:Product: 20020728RSGA.txt
:Issued: 2002 Jul 28 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 209 Issued at 2200Z on 28 Jul 2002
IA.  Analysis of Solar Active Regions and Activity from  27/2100Z
to 28/2100Z:  Solar activity decreased to moderate levels. Region 39
(S15W04) produced an M2/Sf flare at 28/0035 UTC as well as
occasional C-class flares. No significant changes occurred within
Region 39. It remained large and magnetically complex with strong,
persistent delta configurations within its leading and trailing
spots. Region 44 (S21W11) produced isolated C-class flares during
the period. Slight decay was noted in the leading and trailing
portions of the region. However, it became slightly more
magnetically complex as new flux emerged that strengthened the delta
within its intermediate spots. Region 50 (S07E09) was in a rapid
growth phase and produced isolated subflares. New Regions 52
(N09E17), 53 (S17E24), and 54 (S21E70) were numbered.
IB.  Solar Activity Forecast:  Solar activity is expected to be at
moderate to high levels. M-class flares are likely from Regions 39
and 44. Either region could produce a major flare during the period.
Region 50 could produce an isolated M-class flare during the period.
IIA.  Geophysical Activity Summary 27/2100Z to 28/2100Z:
Geomagnetic field activity ranged from quiet to active levels,
possibly due to a weak negative-polarity high-speed stream. The
greater than 10 MeV proton flux at geosynchronous orbit remained
enhanced and continued to gradually decrease toward background
levels.
IIB.  Geophysical Activity Forecast:  A geomagnetic field disturbance
is expected to begin early on 29 July and continue into 30 July in
response to the M8/halo-CME event of 26 July. Active to major storm
levels are possible during this disturbance. Field activity is
expected to decrease to quiet to unsettled levels on 31 July. Region
39 or 44 may produce a proton flare during the period.
III.  Event Probabilities 29 Jul-31 Jul
Class M    80/80/80
Class X    30/30/30
Proton     20/20/20
PCAF       yellow
IV.  Penticton 10.7 cm Flux
Observed           28 Jul 239
Predicted   29 Jul-31 Jul  245/245/240
90 Day Mean        28 Jul 165
V.  Geomagnetic A Indices
Observed Afr/Ap 27 Jul  011/019
Estimated Afr/Ap 28 Jul  010/015
Predicted Afr/Ap 29 Jul-31 Jul  025/030-018/020-010/010
VI.  Geomagnetic Activity Probabilities 29 Jul-31 Jul
A.  Middle Latitudes
Active                40/30/25
Minor storm           20/10/05
Major-severe storm    10/05/01
B.  High Latitudes
Active                45/35/30
Minor storm           25/15/10
Major-severe storm    15/10/01