Joint USAF/NOAA Report of Solar and Geophysical Activity 13 Jul 2005

Prepared jointly by the U.S. Dept. of Commerce, NOAA,

Space Environment Center and the U.S. Air Force.

Updated 2005 Jul 13 2230 UTC

Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 194 Issued at 2200Z on 13 Jul 2005

IA. Analysis of Solar Active Regions and Activity from 12/2100Z
to 13/2100Z: Solar activity increased to high levels. Region 786
(N11W84) continues its very active ways as it rotates around the
west limb. The region was responsible for all flare activity this
period, which included numerous C-class x-ray flares and five
M-class events. The largest and most impressive of these events was
the long duration M5 flare at 13/1449Z. Moderate to strong
centimetric radio bursts accompanied this event including a 2000 sfu
Tenflare. A bright, fast, predominantly westward directed CME (1360
km/s) was also observed. A long duration M1 x-ray event and Tenflare
(250 sfu) occurred at 13/0316Z. A CME was also observed on LASCO
imagery following this event. A relatively impulsive M3 flare
occurred at 13/1219Z. Region 786 is a moderate size sunspot group
with a strong delta configuration. New Region 790 (S10W35) was
numbered today.

IB. Solar Activity Forecast: Solar activity is expected to continue
at moderate to high levels for one more day as Region 786 rotates
around the west limb. Activity is expected to return to low to very
low levels on 15 and 16 July.

IIA. Geophysical Activity Summary 12/2100Z to 13/2100Z:
The geomagnetic field ranged from quiet to minor storm levels. Solar
wind parameters indicated the arrival of new CME material at the ACE
spacecraft early this period. Extended periods of southward IMF Bz
and solar wind speeds exceeding 600 km/s resulted in active to minor
storm conditions at all latitudes. The greater than 10 MeV protons
are slowly rising following today’s M5 flare. The greater than 2 MeV
electron flux at geosynchronous orbit was at high levels again
today.

IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to range from quiet to major storm levels. The CMEs
observed yesterday and today are expected to produce active to minor
storm levels on 15 and 16 July. Isolated major storm periods are
possible at high latitudes. The greater than 10 Mev protons will
likely pass the 10 pfu alert threshold early on 14 July.

III. Event Probabilities 14 Jul-16 Jul

• Class M 50/20/10
• Class X 10/01/01
• Proton 20/10/05
• PCAF yellow

IV. Penticton 10.7 cm Flux

• Observed 13 Jul 092
• Predicted 14 Jul-16 Jul 090/085/080
• 90 Day Mean 13 Jul 097

V. Geomagnetic A Indices

• Observed Afr/Ap 12 Jul 017/048
• Estimated Afr/Ap 13 Jul 020/030
• Predicted Afr/Ap 14 Jul-16 Jul 015/015-020/025-020/025

VI. Geomagnetic Activity Probabilities 14 Jul-16 Jul

A. Middle Latitudes

• Active 25/40/40
• Minor storm 15/20/20
• Major-severe storm 05/10/10

B. High Latitudes

• Active 30/50/50
• Minor storm 20/30/30
• Major-severe storm 10/15/15