:Product: 0913RSGA.txt
:Issued: 2005 Sep 13 2223 UTC
# Prepared jointly by the U.S. Dept. of Commerce, NOAA,
# Space Environment Center and the U.S. Air Force.
#
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 256 Issued at 2200Z on 13 Sep 2005
IA.  Analysis of Solar Active Regions and Activity from  12/2100Z
to 13/2100Z:  Solar activity was high. Region 808 (S11E04) produced
an M1.3 at 13/1121 UTC and an X1.5/3b at 13/1927 UTC. Strong
centimetic radio bursts accompanied this flare including a 4900 sfu
Tenflare and a 24,000 sfu burst on the 8800 MHz frequency. The X1.5
flare initially began as an impulsive flare; however, X-ray flux
values began rising again resulting in a long duration event with a
second peak above X1 levels. LASCO imagery shows a very bright and
fast full halo CME with this event with a preliminary speed estimate
of 1500 km/s. Region 808 underwent some slow decay over the last 24
hours, but still retains a strong beta-gamma-delta configuration.
IB.  Solar Activity Forecast:  Solar activity is expected to be
moderate to high. Region 808 has potential for M and  X-class
activity.
IIA.  Geophysical Activity Summary 12/2100Z to 13/2100Z:
The geomagnetic field has been at unsettled to major storm levels.
Storm conditions persisted through much of this period due to
transient flow from the intense CME activity over the past several
days. Conditions returned to predominantly unsettled levels by the
end of the period. Solar wind speed at ACE remains elevated, but
decreased from a high near 800 km/s to approximately 650 km/s by the
end of the period. The greater than 10 MeV proton event that began
on 08 September fell below the 10 pfu threshold today. The greater
than 2 MeV electron flux at geosynchronous orbit reached high levels
today.
IIB.  Geophysical Activity Forecast:  The geomagnetic field is
expected to be unsettled to minor storm levels on 14 September. On
15 September, major to severe storm periods are possible due to the
expected arrival of the CME associated with today's X1 flare.
Conditions should subside to mostly unsettled to active levels by 16
September, with isolated minor storm periods possible.
III.  Event Probabilities 14 Sep-16 Sep
Class M    80/75/70
Class X    50/40/30
Proton     40/40/30
PCAF       green
IV.  Penticton 10.7 cm Flux
Observed           13 Sep 114
Predicted   14 Sep-16 Sep  115/110/110
90 Day Mean        13 Sep 092
V.  Geomagnetic A Indices
Observed Afr/Ap 12 Sep  032/066
Estimated Afr/Ap 13 Sep  025/060
Predicted Afr/Ap 14 Sep-16 Sep  018/025-050/100-015/020
VI.  Geomagnetic Activity Probabilities 14 Sep-16 Sep
A.  Middle Latitudes
Active                30/10/30
Minor storm           20/20/15
Major-severe storm    10/70/05
B.  High Latitudes
Active                35/10/30
Minor storm           20/20/20
Major-severe storm    15/70/10