Status Report

Joint USAF/NOAA Report of Solar and Geophysical Activity 30 Oct 2003

By SpaceRef Editor

October 30, 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 30 2210 UTC

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 303 Issued at 2200Z on 30 Oct 2003

IA. Analysis of Solar Active Regions and Activity from 29/2100Z
to 30/2100Z: Solar activity was at high levels. Region 486 (S18W23)
produced an X10/2b flare that peaked at the end of the last period
(29/2049Z). Once again, intense radio emissions accompanied this
flare, including a 360,000 sfu burst at 245 MHz, a 2500 sfu
Tenflare, and strong Type II/IV radio sweeps. An extremely fast
(over 1900 km/s) earth-directed full halo CME was observed on LASCO
imagery. A new injection of high energy protons accompanied this
flare. Region 486 maintains its tremendous size and magnetic
complexity. Strong delta configurations exist in this spot group
containing over 2500 millionths of white light areal coverage.
Region 488 (N08W28) continues to develop in size and complexity and
now nears 1800 millionths of areal overage. Despite its impressive
size, this region’s activity levels have so far been limited to high
C-class and low M-class flares. New Regions 494 (S23E08) and 495
(S22E20) were numbered today. Region 495 is a very fast growing
D-type spot group.

IB. Solar Activity Forecast: Solar activity is expected to continue
at high levels. Region 486 has been one of the most active regions
of solar cycle 23 and maintains strong potential for further major
proton flares. Large Region 488 also contains potential for a major
flare.

IIA. Geophysical Activity Summary 29/2100Z to 30/2100Z:
The geomagnetic field was at predominantly minor to severe storm
levels. The intense geomagnetic storm that began at 29/0611Z
continued through the first half of this period. Severe (K8-9)
levels were observed from 29/2100 – 30/0300Z. A short-lived “lull”
(K5-6) in activity preceded the onset of another severe geomagnetic
storm. The very fast CME from the X10 flare that peaked at 29/2049Z
impacted the magnetic field at around 30/1600Z – a remarkably fast
19-hour transit from Sun to Earth. GOES-10,11, and 12 geosynchronous
satellites have experienced magnetopause crossings and in fact have
been outside the magnetopause for much of the time since the onset
of this severe storm. Sustained southward IMF Bz in the -15 to -30
Nt range is assuring a severe response. A Forbush decrease at
around 20% remains in progress. A new surge of high energy protons
followed the X-10 flare, enhancing the existing greater than 10 MeV
and greater than 100 MeV proton events from the X17 flare on the
28th. This enhancement reached 110 pfu (29/2310Z) in the greater
than 100 MeV level, and 3300 pfu (30/1935Z) in the greater than 10
MeV level. A polar cap absorption continues and the proton event
remains in progress.

IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to continue at major to severe storm levels through the
first half of day one. The current severe geomagnetic storm is
expected to gradually subside by the end of day one. Unsettled to
occasional minor storm periods are possible on day two. Mostly
unsettled levels are expected by day three. The greater than 100 MeV
proton event is expected to end by day one. The greater than 10 MeV
proton event will likely persist through day two.

III. Event Probabilities 31 Oct-02 Nov