Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 31 March 2015

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast

SDF Number 90 Issued at 2200Z on 31 Mar 2015

IA.  Analysis of Solar Active Regions and Activity from 30/2100Z to 31/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C4 event observed at 30/2205Z from Region 2303 (N18W0*). There are currently 4 numbered sunspot regions on the disk.

IB.  Solar Activity Forecast: Solar activity is likely to be low with a chance for M-class flares on day one (01 Apr) and expected to be low with a chance for M-class flares on days two and three (02 Apr, 03 Apr).

IIA.  Geophysical Activity Summary 30/2100Z to 31/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed, as measured by the ACE spacecraft, reached a peak speed of 446 km/s at 31/1413Z. Total IMF reached 17 nT at 31/1320Z. The maximum southward component of Bz reached -12 nT at 31/1034Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 560 pfu.

IIB.  Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on days one and two (01 Apr, 02 Apr) and unsettled to active levels on day three (03 Apr).

III.  Event probabilities 01 Apr-03 Apr

Class M    25/25/25

Class X    05/05/05

Proton     01/01/01

PCAF       green

IV.  Penticton 10.7 cm Flux

Observed           31 Mar 128

Predicted   01 Apr-03 Apr 130/140/145

90 Day Mean        31 Mar 132

V.  Geomagnetic A Indices

Observed Afr/Ap 30 Mar  005/009

Estimated Afr/Ap 31 Mar  009/011

Predicted Afr/Ap 01 Apr-03 Apr  010/012-010/012-015/020

VI.  Geomagnetic Activity Probabilities 01 Apr-03 Apr

A.  Middle Latitudes

Active                30/25/35

Minor Storm           05/05/10

Major-severe storm    01/01/01

B.  High Latitudes

Active                15/15/20

Minor Storm           30/20/25

Major-severe storm    35/10/25