Product: Weekly Highlights and Forecasts
:Issued: 2023 Dec 18 1406 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC www.swpc.noaa.gov/content/subscription-services
#
# Weekly Highlights and Forecasts
#
Highlights of Solar and Geomagnetic Activity 11 - 17 December 2023
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Solar activity ranged from low to high levels. Of the 19 numbered active regions that were observed on the visible disk this week, Region 3514 (N05, L=141, class/area=Ekc/470 on 14 Dec) was primarily responsible for the most significant activity.
The region produced an X2.8 flare (R3-Strong) at 14/1702 UTC, the strongest since Sep 2017. Associated with the event were Type II (est. 2118 km/s) and Type IV radio sweeps, radio burst values with a Castelli-U profile, a Tenflare, and extremely high radio burst fluxes reported by the USAF RSTN observatories. Subsequent coronagraph imagery contained a CME signature with a halo shock and ejecta that was primarily headed toward the SW. This ejecta was modeled alongside other CME-producing events, an M5.8 flare (R2 - Moderate) at 14/0744 UTC, an M2.3 flare (R1 - Minor) at 14/1348 UTC and a double peak M6.9 flare at 15/0734 UTC. The resulting WSA-Enlil output suggested anticipated CME influence for late 16 Dec and through 17 Dec.
Other activities of note included coronal dimming on 11 Dec and 12 Dec from the vicinity of Region 3514. The X-ray response from these events was below the R1 event threshold but signatures in coronagraph imagery were identified following the events. Modeling and analysis of these events suggested CME influence likely around 14-15 Dec.
With high levels observed on 14-15 Dec, and moderate levels observed on 17 Dec (all from Region 3514), the remainder of the summary period was at low solar activity levels. Other CME activity observed in coronagraph imagery was determined to not be along the Sun-Earth
line.
The GOES-16 greater than 10 MeV proton flux briefly exceeded the S1 (Minor) threshold at the very end of the 15 Dec UT day. Flux levels reached a peak of 13.9pfu shortly after at 16/0015 UTC. The proton enhancement was thought to be produced by the combined contribution of the CMEs associated with the X2.8 flare at 14/1702 UTC and the M6.9 flare at 15/0734 UTC.
The greater than 2 MeV electron flux at geosynchronous orbit was at high levels on 11-12 Dec. Due to an increase in geomagnetic activity, electron flux levels remained at normal to moderate levels from 13-17 Dec.
Geomagnetic field activity ranged from quiet to G1 (Minor) storm levels. Quiet levels were observed over 11 Dec. An increase to active levels was observed after a brief period of southward Bz reached -12 nT. This was likely caused by a filament eruption on the Sun over 08 Dec. Quiet to unsettled conditions on 13 Dec increased to active levels again on 14 Dec (southward Bz reached ~-11 nT). On 15 Dec, only quiet to unsettled conditions followed the arrival of a CME associated with activity on the Sun over 11-12 Dec.
An increase to active conditions was observed on 16 Dec when solar wind speeds increased to above 500 km/s. Activity would increase to G1 (Minor) geomagnetic storm levels over 17 Dec as CME influence from activity on the Sun over 14-15 Dec passed by Earth. Total magnetic field strength increased to a peak 17 nT and Bz reached as far south -14 nT as the CME passed. Solar wind speeds increased to roughly 550 km/s before decreasing to below 500 km/s by the end of the 17 Dec UT day.
Forecast of Solar and Geomagnetic Activity 18 December - 13 January 2024
Solar activity is expected to be at low levels, with a chance for moderate activity (R1-R2/Minor-Moderate) throughout the outlook period.
No proton events are expected at geosynchronous orbit.
The greater than 2 MeV electron flux at geosynchronous orbit is expected to reach high levels due to multiple, recurrent CH HSSs on 20-22 Dec, 03-05 Jan, and 08-10 Jan. The remainder of the outlook period is likely to be at normal to moderate levels.
Geomagnetic field activity is expected to reach G1 (Minor) storm on 18 Dec due to waning CME influence. Active levels are likely on 19 Dec as solar wind influence is anticipated to transition to a CH HSS. Unsettled levels due to recurrent CH HSSs are also likely on 20-21 Dec, 23 Dec, 30 Dec-02 Jan, and 08-10 Jan. The remainder of the outlook period is expected to be mostly quiet.
Product: 27-day Space Weather Outlook Table 27DO.txt
:Issued: 2023 Dec 18 1406 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC contact www.swpc.noaa.gov/content/subscription-services
#
# 27-day Space Weather Outlook Table
# Issued 2023-12-18
#
# UTC Radio Flux Planetary Largest
# Date 10.7 cm A Index Kp Index
2023 Dec 18 147 15 4
2023 Dec 19 145 15 4
2023 Dec 20 140 12 3
2023 Dec 21 138 8 3
2023 Dec 22 136 5 2
2023 Dec 23 136 8 3
2023 Dec 24 140 5 2
2023 Dec 25 145 5 2
2023 Dec 26 148 5 2
2023 Dec 27 145 5 2
2023 Dec 28 145 5 2
2023 Dec 29 145 5 2
2023 Dec 30 145 8 3
2023 Dec 31 150 8 3
2024 Jan 01 145 10 3
2024 Jan 02 140 8 3
2024 Jan 03 138 5 2
2024 Jan 04 136 5 2
2024 Jan 05 136 5 2
2024 Jan 06 140 5 2
2024 Jan 07 145 5 2
2024 Jan 08 148 10 3
2024 Jan 09 145 10 3
2024 Jan 10 145 8 3
2024 Jan 11 145 5 2
2024 Jan 12 145 5 2
2024 Jan 13 150 5 2
(NOAA)
