CHRISTMAS GEOMAGNETIC STORM WATCH: Two CMEs are expected to strike Earth during the next 48 hours--a minor glancing blow on Dec. 24th followed by a more direct hit on Dec. 25th. The one-two punch could cause a G1 to G2-class geomagnetic storm with high-latitude auroras for Christmas. CME impact alerts: SMS Text
POLAR STRATOSPHERIC CLOUD SIGHTINGS: It's still *very* cold in the polar stratosphere. Jónína Óskarsdóttir just saw visible evidence of the low temperature floating over Fáskrúðsfjörður, Iceland:
"These amazing light and beautiful polar stratospheric clouds (PSCS) appeared behind Mt. Jökultindur on Dec. 23rd," says Óskarsdóttir.
PSCs are a very rare type of cloud. They form in the Arctic stratosphere for a few days each year, usually near the winter solstice when the temperature drops to a staggeringly low -85 C. Sunlight touching the ice crystals inside PSCs cause them to blossom with pastel color.
Although PSCs normally appear only a few times each winter, sky watchers have been seeing them regularly since Dec. 10th, when they were first noticed over Norway. This means the polar cold spell is lasting longer than usual. Until further notice, Arctic photographers should remain alert for PSCs and, please, submit your photos here.
STRONG SOLAR FLARE AND CME: Big sunspot 3932 erupted on Dec. 23rd, producing an M8.9-class solar flare, only percentage points from category X. NOAA's GOES-16 satellite recorded the extreme ultraviolet flash:
The flare produced a brief shortwave radio blackout over Africa and the South Atlantic Ocean. Ham radio operators in the area may have noticed loss of signal below 20 MHz between 1112 UTC and 1127 UTC.
Of greater interest is the coronal mass ejection (CME). SOHO coronagraphs recorded a fast CME emerging from the blast site. The bulk of the CME will miss Earth to the south, however, there is still a significant Earth-directed component. NOAA and NASA forecast models predict it will arrive on Dec. 25th, potentially sparking a G1 to G2-class geomagnetic storm. CME impact alerts: SMS Text
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CHRISTMAS GIFTS FROM THE EDGE OF SPACE: Christmas is almost here! Are you looking for a far-out gift? Check out the Earth to Sky Store. It's filled with unique items that have flown to the edge of space onboard cosmic ray research balloons.
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