Product: Weekly Highlights and Forecasts
:Issued: 2025 Dec 08 0210 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
#
# Weekly Highlights and Forecasts
#
Highlights of Solar and Geomagnetic Activity 01 - 07 December 2025
Solar activity reached high levels this period. Region 4299 (N21, L=268, class/area=Dai/220 on 07 Dec) produced an X1.9/1n flare at 01/0249 UTC; the strongest flare of the period. Other notable activity included an M8.1/2b flare at 06/2039 UTC, also from Region 4299, which produced an full-halo CME that is expected to arrive between late 08 Dec-midday 09 Dec. A CME, first visible in LASCO C2 imagery beginning at 04/0648 UTC off the SE, arrived at Earth late on 07 Dec.
The greater than 10 MeV proton flux became elevated above background levels late 06 Dec-late 07 Dec following the M8.1 flare at 06/2039 UTC from AR4299, but did not reach event levels.
The greater than 2 MeV electron flux at geosynchronous orbit was at normal to moderate levels on 04 Dec, with high levels obserbed throughout the remainder of the period.
Geomagnetic field activity reached active levels on 01 Dec in response to positive polarity CH HSS influences. Quiet to unsettled levels were observed on 02 Dec as CH HSS influences subsided. Periods of G1-G3 (Minor-Moderate) geomagnetic storming were observed on 03 Dec, with G1 storm periods observed on 04 Dec, due to CIR and negative polarity CH HSS influences. Quiet and unsettled levels were observed on 05 Dec, with active conditions observed on 06 Dec, as negative polarity CH HSS influences waned. Active levels were observed again on 07 Dec in response to the passage of a CME from 04 Dec.
Forecast of Solar and Geomagnetic Activity 08 December - 03 January 2026
M-class flares (R1-R2/Minor-Moderate) are likely, with a slight chance for X-class flares (R3/Strong or greater), through much of the outlook period.
There is a slight chance for the greater than 10 MeV proton flux to reach 10 pfu (S1-Minor) through much of the outlook period. The greater than 2 MeV electron flux is expected to reach high levels on 08-09, 12-13, 16-17, 25-29 Dec, and 01-03 Jan. Normal to moderate levels are expected to prevail throughout the remainder of the outlook period.
Geomagnetic field activity is likely to reach G1 (Minor) storm levels on 08 and 10 Dec, with G2-G3 (Moderate-Strong) storming likely on 09 Dec, due to the anticipated arrival and passage of a CME that left the Sun on 06 Dec. Periods of G1 storming are likely on 21-23 Dec in response to negative polarity CH HSS influences, and again on 24-26 Dec under positive polarity CH HSS influences. Period of G2 (Moderate) storms are likely on 30 Dec, with G1 storming likely on 31 Dec, when negative polarity CH HSS influences are anticipated.
Product: 27-day Space Weather Outlook Table 27DO.txt
:Issued: 2025 Dec 08 0210 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC webcontact www.swpc.noaa.gov/content/subscription-services
#
# 27-day Space Weather Outlook Table
# Issued 2025-12-08
#
# UTC Radio Flux Planetary Largest
# Date 10.7 cm A Index Kp Index
2025 Dec 08 190 18 5
2025 Dec 09 190 70 7
2025 Dec 10 185 33 5
2025 Dec 11 175 10 3
2025 Dec 12 155 5 2
2025 Dec 13 140 12 4
2025 Dec 14 130 12 4
2025 Dec 15 130 8 3
2025 Dec 16 135 5 2
2025 Dec 17 135 8 3
2025 Dec 18 140 10 3
2025 Dec 19 140 8 3
2025 Dec 20 140 8 3
2025 Dec 21 140 15 5
2025 Dec 22 140 20 5
2025 Dec 23 145 20 5
2025 Dec 24 160 25 5
2025 Dec 25 170 20 5
2025 Dec 26 180 20 5
2025 Dec 27 180 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
(NOAA)
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