Nature cooks up a fine aurora tonight – don’t miss it

A tall red beam of aurora stands up from the lower green rayed arc in the northern sky around 10:30 p.m. tonight. Even to the eye, this one was obviously pink. Credit: Bob King

A tall red beam of aurora stands up from the lower green rayed arc in the northern sky around 10:30 p.m. tonight. Even to the eye, this clearly looked pink. Credit: Bob King

I can’t believe it. The northern lights are back … again! Sure, they were in the forecast, but that doesn’t always mean they’ll show up.

It’s been quite a wonderful pageant tonight. Lots of rayed arcs with occasional Star Wars “lightsaber” beams. The delicate pink coloration in the ray pictured above was one of the most beautiful I’ve seen in several years of aurora watching.

Around 10:15 p.m. tall, faint red rays stretched toward the North Star from an active green arc. Venus is reflected in the lake at left. Credit: Bob King

Around 10:15 p.m. tall, faint red rays stretched toward the North Star from an active green arc. Venus is reflected in the lake at left. Credit: Bob King

There was a lot of action, but nothing too fast. Rays and rayed arcs slowly materialized, hung back and then reformed over and over in a way that reminded me of a symphonic theme and variations.

Multiple rayed arcs are reflected in still waters in a lake north of Duluth, Minn. Wednesday night. Credit: Bob King

Multiple rayed arcs are reflected in still waters in a lake north of Duluth, Minn. Wednesday night. Credit: Bob King

The Kp-index sits at “5” or minor storm, and the northern lights are still out there as I write. If you can find a dark sky with a good view to the north, I encourage you to lose a little sleep to see what natures’s offering tonight.

* Update 1 a.m. Thursday April 16 – The aurora is now in the flaming phase, where pulses or waves ripple through the lights from bottom to top across the entire northern sky. Although the rays are now fainter, they reach all the way to the zenith compared to earlier in the evening. What are you seeing? Let us know by clicking on and adding a comment.

Red and green all over! Credit: Bob King

Red and green all over! Credit: Bob King

Aurora alert tonight April 15-16

What a display! The aurora on the morning of April 11, 2015 reflected in St. Croix River near Gordon, Wis. Credit: Kathleen Wolleat

What a display! The aurora on the morning of April 11, 2015 reflected in the St. Croix River near Gordon, Wis. Credit: Kathleen Wolleat

Good news on the northern lights front. Earth’s expected to get a bath from subatomic particles streaming from the Sun’s southern hemisphere tonight. They originate from a gap in its magnetic canopy called a coronal hole.

A big, extended coronal hole in the Sun's atmosphere or corona is sending a high-speed package of solar wind our way tonight. This photo was taken on April 13 by NASA's Solar Dynamics Observatory. Credit: NASA

A big, extended coronal hole in the Sun’s atmosphere or corona is sending a high-speed package of solar wind our way tonight. This photo was taken on April 13 by NASA’s Solar Dynamics Observatory. Credit: NASA

Not a big storm. The space weather office at NOAA is calling for a G1 or minor geomagnetic storm, the type that brings arcs and occasional rays of aurora across the northern U.S. and southern Canada.

The last G1 storm we experienced on April 11 produced a fat, quiet arc that broke up into a modest but attractive display visible as far south as Colorado.

The best time to watch for tonight’s possible show will be from nightfall – around 8:30 p.m. – until midnight. In other words, on the early end. There’s no moon in the sky and April brings some of the most pleasant, mosquito-free evenings of the year.

Aurora over Boulder Lake north of Duluth, Minn. on April 11, 2015. Credit: Deb Carroll

Aurora over Boulder Lake north of Duluth, Minn. on April 11, 2015. Credit: Deb Carroll

The northern lights often begin as an arc or rainbow-shaped glow low in the northern sky. When night has begun, the light lingers in the north as if twilight isn’t over yet. Don’t be fooled. That’s the aurora gearing up.

Chance for northern lights tonight April 9-10

A coronal mass ejection sent our way by sunspot group 2320 (right of center) will arrive at Earth later today and possibly fire up auroras tonight. Credit: NASA/SDO

A coronal mass ejection sent our way by sunspot group 2320 (right of center) will arrive at Earth later today and possibly fire up auroras tonight. Credit: NASA/SDO

A small scale but Earth-directed particle blast from the Sun on April 6 will arrive later today and hopefully ring our planet’s magnetospheric bell overnight.

