ARLP006 The ARRL Solar Report

ZCZC AP06

QST de W1AW

Propagation Forecast Bulletin 6 ARLP006

From ARRL Headquarters

Newington, CT February 6, 2026

To all radio amateurs

SB PROP ARL ARLP006

ARLP006 The ARRL Solar Report

Solar activity was at high levels for most of the week, dominated by Region 4366. The most notable event was an impulsive X4.2 flare from that region on February 4. Throughout the period, Region 4366 continued to exhibit a slight reduction in area and a modest simplification of its magnetic complexity. The remaining numbered regions on the visible disk remained stable or in a state of slight decay.

Three eruptions were observed in coronagraph imagery during the period. First was a coronal mass ejection (CME) off the southeastern limb, first observed in C2 imagery on February 4, and was likely associated with flaring near Regions 4370 and 4371. This event was followed by post-eruptive arcades also on February 4 at the same location, which further confirmed the source region despite flare activity being partially obscured by Region 4366. Modeling indicates no Earth-directed component.

The second was a narrow eruption to the NNW, first seen in C2 imagery on February 4. While potentially associated with the aforementioned X4.2 event, it dissipated quickly, and its analysis is low confidence. Lastly, there was another narrow eruption noted off the NE, first visible in SOHO/LASCO C2 imagery. This event was likely a sympathetic eruption triggered by the X4.2, starting between Regions 4366 and 4367.

There is a slight potential of minor glancing blows from these eruptions early on February 8.

Solar wind parameters initially reflected nominal background conditions before showing a clear disturbance beginning February 3. Solar wind speed remained in a slow-wind regime, gradually increasing from about 290 km/s to a peak near 340 km/s.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth’s Ionosphere, February 5, 2026, by F. K. Janda, OK1HH:

Solar activity has increased again, so the maximum of the 25th eleven-year cycle continues. This time, active region No. 4366 is primarily responsible for this. It suddenly emerged on January 30 in the southeast of the solar disk in a simple Beta magnetic configuration. The next day, it did not grow, but changed its configuration to Beta-Gamma-Delta, allowing for larger solar flares. Then, on February 1, it increased its area tenfold, while an extremely strong proton flare was observed in it, peaking on February 2 at 0002 UT.

Until February 4, it had further doubled in size, with the magnetic configuration remaining Beta-Gamma-Delta, while the production of energetically significant flares continued. One to two X-class flares and several M-class flares are recorded daily, while on February 4, active region No. 4366 crossed the central meridian.

This further increased the likelihood of the Earth being hit by an intensified solar wind and the occurrence of stronger geomagnetic disturbances. Their onset was mostly predicted for February 5, with the possibility of occurring one or two days earlier. This is what happened, with the arrival of the CME recorded on February 4 at 1421 UT, and a G1 (Minor) geomagnetic disturbance developing. It is expected to continue until February 6 or possibly February 7. At the same time, the production of energetically significant flares could continue in active region No. 4366 until February 7. At the same time, there will continue a period of slightly increased probability of the Earth being hit by a proton of solar origin. A decrease in solar and geomagnetic activity is expected in the following days.

The Predicted Planetary A Index for February 7 to February 13 is 8, 8, 10, 8, 8, 5, and 20, with a mean of 9.5. Predicted Planetary K Index is 3, 3, 3, 3, 3, 2, and 5 with a mean of 3.1. 10.7-centimeter flux is 125, 130, 135, 140, 135, 140, and 145, with a mean of 135.7.

For more information concerning shortwave radio propagation, see www.arrl.org/propagation and the ARRL Technical Information Service web page at www.arrl.org/propagation-of-rf-signals. For an explanation of numbers used in this bulletin, see www.arrl.org/the-sun-the-earth-the-ionosphere. Information and tutorials on propagation can be found at http://k9la.us.

Also, check this: ”Understanding Solar Indices” from September 2002 QST. https://bit.ly/3Rc8Njt

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