Cloudy Or Clear? Forecasting Tonight’s Total Lunar Eclipse

Worried about clouds rolling in during tonight's total lunar eclipse? Me too. Using the resources below, you might just find a sucker hole. Credit: Bob King
Worried about clouds rolling in during tonight’s total lunar eclipse? Me too. Using the resources below, you might just find a sucker hole. Credit: Bob King

Are you in the same boat I am? Tonight’s forecast calls for mostly cloudy during most of the total lunar eclipse and then clearing after midnight. Now that’s just cruel. But who knows? Maybe with the right tools, we just might find a clear spot.

One of my favorite cloud-checking sites is the GOES East view of the U.S., Canada and Central America taken from geostationary orbit. This map shows the scene at 10:45 a.m. CDT this morning. Credit: NASA
One of my favorite cloud-checking sites is the GOES East view of the U.S., Canada and Central America taken from geostationary orbit. This map shows the scene at 2 p.m. CDT today September 27. The time (upper left) is given in Universal Time. To convert to your local time, subtract 4 hours for Eastern Daylight, 5 for CDT, 6 for MDT and 7 for PDT. Credit: NASA

While planning to see a big astronomical event like an eclipse, I always consult satellite photos readily available around the Internet. I have two favorite sites: NASA’s GOES East site. GOES is an acronym for Geostationary Operational Environmental Satellite. Two keep their eyes trained on the planet from geostationary orbit some 22,200 miles above the planet — GOES East, positioned at 75° West longitude and GOES West at 135° West over the Pacific Ocean. At this altitude, each revolves around the Earth in the same time it takes Earth to make one revolution, which means they hover over the same spot of the planet every day. Taking fresh images every 15 minutes, they continually update weather watchers on cloud conditions, hurricanes and weather fronts.

Regional view of the Midwest at 2:15 p.m. from the GOES East satellite weather site. Credit: NASA
Regional view of the Midwest at 2:15 p.m. from the GOES East satellite weather site. Credit: NASA

When you visit either site, you’ll see a wide-angle photo showing the mainland U.S., a good portion of Canada, Mexico and Central America. To see a close up, regional view, first go down to the boxes marked “width” and “height” and put in the maximum values of 1400 and 1000 respectively. Now click where you live on the map and you’ll see a nearly full screen image with a resolution of 1-kilometer (0.6 miles). In the summer, it’s easy to tell clouds apart from the darker land, but in the winter, snow and ice make reading clouds more difficult though not impossible.

You can check single images every 15 minutes, but an easier way to get a handle on weather trends is to create an animated image loop. Click animate, choose from the most recent 3-30 photos and then click animate image above. You can choose to view the loop in either wide or regional settings. Combine what you learned at the GOES site and then consult your local forecast, too.

Knowing the extent of the clouds, the direction in which they’re moving and the forecast, you can make an escape plan. Pack a snack, get in the car and get the heck out of town. Based upon how fast the clouds appear to be cruising along, you can choose to head in the opposite direction to outrun the weather. Or if you anticipate a clearing trend, it might be wise to drive toward the advancing masses and out the other side. Since clouds often travel from west to east, driving east often means avoidance while driving west means time spent under the clouds followed by the hoped-for clearing. North or south travel options are also possible especially if the “cloud front” is relatively narrow and extends primarily from east to west.

Both GOES sites also offer an infrared viewing channel for nighttime cloud tracking. Just click on the infrared link and you can continue with weather-sleuthing through the night. Another useful weather site, and one that makes an excellent backup in case the other is down, is called NCAR Real-Time Weather Data. It also provides clearer black-and-white infrared images. Check it out.

The cloud cover forecast for Chicago today Sept. 27 through early Tuesday Sept. 29 as depicted in Attilla Danko's Clear Dark Sky site.
The cloud cover forecast for Tucson, Arizona Sept. 27 through early Tuesday Sept. 29 as depicted in Attilla Danko’s Clear Dark Sky site. Copyright: Attilla Danko

So far, we’ve been talking about the weather mostly in real time. One of the finest tools for forecasting cloud cover, along with other weather and astronomy-related conditions, is a website created by Attilla Danko called Clear Dark Skies.  Click on the Clear Sky Charts link and you’ll be able to choose from over 5,000 charts showing cloud cover hour-by-hour across the U.S., Canada and parts of Mexico. Find a location near you, click the chart and explore! Dark blue squares indicate clear sky, pale blue ones, partly cloudy and white means overcast.

Go ahead and click on an individual square and up pops a map showing cloud cover for that hour. I’ve used Danko’s site for years and highly recommend it. Yes, it’s occasionally dead wrong, but more often, it’s right. Besides big stuff like eclipses, I use it daily to plan observing sessions both here and when I travel. Take some time to explore its many options.

So what does the U.S. look like for weather tonight? Mostly clear skies are expected from New York State up through Maine, across the center of the country, the desert Southwest and the Northwest. Expect partly cloudy conditions (with some mostly cloudy spots) for the Upper and central Midwest, and mostly cloudy to overcast skies in the southern and southeastern seaboard states.

I hope you’ll either see the eclipse with little effort or plan a successful escape. If you get skunked, all is not lost. You can always watch the eclipse live online. Here are a couple sites. Good luck!

8 Responses

  1. Troy

    That’s great you have a plan to run away from clouds. Has it ever worked out for you? Mother nature has been teasing me all day with periods of clouds and clear and now a blanket of clouds, though I see clearing on the western horizon. The forecast calls for some decrease after the start of the eclipse, we’ll see. I might try shooting through clouds and hope for clearing during the full eclipse, when clouds would be most pernicious. If not wait until 2018.

  2. BCstargazer

    Luna emerging from Terra’s umbra in a clear sky at as I write this. One observed eclipse out of the Four that made the tetrad isn’t bad I guess considering my all time experience with eclipses of all types.
    The moon rose above the mountain ridge already totality at 7:20pm Pacific time. I’d rate the luminosity at mid-eclipse at a Two on the Danjon scale. It was pretty dark although it was at a low altitude for my location.

    1. astrobob

      Great to hear it Farside! It was really warm in NW Wis. where I was. 71 degrees, nice breeze and mostly clear into totality.

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