Dry and MildAugust 27th, 2014 at 2:23 pm by Bill Steffen under Bill's Blog, Weather
Here’s two pictures from the Muskegon Glerl Cameras (from NOAA Coastwatch). The first is looking east down the channel. You can see the sky is about half covered in “fair weather” cumulus clouds. Those clouds are a little less than a mile above the ground and show no significant vertical development. Over land there is a variation of surface heating. A dark “muck field” in Hudsonville or a parking lot will heat up more than a forest. Warm air rises and the thermals lift surface air. The air cools and reaches the saturation point and some of the invisible water vapor in the air condenses into droplets of water so tiny that the air can hold them up. Sunlight is white light and the clouds have a variation of white to gray, depending on the light that reaches them. Some light always comes through the clouds. Otherwise it would be pitch black in daytime on a cloudy day. The second picture on the right looks west. Over Lake Michigan we have a uniform surface of water and the temperature is cooler. So, there are no cumulus clouds, but you can see some scattered higher level cirrus clouds. Sometimes the clouds will move in different directions because the wind is different at different levels of the atmosphere. Dewpoints are 10° lower today, so it feels more comfortable. The 1 pm temps. include 73° in G.R. with an east wind, 75° at the Holland Airport. Both of these stations have an east wind. At the Muskegon beach, it’s 70° with a northwest wind. So, you can see we have a lake-breeze. It doesn’t penetrate inland very far. There is convergence where the east wind meets the west wind. That’s where the surface wind will be come and air is rising. On a day with more moisture, that’s the place where a shower or even a t-shower could develop. However, the air is too dry for that to happen today. With the warmer Lake Michigan water temperatures (around 70°) there is less contrast between inland areas and the shoreline, so there is less variation in temperature lakeshore to inland and the lake breeze is relatively week. It would be stronger if the Lake Michigan water temperatures were in the low-mid 50s after an episode of upwelling.
It’s a beautiful day. My wife and I just got back from our almost daily walk and I just took my blood pressure and pulse (119/76 and 58). I’m sitting on our 3-season porch, where I can look out in 3 directions almost to the horizon to watch the sky. Everything is green and growing with the timely rain we have had. I have a cup of coffee and a couple of plums that came from the farmer across the street from me. I can watch the birds at my two bird feeders (a couple of purple finches there now). I already have a good start on the forecast (which I usually start at home – fewer distractions here and I like the view. This is a wonderful time of year with a good harvest underway, not only in Michigan, but across most all of the U.S. The drought continues in mainly California (they have had some rain in Arizona and the Pacific NW), but crops in California are irrigated. At this time of year, you can see a wide variety of wildflowers – Queen Anne’s lace, chickory, wild daisies. So much of what I enjoy is free – sky, storms, wildflowers.
Model update: The NAM (caribou) has 0.14″ of rain for G.R. Friday morning and another 0.44″ during the midday/afternoon on Saturday. The GFS plot has 0.20″ in the midday/afternoon Friday and a similar 0.49″ during the midday/afternoon. The GFS is then dry for Sunday (best bet for a dry day over the Labor Day Weekend) and then 0.29″ of rain Monday PM/evening. The GFS is then dry for most of the middle of next week. The NAM (caribou) gives G.R. a high of 74° tomorrow and then 86°-87° on Fri. as the warmer, more humid air pushes back in. The GFS plot has 76° and 83° for Friday. No sign of any really cool air through the first 10 days of Sept. Also, no sign of any big hurricanes hitting the U.S. (Sept. 10 is the peak of the hurricane season). Cristobal (a minimal hurricane) is splitting the difference between the U.S. and Bermuda. Marie (which will be downgraded to a Tropical Storm) far off the coast of Baja, Mexico is also far from land and will weaken as it encounters cooler water. The tornado count remains low for the 2nd year in a row and we continue to have an overall low number of wildfires and acres burned.