Joint USAF/NOAA Report of Solar and Geophysical Activity 18 Jan 2005

Prepared jointly by the U.S. Dept. of Commerce, NOAA,
Space Environment Center and the U.S. Air Force.
Updated 2005 Jan 18 2200 UTC

Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 018 Issued at 2200Z on 18 Jan 2005

IA. Analysis of Solar Active Regions and Activity from 17/2100Z
to 18/2100Z: Solar activity was moderate. Region 720 (N13W44)
continued to flare; however, the largest event in the past 24 hours
was an M4/2n at 18/1551 UTC. Although the region remains large and
magnetically complex, further sunspot restructuring and decay is
evident since yesterday. New Region 724 (S12W07) emerged on the
disk.

IB. Solar Activity Forecast: Solar activity is expected to be
moderate to high. Region 720, although diminishing in complexity,
still has sufficient potential for another major solar event.

IIA. Geophysical Activity Summary 17/2100Z to 18/2100Z:
The geomagnetic field ranged from unsettled to severe storm levels.
The greater than 10 MeV proton event remains in progress with a
start time of 16/0210 UTC and a peak flux of 5040 pfu observed at
17/1750 UTC. The greater than 100 MeV proton event also remains in
progress with a start time of 17/1215 UTC and a 28 pfu peak flux
observed at 17/1700 UTC. GOES spacecraft electron sensors and ACE
SWEPAM instruments remain affected by the energetic proton event.

IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to remain at active to severe storm levels for the next 24
to 48 hours. The arrival of the CME associated with the X3 flare on
17 January has not yet been observed but is expected to contribute
to geomagnetic activity over the next 12 to 24 hours. The greater
than 100 MeV proton event is expected to end by early on 19 January,
barring a new major flare. The greater than 10 MeV proton event is
expected to remain in progress through late 19 to early 20 January.

III. Event Probabilities 19 Jan-21 Jan

• Class M 90/90/90
• Class X 30/20/10
• Proton 80/75/50
• PCAF in progress

IV. Penticton 10.7 cm Flux

• Observed 18 Jan 124
• Predicted 19 Jan-21 Jan 120/110/100
• 90 Day Mean 18 Jan 107

V. Geomagnetic A Indices

• Observed Afr/Ap 17 Jan 027/063
• Estimated Afr/Ap 18 Jan 040/080
• Predicted Afr/Ap 19 Jan-21 Jan 030/075-020/030-015/020

VI. Geomagnetic Activity Probabilities 19 Jan-21 Jan

A. Middle Latitudes

• Active 30/25/25
• Minor storm 60/50/20
• Major-severe storm 10/05/05

B. High Latitudes

• Active 10/25/50
• Minor storm 70/60/30
• Major-severe storm 20/15/05