At 0725 UTC on February 15 the Australian Space Weather Forecasting Centre issued a geomagnetic disturbance warning: "A CME impact occurred around 2200 UTC on February 14. Bz has been southward for the majority of time since impact and there is a chance of G1 geomagnetic conditions."
Bz is the north-south direction of the Interplanetary Magnetic Field (IMF).
They predicted a disturbance for February 15-16.
They issued a new warning on February 17 at 0206 UTC:
"A partial halo CME observed on 15-Feb is due to impact Earth's magnetosphere late on 17-Feb or early 18-Feb UTC. G1 geomagnetic conditions are expected on 18-Feb, with a slight chance of G2.
"INCREASED GEOMAGNETIC ACTIVITY EXPECTED DUE TO CORONAL MASS EJECTION FROM 17-19 FEBRUARY 2023."
For the latest geomagnetic conditions, I prefer this source:
More on the IMF:
Many sunspots appeared over this reporting week (February 9-15) with three new sunspot groups on February 9, one more on February 10, two more on February 11, another on February 12 and three more on February 13. Finally, there was one more yesterday, Thursday, February 16.
Recent sunspot images:
That one is for February 12. To see February 13, just change the 12-feb-23 string to 13-feb-23, and so on, for any other date.
Average daily sunspot numbers increased from 95.1 to 182.4, and average daily solar flux from 155.9 to 196.4.
Geomagnetic activity also rose, with average daily planetary A index going from 11.7 to 13.7, and middle latitude numbers from 7.6 to 10.7.
The most active days were at the beginning and end of the week, with planetary A index at 21 on February 9 and 29 on February 15. On those two days the college A index at Fairbanks, Alaska was 33 and 46. The quietest day was Monday, February 13 when the planetary A index was 4.
The outlook for the next month seems modest, with predicted solar flux at 155, 160, 155, 145 and 135 on February 17-21, 125 on February 22-23, 130 on February 24-26, 140 on February 27 to March 1, 145 on March 2-3, then 150, 155 and 165 on March 4-6, 180 on March 7-13, 170 on March 14-15, 160 on March 16-18, and 150 on March 19, 140 on March 20-21, and 135 on March 22-25.
Predicted planetary A index is 22, 30, 12, 8 and 12 on February 17-21, 10 on February 22-24, then 5, 5 and 8 on February 25-27, another 5, 5, and 8 on February 28 through March 2, then 5, 5 and 16 on March 3-5, then 18, 15 and 8 on March 6-8, and 5 on March 9-20, then 10 on March 21-23, and 5, 5 and 8 on March 24-26, and another 5, 5 and 8 on March 27-29.
Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere - February 16, 2023, from F.K. Janda, OK1HH:
"On February 11, we observed a seemingly dangerous sunspot group AR3217, whose magnetic field had a beta-gamma-delta configuration, in which large flares are often observed, up to X-class flares accompanied by CMEs. This is what we saw at 1548 UTC, while extreme UV radiation ionized the upper part of the Earth's atmosphere. Direct result was the Dellinger effect, which disrupted shortwave communications over all of South America.
"But this particular eruption did not create a CME. Another explosion did. Five hours before the X eruption, a magnetic filament appeared in the northern hemisphere of the Sun, which spewed a CME into space. Thereafter we were expecting an Earth impact on Valentine's Day, February 14. This was a fairly accurate prediction because the Earth's intervention occurred just one day later, on February 15. It was not a direct hit, only a weak G1 class geomagnetic storm developed.
"On February 15 a magnetic filament eruption near the solar equator and another CME heading towards Earth was observed. We can expect an arrival on February 17-18, again as a weak G1 class geomagnetic storm, perhaps intensifying to a mild G2 class storm on February 18. Further we can expect to see more M-class solar flares in the next few days. Also, an X-class flare is not out of the question. In addition, the AR3226 sunspot group with an unstable magnetic field, is directly facing the Earth."
Impossible but dramatic solar image:
Spaceweather.com warns:
"GEOMAGNETIC STORM WATCH: Photographers, warm up your cameras. A CME is heading for Earth, and it could spark an unusually good display of Northern Lights when it arrives on Feb. 17-18. NOAA forecasters say that moderate G2-class geomagnetic storms are possible. During such storms, auroras have been seen in the USA as far south as, e.g., New York and Idaho."
From the Western Washington DX Club email list:
WT8P posted at 1855 UTC on February 16:
"6M FT8 open to central and SA At 1845 UTC, LU9AEA (Argentina) and TG9AJR (Guatemala) on FT8, 50.313 MHz."
W7YED posted at 1939 UTC, February 16:
"I was able to pick up 5 new ones on 6m in the space of about 20 minutes. Nice opening!
"TI, CX, CE, LU, TG were all between +3 and -18."
A story about "vicious solar storms":
Aurora on Valentine's Day:
A video last week from Dr. Tamitha Skov, WX6SWW:
This weekend is the CW portion of the ARRL International DX Contest.
For details see: https://www.arrl.org/arrl-dx .
Send your tips, reports, observations, questions and comments to k7ra@arrl.net. When reporting observations, don't forget to tell us which mode you were operating.
For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation and the ARRL Technical Information Service at http://arrl.org/propagation-of-rf-signals . For an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere .
An archive of past propagation bulletins is at http://arrl.org/w1aw-bulletins-archive-propagation . More good information and tutorials on propagation are at http://k9la.us/ .
Instructions for starting or ending email distribution of ARRL bulletins are at http://arrl.org/bulletins .
Sunspot numbers for February 9 through 15, 2023 were 150, 190, 209, 197, 185, 206, and 140, with a mean of 182.4. 10.7 cm flux was 214.9, 207.8, 209.5, 199.7, 189.2, 179.7, and 173.7, with a mean of 196.4. Estimated planetary A indices were 21, 16, 11, 7, 4, 8, and 29, with a mean of 13.7. Middle latitude A index was 16, 12, 10, 5, 3, 6, and 23, with a mean of 10.7.
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