Joint USAF/NOAA Report of Solar and Geophysical Activity 09 Apr 2005

Prepared jointly by the U.S. Dept. of Commerce, NOAA,
Space Environment Center and the U.S. Air Force.
Updated 2005 Apr 09 2210 UTC

Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 099 Issued at 2200Z on 09 Apr 2005

IA. Analysis of Solar Active Regions and Activity from 08/2100Z
to 09/2100Z: Solar activity was very low. Region 751 (S07W74)
produced several B-class flares during the period. This region has
grown in both sunspot count and white light area coverage and is now
a Dai beta spot group. The SOHO/LASCO imagery observed two CME’s
today off the SW limb. The first was around 09/0826 UTC and the
second was at 09/1350 UTC. Both appear to be from a backside event.
No new regions were numbered today.

IB. Solar Activity Forecast: Solar activity is expected to be very
low to low.

IIA. Geophysical Activity Summary 08/2100Z to 09/2100Z:
The geomagnetic field has been quiet to unsettled. The greater than
2 MeV flux at geosynchronous orbit was at high levels today.

IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be predominately quiet to unsettled for 10-12 April.
Periods of active conditions are possible on 11-12 April due to a
recurrent coronal hole high speed stream.

III. Event Probabilities 10 Apr-12 Apr

• Class M 05/05/05
• Class X 01/01/01
• Proton 01/01/01
• PCAF green

IV. Penticton 10.7 cm Flux

• Observed 09 Apr 088
• Predicted 10 Apr-12 Apr 085/085/085
• 90 Day Mean 09 Apr 096

V. Geomagnetic A Indices

• Observed Afr/Ap 08 Apr 002/004
• Estimated Afr/Ap 09 Apr 005/005
• Predicted Afr/Ap 10 Apr-12 Apr 008/010-010/015-015/020

VI. Geomagnetic Activity Probabilities 10 Apr-12 Apr

A. Middle Latitudes

• Active 15/20/25
• Minor storm 05/10/10
• Major-severe storm 01/01/05

B. High Latitudes

• Active 20/25/35
• Minor storm 10/15/20
• Major-severe storm 01/05/05