NOAA space weather experts forecast a G1 minor geomagnetic storm peaking this evening between sunset and 10 p.m. (CDT) and continuing at a lower level through the night.

G1 conditions usually mean an aurora that appears in the lower half of the northern sky from the northern tier of states and Canadian provinces. With no moon till after midnight, conditions are perfect for seeing even faint auroras. The first thing I look for is a low, pale green arc quietly biding its time 5° or three finger-widths above the northern horizon.

The Sun early this morning photographed by the Solar and Heliospheric Observatory (SOHO). The Sun itself is hidden behind a opaque disk, so we can better see its corona - the spiky stuff. The planet Mercury is only 1° from the Sun and will soon make its best appearance of the year in the evening sky late this month. Credit: NASA/ESA

The Sun photographed early this morning by the Solar and Heliospheric Observatory (SOHO). The Sun itself is hidden behind a opaque disk, so we can better see its corona – the spiky stuff. The planet Mercury is only 1° away and will make its best appearance of the year in the evening sky later this month. Credit: NASA/ESA

If activity increases, a second, higher arc often appears, and if we’re lucky, its bottom border will brighten and break up into whirling rays. Keep an eye out tonight!

St. Patrick’s Day aurora storm strongest in a decade

Using the “day-night band” (DNB) of the Visible Infrared Imaging Radiometer Suite (VIIRS), the Suomi NPP satellite acquired this view (above) of the aurora borealis around 1:30 a.m. Eastern Daylight Time on March 18, 2015. Auroras appear as white streaks over Hudson Bay, southern Canada, and the northern United States. The DNB sensor detects dim light signals such as auroras, airglow, gas flares, city lights, and reflected moonlight. In the image above, the sensor detected visible light emissions as energetic particles rained down from Earth’s magnetosphere into the gases of the upper atmosphere.

The Suomi NPP satellite photographed the aurora borealis around 12:30 a.m. CDT on March 18, 2015. Auroras appear as white streaks over Hudson Bay, southern Canada, and the northern United States. In the image above, the sensor recorded the emission of light as energetic particles rained down from Earth’s magnetosphere into the gases of the upper atmosphere. Credit: NASA/Suomi NPP – VIIRS

Earth celebrated St. Patrick’s Day on March 17 with vivid red, white and green auroras seen as far south as the southern U.S. and as far north as New Zealand in the southern hemisphere.

It turns out the geomagnetic storm that sparked the lights was the strongest in a decade. On Sunday, March 15, a coronal mass ejection exploded off the Sun towards Earth as seen by the Solar Heliospheric Observatory (SOHO).

The Kp index over the three days starting March 16 tells the story of the geomagnetic storm in red bars of high activity. The times shown are CDT at the height of the storm. Credit: NOAA

The Kp index over the three days starting March 16 tells the story of the geomagnetic storm in red bars of high activity. The times shown are CDT at the height of the storm. Credit: NOAA

By March 17, the burst of solar particles and energy reached Earth and kept the solar wind stream at potent levels for more than 24 hours. The storm reached a G4 or “severe” level on NOAA’s geomagnetic storm scale. Meanwhile, the Kp index, an indicator of global geomagnetic storm activity, fluctuated between 6 to 8 on a scale that goes to 9.

The storm peaked during the daylight hours for observers in the U.S. and Canada. Some observers caught it on the rise in the early morning hours of the 17th while many more saw it rage into the night. Auroras continued to reverberate – albeit on the quieter side – for the remainder of the week.

The Aurorasaurus site was designed by researchers from the New Mexico Consortium, NASA, Pennsylvania State University, and Science Education Solutions to improve chances for people to catch an aurora by collecting real-time tweets and information from other sites. Credit: Aurorasaurus

The Aurorasaurus site was designed by researchers from the New Mexico Consortium, NASA, Pennsylvania State University, and Science Education Solutions to improve chances for people to see an aurora by collecting real-time tweets from aurora watchers. Credit: Aurorasaurus

Many people submitted photos and observations of the display through the Aurorasaurus website, a new citizen science project that aims to improve chances for folks to see an aurora by collecting and sharing tweets and information from other sources in real-time. Aurorasaurus gathered 35,000 aurora-related tweets and reports and confirmed 250 of them as positive sightings.

The project’s designers hope to improve our understanding of the auroral oval, two rings-shaped zones of auroras centered on Earth’s geomagnetic poles.

