‘Hunter’s Moon’ eclipse tonight, 50-50 chance for coldest Halloween in 62 years?

Sky watchers in the Upper Midwest will enjoy the rare celestial treat in the sky tonight.

The full “Hunter’s Moon” will be in partial eclipse as it rises in the east tonight after sunset.

Image: NASA

This “penumbral eclipse” is a partial eclipse and the shading will be quite subtle on the lower end of the moon.

Image: NASA

In Minnesota, the best viewing will be between 6:30 p.m. and 7:10 p.m. as the moon begins to gain elevation in the eastern sky.

Here’s more from NASA.

The last lunar eclipse of the year is a relatively deep penumbral eclipse with a magnitude of 0.7649. It should be easily visible to the naked eye as a dusky shading in the southern half of the Moon. The times of the major phases are listed below.

               Penumbral Eclipse Begins:  21:50:38 UT                 Greatest Eclipse:          23:50:17 UT                 Penumbral Eclipse Ends:    01:49:49 UT  

Note that the beginning and end of a penumbral eclipse are not visible to the eye. In fact, no shading can be detected until about 2/3 of the Moon’s disk is immersed in the penumbra. This would put the period of nominal eclipse visibility from about 23:30 to 00:10 UT. Keep in mind that this is only an estimate. Atmospheric conditions and the observer’s visual acuity are important factors to consider. An interesting exercise is to note when penumbral shading is first and last seen.

Figure 4 shows the path of the Moon through the penumbra as well as a map of Earth showing the regions of eclipse visibility. Eastern Canada will see the entire event while the rest of Canada and the USA will see moonrise with the eclipse already in progress. Observers in Europe and Africa will also see the entire event, while eastern Asia misses the end because of moonset.

The October 18 penumbral lunar eclipse is the 52nd member of Saros 117, a series of 71 eclipses in the following sequence: 8 penumbral, 9 partial, 24 total, 7 partial, and 23 penumbral lunar eclipses (Espenak and Meeus, 2009). Complete details for the series can be found at:

eclipse.gsfc.nasa.gov/LEsaros/LEsaros117.html

Chill-tober Weekend

Our November-like chill is here to stay. Frost is likely in the metro suburbs the next several nights and will gradually creep into the downtown areas.  Days are numbered for the growing season which began with the last 32 degree temp at Minneapolis-St. Paul International Airport on April 24.

Here’s a look at where temps bottom out according to the Euro model the next few nights.

Image: Weatherspark

Season’s first flakes?

A weak clipper type low spins through Sunday. It looks cold enough to produce the season’s first flakes for parts of Minnesota Sunday and Sunday evening. The best chance of some renegade snow squalls will be just north of the Twin Cities, but I can’t rule out (or in) a few stray snowflakes Sunday!

Image: NOAA via Weatherspark

Scary cold Halloween: Coldest in 62 years?

Weather Lab pumpkins Image: Paul Huttner/MPR News

The Global Forecast System is looking downright scary cold as we head toward Halloween 2013.

Keep in mind the GFS is notorious for overdoing cold air outbreaks a week or two out, but the pattern does seem to support a chilly Halloween week this year.

(Image: NOAA via IPS Meteostar)

My hunch is the GFS will pull back and moderate these numbers (highs in the 20s) some in the next week. But if the high temp on Halloween is 31 degrees or colder, it would be the coldest Halloween in 62 years since we staggered to 30 degrees in 1951.

Here’s much more on Halloween climatology from the Minnesota Climatology Working Group.

Halloween is typically a time of crunchy leaves on the ground, and a bit of chill in the air. High temperatures in the Twin Cities are generally in the 40′s and 50′s. It is more common for the daily high on Halloween to be in the 60′s than in the 30′s. 70′s tend to be a bit rare, with only eight Halloween high temperatures being 70 degrees or above. The warmest Halloween on record was 83 degrees in 1950, with the second coldest maximum temperature on record arriving one year later with a high of 30 in 1951. The coldest Halloween maximum temperature was a chilly 26 degrees back in 1873. The last fifteen years have had some balmy Halloween afternoons with a 71 degrees in 2000, and some quite cool ones as well with a 34 in 2002. There hasn’t been a Halloween washout since 1997.

Measurable precipitation has occurred on Halloween only 26% of the time in the Twin Cities, or 37 times out of 141 years. The most rain recorded was in 1979 with .78 inches. In 1991 .85 inches of precipitation fell, which was snow. In spite of the 1991 Halloween Blizzard, measurable snow on Halloween is about as rare as getting a full sized candy bar in your trick or treat bag. Since 1872 there’s been enough snow to measure only six times: .6 in 1884, .2 in 1885, 1.4 in 1932, .4 in 1954, .5 in 1995 and of course 8.2 inches with the Halloween Blizzard of 1991.

It’s still a long way out to have high confidence in this forecast, but at this point I’d give it a 50/50 shot that highs will be stuck in the 30s on Halloween day 2013.

BOO!