Status Report

Joint USAF/NOAA Report of Solar and Geophysical Activity 31 Oct 2003

By SpaceRef Editor
October 31, 2003
Filed under , ,

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

Updated 2003 Oct 31 2210 UTC

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 304 Issued at 2200Z on 31 Oct 2003

IA. Analysis of Solar Active Regions and Activity from 30/2100Z
to 31/2100Z: Solar activity was moderate. Region 488 (N08W42)
produced an M1/Sf at 31/0616Z and occasional C-class flares
throughout the period. This region maintains considerable size and
complexity, but has yet to produce a major flare. An M2 flare was
observed at 31/0433Z. Space-based imagery indicates that the source
was likely behind the west limb (probably old Region 484 at N03,
L=355). Huge Region 486 (S17W36) is finally showing some signs of
decay. Activity this period was limited to occasional C-class
flares. Despite its relative calm, this region still maintains a
very complex magnetic structure in over 2000 millionths of white
light areal coverage. New Region 496 (S12E09) was numbered today.

IB. Solar Activity Forecast: Solar activity is expected to be
moderate to high. Though some decay was noted in Region 486, it
still maintains potential for a major solar flare. Region 488 also
contains potential for a major flare.

IIA. Geophysical Activity Summary 30/2100Z to 31/2100Z:
The geomagnetic field ranged from active to severe storm levels. The
intense geomagnetic storm that began at around 30/1600Z, continued
well into this period. Severe storm levels persisted from 30/2100Z
through 31/0900Z. Mostly active to major storm periods occurred
through the latter half of the period. Solar radiation contamination
on the ACE SWEPAM instrument finally ended at 31/0052Z. Solar wind
speed was at an exceptionally high 1200 km/s, but has been in a
gradual decline, ending the period at over 800 km/s. The prolonged
periods of southward IMF Bz that occurred early in the period have
ended. Bz has been mostly northward since 31/0200Z. The greater than
100 MeV proton event in progress since 28/1145Z, ended at 31/0145Z.
This prolonged high energy proton event was actually two distinct
events associated with the X17 and X10 flares on the 28th and 29th
respectively. The peak measurements for both events were 186 pfu at
29/0015Z and 110 pfu at 29/2310Z. The greater than 10 MeV proton
event remains in progress, but is quickly declining to the 10 pfu
alert threshold. The two peak measurements at 10 MeV were 29,000 pfu
at 29/0615Z and 3300 pfu at 30/1935Z. The PCA event has ended.

IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at unsettled to minor storm levels through 1
November. Isolated major storm periods are possible at higher
latitudes due to the very elevated solar wind speeds. The 2nd and
3rd of November should see a return to quiet to unsettled levels
with isolated active periods. The greater than 10 MeV proton event
that began on the 28th is expected to end on 1 November.

III. Event Probabilities 01 Nov-03 Nov

  • Class M 75/70/60
  • Class X 40/35/30
  • Proton 99/50/20
  • PCAF Yellow

IV. Penticton 10.7 cm Flux

  • Observed 31 Oct 249
  • Predicted 01 Nov-03 Nov 240/230/220
  • 90 Day Mean 31 Oct 130

V. Geomagnetic A Indices

  • Observed Afr/Ap 30 Oct 144/162
  • Estimated Afr/Ap 31 Oct 075/110
  • Predicted Afr/Ap 01 Nov-03 Nov 025/040-010/015-010/010

VI. Geomagnetic Activity Probabilities 01 Nov-03 Nov

A. Middle Latitudes

  • Active 50/25/25
  • Minor storm 20/10/10
  • Major-severe storm 05/01/01

B. High Latitudes

  • Active 60/30/30
  • Minor storm 30/15/15
  • Major-severe storm 10/05/05

SpaceRef staff editor.