Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 19 April 2014

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 109 Issued at 2200Z on 19 Apr 2014

IA. Analysis of Solar Active Regions and Activity from 18/2100Z to
19/2100Z: 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
19/1932Z from Region 2032 (N12W83). There are currently 12 numbered
sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is likely to be moderate
with a slight chance for an X-class flare on day one (20 Apr) and
expected to be low with a chance for M-class flares on days two and
three (21 Apr, 22 Apr).

IIA. Geophysical Activity Summary 18/2100Z to 19/2100Z: The geomagnetic
field has been at quiet to active levels for the past 24 hours. Solar
wind speed, as measured by the ACE spacecraft, reached a peak speed of
583 km/s at 19/1858Z. Total IMF reached 10 nT at 18/2118Z. The maximum
southward component of Bz reached -6 nT at 18/2345Z. Protons greater
than 10 MeV at geosynchronous orbit reached a peak level of 58 pfu at
19/0105Z. Electrons greater than 2 MeV at geosynchronous orbit reached a
peak level of 242 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected
to be at unsettled to major storm levels on day one (20 Apr), quiet to
minor storm levels on day two (21 Apr) and quiet to active levels on day
three (22 Apr). Protons are expected to remain above the 10 pfu
threshold on days one and two (20-21 Apr) and have a chance of crossing
threshold on day three (22 Apr).

III. Event probabilities 20 Apr-22 Apr
Class M 55/50/50
Class X 10/05/05
Proton 99/75/50
PCAF red

IV. Penticton 10.7 cm Flux
Observed 19 Apr 169
Predicted 20 Apr-22 Apr 170/170/160
90 Day Mean 19 Apr 156

V. Geomagnetic A Indices
Observed Afr/Ap 18 Apr 007/006
Estimated Afr/Ap 19 Apr 014/017
Predicted Afr/Ap 20 Apr-22 Apr 022/035-021/025-009/010

VI. Geomagnetic Activity Probabilities 20 Apr-22 Apr
A. Middle Latitudes
Active 30/40/35
Minor Storm 40/35/15
Major-severe storm 20/10/01
B. High Latitudes
Active 05/05/10
Minor Storm 15/20/25
Major-severe storm 75/75/50