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

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

Updated 2004 Jul 13 2200 UTC

Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 195 Issued at 2200Z on 13 Jul 2004

IA. Analysis of Solar Active Regions and Activity from 12/2100Z
to 13/2100Z: Solar activity was high. Region 646 (N13W60) emerged
rapidly during the past 24 hours and produced three major flares: an
M6 at 0017 UTC, an M5/1n at 0848 UTC, and an M6/1b at 1932 UTC.
CME’s were observed in association with the first and second major
flares which were technically classified as halo events, although
the majority of the mass erupted off the northwest limb. Region 646
grew from 70 to 220 millionths and has some magnetic complexity
along a northeast-to-southwest inversion line. Region 649 (S10E64)
is the largest group on the disk with an area of 350 millionths. The
region produced numerous C-class events as well as two M-class
flares: an M2 at 1208 UTC and an M1/Sf at 1838 UTC.

IB. Solar Activity Forecast: Solar activity is expected to be
mostly moderate, with Region 646 and 649 the most likely sources for
activity. There is a fair chance for continued major flare activity,
particularly out of Region 646.

IIA. Geophysical Activity Summary 12/2100Z to 13/2100Z:
The geomagnetic field ranged from quiet to active levels during the
past 24 hours. Solar wind data countinue to show that the earth is
under the influence of a high-speed stream driven by a coronal hole
(with typical speeds today between 500 to 600 km/s). There was an
enhancement of greater than 10 MeV protons, which began around 0100
UTC and reached maximum values of about 1 PFU.

IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be mostly unsettled for the next three days. Unsettled
with some active periods at high latitudes is expected on the third
day as a possible response to a glancing blow from one or the other
of today’s CMEs.

III. Event Probabilities 14 Jul-16 Jul

• Class M 75/75/75
• Class X 15/15/15
• Proton 15/15/15
• PCAF green

IV. Penticton 10.7 cm Flux

• Observed 13 Jul 127
• Predicted 14 Jul-16 Jul 135/140/140
• 90 Day Mean 13 Jul 098

V. Geomagnetic A Indices

• Observed Afr/Ap 12 Jul 012/013
• Estimated Afr/Ap 13 Jul 012/015
• Predicted Afr/Ap 14 Jul-16 Jul 010/012-010/012-012/020

VI. Geomagnetic Activity Probabilities 14 Jul-16 Jul

A. Middle Latitudes

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

B. High Latitudes

• Active 35/35/40
• Minor storm 20/20/20
• Major-severe storm 05/05/05