Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 16 April 2015 (corrected)

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast

SDF Number 106 Issued at 2200Z on 16 Apr 2015

IA.  Analysis of Solar Active Regions and Activity from 15/2100Z to 16/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C5 event observed at 16/0907Z from Region 2324 (N18E34). There are currently 5 numbered sunspot regions on the disk.

IB.  Solar Activity Forecast: Solar activity is expected to be low with a chance for M-class flares and a slight chance for an X-class flare on days one, two, and three (17 Apr, 18 Apr, 19 Apr).

IIA.  Geophysical Activity Summary 15/2100Z to 16/2100Z: The geomagnetic field has been at unsettled to minor storm levels for the past 24 hours. Solar wind speed, as measured by the ACE spacecraft, reached a peak speed of 720 km/s at 16/2049Z. Total IMF reached 13 nT at 16/0503Z. The maximum southward component of Bz reached -12 nT at 16/0524Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 2108 pfu.

IIB.  Geophysical Activity Forecast: The geomagnetic field is expected to be at unsettled to minor storm levels on day one (17 Apr) and quiet to unsettled levels on days two and three (18 Apr, 19 Apr).

III.  Event probabilities 17 Apr-19 Apr

Class M    40/40/40

Class X    10/10/10

Proton     01/01/01

PCAF       green

IV.  Penticton 10.7 cm Flux

Observed           16 Apr 150

Predicted   17 Apr-19 Apr 150/155/155

90 Day Mean        16 Apr 129

V.  Geomagnetic A Indices

Observed Afr/Ap 15 Apr  020/028

Estimated Afr/Ap 16 Apr  025/036

Predicted Afr/Ap 17 Apr-19 Apr  016/020-007/008-007/008

VI.  Geomagnetic Activity Probabilities 17 Apr-19 Apr

A.  Middle Latitudes

Active                35/25/20

Minor Storm           15/05/05

Major-severe storm    01/01/01

B.  High Latitudes

Active                15/15/15

Minor Storm           30/30/30

Major-severe storm    45/30/25