Perseid sky show may dazzle, heat builds

The Perfect Summer of 2015 rolls on for now.

By Wednesday afternoon, upper level wind flow begins to buckle as an amplifying ridge of high pressure in the west expands influence over the Upper Midwest.

Translation? Temperatures and humidity are on the rise this week as southwest winds kick in at the surface behind a departing high pressure cell. Scattered thunderstorms reappear by early Thursday morning.

We've sweated through just two days at or above 90 degrees so far this summer. We have a chance to double that number by Saturday afternoon as temps nudge the 90 degree mark Thursday through Saturday.

The European Centre for Medium-Range Weather Forecasts model below is aggressive with temps Thursday through Saturday. My read is Saturday marks the best chance for putting another 90-plus degrees reading on the board. The actual air temperature may be academic. With dew points pushing 70 degrees again you'll sweat even if temps stall in the upper 80s.

The best chances for more timely rainfall appear to be early Thursday, Friday and Sunday mornings.

Perseid meteors this week

This is the week to check out the annual Perseid Meteor Shower. Viewing could be especially good this year, as the new moon Friday means little moonlight to interfere with the shooting streaks across the sky. As many as 50 to 100 meteors per hour could be visible in dark locations. Dry skies should help viewing over Minnesota tonight.

The Perseids occur as earth passes through the debris stream from the Comet Swift-Tuttle. Here's more from space.com.

The Perseid meteor shower is the most widely observed and dependable annual meteor display of the year, and its peak this week has all the earmarks of being an excellent example of celestial fireworks, weather permitting.

This year, the Perseids will peak in the overnight hours of Wednesday and Thursday (Aug. 12 and 13) just one day before the new moon. Unlike last year, when a brilliant and nearly full moon washed out all but the brightest meteors, 2015 should be a very opportune year for observing "shooting stars" with your own eyes or cameras. Today, NASA released a video on how to see the 2015 Perseid meteor shower.

Most meteor showers evolve from comets, and thePerseid meteor shower is no different. It is made of pieces of Comet Swift-Tuttle, a comet first discovered in 1862 that takes 133 years to make one trip around the sun. Comet Swift-Tuttle was last visible in the night sky in 1992 and won't return until 2126.

Comet Swift-Tuttle must have passed the sun well over 1,000 times to produce the present stream of Perseid meteors. The comet debris has become distributed all around the Swift-Tuttle's elongated elliptical orbit, which reaches out beyond the realms of Pluto and ultimately brings them back to intersect Earth's orbit at almost a right angle, producing a fairly predictable meteor display that lasts for several days in mid-August

The particles responsible for most of the streaks of light that observers see are quite small, ranging in size from large grains of sand to small pebbles, but with the consistency of cigar ash. They're invisible until, upon entering Earth's atmosphere with immense velocity — 37 miles per second (60 kilometers per second) — their kinetic energy is used up in such processes as the production of light and heat, and ionization. They cannot survive the shock of entry, so they streak across the sky in a brief, blazing finale.

NASA has more on why this could be a particularly good show.

Circle of Blue Town Hall meetings on California water crisis

Is crisis to big a word for water issues in California these days? Absolutely not. Circle of Blue is holding some interesting discussions on the state of the water crisis in California this month.