Auroras may return tonight, Saturday

Aurora near Yellowknife, Northwest Territory, Canada during the big St. Patrick's Day display. Credit: Joe Culler

Amazing curtains of aurora breaking up into rays near Yellowknife, Northwest Territory, Canada during the big St. Patrick’s Day display. Credit: Joe Culler

Thanks to a change-up in the solar wind called a co-rotating interaction region (CIR) followed by more gusty winds from a hole in the Sun’s corona, we have a shot at seeing auroras both tonight and Saturday night. CIRs are compression regions between a slow-flowing solar wind and a fast one. Material can pile up in a CIR, creating delicious auroral havoc upon its arrival at Earth.

Multiple curtains of northern lights float over conifers near Yellowknife during the mid-March aurora storm widely seen across the central and northern U.S. Credit: Joe Culler

Multiple curtains of northern lights float over conifers near Yellowknife during the mid-March aurora storm widely seen across the central and northern U.S. Credit: Joe Culler

NOAA space weather experts are calling for G1 minor geomagnetic storms during the hours leading up to midnight both nights. Minor storms usually mean auroras across the northern parts of the northern states and southern Canada, but as you’re probably aware, the magnetic direction of material coming our way makes a big difference as to whether it creates a storm.

If the south pole of the cloud brushes our magnetic domain, it’s far more likely to connect with Earth’s northward-pointing field. Like magnets snapping together, cloud and Earth-field are drawn to each other. Particles from the Sun can then follow Earth’s magnetic field lines into the polar regions where they strike and excite the atoms that produce the aurora.

ACE plot of magnetic field direction or Bz from last night. You can see how the storm dissipated once the magnetic direction of the cloud changed from south (during the storm) to north (above the white horizontal line). Credit: NASA

ACE plot of magnetic field direction or Bz from a storm last September. You can see how the storm dissipated once the magnetic direction of the cloud changed from south (during the storm) to north (above the white horizontal line). Credit: NASA

I always check the Bz, a measure of whether the arriving solar wind is pointing north or south. When the Bz drops below the centerline and especially if it’s at -10 or lower (south), there’s a fair chance you’ll see northern lights. Click over the ACE satellite page to check to get the lowdown on the Bz. Use the topmost graph with the red squiggly line.

The 8-day-old moon will fill your eyes with craters. Credit: Bob King

The 8-day-old moon will fill your eyes with craters. Credit: Bob King

Unlike the recent St. Patrick’s Day display, which happened in a moonless sky, we have an 8-day-moon to contend with tonight. That’s not an aurora killer but it will reduce contrast. Also, don’t be fooled by a lighter horizon in the northern sky. Normally, that’s a sign of aurora, but moonlight can also make the sky near the horizon appear brighter.

Not that there’s anything wrong with the moon. Now’s the best time to see it in a telescope – it’s high in the south and its current phase shows off a spectacular diversity of craters and land forms.

Let’s hope we get a nice aurora sometime this weekend.

One other tidbit for those following the nova in Sagittarius (Nova Sagittarii 2015 No.2). After fading early this week to around 6th magnitude, it’s rebrightened! I was surprised to see it back up to 5.0 this morning.

Weird “teardrop” aurora airbrushes the first night of spring

Peculiar teardrop-shaped auroral patch in the northwestern sky this evening near the Pleiades star cluster (upper left). Credit: Bob King

Peculiar teardrop-shaped auroral patch in the northwestern sky this evening near the Pleiades star cluster (upper left). The aurora slowly pulsated in brightness. Credit: Bob King

Just got back from looking at some pretty weird northern lights. A bright teardrop-shaped patch glowed alone low in the northwestern sky around 10:30-11 p.m. 10 minutes later, another oval patch mysteriously appeared in the north. The two swelled in size and length and almost appeared to join … but didn’t . Instead, the teardrop faded away while the oval brightened. Then it slowly disappeared. When I last looked, the oval had returned but was fainter.

The teardrop on the left and oval to the right. Each slowly pulsed, fading and brightening. Credit: Bob King

The teardrop on the left and oval to the right. Each slowly pulsed, fading and brightening. Credit: Bob King

To look at the aurora indicators we’ve tapped into the past few nights — the  Kp index and auroral oval — you’d think there’d be no reason to don hat and coat and go aurora-hunting on cold, windy night. Both indicators are nearly flat, having dropped from minor storm level during the late afternoon (CDT). Yet Earth magnetic bubble keeps on jiggling, shaking out some peculiar forms of aurora.

