Joint USAF/NOAA Report of Solar and Geophysical Activity 29 Dec 2004

Prepared jointly by the U.S. Dept. of Commerce, NOAA,
Space Environment Center and the U.S. Air Force.
Updated 2004 Dec 29 2210 UTC

Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 364 Issued at 2200Z on 29 Dec 2004

IA. Analysis of Solar Active Regions and Activity from 28/2100Z
to 29/2100Z: Solar activity increased to moderate levels today.
Region 715 (N04E61) produced the largest flare of the period, an M2
x-ray flare that occurred at 29/1627Z. An associated Tenflare (510
sfu) and a spectral Type II radio sweep with an estimated shock
velocity of 411 km/s. This flare also produced a CME that does not
appear to be Earth directed. Several lesser C-class flares were
also reported from this region during the period. The large
asymmetrical sunspot contains both polarities and appears to be
magnetically complex. Region 713 (S09W91) produced an M1 x-ray
flare that occurred at 29/1920Z. Multiple lesser C-class flares
originated from this region and the sunspot cluster was in a growth
phase as the spot group transited the solar west limb. No new
regions were numbered today.

IB. Solar Activity Forecast: Solar activity is expected to be at
low to moderate levels. Region 715 is capable of producing isolated
M-class flare activity.

IIA. Geophysical Activity Summary 28/2100Z to 29/2100Z:
The geomagnetic field was at quiet to active levels. The elevated
conditions were most likely the result of the geoeffective
transequatorial high speed coronal hole stream that had a mean
radial speed today of approximately 430km/s. The greater than 2 MeV
electron flux at geosynchronous orbit reached high levels today.

IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at predominantly quiet to unsettled levels throughout
the period. Isolated active conditions early on the first day (30
Dec) of the period are possible as the coronal hole rotates out of
geoeffective position.

III. Event Probabilities 30 Dec-01 Jan

• Class M 60/50/50
• Class X 10/10/10
• Proton 05/05/05
• PCAF green

IV. Penticton 10.7 cm Flux

• Observed 29 Dec 099
• Predicted 30 Dec-01 Jan 100/100/105
• 90 Day Mean 29 Dec 105

V. Geomagnetic A Indices

• Observed Afr/Ap 28 Dec 012/016
• Estimated Afr/Ap 29 Dec 018/022
• Predicted Afr/Ap 30 Dec-01 Jan 008/008-008/008-008/008

VI. Geomagnetic Activity Probabilities 30 Dec-01 Jan

A. Middle Latitudes

• Active 20/20/20
• Minor storm 01/01/01
• Major-severe storm 01/01/01

B. High Latitudes

• Active 20/20/20
• Minor storm 05/05/05
• Major-severe storm 01/01/01