Monday, June 28, 2010

Sunday Sail

Sunday afternoon was perfect sailing! The morning rain, heat, and humidity gave way to cooler, dry air.

Conor and Emmet were with us so for simplicity we sailed under partially reefed genoa alone. With the west winds in the high teens and flat seas we sailed at hull speed plus (7-8 knots) on a reach south to Northerly Island then back by the Chicago Lighthouse and through the harbor entrance, where this picture was taken.

We anchored at the playpen for several hours for a late lunch and a swim before returning home at sunset.

Capt. Kyle, Karen, Conor, Emmet, Mike, Megan and Jeremy all had a great time!

Wednesday, June 23, 2010

More Post Storm Pictures

Here are some more pictures. There were a lot of people taking pictures from their balconies. They flashes looked liked fireflies on the build.

This is a quick and dirty panoramic shot stitched together from 3 pictures.

The texture of the clouds was amazing. This failed to capture the color...

There was a double rainbow to the south! One was horizon to horizon!

After the Storm

It was amazing on Donnybrook after the storms passed! This is what it loked like from the foredeck. Lightning bolts were flashing overhead and it was dark to the south while the sky was golden to the north and west. The air was cool and dry. This picture doesn't do it justice.

Thunderstorm Lifecycle

All these storms got me thinking about why thunderstorms happen. I found these slides from a quick Google search on "thunderstorm life cycle." The below slides are from Severe Storm Spotter Training (http://www.wrh.noaa.gov/mso/train/img0.html from the National Weather Service Western Region Headquarters).

Below is my interpretation of the different stages:

Developing Stage: These are the white, fluffy clouds you see on warm summer days. They are formed by convection during sunlight hours. There's little convection over southern Lake Michigan in the summer which is why you typically don't see fluffy clouds over the lake. In the summer you do see them on the northern part of the lake where the air and lake temperatures are closer or the lake is warmer than the air. You see them over the lake in the fall when the lake is warm and air cool. You also see them off the east coast of Florida over the Gulf Stream (relatively warm water).

Slide 19

Mature Stage: These are the storms to watch out for. Scattered storms are caused by convection that lifts the moist air high enough to cause condensation into rain. Lines of thunderstorms are caused by a cool front which lifts the warm air into the atmosphere. The warmer the air and faster moving the cold front, the higher the lift. Falling rain creates the wind gust, multiplied by the speed of the cold front. That is why a fast moving cold front creates short lived but potentially violent storms.

The updraft may change or reverse the prevailing wind, hence the phrase "calm before the storm."

Slide 21

Dissipating Stage: The sloppy end of a storm. You might see the "anvil" falling over on itself. A cold front will move it along replacing it with relatively cooler, drier air. I've observed the largest raindrops are just before the rain stops.

Slide 23

I find weather fascinating to watch. When sailing you learn to appreciate the subtle changes to the weather. If you understand and can predict what will happen next, you'll have more confidence about uncontrollable weather and can appreciate it's amazing power and beauty!

Tuesday, June 22, 2010

The Longest Day Off

You can still get sunburn on a day like this! I took Monday off to enjoy the summer solstice. The forecast was for showers and thunderstorms all day. It rained for a few minutes in the morning then a real gully buster near midnight.
This was a perfect day off: Some boat maintenance (a past due pump-out) in the morning, a solo sail with lunch on the water, and finally a nap back at dock followed by washing the topsides. A nice rum drink (thanks, Megan!) ended my day on the boat. The only thing I didn't get to do was swim. Maybe Wednesday.
I ended the longest day of the year at home with the family and dinner.

Friday, June 18, 2010

Storm on the Lake

This is the back side of Friday's severe thunderstorm. It was over Michigan when this picture was taken two hours after it passed.
The data below is from the Harrison-Dever water crib about 3 miles east of Chicago. Note winds increased from 8 to 48 knots with a 66 knot gust in just 10 minutes (1620 to 1645)!
Also not the temperature dropped 20 degrees at the same time. There was a definite calm before the storm.
The worst only lasted 30 minutes then conditions were perfect for sailing with a nice breeze and flat lake.
------------Previous 3 Hours-------------
---------CDT- kts kts deg deg F
2010 169 1745 17.24 20.76 257 70.7
2010 169 1740 19.25 24.77 262 70.6
2010 169 1735 22.16 26.67 275 70.6
2010 169 1730 23.97 31.05 280 70.4
2010 169 1725 26.01 34.10 287 70.9
2010 169 1720 25.37 32.19 283 71.2
2010 169 1715 23.85 32.39 283 70.7
2010 169 1710 22.06 27.82 285 70.5
2010 169 1705 25.19 29.92 284 70.1
2010 169 1700 26.13 31.43 286 69.5
2010 169 1655 28.87 38.49 284 69.3
2010 169 1650 29.06 38.86 282 68.7
2010 169 1645 34.55 42.11 288 67.0
2010 169 1640 40.32 48.39 288 65.8
2010 169 1635 43.74 54.86 285 66.3
2010 169 1630 48.54 66.87 280 69.4
2010 169 1625 15.67 46.68 284 85.3
2010 169 1620 8.10 11.24 228 86.1
2010 169 1615 15.14 19.62 211 85.5
2010 169 1610 13.67 17.71 211 86.9