Product: Weekly Highlights and Forecasts
:Issued: 2026 Apr 27 0538 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 20 - 26 April 2026
Solar activity ranged from low to high levels. The strongest events of the period were an X2.4 flare (R3-Strong) at 24/0107 UTC and an X2.5/2B (R3) at 24/0813 UTC from Region 4419 (N14, L=314,
class/area=Eki/360 on 17 Apr). The X2.4 flare had an associated Tenflare and CME signature. Modeling of the CME indicated possible influence from the far periphery of the event on 26 Apr. The X2.5
flare had an associated Type II (est 1,293 km/s), Type IV, and Tenflare (570sfu) as well as a CME signature in coronagraph imagery. Modeling of this event suggested the primary bulk of the plasma was
not on the Sun-Earth line.
Other major X-ray events included an M6.4/1F (R2-Moderate) at 24/1815 UTC from Region 4419. The resulting CME was off the Sun-Earth line. An M6.0 (R2) flare 26/2257 UTC from Region 4420
(N16, L=225, class/area=Fki/400 on 25 Apr). As associated Type II (est 834 km/s) was reported with this event as well as a 30,000sfu burst on 245MHz. No CME signature was identified in subsequent
coronagraph imagery.
13 other M-class (R1-Minor) events were observed over the past week with many producing radio and CME signatures. However, those events that were associated with CMEs did not contain an Earth-directed component.
No proton events were observed at geosynchronous orbit.
The greater than 2 MeV electron flux at geosynchronous orbit reached high levels on 20-24 Apr and remained at normal background to moderate levels for the remainder of the report reporting period.
Geomagnetic field activity reached G1 (Minor) storm levels on 20-21Apr due to the influence of a negative polarity CH HSS. Solar wind speeds peaked around 550 km/s and total magnetic field strength
increased to a brief peak of 10 nT on 20 Apr. The Bz component reached as far south as -8 nT during the HSS. Quiet to unsettled conditions were observed over 22-25 Apr. A negative polarity coronal
hole, with possible weak embedded influence from a CME that left the Sun on 24 Apr, caused isolated active levels on 26 Apr. Solar wind speeds remained below 500 km/s with this coronal hole.
Forecast of Solar and Geomagnetic Activity 27 April - 23 May 2026
Solar activity is expected to reach moderate levels (R1-R2/Minor-Moderate), with a slight chance for high (R3/Strong), from 27 Apr - 04 May due to the flare potential from multiple active regions on the solar disk. The remainder of the outlook period is likely to be at low levels, with a slight chance for M-class (R1-R2).
No proton events are expected at geosynchronous orbit.
The greater than 2 MeV electron flux at geosynchronous orbit is expected to reach high levels on 12 Apr, 29 Apr - 05 May, 08-14 May, and 17-21 May due to the anticipated influence from multiple, recurrent, CH HSS. The remainder of the outlook period is likely to be at normal to moderate levels.
Geomagnetic field activity is expected to reach G1 (Minor) geomagnetic storm levels on 07 May and 15-16 May. Active conditions are likely on 27 Apr, 30 Apr, 08 May, 17-18 May, and 23 May.
Unsettled conditions are likely on 29 Apr, 01 May, 03-04 May, 09 May, and 21-22 May. All enhancements in geomagnetic activity are due to the anticipated influence of multiple, recurrent, CH HSSs. The remainder of the outlook period is expected to be at mostly quiet.
Product: 27-day Space Weather Outlook Table 27DO.txt
:Issued: 2026 Apr 27 0538 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 2026-04-27
#
# UTC Radio Flux Planetary Largest
# Date 10.7 cm A Index Kp Index
2026 Apr 27 155 12 4
2026 Apr 28 150 7 2
2026 Apr 29 150 10 3
2026 Apr 30 152 14 4
2026 May 01 152 8 3
2026 May 02 148 5 2
2026 May 03 142 8 3
2026 May 04 140 8 3
2026 May 05 140 5 2
2026 May 06 135 5 2
2026 May 07 135 20 5
2026 May 08 135 15 4
2026 May 09 120 8 3
2026 May 10 110 5 2
2026 May 11 115 5 2
2026 May 12 115 5 2
2026 May 13 120 5 2
2026 May 14 120 5 2
2026 May 15 118 25 5
2026 May 16 130 20 5
2026 May 17 135 20 4
2026 May 18 135 15 4
2026 May 19 135 5 2
2026 May 20 140 5 2
2026 May 21 140 8 3
2026 May 22 145 10 3
2026 May 23 145 12 4
(NOAA)
