Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 20 April 2014
Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 110 Issued at 2200Z on 20 Apr 2014
IA. Analysis of Solar Active Regions and Activity from 19/2100Z to
20/2100Z: Solar activity has been at low levels for the past 24 hours.
The largest solar event of the period was a C6 event observed at
20/0813Z from Region 2033 (N11W84). There are currently 9 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 (21 Apr) and
expected to be low with a chance for M-class flares on days two and
three (22 Apr, 23 Apr).
IIA. Geophysical Activity Summary 19/2100Z to 20/2100Z: The geomagnetic
field has been at quiet to minor storm levels for the past 24 hours.
Solar wind speed, as measured by the ACE spacecraft, reached a peak
speed of 765 km/s at 20/1125Z. Total IMF reached 21 nT at 20/1114Z. The
maximum southward component of Bz reached -8 nT at 20/1752Z. Protons
greater than 10 MeV at geosynchronous orbit reached a peak level of 51
pfu at 19/2310Z. Electrons greater than 2 MeV at geosynchronous orbit
reached a peak level of 237 pfu.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to minor storm levels on day one (21 Apr), quiet to
active levels on day two (22 Apr) and quiet levels on day three (23
Apr). Protons greater than 10 Mev have a slight chance of crossing
threshold on days one and two (21 Apr, 22 Apr).
III. Event probabilities 21 Apr-23 Apr
Class M 55/50/50
Class X 10/05/05
Proton 10/10/05
PCAF green
IV. Penticton 10.7 cm Flux
Observed 20 Apr 163
Predicted 21 Apr-23 Apr 165/160/150
90 Day Mean 20 Apr 156
V. Geomagnetic A Indices
Observed Afr/Ap 19 Apr 013/013
Estimated Afr/Ap 20 Apr 016/023
Predicted Afr/Ap 21 Apr-23 Apr 016/020-009/010-007/008
VI. Geomagnetic Activity Probabilities 21 Apr-23 Apr
A. Middle Latitudes
Active 40/25/20
Minor Storm 25/05/05
Major-severe storm 05/01/01
B. High Latitudes
Active 05/15/15
Minor Storm 20/25/20
Major-severe storm 60/30/25