A closer look at the featureless northern lights oval seen around 11 p.m. in the northern sky. Credit: Bob King

A closer look at the featureless northern lights oval seen around 11 p.m. in the northern sky. Credit: Bob King

One hint that solar excitement still lingers in Earth’s vicinity comes from the live information sent to us by the Advanced Composition Explorer (ACE) satellite, which taps into the Sun’s wind a million miles upstream of our planet. Around 10:30 p.m. (CDT), ACE recorded a southward dip in the magnetic field embedded in the solar wind – perfect for linking into Earth’s field and firing up auroras.

As always, it’s hard to know how long these “glows” may last, but if you’re out, don’t be surprised if you see them. We’re now at five nights in a row and counting for northern lights displays this week. Looks like we’re in for more. The forecast calls for yet another G1 geomagnetic storm Saturday evening (March 21) from about 7-10 p.m. CDT.

Northern lights recap and planning for the next show

Northern Lights over Caribou Lake, Minn. by Guy Sander of Duluth, Minn.

How to describe last night’s northern lights? Grand expectations – brief but spectacular display around 9:30 p.m. – long lull till nearly midnight – second blast low in the sky around midnight.

Aurora over an ice-covered lake north of Duluth last night March 17. Credit: Bob King

Aurora over an ice-covered lake north of Duluth last night March 17. Credit: Bob King

If you lived near city lights or in an area where there were trees to your north, you might have wondered what all the fuss was about. At best, you may seen just a big glow in the northern sky. Most of the action from mid-northern latitudes was low enough that buildings, hills and trees would have blocked the view.

Aurora seen over Lake Superior from Wisconsin Point in Superior, Wis. around 11:55 p.m. Credit: Matthew Moses

Aurora seen over Lake Superior from Wisconsin Point in Superior, Wis. around 11:55 p.m. Credit: Matthew Moses

There are two key things to plan in advance of an aurora – a place with a wide open view of the northern sky and one where there are no concentrations of city lights in that direction. When a display is imminent, drive to that spot, watch and wait. I nearly missed last night’s peak because of a commitment till 9. On the way out, the sky broke loose with brilliant, rippling rays while I was still in the car. Luckily I arrived in time to see part of the great unfurling.

Of course, you may get skunked. Either by clouds or a disappointing show. But the longer you hang in there, the better your odds of being present when the sky cuts loose. I try to look at the up side. Even if no aurora appears, the company of the stars, the occasional meteor and sounds of the night are always a welcome break from work or sitting around the house.

Auroras may poke out again tonight. The forecast calls for a G2 geomagnetic storm with any northern lights reaching as far south as New York and Idaho. Last night’s show was visible as far south as southern New Jersey and perhaps further.

Beautiful rays returned at midnight seen here over Boulder Lake north of Duluth, Minn. Credit: Clint Austin

Beautiful rays returned at midnight seen here over Boulder Lake north of Duluth, Minn. Credit: Clint Austin

Aurora colors always fascinate. All the green and most of the reds you see are caused by oxygen atoms in our atmosphere. When high-speed particles from the Sun come racing down Earth’s magnetic fields lines towards the geomagnetic poles, they eventually strike the upper atmosphere anywhere from about 70 to 200 miles overhead. There they strike and transfer their energy to oxygen and nitrogen atoms. As the atoms return to their “rest states” they release the energy as tiny zaps of green and red light called photons.

Nature is so generous it swells me up inside. Good luck to you with clear skies in your forecast tonight.

Aurora’s out tonight as forecast – take a look!

After all the mush, a gorgeous outbreak of the northern lights around 9:30 p.m. (CDT) this evening. Here the lights are reflected off the ice in a lake north of Duluth, Minn. Credit: Bob King

After all the mush, a gorgeous outbreak of the northern lights around 9:30 p.m. (CDT) this evening. Here the lights are reflected off the ice in a lake north of Duluth, Minn. Credit: Bob King

Good news! So far the forecast has been accurate. The aurora’s out right now filling the entire northern sky. It massive but still rather faint, soft and with little structure. I’m picking up a few dim rays. Many potentially strong aurora start this way but eventually break out into amazing lights.

