Prepared jointly by the U.S. Dept. of Commerce, NOAA, Space Environment Center and the U.S. Air Force.
Updated 2005 May 09 0120 UTC
Joint USAF/NOAA Report of Solar and Geophysical Activity SDF Number 128 Issued at 2200Z on 08 May 2005
IA. Analysis of Solar Active Regions and Activity from 07/2100Z to 08/2100Z: Solar activity was low. There was one C-class event at 0928 UTC from newly numbered Region 759 (N12E71). The group so far appears to be a moderately large D-type sunspot group. A CME was observed moving off the west limb at 1630 UTC but appears to be from the backside of the disk.
IB. Solar Activity Forecast: Solar activity is expected to be low. There is a slight chance for an isolated M-class event during the next three days.
IIA. Geophysical Activity Summary 07/2100Z to 08/2100Z: The geomagnetic field ranged from active to major storm levels during the past 24 hours with a severe storm period at high latitudes from 1200-1500 UTC. Magnetopause crossings were seen at GOES-12 at about 1330 UTC and 1610 UTC. Solar wind speed increased during the past 24 hours with peak values just below 900 km/s from 0900-1300 UTC. Intervals of strongly negative Bz were seen around 07/2100-08/0100 UTC and again from 0900-1300 UTC. The solar wind signatures appear to indicate the onset of a coronal hole high speed stream which has been modified by transient flow from the CME of 06/1728 UTC. The greater than 10 MeV protons gradually decayed from enhanced levels to nearly background level by forecast issue time.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at active to minor storm levels for the next two days (09-10 May) as the current disturbance persists. Conditions are expected to subside to mostly unsettled levels by the third day (11 May).
III. Event Probabilities 09 May-11 May
IV. Penticton 10.7 cm Flux
V. Geomagnetic A Indices
VI. Geomagnetic Activity Probabilities 09 May-11 May
A. Middle Latitudes
B. High Latitudes