Joint USAF/NOAA Report of Solar and Geophysical Activity 29 Jul 2002
:Product: Report of Solar-Geophysical Activity
:Issued: 2002 Jul 29 2210 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 210 Issued at 2200Z on 29 Jul 2002
IA. Analysis of Solar Active Regions and Activity from 28/2100Z
to 29/2100Z: Solar activity remained at moderate levels. Region 44
(S21W24) produced four M-class flares during the period: an M2 at
28/2312 UTC, an M1 at 29/0023 UTC, an M4/1f at 29/0238 UTC
associated with a 380 sfu Tenflare and a Type II radio sweep, and a
long-duration M4 at 29/1044 UTC. The M4 flare at 29/1044 UTC may
have been associated with a partial-halo CME. Region 44 showed a
slight increase in sunspot area in its trailer portion. However, the
region simplified slightly as the delta magnetic configuration
within its intermediate spots showed signs of decay. Region 39
(S11W18) produced isolated C-class flares during the period. It
remained large and magnetically complex with delta magnetic
configurations within its leading and trailing spots, though the
trailing delta may be decaying. Region 43 (N12W26) remained in a
gradual growth phase and produced a C5/Sf flare late in the period.
Region 50 (S07W06) produced a C8/Sf flare at 29/1941 UTC as it
continued to increase in area and complexity. A magnetic delta may
have formed within its intermediate spots. New Region 55 (N14E75)
was numbered.
IB. Solar Activity Forecast: Solar activity is expected to be at
moderate to high levels. Regions 39 and 44 are expected to produce
M-class flares. 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 28/2100Z to 29/2100Z:
Geomagnetic field activity was at quiet to unsettled levels during
the first half of the period. ACE solar wind data indicated a shock
passage at L1 at 29/1241 UTC followed by a weak sudden impulse (SI)
at Earth at 29/1330 UTC (9 nT, as measured by the Boulder USGS
magnetometer). Field activity increased to unsettled to active
levels following the SI.
IIB. Geophysical Activity Forecast: Geomagnetic field activity is
expected to be at unsettled to active levels on 30 July decreasing
to quiet to unsettled levels on 31 July. Field activity is expected
to increase to active levels on 01 August in response to today’s
long-duration M4 flare. There is a chance for a proton event during
the period.
III. Event Probabilities 30 Jul-01 Aug
Class M 80/80/80
Class X 30/30/30
Proton 20/20/20
PCAF yellow
IV. Penticton 10.7 cm Flux
Observed 29 Jul 234
Predicted 30 Jul-01 Aug 235/230/230
90 Day Mean 29 Jul 166
V. Geomagnetic A Indices
Observed Afr/Ap 28 Jul 009/012
Estimated Afr/Ap 29 Jul 013/015
Predicted Afr/Ap 30 Jul-01 Aug 015/015-010/010-020/020
VI. Geomagnetic Activity Probabilities 30 Jul-01 Aug
A. Middle Latitudes
Active 35/25/40
Minor storm 15/05/20
Major-severe storm 05/01/10
B. High Latitudes
Active 40/30/45
Minor storm 20/20/25
Major-severe storm 10/01/15