The aurora returns to its soft, mushy state around 10:30 p.m. Tuesday night. Credit: Bob King

The aurora returns to its soft, mushy state around 10:30 p.m. Tuesday night. Credit: Bob King

Well, it happened. The mush congealed into a long curtain across the northern sky and shattered into a display of brilliant rays around 9:30 p.m. This lasted till around 10 when the lights died back to glows and soft rays. As of 11 p.m. it’s still out there but quiet for the moment. I wouldn’t be surprised at all if a rerun happened around midnight.

Auroras paint the sky green (and red!) on St. Patrick’s Day

Wow! Tall green and red rays of northern lights fill the northern sky earlier this morning. More may arrive tonight. "It was great to see the color in them - green and red - appropriate for the day," said Schaff said

Wow! Tall green and red rays of northern lights fill the northern sky earlier this morning. More may arrive tonight. “It was great to see the color in them – green and red – appropriate for the day,” said Schaff. Credit: Jim Schaff

What a colorful coincidence! On the morning of St. Patrick’s Day an unexpected and HUGE geomagnetic storm blew our way. And it’s still blowing. If it wasn’t for that new nova in Sagittarius, I would have slept through the whole thing. Maybe some of you rose before dawn to see the nova and turned around in surprise at what was going on behind your back.

Deliciously delicate "paws" of aurora leave temporary impressions in the northern sky this morning around 5:45 a.m. Credit: Bob King

Deliciously delicate “paws” of aurora leave temporary impressions in the northern sky this morning around 5:45 a.m. Credit: Bob King

Jim Schaff of Duluth happened to be up around 2:30 and wisely set up camera on tripod to capture the magnificent and colorful display. Even as the sky blued at the coming of dawn, the northern lights wouldn’t quit. I stood and watched two bands of green toss out rays like clowns throwing candy in a parade. Beautiful.

The Sagittarius Teapot with the new nova arrowed photographed yesterday morning March 16. Credit: Justin Cowart

The Sagittarius Teapot with the new nova arrowed photographed yesterday morning March 16. Credit: Justin Cowart

Oh and yes, there was the nova. Caught up in a green auroral haze, I nearly forgot to look, but when I did, the news was good. Reports from late yesterday indicated our new “guest star” had already faded a bit, but I saw it plainly in 10×50 binoculars at magnitude +5.6, a little brighter.

Then came another surprise – the crescent moon. The slender slipper rose above the rose ribbon of an impending sunrise. But the light was gaining. Sagittarius soon faded away as did the aurora.

The Kp or K-index measures the amount of magnetic activity high in Earth's atmosphere. Kp=8 means a severe storm. Minor auroras show up when Kp = 4 or 5. Click to see the live version which is updated every 3 hours. Credit: NOAA

The Kp or K-index measures the amount of magnetic activity high in Earth’s atmosphere. Kp=8 means a severe storm. Minor auroras show up when Kp = 4 or 5. Click to see the live version which is updated every 3 hours. Times are CDT. Credit: NOAA

Not so fast. Just because the sky turned blue didn’t mean the aurora wasn’t still in the house. Throughout the morning it continued and blossomed from a strong G3 geomagnetic storm into rather rare G4 or severe storm. G4 storms can cause electrical currents in oil pipelines, fading of shortwave radio frequencies, problems with satellite navigation and auroras as far south as Alabama. Too bad it’s daytime!

Wide open view of this morning's aurora shows two active rayed arcs. Credit: Bob King

Wide open view of this morning’s aurora shows two active rayed arcs. Credit: Bob King

Tonight, NOAA space weather forecasters are calling for G1 level or minor storms (check update below). That usually means auroras only visible from the northern tier of states and points north. You never know. The Earth’s magnetic environment is highly disturbed after being hit with blasts of solar particles from recent explosions related to the supercharged sunspot group 2297 as well as a large coronal hole. The best time to look tonight will be from about 7 p.m. to 1 a.m. CDT. Watch for low bright arcs or occasional feather-like rays in the northern sky.

The auroral oval this morning just before 5 a.m. CDT. Intense auroras were seen in the red area. Click to go to the current view of the oval. Credit: NOAA

The auroral oval this morning just before 5 a.m. CDT. Intense auroras were seen in the red area. Click to go to the current view of the oval. Credit: NOAA

Another great tool to help you predict or know when the aurora’s out is the Aurora – 30 Minute Forecast put out by NOAA. It shows the extent of the permanent aurora that’s centered on Earth’s geomagnetic pole. When the Sun’s magnetic field links up with Earth’s magnetic bubble, particles get funneled into this beanie-cap affair, causing it to expand southward. During a big aurora, it expands far enough south that folks in the Midwest and southern states can see the northern lights.

