:Product: 20040520RSGA.txt
:Issued: 2004 May 20 2200 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 141 Issued at 2200Z on 20 May 2004
IA.  Analysis of Solar Active Regions and Activity from  19/2100Z
to 20/2100Z:  Solar activity was low. Newly assigned Region 618
(S10E69) produced all of today's three C-class flares. The other
sunspot regions on the disk were quiet and stable. A filament in the
northeast quadrant erupted at 0136 UTC and was associated with a CME
off the northeast solar limb. The angular width of the CME was
narrow and the transient does not appear to be directed towards
Earth.
IB.  Solar Activity Forecast:  Solar activity is expected to be low.
Most of the activity is expected to occur in Region 618.
IIA.  Geophysical Activity Summary 19/2100Z to 20/2100Z:
The geomagnetic field was mostly quiet to unsettled. However, there
was a period of minor storm levels from 0900-1200 UTC. Solar wind
data at ACE showed a steady increase in solar wind velocity from
initial values around 380 km/s up to about 500 km/s by forecast
issue time. Elevated solar wind temperature and wave patterns in the
magnetic field data suggest that the enhancement may originate from
a coronal hole.
IIB.  Geophysical Activity Forecast:  The geomagnetic field is
expected to be mostly unsettled but with a fair chance for some
isolated active periods during the next two days (21-22 May). A
decline to quiet to unsettled is expected around mid-day on the
third day (23 May).
III.  Event Probabilities 21 May-23 May
Class M    15/15/15
Class X    01/01/01
Proton     01/01/01
PCAF       green
IV.  Penticton 10.7 cm Flux
Observed           20 May 105
Predicted   21 May-23 May  105/100/100
90 Day Mean        20 May 105
V.  Geomagnetic A Indices
Observed Afr/Ap 19 May  006/006
Estimated Afr/Ap 20 May  015/015
Predicted Afr/Ap 21 May-23 May  012/015-012/015-010/012
VI.  Geomagnetic Activity Probabilities 21 May-23 May
A.  Middle Latitudes
Active                30/30/25
Minor storm           20/20/15
Major-severe storm    10/10/05
B.  High Latitudes
Active                35/35/30
Minor storm           20/20/10
Major-severe storm    10/10/05