Joint USAF/NOAA Report of Solar and Geophysical Activity 23 Oct 2003

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

Updated 2003 Oct 23 2200 UTC

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 296 Issued at 2200Z on 23 Oct 2003

IA. Analysis of Solar Active Regions and Activity from 22/2100Z
to 23/2100Z: Solar activity was at high levels again today. Region
486 (S16E70) produced a major flare at 23/0835 UTC; it was an X5/1b
event, with an associated Tenflare and a Type II radio sweep that
had an estimated shock velocity of 967 km/s. An associated CME was
also seen on SOHO/LASCO imagery. A second major flare from this
region occurred at 23/2004 UTC, which was an impulsive X1/1n flare.
This region is just rotating into view on the southeast limb, and is
obviously a very large group, with a complex beta-gamma-delta
magnetic configuration. Region 484 (N04W00) was active
producing several M-class flares today. The largest was an M3/1n
event that occurred at 23/0708 UTC. This region continues to depict
a complex beta-gamma-delta magnetic structure. No new regions were
numbered today. The F10 value is estimated and is based on the
Penticton morning reading due to a flare enhancement during the
reading of the noon value.

IB. Solar Activity Forecast: Solar activity is expected to be at
high levels. Regions 484 and 486 are both very capable of producing
major flares.

IIA. Geophysical Activity Summary 22/2100Z to 23/2100Z:
The geomagnetic field was at quiet to unsettled levels. The greater
than 2 MeV electron fluxes at geosynchronous orbit were at high
levels today.

IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to range from active to major storm levels for the forecast
period. These elevated conditions are expected as a result of the
partial halo CME on 22/0754 UTC and from the X5/1b flare at 23/0835
UTC.

III. Event Probabilities 24 Oct-26 Oct

• Class M 90/90/90
• Class X 50/50/50
• Proton 25/30/35
• PCAF yellow

IV. Penticton 10.7 cm Flux

• Observed 23 Oct 183
• Predicted 24 Oct-26 Oct 190/195/195
• 90 Day Mean 23 Oct 114

V. Geomagnetic A Indices

• Observed Afr/Ap 22 Oct 020/033
• Estimated Afr/Ap 23 Oct 008/010
• Predicted Afr/Ap 24 Oct-26 Oct 040/050-040/050-030/050

VI. Geomagnetic Activity Probabilities 24 Oct-26 Oct

A. Middle Latitudes

• Active 30/30/40
• Minor storm 40/40/30
• Major-severe storm 30/30/20

B. High Latitudes

• Active 20/20/20
• Minor storm 40/40/40
• Major-severe storm 40/40/40