Joint USAF/NOAA Report of Solar and Geophysical Activity 07 May 2004

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

Updated 2004 May 07 2200 UTC

Joint USAF/NOAA Report of Solar and Geophysical Activity 07 May 2004

SDF Number 128 Issued at 2200Z on 07 May 2004

IA. Analysis of Solar Active Regions and Activity from 06/2100Z
to 07/2100Z: Solar activity was low. Region 605 (S12W45) produced a
C1/Sf flare at 07/1403Z. A rather faint CME was visible on LASCO
imagery following this flare. Region 605 continues to gradually
decay and now exists as a simple alpha spot group. New Region 606
(S09E81) rotated into view on the east limb during this period. Limb
proximity makes it difficult to accurately assess true size and
complexity; however, a CME was observed to erupt from this location
at 07/1050Z. An associated Type II radio sweep (739 km/s) also
occurred. No other significant activity was noted.

IB. Solar Activity Forecast: Solar activity is expected to be low.
New Region 606 possesses the best potential for C-class activity.

IIA. Geophysical Activity Summary 06/2100Z to 07/2100Z:
The geomagnetic field was quiet to active. The high speed coronal
hole stream that became geoeffective on 05 May continues to buffet
the geomagnetic field. Frequent southward IMF Bz oscillations over
the last 24 hours are responsible for the most disturbed periods.
The high speed stream does appear to be subsiding: solar wind speed
decreased to below 500 km/s late in the period. 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 quiet to active. Isolated active periods are possible
early on 08 May as the coronal hole high speed stream subsides. Weak
transient material from today’s C1 flare and CME may produce
occasional unsettled to active periods on 10 May.

III. Event Probabilities 08 May-10 May

• Class M 10/10/10
• Class X 01/01/01
• Proton 01/01/01
• PCAF green

IV. Penticton 10.7 cm Flux

• Observed 07 May 085
• Predicted 08 May-10 May 085/090/095
• 90 Day Mean 07 May 106

V. Geomagnetic A Indices

• Observed Afr/Ap 06 May 010/008
• Estimated Afr/Ap 07 May 015/018
• Predicted Afr/Ap 08 May-10 May 008/008-005/008-010/015

VI. Geomagnetic Activity Probabilities 08 May-10 May

A. Middle Latitudes

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

B. High Latitudes

• Active 25/20/30
• Minor storm 10/05/15
• Major-severe storm 05/01/05