a lake breeze/warm front hybird type of thing.

Like mr. dale said, most days when there is a true lake breeze, winds are light and dynamics are lacking.

David Draun
06-04-2007, 09:09 PM
LOL, yes, it was MY signature that said "destroy the convective deflector." It seems there is somewhat of a "Norman Bubble" effect along and north of I-88/290 to the WI state line. This usually begins at the "Dekalb Donut" (coined by Glibert Sebenste in his area forecast discussions) In this area, storms sometimes drop tens of dBz in what seems like just a few miles, lose supercell characteristics if they have them initially, or just peter out to barely sprinkles. Or they shoot north or south of the area and INTENSIFY! I don't think the lake breeze is responsible for that.

Rdale mentioned "dynamic weather days" where the lake breeze is not present. I'm reminded of 5/10/03, a major synoptically-evident tornado day for Illinois and Missourri. The warm front stayed south of Chicago for much of the day, creating a strong ESE lake breeze and sub-70 degree temps fairly well inland until after dark when it pushed northward. Areas to the west warmed into the 80's. That was a day when storms didn't immediately weaken as they moved east. I remember taking cover with my family for a midnight tornado warning as storms maintained discrete supercell structure.

Sometimes I would hate to imagine what could happen to Chicago if Lake Michigan was a WARM body of water, especially on days with strong SE surface winds.

I've also noticed lake breezes do interesting things when interacting with a stationary front sprawled across the area on a hot summer evening, or with a backdoor coldfront from due north. Some big rains caused by explosive thunderstorm development!:cool:

cdcollura
06-05-2007, 10:36 AM
Good day,

The US / Canada Great Lakes are very large bodies of water, and indeed will set up lake-breeze boundaries, just like a seabreeze does.

I am very familiar with sea-breeze convection as in my early chase days in Florida, I would love the convection that fired along the east-coast seabreeze boundary. The key to a "good setup" was a west or southwest surface wind (I lived on the SE FL coast) and the sea-breeze would move west and create convergence. If the winds were easterly (surface), then the convergence would be on the FL west coast.

Often, a good storm would develop from the following: The daytime heating would set up the east coast seabreeze and it's associated boundary (seabreeze front). This boundary would move west with east and southeast winds east of it, and southwest (as they were originally) west of it. Another smaller lake-breeze also setup by afternoon from Lake Okeechobee, that big lake in the middle of FL. The lake breeze would push to the southeast and create a little "triple-point" where it intersected the sea breeze. North of this lake induced boundary, winds were light northerly.

A thunderstorm cell often developed at this intersection, and created an outflow boundary moving southward as it pulsed out, and re-inforced the lake breeze boundary. Subsequent development occurred until the area was "worked-over" (south FL is only 100 miles across). Often, the normally lighter SW flow aloft - if it even existed - would not be strong enough for the storms to reach supercell status, regardless of the CAPE. In rare cases, the multicell storms sometimes briefly would become supercellular, and tornadoes / hail affected Miami-Dade / Broward counties.

With this example, lets look at the Lake Breeze. A lot of states are mentioned here, and things can get a bit more trickier than having a "simpler" coast, like Eastern FL. Ohio's lake breeze would be oriented W to E off Lake Erie, while near Chicago, it would be oriented N to S. The air (behind) this lake breeze would also be quite cool compared to the aforementioned FL sea-breeze (Great Lakes water temperatures can be in the 40's F until May, I saw 45 F off Cleveland, OH May 12)!

There are many things to consider. The environmental (pre-existing) winds must create CONVERGENCE when interacting with a boundary - any boundary - including lake and sea breezes. A south wind over Ohio reaching lake Erie's northerly lake breeze is a good example. Second, how temperatures across the boundary my affect convection. I see lots of slang on the "convective deflector". Thunderstorms rely on high theta-e air (warm and moist). A storm crossing a lake-breeze boundary, from 85 degree F air with 65 dewpoints to 60 degree F air with 65 dewpoints would obviously become elevated and / or weaken substantially! The lake breeze near Chicago does this VERY often (aka the "deflector") ;-)

Third, vorticity. Boundaries often have horizontal vorticity associated with them. A cool north wind sliding under a warm southerly wind along an E-W oriented boundary should create a horizontal "vortex" along that boundary, and just above the surface, also oriented E-W (looking due west along that E-W oriented boundary axis, one would see the air rotating clockwise gently, with the cool air sliding from right to left near the ground, and warmer air from the south rising up and over and going left to right.

