Joint USAF/NOAA Report of Solar and Geophysical Activity 20 Jun 2004

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

Updated 2004 Jun 20 2210 UTC

Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 172 Issued at 2200Z on 20 Jun 2004

IA. Analysis of Solar Active Regions and Activity from 19/2100Z
to 20/2100Z: Solar activity was at low levels today. Region 635
(S12W01) produced several C-class flares during the period. The
largest was a C2/Sf event that occurred at 20/1332Z. There was
continued growth in the sunspot area, most notably around the
intermediate spots. Region 635 continues to exhibit a delta
magnetic configuration in the trailing portion of the active region.
Region 634 (N12W18) was quiescent today with little change observed
over the period. The large, lead asymmetrical spot continues to
display a delta magnetic structure. New Region 636 (S10E30) was
numbered today.

IB. Solar Activity Forecast: Solar activity is expected to be at
low to moderate levels. Regions 634 and 635 are capable of
producing M-class flare activity.

IIA. Geophysical Activity Summary 19/2100Z to 20/2100Z:
The geomagnetic field was at quiet levels.

IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at quiet to unsettled levels throughout the forecast
period.

III. Event Probabilities 21 Jun-23 Jun

• Class M 60/60/60
• Class X 10/10/10
• Proton 05/05/05
• PCAF green

IV. Penticton 10.7 cm Flux

• Observed 20 Jun 119
• Predicted 21 Jun-23 Jun 120/115/115
• 90 Day Mean 20 Jun 102

V. Geomagnetic A Indices

• Observed Afr/Ap 19 Jun 004/005
• Estimated Afr/Ap 20 Jun 003/005
• Predicted Afr/Ap 21 Jun-23 Jun 004/005-004/008-004/008

VI. Geomagnetic Activity Probabilities 21 Jun-23 Jun

A. Middle Latitudes

• Active 15/15/15
• Minor storm 01/01/01
• Major-severe storm 01/01/01

B. High Latitudes

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