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 2018 Sep 10 2200 UTC

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 253 Issued at 2200Z on 10 Sep 2018

IA.  Analysis of Solar Active Regions and Activity from 09/2100Z to
10/2100Z: Solar activity has been at very low levels for the past 24
hours. There are currently 0 numbered sunspot regions on the disk.

IB.  Solar Activity Forecast: Solar activity is expected to be very low
on days one, two, and three (11 Sep, 12 Sep, 13 Sep).

IIA.  Geophysical Activity Summary 09/2100Z to 10/2100Z: The geomagnetic
field has been at quiet to minor storm levels for the past 24 hours.
Solar wind speed reached a peak of 468 km/s at 10/2052Z. Total IMF
reached 14 nT at 10/2041Z. The maximum southward component of Bz reached
-11 nT at 10/2000Z. Electrons greater than 2 MeV at geosynchronous orbit
reached a peak level of 861 pfu.

IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at unsettled to major storm levels on day one (11 Sep), quiet to
minor storm levels on day two (12 Sep) and quiet to active levels on day
three (13 Sep).

III.  Event probabilities 11 Sep-13 Sep
Class M    01/01/01
Class X    01/01/01
Proton     01/01/01
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           10 Sep 069
Predicted   11 Sep-13 Sep 068/068/068
90 Day Mean        10 Sep 070

V.  Geomagnetic A Indices
Observed Afr/Ap 09 Sep  006/005
Estimated Afr/Ap 10 Sep  013/018
Predicted Afr/Ap 11 Sep-13 Sep  023/035-012/015-011/012

VI.  Geomagnetic Activity Probabilities 11 Sep-13 Sep
A.  Middle Latitudes
Active                30/35/35
Minor Storm           35/30/20
Major-severe storm    25/10/05
B.  High Latitudes
Active                05/05/10
Minor Storm           15/20/25
Major-severe storm    80/70/50