This was a busy week for geomagnetic storms. A solar wind stream from an equatorial hole and a Coronal Mass Ejection (CME) seemingly blew geomagnetic numbers off the scale, with the planetary A index on Monday hitting 94. An aurora was visible as far south as Colorado.
This week, the source of the 10.7-centimeter solar flux from the Dominion Radio Astrophysical Observatory in Kaleden, British Columbia, was again saturated by solar wind on February 25, and the measurement was 279.3. The National Oceanic and Atmospheric Administration (NOAA) corrected this to 152, which I thought was a bit too low. The other recent saturation was on February 17, at 343.1, but for some reason, the NOAA let this stand.
https://services.swpc.noaa.gov/text/daily-solar-indices.txt
Average daily sunspot numbers rose from 107 to 126.3, but average daily solar flux declined from 162.4 to 158.2.
Average daily planetary A index rose from 10.6 to 27.7.
Over the next few weeks, it appears that solar flux values should hit a peak around March 17 – 18.
Predicted solar flux is 164, 162, and 158 on March 2 – 4; 154 on March 5 – 8; 165 on March 9 – 12; 170 on March 13 – 15; 175 on March 16; 180 on March 17 – 18; 175, 170, and 165 on March 19 – 21; 160 on March 22 – 23; 155 on March 24 – 26; 150 on March 27 – 28; 145 on March 29 – 30, and 140, 145, 150, 155, and 160 on March 31 through April 4.
Predicted planetary A index is 8, 5, 12, 18, 24, 14, and 8 on March 2 – 8; 5 on March 9 – 14; 15, 8, 8, 5, 8, and 15 on March 15 – 20; 5 on March 21 – 23; 12, 16, 56, 32, 16, and 10 on March 24 – 29; 8 on March 30 – 31, and 16, 18, and 15 on April 1 – 3.
The predicted A index of 56 and 32 on March 26 – 27 suggests a return of this week’s disturbance in the next solar rotation.
Newsweek reported a radio blackout at the following link:
Sky & Telescope also reported on aurora season:
The News Tribune wrote a story about the northern lights:
The above story features western Washington, where I live. Unfortunately, the sky was overcast, but folks in eastern Washington were able to see the aurora. Remember that many of the images you see were from cameras with a long exposure time, which makes them much brighter than what can be seen with the naked eye.
Thanks to spaceweather.com for this NASA video clip of sunspot group AR3234 growing as it comes over our sun’s eastern limb:
Sunspot numbers for February 23 through March 1, 2023, were 108, 130, 129, 120, 192, 100, and 105, with a mean of 107. The 10.7-centimeter flux was 148.2, 164.1, 152, 159, 161.2, 160.9, and 162, with a mean of 162.4. Estimated planetary A indices were 22, 6, 10, 26, 94, 28, and 8, with a mean of 10.6. Middle latitude A index was 16, 4, 9, 18, 60, 19, and 6, with a mean of 8.4.