Wednesday, October 04, 2017

Nowhere, October 4

Why didn't we swim today? Because of this chart from the Wilmette Buoy:

The blue is the water temperature, the black is the air. Notice the lack of correlation, the factor is the wind direction, which became almost westerly yesterday afternoon when you see the final plunge on a warm sunny day. For us Americans the high water temperature was 71.5 F early in the week and 61.5 F this morning. Since temperatures at our spot have been running a degree or so below the buoy. So we could expect right around 60, maybe even less. It wasn't worth finding out.

Monday, October 02, 2017

Evanston October 2

Once again we make it into October. Small craft warnings again but this time it is fake news. Mostly 2 foot trochoidal waves with large periods. A few 3 footers which is unusual for reflected waves. But not too hard to swim. The buoy temps were posted in the 66 degree range, cooling down before midnight but rising again towards morning. Apparently that was not happening where we were as it ranged from the upper 63 to lower 64. The sun was behind lake clouds much of our swim so the affect was cold. We shortened our swim a little but did visit the south wall to compare the crashing waves on the south side of the wall to the quiet lake on the north.

Is this it or will be back? Keep up with us for a few more weeks to find out.

Friday, September 29, 2017

Evanston September 29

Small Craft Warning, 5-7ft waves with occasional 8-9 foot waves, strong NW wind, water temperature dropping 3 degrees, cold air ... So says the Weather service and press. So why are we at the Lake at Evanston? Actually if today were a Saturday instead of Friday I would have preferred Ohio Street, but I hate dealing with traffic and parking downtown on weekdays. Jody points out that Ohio St would have lower waves but much more chop and be worse to swim in. But more because careful parsing of the reports indicated that this dire forecast was really for later in the day and with nighttime wind from the west the wind waves would be offshore with only soft reflection nearshore. As for the temperature we were hoping that the waves would mix the water, our cold earlier in the week with the warmer offshore water. Also the mere existence of waves adds a degree or 2 of warmth to the water.

But all of the above, the official forecast and my interpretation was off. There were actually 2-4 foot wind waves coming in from the northeast, remember waves always come in towards shore regardless of wind direction. In addition there were some larger waves. And these brought the warmer water that had been blown offshore by the recent SW winds. So water temperatures were in the low 67's. The air was actually about 64 with bright sun so it was certainly warm enough to swim. Going north the waves were hard to swim in, we mostly did breast stroke, partly to keep our heads out of the water and partly to stick closer together. Up by the north wall the waves were larger but with longer wavelengths. We stood on our sandbar about 50 yards from the wall and shore for a while but that got us cold. We swam crawl back to the beach non-stop and what was usually a 20 minute swim only took about 10. This warmed us up. Back at the beach there were some waves big and hard enough to body surf so we did that for a while. Then, for some strange reason, park district workers came to paint the guard chairs. Since that is where we left our stuff we had to get out.

So why were we here today? Because it was loads of fun.

Tuesday, September 26, 2017

Evanston September 26

The heat continues, another hot day predicted. Although there was some talk of wavy conditions that was not the case this morning. By the beach we had glass smooth water although there was some chop and even a few waves, boat wakes from far off boats? But the water was colder again, more homogeneous but in the 64-65 range. This is somewhat strange since all the reporting stations seem to insist that the water is still in the 70's. But for anyone who follows this blog that it is not unusual during an August heat wave for the water to drop from 70 on one hot day to 58 on the next. I have called this the "August inversion" where a west wind blows the warm top layer out to be replaced by "up-welling" of cold water from lower in the Lake. But this year our heat wave came in September and we did not really have strong west winds. So perhaps it was only a half-hearted inversion so only dropped the temperature by a couple of degrees and then only near shore.

As Jody and I were leaving a lone woman about our age swam into our beach with a safety buoy seemingly from nowhere. Since we were curious we greeted her as she came in an asked her where she came from. She apparently got in the lake at Lighthouse beach on the far north side of Evanston and swam the the 3.5 miles to our beach. She was actually relieved when we told her that the water was 65. She thought it felt cold but maybe it was just her and was glad to hear that it really was colder then it had been. And we were relieved to know that we aren't the only crazy ones swimming in the lake in late September.

Monday, September 25, 2017

Evanston, September 25

We are still in our September heat wave, air temperatures are still expected to get near 90. But the Lake has cooled anyway, although pockets of cooler and warmer water were still present the average was a consistent 67. Probably upwelling from the bottom of the lake was responsible. Not much in the way of waves today, we did see a lot of algae accumulation near the beach, some waves would have helped. Did a quick out and back because I was due at the dentist shortly.

Sunday, September 24, 2017

Evanston, September 23

Not quite as perfect as yesterday but still probably best September 23rd ever. Slight air quality alert problem and a south breeze with a few small waves in the middle, flat near the walls. Got buzzed by a jet ski. The big change in the water is that the absence of bigger waves has left the water unmixed both horizontally and vertically. Although generally the water was in the 70-72 degree range there were areas of warmth and areas, especially under the surface where it was quite cold. Jody and I both volunteered at a 5K running race so we came later than usual. Quite a crowd on the beach. We even saw one other swimmer.

Friday, September 22, 2017

Evanston, September 22

A perfect summer swim. Except it is no longer summer but Fall as of today. Water was 71 air on its way to a high of 94, bright sun, no wind, no waves, just a little light chop. I had on my summer gear, no magic (neoprene) pants, no thermal cap, no jacket or sweatshirt on the way to or from the beach. Not much to say other than it was perfect.