DENSE SOLAR WIND: Today, Dec. 19th, Earth is entering a slow but dense zone of solar wind. Compressed magnetic fields in this region could link to Earth's own magnetic field, sparking geomagnetic activity around the poles. Arctic sky watchers should be alert for auroras.

AN EXPLOSION ON THE SUN: Yesterday, an active region emerging from the sun's southeastrn limb exploded, producing a C6-class solar flare and a beautiful loop-shaped prominence:

Debris from the explosion will miss Earth. However future eruptions might be geoeffective as the unstable blast site moves into our planet's strike zone later this week.

Solar wind
speed: 574.5 km/sec
density: 14.7 protons/cm3
Updated: Today at 1356 UT

X-ray Solar Flares
6-hr max: C3 1018 UT Dec22
24-hr: M1 0706 UT Dec22
Updated: Today at: 1400 UT

Daily Sun: 22 Dec 21

There are 10 numbered sunspot groups on the solar disk--the most since the peak of the previous Solar Cycle almost 11 years ago. Credit: SDO/HMI

Planetary K-index
Now: Kp= 2 quiet
24-hr max: Kp= 3 quiet

Interplanetary Mag. Field
Btotal: 4.7 nT
Bz: -1.2 nT south
Updated: Today at 1355 UT

Coronal Holes: 22 Dec 21

Earth is inside a stream of solar wind flowing from the indicated coronal hole. Credit: SDO/AIA

GEOMAGNETIC STORM WATCH: A CME is heading for Earth. The faint storm cloud left the sun on Dec. 20th (1136 UT), propelled by an M1.9-class solar flare in the magnetic canopy of sunspot AR2908. NOAA forecasters expect a glancing blow to Earth's magnetic field on Dec. 23rd, possibly sparking a G1-class geomagnetic storm. Christmas Lights, anyone?

Solar wind
speed: 438.0 km/sec
density: 5.0 protons/cm3
more data: ACE, DSCOVR
Updated: Today at 1230 UT

X-ray Solar Flares
6-hr max: C5 0719 UT Dec24
24-hr: C7 0342 UT Dec24
explanation | more data
Updated: Today at: 1235 UT

CHANCE OF CHRISTMAS STORMS (UPDATED): Multiple M-class solar flares this week have hurled at least two faint CMEs toward Earth. NOAA forecast models predict glancing blows on Dec. 24th and 25th.

The impacts, albeit weak, could combine to produce G1-class geomagnetic storms and high-latitude auroras during the Christmas holiday.

Solar wind
speed: 436.5 km/sec
density: 4.7 protons/cm3
more data: ACE, DSCOVR
Updated: Today at 2340 UT

X-ray Solar Flares
6-hr max: C3 1905 UT Dec25
24-hr: C3 1905 UT Dec25
explanation | more data
Updated: Today at: 2345 UT

ALL I WANT FOR CHRISTMAS IS A ... CME? A CME impact expected on Dec. 24th did not materialize. NOAA forecasters say the CME may still be coming, with a delayed impact on Christmas Day. The glancing blow could spark minor G1-class geomagnetic storms and auroras around the Arctic Circle

Planetary K-index
Now: Kp= 2 quiet
24-hr max: Kp= 3 quiet
explanation | more data

Interplanetary Mag. Field
Btotal: 4.4 nT
Bz: -0.3 nT south
more data: ACE, DSCOVR
Updated: Today at 2340 UT

Solar wind
speed: 345.8 km/sec
density: 3.1 protons/cm3
Updated: Today at 1935 UT

X-ray Solar Flares
6-hr max: C1 1859 UT Dec26
24-hr: C2 0036 UT Dec26
Updated: Today at: 1940 UT

Daily Sun: 26 Dec 21

Sunspot AR2916 has a 'delta-class' magnetic field that harbors energy for X-class solar flares. Credit: SDO/HMI

Planetary K-index
Now: Kp= 0 quiet
24-hr max: Kp= 1 quiet

Interplanetary Mag. Field
Btotal: 3.5 nT
Bz: -1.3 nT south

Updated: Today at 1935 UT

BIG SUNSPOT TURNS TOWARD EARTH: This weekend, sunspot AR2916 has quadruped in size, turning into one of the largest spots of Solar Cycle 25. This 48-hour movie from NASA's Solar Dynamics Observatory shows the active region growing and turning toward Earth

Details:

Sunspot group AR2916 has been growing since its emergence.

Photographer's website:

https://www.flickr.com/photos/michael_teoh

THE GRINCH STOLE MY GEOMAGNETIC STORM: Arctic sky watchers hoping for a geomagnetic storm were disappointed on Christmas when a CME did *not* hit Earth's magnetic field. The incoming storm cloud either missed or it is moving much more slowly than NOAA forecast models predicted. Either way, a storm is now unlikely this weekend.