Joint USAF/NOAA Report of Solar and Geophysical Activity 13 May 2004

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

Updated 2004 May 13 2210 UTC

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 134 Issued at 2200Z on 13 May 2004

IA. Analysis of Solar Active Regions and Activity from 12/2100Z
to 13/2100Z: Solar activity was low. Region 609 (S03E24) produced
three C-class flares including a C7/Sf at 13/1330Z. This region
underwent rapid growth in the past 36 hours and now exhibits a
moderately complex beta-gamma configuration. CME activity was
observed off the east limb. New Regions 612 (N10E07) and 613
(S08E83) were numbered today.

IB. Solar Activity Forecast: Solar activity is expected to continue
at low levels. Region 609 will likely produce C-class activity and
may soon possess potential for M-class events.

IIA. Geophysical Activity Summary 12/2100Z to 13/2100Z:
The geomagnetic field was mostly quiet to unsettled with an isolated
active to minor storm period between 13/0600 – 0900Z. Occasional
periods of sustained southward IMF Bz account for the most disturbed
periods.

IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be quiet to active with isolated active periods.

III. Event Probabilities 14 May-16 May

• Class M 20/20/20
• Class X 05/05/05
• Proton 01/01/01
• PCAF green

IV. Penticton 10.7 cm Flux

• Observed 13 May 101
• Predicted 14 May-16 May 105/110/115
• 90 Day Mean 13 May 104

V. Geomagnetic A Indices

• Observed Afr/Ap 12 May 009/011
• Estimated Afr/Ap 13 May 012/014
• Predicted Afr/Ap 14 May-16 May 010/012-010/015-008/012

VI. Geomagnetic Activity Probabilities 14 May-16 May

A. Middle Latitudes

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

B. High Latitudes

• Active 30/35/30
• Minor storm 20/20/15
• Major-severe storm 05/05/05