Another thing to consider is that the marine air (cooler air behind the lake / sea breeze boundary) is shallow and can easily be MODIFIED (warmed up). A lake breeze can be in the 60's F at the coast with the 80's F 20 miles inland to start out. Then, this boundary can push farther inland and become modified by the strong spring / summer sun. The result is a boundary well inland with 80's F both behind it and in front of it, but still with the SAME wind shift (backed winds on the modified marine side of it) ... A developing storm crossing such a boundary from the SW to NE will "experience" a jump in storm relative shear as it "ingests" the backed flow!

Sea / Lake Breezes are strongest on sunny summer days (lots of insolation) ... Cloudy days / winter often have no sea or lake breezes at all! Heating is the key.

Storms developing on ("anchored") on such boundaries - Especially where boundaries may intersect as in the case of the FL (the Lake breeze and east coast sea breeze) severe storms I mentioned earlier - Any horizontal vorticity can be tilted (and stretched) into a vertical position, especially in a high CAPE environment.

One post I saw on this site was a large waterspout in Singapore harbor with ships around it. Deep in the tropics, with the jet stream and shear thousands of miles away and the 500 MB temps +5 C you wonder how can such rotation be sought - Most likely a sea breeze / mesoscale boundary (outflow from another storm) was the culprit.

Also, Lake Breezes, just like Sea Breezes, are diurnal mesoscale circulations. They are weakest in the early morning and strongest in the late afternoon when the land is much warmer than the water. At night, the opposite sometimes occurs, where the water is warmer as the land cools, and a LAND BREEZE sets up. In Florida the land-breeze can become strong enough to cause storms to develop at night over the ocean.

With that said, the lake breeze effect can sometimes work that extra bit of magic into a great-lakes storm!

Kevin Bowman
06-05-2007, 10:37 AM
LOL, yes, it was MY signature that said "destroy the convective deflector." It seems there is somewhat of a "Norman Bubble" effect along and north of I-88/290 to the WI state line. This usually begins at the "Dekalb Donut" (coined by Glibert Sebenste in his area forecast discussions) In this area, storms sometimes drop tens of dBz in what seems like just a few miles, lose supercell characteristics if they have them initially, or just peter out to barely sprinkles. Or they shoot north or south of the area and INTENSIFY! I don't think the lake breeze is responsible for that.

Rdale mentioned "dynamic weather days" where the lake breeze is not present. I'm reminded of 5/10/03, a major synoptically-evident tornado day for Illinois and Missourri. The warm front stayed south of Chicago for much of the day, creating a strong ESE lake breeze and sub-70 degree temps fairly well inland until after dark when it pushed northward. Areas to the west warmed into the 80's. That was a day when storms didn't immediately weaken as they moved east. I remember taking cover with my family for a midnight tornado warning as storms maintained discrete supercell structure.

Sometimes I would hate to imagine what could happen to Chicago if Lake Michigan was a WARM body of water, especially on days with strong SE surface winds.

I've also noticed lake breezes do interesting things when interacting with a stationary front sprawled across the area on a hot summer evening, or with a backdoor coldfront from due north. Some big rains caused by explosive thunderstorm development!:cool:

Dont forget 9/22/06 when 2 supercells within 30 minutes of each other tracked over ohare, and my house. the 2nd went out to produce a tornado over Loyola in Rogers Park and then went out over the lake.

http://www.youtube.com/watch?v=fhUST6b6qNg

something you dont hear or see everyday, all the sirens going in the city of Chicago on 9/22 as well (outside of the monthly tests)
http://www.youtube.com/watch?v=F0m1BN4ZmAQ&mode=related&search=

David Draun
06-05-2007, 02:47 PM
Yes Kevin, I chased on 9/22/06 in Dekalb/Lee counties. I was pretty much on initiation. Explosive storm development for low-toppers.:cool: Traffic prevented me from chasing them toward the city. 9/22 was a day when the lake breeze would have been warmer or just as warm as the 70F air it was moving into. It was autumn, and the lake still had some heat left over from the summer. The supercells didn't have their inflows contaminated by lake-cooled air.

I've also noticed storms that approach the area from the NW are less likely to weaken as they approach the Chicago Metro area.