Product: Weekly Highlights and Forecasts
:Issued: 2025 Apr 07 0314 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 31 March - 06 April 2025
Solar activity ranged from low to moderate levels. An M5.6 flare on Tuesday at 0734 UTC from Region 4046 (N10, L=298, class/area=Cho/0250 on 01 April) was the largest of the week. It was accompanied by a 195 sfu Tenflare and some unremarkable discrete frequency bursts. No Earth-directed CME was associated with this event, and in fact, all CME detections throughout the week were judged to miss Earth.
The only other M-flare for the remainder of the week occurred later that same day at 2231 UTC, an M2.5 from Region 4048 (S16, L=278, class/area=EKC/0450), the largest active region on the disk throughout the week. The only other M-flare to occur earlier in the week, an M1.2 event, happened on 31 March at 1024. This was also from Region 4048, and was associated with an enhancement in proton flux described in the next paragraph.
Solar particle events more than made up for the lackluster flare performance. Proton flux had been rising, most likely in response to an X1.1 flare that had occurred late last week (see PRF 2578). The 10 MeV protons crossed the 10 pfu threshold briefly on 31 Mar at 1105 UTC before falling below at 1115 UTC. This bump was possibly related to the M1.2 event described earlier. There was only a brief respite, however, because the flux again crossed the 10 pfu threshold at 1430 UTC, peaked on 01 Apr at 0425 UTC (147 pfu), and ended on 02 Apr at 0910 UTC.
Proton flux was above the 100 pfu threshold on 01 April, from 0205 UTC to 0910 UTC. Note: In the 10 MeV proton event summary, the start time was recorded as 31/1105 UTC despite the subsequent 3 hours below the 10 pfu threshold.
The greater than 2 MeV electron flux at geosynchronous orbit was high on 31 Mar-01 April before falling to moderate levels on 2-4 April. A fast solar wind stream became geoeffective on 04 April and drove flux back to high levels on 05-07 April.
Geomagnetic field activity was at quiet to active levels to begin the week, with an isolated minor storm period on 03 Apr attributed to a solar sector boundary crossing. By 04 Apr, conditions had increased to minor storm levels with the arrival of a negative polarity coronal hole and fast wind stream. Activity peaked at moderate storm levels (Kp=6m) during the first synoptic period of 05 April. Conditions remained at disturbed, ranging from unsettled to minor storm levels, through the first period of 06 April. Once the fast stream became established, conditions decreased to active to unsettled levels which persisted through the end of the week.
Forecast of Solar and Geomagnetic Activity 07 April - 03 May 2025
Solar activity is expected to be low for the first nine days of the forecast period; 11 regions are wil exit the visible disk, with only 4 regions expected to return during the same period. The declining trend in solar flux and activity is expected to bottom out around 15 April, after which a slowly increasing period is expected. The anticipated return on 22 April of the active longitudes that gave rise to Region 4046 (responsible for X-flare activity) should bring solar activity to moderate and occasionally high levels through the end of the forecast period.
No proton events are expected at geosynchronous orbit until the expected increase in flare activity beginning on 22 April. Then there will be an increasing chance for an isolated proton event as the more potent regions approach the west limb by the end of the forecast period.
The greater than 2 MeV electron flux at geosynchronous orbit is expected to begin the forecast period at high levels in response to the fast solar wind stream. Flux will subside to moderate levels after 12 April as effects from the fast stream wane. 19 April is expected to bring a return to high levels, again in response to another recurrent fast stream. The elevated conditions are expected to remain through 28 April before returning to moderate levels.
Geomagnetic field activity is expected to be primarily quit to unsettled, with an isolated active period, until the return of a recurrent geoeffective coronal hole between 19-21 April. Active condistions are expected to prevail through 24 April before the fast solar wind stream wanes. Another recurrent hole is expected to arrive aorund 01 May, bringing minor storm conditions with the threat of an isolated moderate storm period.
:Product: 27-day Space Weather Outlook Table 27DO.txt
:Issued: 2025 Apr 07 0314 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 2025-04-07
#
# UTC Radio Flux Planetary Largest
# Date 10.7 cm A Index Kp Index
2025 Apr 07 165 16 4
2025 Apr 08 160 14 3
2025 Apr 09 150 8 3
2025 Apr 10 150 5 2
2025 Apr 11 145 12 3
2025 Apr 12 140 12 3
2025 Apr 13 140 12 3
2025 Apr 14 140 12 3
2025 Apr 15 135 8 3
2025 Apr 16 140 5 2
2025 Apr 17 140 5 2
2025 Apr 18 145 5 2
2025 Apr 19 145 8 3
2025 Apr 20 150 10 3
2025 Apr 21 150 15 4
2025 Apr 22 165 15 4
2025 Apr 23 165 15 4
2025 Apr 24 165 15 4
2025 Apr 25 165 10 3
2025 Apr 26 165 5 2
2025 Apr 27 165 5 2
2025 Apr 28 170 5 2
2025 Apr 29 170 5 2
2025 Apr 30 165 5 2
2025 May 01 160 35 6
2025 May 02 160 40 6
2025 May 03 160 20 4
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