Joint USAF/NOAA Report of Solar and Geophysical Activity 30 Apr 2005
Prepared jointly by the U.S. Dept. of Commerce, NOAA,
Space Environment Center and the U.S. Air Force.
Updated 2005 Apr 30 2210 UTC
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 120 Issued at 2200Z on 30 Apr 2005
IA. Analysis of Solar Active Regions and Activity from 29/2100Z
to 30/2100Z: Solar activity was low. Region 756 (S07E01) produced a
C1/Sf flare at 30/1824 UTC. Region 756 continues to increase in
area; however, this region has only managed to produced lower level
C-flares. No new regions were numbered today.
IB. Solar Activity Forecast: Solar activity is expected to be low
with a chance for an isolated M-flare from Region 756.
IIA. Geophysical Activity Summary 29/2100Z to 30/2100Z:
The geomagnetic field was unsettled to active with an isolated minor
storm period between 30/0000 UTC and 0300 UTC. Heightened activity
was due to the onset of a geoeffective coronal hole high speed
stream. Solar wind speed at ACE increased from approximately 380
km/s to 600 km/s.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be unsettled to active with minor storm periods possible
on 01 May. Conditions are expected to settled down to quiet to
unsettled levels with active periods possible for the remainder of
the period.
III. Event Probabilities 01 May-03 May
- Class M 30/30/30
- Class X 01/01/01
- Proton 01/01/01
- PCAF green
IV. Penticton 10.7 cm Flux
- Observed 30 Apr 106
- Predicted 01 May-03 May 105/110/110
- 90 Day Mean 30 Apr 091
V. Geomagnetic A Indices
- Observed Afr/Ap 29 Apr 008/012
- Estimated Afr/Ap 30 Apr 016/020
- Predicted Afr/Ap 01 May-03 May 020/040-018/020-008/015
VI. Geomagnetic Activity Probabilities 01 May-03 May
A. Middle Latitudes
- Active 35/30/20
- Minor storm 15/15/10
- Major-severe storm 10/05/01
B. High Latitudes
- Active 30/35/25
- Minor storm 30/15/10
- Major-severe storm 20/10/05
