roduct: Weekly Highlights and Forecasts
:Issued: 2025 Dec 15 0446 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC cweb www.swpc.noaa.gov/content/subscription-services
#
# Weekly Highlights and Forecasts
#
Highlights of Solar and Geomagnetic Activity 08 - 14 December 2025
Solar activity reached high levels this week, with a single X-flare and multiple (16) M-flares. Region 4298 (S16, L=305, class/area Cso/60 on 10 Dec) produced the only X-flare of the period: an X1.1/2b flare at 08/0501 UTC. Other notable activity included multiple M-class flares from several different regions. Region 4294
(S15, L=284, class/area Ekc/1180 on 08 Dec) was responsible for the majority of the M-flares, including: an M2.2/1n at 08/0036 UTC, an M1.0/Sf at 08/1305 UTC, an M3.1/Sf at 08/2117 UTC, an M1.1 at 09/0138 UTC, an M1.0/Sf at 09/0729 UTC, an M1.3/Sf at 090739 UTC, an M1.6/Sf at 09/0747 UTC, an M1.5/Sf at 091514 UTC, an M1.2/Sf at 10/0422 UTC, an M1.9/Sf at 10/0737 UTC, an M1.0/1f at 10/0955 UTC, an M1.6/Sf at 10/1343 UTC, an M4.4/2b at 10/2208 UTC, and an M1.1 at 12/0544 UTC. Region 4296 (S14, L=272, class/area Ekc/500 on 08 Dec) contributed two M-flares: an M1.5/Sf at 09/2327 UTC, and an M2.0 at 12/0505 UTC. Region 4299 (N22, L=267, class/area Dai/130 on 08 Dec) added three M-flares: an M2.4/2n at 08/0012 UTC, an M1.2/Sn at 08/2228 UTC, and an M2.0 at 09/0058 UTC. Finally, Region 4304 (N26, L=252, class/area Cai/110 on 11 Dec) produced a single M-flare: an M1.8/1n at 08/0654 UTC.
Multiple radio events accompanied some of the flares, with a total of eight Type II and three Type IV radio sweeps, as well as a 10cm radio burst. These included: a Type II (est 317 km/s) associated with the M2.4/2n at 08/0012 UTC, a Type II (est 347 km/s) associated with the X1.1/2b at 08/0036 UTC, a Type II (est 1825 km/s) and Type IV associated with the M1.1 at 09/0138 UTC, a Type II (est 759 km/s) thought to be associated with a far sided flare event, a Type II (est 1053 km/s) associated with the M1.6/Sf at 10/1343 UTC, a Type II (est 849 km/s) and 10cm burst (168 sfu) associated with the M4.4/2b at 10/2208 UTC, a Type II (est 410 km/s) and Type IV associated with the M2.0 at 12/0505 UTC, and a Type IV associated with the M1.1 at 12/0544 UTC.
Several CMEs were analyzed throughout the period, with only a couple thought to have an Earth-directed component. The most notable event was from the X1.1/2b flare that had a westerly trajectory with an analyzed glancing arrival at Earth late on 10 Dec to early on 11 Dec. There is a possibility this CME contributed to the G2 (Mod) geomagnetic storming event on 10-11 Dec. There was also a CME from the M4.4/2b flare from Region 4294 at 10/2208 UTC, but the resulting analysis indicated the bulk of the ejecta would pass ahead of Earth. However, it is possible more of the ejecta could have passed near enough to Earth on 13 Dec, combined with CH HSS effects, and enhanced conditions to the G1 (Minor) storm levels. The majority of the other CMEs were deemed to not have Earth-directed components.
The greater than 10 MeV proton flux was at background levels throughout the period.
The greater than 2 MeV electron flux at geosynchronous orbit was at high levels on 08-09 Dec, and at normal to moderate levels on 10-14 Dec.
Geomagnetic field activity was at quiet to unsettled levels on 08, 09, and most of 10 Dec, as well as 14 Dec. G2 (Moderate) storm levels were observed the last period of 10 Dec and the first synoptic period on 11 Dec following the arrival of a CME that likely left the Sun on 08 Dec. Active to G1 (Minor) storming was observed on 12 and 13 Dec in response to negative polarity CH HSS influence mixed with possible transient effects.
Forecast of Solar and Geomagnetic Activity 15 December - 10 January 2026
M-class flares (R1-R2/Minor-Moderate) are likely, with a chance for X-class (R3/Strong) flares through the outlook period. Chances could increase if new, more magnetically complex regions develop or return during the period.
Barring significant development of new active regions, the greater than 10 MeV proton flux is expected to remain below the 10 pfu (S1-Minor) levels throughout the outlook period.
The greater than 2 MeV electron flux is expected to reach high levels on 16-19 Dec, 25-29 Dec, and 01-06 Jan. Normal to moderate levels expected to prevail on 15, 20-24, 30-31 Dec, and 07-10 Jan.
Geomagnetic field activity is likely to reach G1 (Minor) storm levels on 18 Dec, 30-31 Dec, and possibly 09 Jan, due to negative
polarity CH HSS influences. G1 levels are also likely on 22-26 Dec, due to positive polarity CH HSS influences. Unsettled to active levels are likely on 15-17, 19-20 Dec, 01-03 Jan, and 08-10 Jan under the influence of negative polarity CH HSS, and on 27-29 Dec under positive polarity CH HSS influence. Mostly quiet conditions
are expected on 21 Dec and 04-08 Jan. 2026
Product: 27-day Space Weather Outlook Table 27DO.txt
:Issued: 2025 Dec 15 0446 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC web contact www.swpc.noaa.gov/content/subscription-services
#
# 27-day Space Weather Outlook Table
# Issued 2025-12-15
#
# UTC Radio Flux Planetary Largest
# Date 10.7 cm A Index Kp Index
2025 Dec 15 120 10 3
2025 Dec 16 120 8 3
2025 Dec 17 120 10 3
2025 Dec 18 120 15 5
2025 Dec 19 115 12 4
2025 Dec 20 115 10 3
2025 Dec 21 115 5 2
2025 Dec 22 125 20 5
2025 Dec 23 135 20 5
2025 Dec 24 145 25 5
2025 Dec 25 155 20 5
2025 Dec 26 165 20 5
2025 Dec 27 175 15 4
2025 Dec 28 180 10 3
2025 Dec 29 175 8 3
2025 Dec 30 180 30 6
2025 Dec 31 180 25 5
2026 Jan 01 175 10 3
2026 Jan 02 170 10 3
2026 Jan 03 170 8 3
2026 Jan 04 170 5 2
2026 Jan 05 170 5 2
2026 Jan 06 170 5 2
2026 Jan 07 150 5 2
2026 Jan 08 140 5 2
2026 Jan 09 135 15 5
2026 Jan 10 125 10 3
(NOAA)
