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

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

Updated 2004 Apr 29 2200 UTC

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 120 Issued at 2200Z on 29 Apr 2004

IA. Analysis of Solar Active Regions and Activity from 28/2100Z
to 29/2100Z: Solar activity has been very low. Region 596 (S07W92)
has moved beyond the visible limb, but produced some minor B-Class
flaring as it departed. A new active region (N05E61) has appeared
near the East limb, and produced a minor B-class flare event on 29
Apr at 0926 UTC. It has some plage, but no discernable spots and
therefore has not yet been numbered.

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

IIA. Geophysical Activity Summary 28/2100Z to 29/2100Z:
The geomagnetic field has been at mostly quiet levels.

IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to rise to active levels for the 30th of April, due to a
possible transient passage associated with a C3.1 x-ray event on 27
April. The geomagnetic field should return to quiet to unsettled
levels for the 1st and 2nd of May.

III. Event Probabilities 30 Apr-02 May

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

IV. Penticton 10.7 cm Flux

• Observed 29 Apr 089
• Predicted 30 Apr-02 May 090/090/090
• 90 Day Mean 29 Apr 107

V. Geomagnetic A Indices

• Observed Afr/Ap 28 Apr 008/008
• Estimated Afr/Ap 29 Apr 008/008
• Predicted Afr/Ap 30 Apr-02 May 015/020-010/010-012/012

VI. Geomagnetic Activity Probabilities 30 Apr-02 May

A. Middle Latitudes

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

B. High Latitudes

• Active 35/35/35
• Minor storm 30/20/20
• Major-severe storm 05/05/05