Viewing archive of Friday, 17 May 2013
Solar activity report
Any mentioned solar flare in this report has a scaling factor applied by the Space Weather Prediction Center (SWPC). Because of the SWPC scaling factor, solar flares are reported as 42% smaller than for the science quality data. The scaling factor has been removed from our archived solar flare data to reflect the true physical units.
Report of Solar-Geophysical Activity 2013 May 17 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 137 Issued at 2200Z on 17 May 2013IA. Analysis of Solar Active Regions and Activity from 16-2100Z to 17-2100Z Solar activity has been at moderate levels for the past 24
hours. The largest solar event of the period was a M3 event observed at
17/0857Z from Region 1748 (N12E23). There are currently 10 numbered
sunspot regions on the disk.
IB. Solar Activity Forecast
Solar activity is expected to be at
moderate to high levels with a chance for X-class flares on days one,
two, and three (18 May, 19 May, 20 May).
IIA. Geophysical Activity Summary 16-2100Z to 17-2100Z
The geomagnetic
field has been at quiet to unsettled levels for the past 24 hours. Solar
wind speed, as measured by the ACE spacecraft, reached a peak speed of
431 km/s at 17/0120Z. Total IMF reached 7 nT at 17/1927Z. The maximum
southward component of Bz reached -5 nT at 16/2126Z. Protons greater
than 10 MeV at geosynchronous orbit reached a peak level of 41 pfu at
17/1720Z. Electrons greater than 2 MeV at geosynchronous orbit reached a
peak level of 203 pfu.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected
to be at quiet to unsettled levels on day one (18 May), quiet to major
storm levels on day two (19 May) and quiet to active levels on day three
(20 May). Protons are expected to continue above threshold levels on
days 1-3 (18-20 May).
III. Event Probabilities 18 May to 20 May
| Class M | 75% | 75% | 75% |
| Class X | 50% | 50% | 50% |
| Proton | 99% | 95% | 90% |
| PCAF | red | ||
IV. Penticton 10.7 cm Flux
Observed 17 May 136 Predicted 18 May-20 May 140/140/135 90 Day Mean 17 May 120
V. Geomagnetic A Indices
Observed Afr/Ap 16 May 012/015 Estimated Afr/Ap 17 May 010/012 Predicted Afr/Ap 18 May-20 May 008/008-017/034-012/016
VI. Geomagnetic Activity Probabilities 18 May to 20 May
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 15% | 35% | 30% |
| Minor storm | 05% | 30% | 10% |
| Major-severe storm | 01% | 20% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 15% | 05% | 15% |
| Minor storm | 25% | 20% | 30% |
| Major-severe storm | 25% | 75% | 40% |
All times in UTC
Latest news
Sunday, 7 December 2025
M8.1 solar flare with earth-directed CME
Monday, 1 December 2025
X1.9 solar flare, Coronal hole faces Earth
Friday, 14 November 2025
X4.0 solar flare
Latest forum messages
AR4294 / 4296 / 4298 391AR 4299 116AR4299 M8.1 CME 2025/12/06 87New paper on the Gannon Storm 10-11 May 2024 2Electron event 10
More topicsSupport SpaceWeatherLive.com!
A lot of people come to SpaceWeatherLive to follow the Solar activity or if there is a chance to see the aurora, but with more traffic comes higher costs to keep the servers online. If you like SpaceWeatherLive and want to support the project you can choose a subscription for an ad-free site or consider a donation. With your help we can keep SpaceWeatherLive online!
Space weather facts
| Last X-flare | 2025/12/08 | X1.1 |
| Last M-flare | 2025/12/08 | M1.8 |
| Last geomagnetic storm | 2025/12/04 | Kp5 (G1) |
| Spotless days | |
|---|---|
| Last spotless day | 2022/06/08 |
| Monthly mean Sunspot Number | |
|---|---|
| November 2025 | 91.8 -22.8 |
| December 2025 | 162.7 +70.9 |
| Last 30 days | 108 +13.3 |