Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 28 April 2015

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast

SDF Number 118 Issued at 2200Z on 28 Apr 2015

IA.  Analysis of Solar Active Regions and Activity from 27/2100Z to 28/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C1 event observed at 28/0519Z from Region 2331 (S09W87). There are currently 3 numbered sunspot regions on the disk.

IB.  Solar Activity Forecast: Solar activity is likely to be low on day one (29 Apr) and expected to be very low with a chance for a C-class flares on days two and three (30 Apr, 01 May).

IIA.  Geophysical Activity Summary 27/2100Z to 28/2100Z: The geomagnetic field has been at quiet levels for the past 24 hours. Solar wind speed, as measured by the ACE spacecraft, reached a peak speed of 354 km/s at 28/1438Z. Total IMF reached 8 nT at 28/1401Z. The maximum southward component of Bz reached -5 nT at 28/0026Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 195 pfu.

IIB.  Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to unsettled levels on days one, two, and three (29 Apr, 30 Apr, 01 May).

III.  Event probabilities 29 Apr-01 May

Class M    05/01/01

Class X    01/01/01

Proton     01/01/01

PCAF       green

IV.  Penticton 10.7 cm Flux

Observed           28 Apr 108

Predicted   29 Apr-01 May 100/095/095

90 Day Mean        28 Apr 130

V.  Geomagnetic A Indices

Observed Afr/Ap 27 Apr  005/004

Estimated Afr/Ap 28 Apr  005/006

Predicted Afr/Ap 29 Apr-01 May  007/008-007/010-007/010

VI.  Geomagnetic Activity Probabilities 29 Apr-01 May

A.  Middle Latitudes

Active                15/20/20

Minor Storm           05/05/05

Major-severe storm    01/01/01

B.  High Latitudes

Active                15/15/15

Minor Storm           25/30/30

Major-severe storm    20/25/25