Report of Solar Geophysical Activity

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 268 Issued at 2200Z on 25 Sep 2017

IA.  Analysis of Solar Active Regions and Activity from 24/2100Z to
25/2100Z: Solar activity has been at very low levels for the past 24
hours. There are currently 3 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 (26 Sep,
27 Sep, 28 Sep).

IIA.  Geophysical Activity Summary 24/2100Z to 25/2100Z: The geomagnetic
field has been at quiet to unsettled levels for the past 24 hours. Solar
wind speed reached a peak of 455 km/s at 25/0758Z. Total IMF reached 10
nT at 24/2216Z. The maximum southward component of Bz reached -9 nT at
24/2230Z. Electrons greater than 2 MeV at geosynchronous orbit reached a
peak level of 1050 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet levels on day one (26 Sep), quiet to minor storm levels
on day two (27 Sep) and active to major storm levels on day three (28
Sep).

III.  Event probabilities 26 Sep-28 Sep
Class M    15/15/15
Class X    01/01/01
Proton     01/01/01
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           25 Sep 090
Predicted   26 Sep-28 Sep 095/095/095
90 Day Mean        25 Sep 082

V.  Geomagnetic A Indices
Observed Afr/Ap 24 Sep  005/006
Estimated Afr/Ap 25 Sep  006/008
Predicted Afr/Ap 26 Sep-28 Sep  006/005-016/025-024/032

VI.  Geomagnetic Activity Probabilities 26 Sep-28 Sep
A.  Middle Latitudes
Active                15/35/35
Minor Storm           05/30/40
Major-severe storm    01/05/10
B.  High Latitudes
Active                15/05/05
Minor Storm           25/20/20
Major-severe storm    25/65/80

Radio Events Observed 25 Sep 2017
A.  245 MHz Bursts
Start  End   Peak Flux  Time of Peak  Duration
0654   0654    110          0654        0000  
1711   1711    200          1711        0000  
B.  245 MHz Noise Storms
No 245 MHz Noise Storms Observed.

**** SPACE WEATHER OUTLOOK ****

Summary For September 18-24

G1 (Minor) geomagnetic storm conditions were observed on 18 Sep due to coronal hole high speed stream influence.

No other significant space weather was observed during the summary period.

Outlook For September 25-October 1

G1 (Minor) geomagnetic storms are likely on 27 and 29 Sep while G2 (Moderate) geomagnetic storms are likely on 28 Sep, all due to effects from the anticipated arrival of a recurrent coronal hole high speed stream.

No other siginificant space weather is expected for the outlook period.