NOAA / Space Weather Prediction Center

Solar Flare 3-day Report of Solar and Geophysical Activity
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Prepared jointly by the U.S. Dept. of Commerce, NOAA,
Space Weather Prediction Center and the U.S. Air Force.
Updated 2017 Sep 23 2200 UTC

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 266 Issued at 2200Z on 23 Sep 2017

IA.  Analysis of Solar Active Regions and Activity from 22/2100Z to
23/2100Z: Solar activity has been at very low levels for the past 24
hours. There are currently 1 numbered sunspot regions on the disk.

IB.  Solar Activity Forecast: Solar activity is likely to be low with a
slight chance for an M-class flare on days one, two, and three (24 Sep,
25 Sep, 26 Sep).

IIA.  Geophysical Activity Summary 22/2100Z to 23/2100Z: The geomagnetic
field has been at quiet levels for the past 24 hours. Solar wind speed
reached a peak of 410 km/s at 23/0904Z. Total IMF reached 5 nT at
23/0052Z. The maximum southward component of Bz reached -4 nT at
23/0343Z. Electrons greater than 2 MeV at geosynchronous orbit reached a
peak level of 2143 pfu.

IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to active levels on days one and two (24 Sep, 25 Sep) and
quiet to unsettled levels on day three (26 Sep).

III.  Event probabilities 24 Sep-26 Sep
Class M    15/15/15
Class X    01/01/01
Proton     01/01/01
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           23 Sep 081
Predicted   24 Sep-26 Sep 085/090/090
90 Day Mean        23 Sep 081

V.  Geomagnetic A Indices
Observed Afr/Ap 22 Sep  005/004
Estimated Afr/Ap 23 Sep  004/005
Predicted Afr/Ap 24 Sep-26 Sep  009/012-014/016-008/008

VI.  Geomagnetic Activity Probabilities 24 Sep-26 Sep
A.  Middle Latitudes
Active                25/30/15
Minor Storm           10/15/05
Major-severe storm    01/01/01
B.  High Latitudes
Active                15/15/15
Minor Storm           25/25/25
Major-severe storm    40/50/25