Report of Solar Geophysical Activity

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 109 Issued at 2200Z on 18 Apr 2016

IA.  Analysis of Solar Active Regions and Activity from 17/2100Z to
18/2100Z: Solar activity has been at high levels for the past 24 hours.
The largest solar event of the period was a M6 event observed at
18/0029Z from Region 2529 (N10W67). There are currently 2 numbered
sunspot regions on the disk.
IB.  Solar Activity Forecast: Solar activity is expected to be low with
a slight chance for an M-class flare on day one (19 Apr) and expected to
be very low with a chance for a C-class flares and a slight chance for
an M-class flare on day two (20 Apr) and expected to be very low with a
slight chance for a C-class flare on day three (21 Apr).

IIA.  Geophysical Activity Summary 17/2100Z to 18/2100Z: The geomagnetic
field has been at quiet to unsettled levels for the past 24 hours. Solar
wind speed reached a peak of 419 km/s at 18/0051Z. Total IMF reached 12
nT at 18/0112Z. The maximum southward component of Bz reached -6 nT at
18/0744Z. Electrons greater than 2 MeV at geosynchronous orbit reached a
peak level of 207 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to active levels on day one (19 Apr), quiet to unsettled
levels on day two (20 Apr) and quiet levels on day three (21 Apr).
Protons greater than 10 Mev have a slight chance of crossing threshold
on day one (19 Apr).

III.  Event probabilities 19 Apr-21 Apr
Class M    20/10/01
Class X    05/01/01
Proton     15/05/01
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           18 Apr 095
Predicted   19 Apr-21 Apr 095/090/088
90 Day Mean        18 Apr 099

V.  Geomagnetic A Indices
Observed Afr/Ap 17 Apr  017/021
Estimated Afr/Ap 18 Apr  007/009
Predicted Afr/Ap 19 Apr-21 Apr  010/012-008/008-006/005

VI.  Geomagnetic Activity Probabilities 19 Apr-21 Apr
A.  Middle Latitudes
Active                35/15/15
Minor Storm           10/10/05
Major-severe storm    01/01/01
B.  High Latitudes
Active                15/15/15
Minor Storm           30/20/20
Major-severe storm    45/25/20

Radio Events Observed 18 Apr 2016
A.  245 MHz Bursts
Start  End   Peak Flux  Time of Peak  Duration
0035   0035    150          0035        0000  
0211   0212    110          0212        0001  
1756   1756    150          1756        0000  
B.  245 MHz Noise Storms
No 245 MHz Noise Storms Observed.

**** SPACE WEATHER OUTLOOK ****

Summary For April 11-17

Category G1 (Minor) geomagnetic storms were observed on 12-14 April due to effects from a negative polarity coronal hole high speed stream.



Outlook For April 18-24

Category R1-R2 (Minor-Moderate) radio blackouts are possible on 18-19 April as active Region 2529 approaches and exits the west limb.