:Product: 1220RSGA.txt
:Issued: 2015 Dec 20 2200 UTC
# Prepared jointly by the U.S. Dept. of Commerce, NOAA,
# Space Weather Prediction Center and the U.S. Air Force.
#
Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 354 Issued at 2200Z on 20 Dec 2015

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 C4 event observed at
19/2228Z. There are currently 2 numbered sunspot regions on the disk.
IB.  Solar Activity Forecast: Solar activity is likely to be low with a
slight chance for an M-class flare on days one, two, and three (21 Dec,
22 Dec, 23 Dec).

IIA.  Geophysical Activity Summary 19/2100Z to 20/2100Z: The geomagnetic
field has been at active to major storm levels for the past 24 hours.
Solar wind speed, as measured by the ACE spacecraft, reached a peak
speed of 536 km/s at 19/2326Z. Total IMF reached 18 nT at 20/2054Z. The
maximum southward component of Bz reached -18 nT at 20/0412Z. Electrons
greater than 2 MeV at geosynchronous orbit reached a peak level of 167
pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to minor storm levels on day one (21 Dec), quiet to
unsettled levels on day two (22 Dec) and quiet levels on day three (23
Dec).

III.  Event probabilities 21 Dec-23 Dec
Class M    15/15/15
Class X    01/01/01
Proton     01/01/01
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           20 Dec 117
Predicted   21 Dec-23 Dec 120/125/125
90 Day Mean        20 Dec 109

V.  Geomagnetic A Indices
Observed Afr/Ap 19 Dec  008/010
Estimated Afr/Ap 20 Dec  038/059
Predicted Afr/Ap 21 Dec-23 Dec  019/020-009/010-006/005

VI.  Geomagnetic Activity Probabilities 21 Dec-23 Dec
A.  Middle Latitudes
Active                30/15/10
Minor Storm           10/05/01
Major-severe storm    01/01/01
B.  High Latitudes
Active                20/20/15
Minor Storm           35/25/20
Major-severe storm    40/20/10