Joint USAF/NOAA Report of Solar and Geophysical Activity 14 Sep 2004

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

Updated 2004 Sep 14 2210 UTC

Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 258 Issued at 2200Z on 14 Sep 2004

IA. Analysis of Solar Active Regions and Activity from 13/2100Z
to 14/2100Z: Solar activity has been moderate. Region 672 (N05E10)
produced several C-class flares and an M1.5/1f at 0930 UTC. A Type
II radio sweep (1018 km/s) was observed in association with the M
flare. No evidence of a CME associated with the M flare was
available due to a LASCO data gap. Surging and plage fluctuations
were observed in Region 672, which is now in a beta-delta magnetic
configuration. No new regions were numbered today.

IB. Solar Activity Forecast: Solar activity is expected to be low
to moderate. Region 672 is expected to produce C- class flares, and
may produce isolated M-class flares.

IIA. Geophysical Activity Summary 13/2100Z to 14/2100Z:
The geomagnetic field has been unsettled to active. Lingering
effects of the CME which arrived on 13 September led to persistent
active conditions early in the period. The greater than 10 MeV
protons have been steadily delining since reaching a maximum of 273
pfu at 14/0005 UTC, and are currently at 17 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be quiet to unsettled on 15 September as the effects of
the current distrurbance subside. A CME originating from the M1.5
flare observed today may interact with Earth’s geomagnetic field
beginning midday on 16 September, and lasting through 17 September.
Predominantly active conditions, with isolated minor or major
storming, is likely on 16-17 September as a result of this CME
arrival. The greater than 10 MeV Proton levels may increase as well
in association with a CME shock arrival.

III. Event Probabilities 15 Sep-17 Sep

• Class M 25/25/25
• Class X 05/05/05
• Proton 99/10/10
• PCAF Green

IV. Penticton 10.7 cm Flux

• Observed 14 Sep 115
• Predicted 15 Sep-17 Sep 115/115/110
• 90 Day Mean 14 Sep 112

V. Geomagnetic A Indices

• Observed Afr/Ap 13 Sep 005/008
• Estimated Afr/Ap 14 Sep 020/030
• Predicted Afr/Ap 15 Sep-17 Sep 015/015-020/025-020/025

VI. Geomagnetic Activity Probabilities 15 Sep-17 Sep

A. Middle Latitudes

• Active 30/40/40
• Minor storm 20/25/25
• Major-severe storm 01/01/01

B. High Latitudes

• Active 35/35/35
• Minor storm 25/30/30
• Major-severe storm 01/05/05