Status Report

Joint USAF/NOAA Report of Solar and Geophysical Activity 29 Oct 2003

By SpaceRef Editor

October 29, 2003

Filed under Space Weather Prediction Center (NOAA), Space Weather Solar-Geophysical Activity, US

Prepared jointly by the U.S. Dept. of Commerce, NOAA,
Space Environment Center and the U.S. Air Force.

Updated 2003 Oct 29 2210 UTC

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 302 Issued at 2200Z on 29 Oct 2003

IA. Analysis of Solar Active Regions and Activity from 28/2100Z
to 29/2100Z: Solar activity was high. Region 486 (S17W09) has
produced another major flare, an X10 flare at 29/2049Z. This very
large flare was still in progress at the end of the period.
Associated activity and the potential impact of this flare will be
assessed during the next period. Region 486 also produced an M3 at
29/0511Z. This region with 2600 millionths of white light areal
coverage is now the largest sunspot group of solar cycle 23. It
maintains a strong and complex beta-gamma-delta configuration and is
still growing. Region 488 (N08W18) is also a large, complex active
region and now exceeds 1200 millionths in a beta-gamma-delta
configuration. C-class activity and low M-class flares were observed
in this region. The very large and active Region 484 (N01W81) is
relatively quiet as it rotates around the west limb.

IB. Solar Activity Forecast: Solar activity is expected to continue
at high levels. The very large and complex Region 486 will likely
produce more major flare activity during its remaining 5-6 days on
the visible disk. A major event is also possible from Region 488.

IIA. Geophysical Activity Summary 28/2100Z to 29/2100Z:
The geomagnetic field ranged from unsettled to severe storming. The
powerful CME from the X17/4b flare on 28/1110Z, impacted the Earth’s
magnetic field at 29/0613Z. The transit time for this CME was around
19 hours, making it one of the fastest on record. The sudden impulse
measured 140 nT on the Boulder magnetometer. Strong southward IMF Bz
initiated severe (K9) storming at middle and high latitudes in the
29/0600 – 0900Z period. Mostly northward Bz occurred from 29/0900 –
1800Z; however, major to severe storming persisted. A sharp
southward turn in the Bz occurred at around 1800Z ending the period
with K8-9 severe storming. A strong Forbush decrease (over 20%) is
in progress. The large proton event and GLE that followed the X17
flare is now in decline. The greater than 10 MeV proton event that
began on 28/1215Z, peaked at 29/0615Z at 29,500 pfu, making it the
second largest greater than 10 MeV proton event this cycle (second
only to the 31,700 pfu proton event in November 2001). The greater
than 100 MeV proton event began at 28/1145Z, and peaked at 29/0015Z
at 186 pfu. This proton event remains in progress.

IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to continue at severe storm levels through day one. The IMF
Bz is now sustained southward at near -30 nT, resulting in severe
storm levels. This condition is expected to persist through at least
the first half of day one. A gradual decline to unsettled to minor
storm levels is expected by day two. The potential geomagnetic
impact from today’s X10 flare will be assessed next period;
predictions for days two and three will likely change considerably.
The greater than 10 MeV proton event, currently in progress is
expected to continue through day three. The greater than 100 MeV
proton event will likely continue as high energy protons quickly
stream in from the X10 flare that occurred late in the period.

III. Event Probabilities 30 Oct-01 Nov