Monday, April 20, 2026

Weekly Propagation Forecast Bulletins

 Product: Weekly Highlights and Forecasts
:Issued: 2026 Apr 20 0331 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC web contact https://www.swpc.noaa.gov/content/subscription-services
#
#                Weekly Highlights and Forecasts
#
Highlights of Solar and Geomagnetic Activity 13 - 19 April 2026


Solar activity was at very low to low levels during the period. Very low levels occurred on 14, 15 and 19 Apr, while low levels were observed on 13, 16, 17, and 18 April. 

Region 4419 (N14, L=314, class/area=Eki/360 on 17 Apr) was the most active region of the period, responsible for 5 out of the 7 C-class flares observed during the week, including the largest one: a C4.1/Sf at 17/0442 UTC. The remaining 2 C-class flares of the period were: a C1.1/Sf at 13/1137 UTC from Region 4414 (N15, L=026, class/area=Dro/030 on 08 Apr) and a C1.6 at 18/0704 UTC from Region 4416 (N19, L=047, class/area=Dai/140 on 12 Apr). Coronal activity was observed during the week with some filament eruptions and few CMEs without Earth-directed components. 

No proton events were observed at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit was at high levels on 13-17 Apr, followed by a day at moderate levels on 18 Apr and returning to high levels on 19 Apr, with a maximum flux of 3,250 pfu observed at 15/1800 UTC. 

Geomagnetic field activity was quiet to Moderate storm levels during the period. From 13 to 17 Apr, the geomagnetic activity remained at quiet levels. On 18 Apr, the arrival of a negative polarity CH HSS influence disturbed the Geospace, elevating the activity from unsettled to Moderate storm levels. On 19 Apr, Moderate storm levels were observed during an isolated synoptic period (0600-0900 UTC) and the geomagnetic activity returned to quiet level by the end of the day as the CH HSS effects waned. 

Forecast of Solar and Geomagnetic Activity 20 April - 16 May 2026

Solar activity is expected to be at low levels, with a varying chance for M-class (R1-R2/Minor-Moderate) flares and a slight chance for X-class (R3/Strong or greater) flares through 16 May. 

No proton events are expected at geosynchronous orbit, barring any significant, non-recurrent solar activity. 

The greater than 2 MeV electron flux at geosynchronous orbit is expected to reach high levels on 20-22 Apr, 27-28 Apr, 30 Apr-05 May, and 08-14 May. Normal to moderate electron flux levels are expected on 23-26 Apr, 29 Apr, 06-07 May, and 15-16 May. 

Geomagnetic field activity is expected to remain at quiet to active levels during most of the outlook period, with the exception of 5 days when G1 (Minor) storm levels are anticipated due to the recurrent influence of CH HSS: 29-30 Apr (-CH HSS), 07 May (+CH HSS) and 15-16 May (-CH HSS). 

Product: 27-day Space Weather Outlook Table 27DO.txt
:Issued: 2026 Apr 20 0331 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
#
#      27-day Space Weather Outlook Table
#                Issued 2026-04-20
#
#   UTC      Radio Flux   Planetary   Largest
#  Date       10.7 cm      A Index    Kp Index
2026 Apr 20     105          18          4
2026 Apr 21     110          15          4
2026 Apr 22     120           8          3
2026 Apr 23     125           5          2
2026 Apr 24     120           8          3
2026 Apr 25     115           8          3
2026 Apr 26     120           5          2
2026 Apr 27     125           5          2
2026 Apr 28     125           5          2
2026 Apr 29     125          20          5
2026 Apr 30     125          18          5
2026 May 01     125          12          4
2026 May 02     125          10          4
2026 May 03     115           8          3
2026 May 04     108           8          3
2026 May 05     105           5          2
2026 May 06     100           5          2
2026 May 07      95          20          5
2026 May 08      90          15          4
2026 May 09      90           8          3
2026 May 10      95           5          2
2026 May 11     100           5          2
2026 May 12     105           5          2
2026 May 13     110           5          2
2026 May 14     110           5          2
2026 May 15     105          25          5
2026 May 16     105          20          5
(NOAA)