Things weren't too bad in Alaska either. This spectacular photo was taken early this morning from Donnelly Creek. Nothing like a little green on St. Patrick's Day. Credit: Sebastian Saarloos

Things weren’t too bad in Alaska either. This spectacular photo was taken early this morning from Donnelly Creek. Nothing like a little green on St. Patrick’s Day. Credit: Sebastian Saarloos

May the luck of the Irish be with you tonight.

**UPDATE: The new forecast is much better. Strong to severe storms (G3-4) are now in the forecast for the remainder of the day and tonight. Start looking as soon as it gets dark.

March opens with auroras popping

Rays reach across the northern sky during last night's display of the northern lights. Credit: Bob King

Rays reach across the northern sky during last night’s display of the northern lights. Pardon the quality – it’s a hand-held exposure wedged against my deck railing. Credit: Bob King

Today begins a brand new month and maybe a break from February’s long cold spell. It might also be the start of a new round of auroral activity. Last night a nice G1 geomagnetic storm brought us active streamers and rays across the northern sky. This despite moonlight and, at least for northern Minnesota, pesky clouds, too.

NOAA space weather forecasters are calling for a second round of G1 or minor auroral storms this evening between about 6 p.m. and midnight (CST). Solar disturbances at Earth are rated on a 1 to 5 scale. G1 events usually bring auroras down to the northern tier of U.S. states from Maine to Washington. Other effects include minor fluctuations in power grids and possible impacts on computer hardware in orbiting satellites.

A good way to keep tabs on whether or not the aurora is out is to check the K or Kp index, a measure of magnetic activity in Earth's high atmosphere. The index is updated every 3 hours. The dotted line is 6 p.m. CST (0 hours UT). A Kp index of 5 often means auroras are out in the northern U.S. Credit: NOAA

A good way to keep tabs on the aurora is to check the K or Kp index, a measure of magnetic activity in Earth’s upper atmosphere. The index is updated every 3 hours. The dotted vertical line marks 6 p.m. CST (0 hours UT). A Kp index of 5 indicates a G1 storm is in progress; Kp=6 equals a moderate storm and Kp=9 an extreme event. Click to see the live index. Credit: NOAA with annotations by the author

With a G5 or extreme storm, even Floridians should expect auroras. Satellite electronics and poorly protected power grids can suffer damage, shortwave radio propagation cuts out and induced electric charges in oil pipelines by rapidly changing electrical currents in Earth’s ionosphere can lead to corrosion.

Let’s hope tonight’s predicted aurora brings a similar parade of active rays in the northern sky. Naturally, the moon will be a problem, but if your sky is otherwise dark, you might see a fair show.

This Sun this morning March 1 photographed in UV light by SDO. Credit: NASA

This Sun this morning March 1 photographed in UV light by SDO. Credit: NASA

Like last night, tonight’s source of auroral inspiration is that large, dark “hole” seen in images taken in ultraviolet light by NASA’s orbiting Solar Dynamics Observatory (SDO). Coronal holes are regions small and large on the Sun, where the solar wind of electrons and protons flows freely away from our star at high speeds. All the fluffy yellow plumage in the photo above are magnetic fields that form a sort of canopy over much of the Sun, constraining the flow of particles into space. Holes are free-for-all zones.

Video showing the Sun rotating with a coronal hole

Last night, the magnetic field embedded within the stream pointed south upon its arrival, canceling Earth’s northward-pointing magnetic field and opening a channel into our protective magnetic domain called the magnetosphere. Once “in the building”, the particles shot down into the upper atmosphere and struck atoms and molecules there to create the aurora we saw.

Forecast for midnight tonight Feb. 28-March 1 showing how the auroral oval has expanded southward across southern Canada and the northern U.S. Credit: NOAA

Forecast from last night Feb. 28-March 1 showing how the auroral oval expanded southward across southern Canada and the northern U.S. Credit: NOAA

Besides the K-index described above, another excellent tool to check on aurora is the Aurora 30-minute forecast site. Here you’ll see a near-live view of the auroral oval, the halo of permanent auroras found centered on Earth’s geomagnetic poles. When a storm ensues, the oval (or ovals – there’s a southern one, too) expands southward from its polar lair into southern Canada and the U.S.

The forecast here is for clear tonight, so I’ll be out watching. Check back for an update then.  Good luck!