Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 26 April 2017

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast

SDF Number 115 Issued at 2200Z on 25 Apr 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 expected to be very low with a slight chance for a C-class flare on days one, two, and three (26 Apr, 27 Apr, 28 Apr).

IIA.  Geophysical Activity Summary 24/2100Z to 25/2100Z: The geomagnetic field has been at quiet to active levels for the past 24 hours. Solar wind speed reached a peak of 714 km/s at 25/0153Z. Total IMF reached 5 nT at 25/1820Z. The maximum southward component of Bz reached -4 nT at 25/1113Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 52302 pfu.

IIB.  Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to minor storm levels on day one (26 Apr), quiet to active levels on day two (27 Apr) and quiet to unsettled levels on day three (28 Apr).

III.  Event probabilities 26 Apr-28 Apr

Class M    01/01/01

Class X    01/01/01

Proton     01/01/01

PCAF       green

IV.  Penticton 10.7 cm Flux

Observed           25 Apr 081

Predicted   26 Apr-28 Apr 081/081/082

90 Day Mean        25 Apr 078

V.  Geomagnetic A Indices

Observed Afr/Ap 24 Apr  019/022

Estimated Afr/Ap 25 Apr  015/016

Predicted Afr/Ap 26 Apr-28 Apr  013/016-013/014-011/012

VI.  Geomagnetic Activity Probabilities 26 Apr-28 Apr

A.  Middle Latitudes

Active                40/30/30

Minor Storm           25/05/05

Major-severe storm    01/01/01

B.  High Latitudes

Active                10/15/15

Minor Storm           25/30/30