Status Report

Joint USAF/NOAA Report of Solar and Geophysical Activity 31 Oct 2004

By SpaceRef Editor

October 31, 2004

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 2004 Oct 31 2210 UTC

Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 305 Issued at 2200Z on 31 Oct 2004

IA. Analysis of Solar Active Regions and Activity from 30/2100Z
to 31/2100Z: Solar activity was moderate for the past 24 hours.
Region 691 (N14W40) produced two M-class flares: an M1 at 0226 UT
and an M2/Sf at 0532 UT. The M2 was accompanied by type II and type
IV radio sweeps. Newly received LASCO data for 30 October indicated
a nearly full halo CME after yesterday’s M5 x-ray event: the CME is
first visible in C2 at 30/1654 UTC and has plane-of sky velocity of
about 700-800 km/s. The CME is not symmetric and most of the
material appears to be moving away from the southwest limb. Region
691 has become somewhat quieter in the last 24 hours. The leader
spots show slight decline, but the trailer spots have been growing.
Region 693 (S16E20) showed growth during the past 24 hours, with the
emergence of spots in the middle portion of the group, but the
region only managed to produce one C-class flare.

IB. Solar Activity Forecast: Solar activity is expected to be
moderate, with a slight chance for major flare activity. Region 691
is the main threat for moderate or higher activity levels, although
Region 693 might also contribute. There is also a slight chance for
a proton event from Region 691, given its favorable location on the
disk.

IIA. Geophysical Activity Summary 30/2100Z to 31/2100Z:
The geomagnetic field was quiet to unsettled during the past 24
hours. The > 10 MeV proton enhancement that began yesterday reached
a maximum of 2.5 PFU at 30/2150 UTC and has been steadily declining
since then.

IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to continue at quiet to unsettled levels until sometime
around mid-day tomorrow (01 November) when transient flow from the
energetic solar events of 30 October are expected to arrive at
Earth. Active conditions with some periods of minor storm levels are
expected to follow and persist for 24-36 hours. Conditions are
expected to subside to unsettled to active levels on the third day
(03 November).

III. Event Probabilities 01 Nov-03 Nov