Viewing archive of Saturday, 18 September 2021
Solar activity report
Report of Solar-Geophysical Activity 2021 Sep 18 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 261 Issued at 2200Z on 18 Sep 2021IA. Analysis of Solar Active Regions and Activity from 17-2100Z to 18-2100Z Solar activity has been at low levels for the past 24 hours.
The largest solar event of the period was a C2 event observed at
18/0827Z from Region 2871 (S28E73). There are currently 1 numbered
sunspot regions on the disk.
IB. Solar Activity Forecast
Solar activity is expected to be very low
with a chance for a C-class flares on days one, two, and three (19 Sep,
20 Sep, 21 Sep).
IIA. Geophysical Activity Summary 17-2100Z to 18-2100Z
The geomagnetic
field has been at quiet to minor storm levels for the past 24 hours.
Solar wind speed reached a peak of 426 km/s at 18/0408Z. Total IMF
reached 15 nT at 17/2125Z. The maximum southward component of Bz reached
-5 nT at 18/0738Z. Electrons greater than 2 MeV at geosynchronous orbit
reached a peak level of 179 pfu.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected
to be at quiet to unsettled levels on days one and three (19 Sep, 21
Sep) and quiet levels on day two (20 Sep).
III. Event Probabilities 19 Sep to 21 Sep
| Class M | 05% | 05% | 05% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | green | ||
IV. Penticton 10.7 cm Flux
Observed 18 Sep 074 Predicted 19 Sep-21 Sep 076/076/076 90 Day Mean 18 Sep 082
V. Geomagnetic A Indices
Observed Afr/Ap 17 Sep 019/021 Estimated Afr/Ap 18 Sep 010/011 Predicted Afr/Ap 19 Sep-21 Sep 006/008-006/005-007/008
VI. Geomagnetic Activity Probabilities 19 Sep to 21 Sep
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 20% | 10% | 20% |
| Minor storm | 05% | 01% | 05% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 20% | 15% | 20% |
| Minor storm | 30% | 20% | 30% |
| Major-severe storm | 25% | 20% | 25% |
All times in UTC
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