Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 25 April 2015

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast

SDF Number 115 Issued at 2200Z on 25 Apr 2015

IA.  Analysis of Solar Active Regions and Activity from 24/2100Z to 25/2100Z: 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 24/2145Z. There are currently 5 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 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 levels for the past 24 hours. Solar wind speed, as measured by the ACE spacecraft, reached a peak speed of 389 km/s at 24/2329Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 1305 pfu.

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

III.  Event probabilities 26 Apr-28 Apr

Class M    10/10/10

Class X    01/01/01

Proton     01/01/01

PCAF       green

IV.  Penticton 10.7 cm Flux

Observed           25 Apr 126

Predicted   26 Apr-28 Apr 125/125/125

90 Day Mean        25 Apr 131

V.  Geomagnetic A Indices

Observed Afr/Ap 24 Apr  005/005

Estimated Afr/Ap 25 Apr  005/008

Predicted Afr/Ap 26 Apr-28 Apr  008/008-008/008-007/010

VI.  Geomagnetic Activity Probabilities 26 Apr-28 Apr

A.  Middle Latitudes

Active                15/15/25

Minor Storm           05/05/05

Major-severe storm    01/01/01

B.  High Latitudes

Active                15/15/15

Minor Storm           25/25/30

Major-severe storm    20/20/30