Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 27 April 2015

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast

SDF Number 117 Issued at 2200Z on 27 Apr 2015

IA.  Analysis of Solar Active Regions and Activity from 26/2100Z to 27/2100Z: 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 on days one, two, and three (28 Apr, 29 Apr, 30 Apr).

IIA.  Geophysical Activity Summary 26/2100Z to 27/2100Z: 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 370 km/s at 27/1644Z. Total IMF reached 7 nT at 27/1131Z. The maximum southward component of Bz reached -6 nT at 27/0935Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 874 pfu.

IIB.  Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet levels on day one (28 Apr) and quiet to unsettled levels on days two and three (29 Apr, 30 Apr).

III.  Event probabilities 28 Apr-30 Apr

Class M    05/05/05

Class X    01/01/01

Proton     01/01/01

PCAF       green

IV.  Penticton 10.7 cm Flux

Observed           27 Apr 108

Predicted   28 Apr-30 Apr 110/105/105

90 Day Mean        27 Apr 130

V.  Geomagnetic A Indices

Observed Afr/Ap 26 Apr  003/002

Estimated Afr/Ap 27 Apr  005/005

Predicted Afr/Ap 28 Apr-30 Apr  006/005-007/008-007/010

VI.  Geomagnetic Activity Probabilities 28 Apr-30 Apr

A.  Middle Latitudes

Active                10/15/20

Minor Storm           01/05/05

Major-severe storm    01/01/01

B.  High Latitudes

Active                20/15/15

Minor Storm           20/25/30

Major-severe storm    10/20/25