Joint USAF/NOAA Report of Solar and Geophysical Activity 5 August 2011

Status Report From: Space Weather Prediction Center (NOAA)
Posted: Friday, August 5, 2011

:Product: Report of Solar-Geophysical Activity
:Issued: 2011 Aug 05 2200 UTC
# Prepared jointly by the U.S. Dept. of Commerce, NOAA,
# Space Weather Prediction Center and the U.S. Air Force.
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 217 Issued at 2200Z on 05 Aug 2011
IA. Analysis of Solar Active Regions and Activity from 04/2100Z
to 05/2100Z: Solar activity was low. Only low level C-flares were
observed. Region 1261 (N14W64) was the major producer for C-flare
activity. Region 1261 has decayed greatly in area and is now
classified a Dsi spot class with a Beta-Gamma magnetic
configuration. Region 1263 (N16W31) has remained largely unchanged
and maintains a Beta-Gamma-Delta magnetic configuration. New Region
1267 (S17E26) was numbered today.
IB. Solar Activity Forecast: Solar activity is expected to be low
with a chance for M-flares from Regions 1261 or 1263.
IIA. Geophysical Activity Summary 04/2100Z to 05/2100Z:
The geomagnetic field began the period at unsettled levels from
04/2100-05/0300Z. Quiet levels prevailed until after 1800Z. From
1800-2100Z, minor to severe storm levels dominated. Solar wind data
from ACE showed a shock-like feature passing ACE at 04/2105Z which
was followed by a 20 nT sudden impulse at 04/2155Z. The solar phi
angle showed rotation from negative to positive between 0300-1400Z.
An additional shock passage was seen at ACE at 1722Z followed by a
noticeable increase in solar wind density, velocity and magnetic
field. An additional enhancement in the solar wind parameters was
observed at 1834Z which include Bz fluctuation to -20 nT. Although
the interpretation is not yet certain, timing analysis and model
simulation suggest that the 1722Z & 1834Z enhancements are the first
two of the three expected CME passages. GOES 15 observed
magnetopause crossings between 1900Z-1915Z and 2000Z-2030Z. GOES 13
also observed magnetopause crossings between 2000Z-2030Z. The
greater than 10 MeV proton event that began at 04/0635Z reached a
peak of 83 PFU at 05/1755Z and continues in progress.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to reach minor to major storm levels with a chance for
severe storm periods on 06 August. Heightened activity is expected
due to continued effects from the CMEs of 02, 03, and 04 August.
Activity is expected to decrease to unsettled to active levels on 07
August. Quiet to unsettled conditions are expected on 08 August.
III. Event Probabilities 06 Aug-08 Aug
Class M 40/40/35
Class X 10/10/05
Proton 95/50/25
PCAF red
IV. Penticton 10.7 cm Flux
Observed 05 Aug 109
Predicted 06 Aug-08 Aug 110/110/100
90 Day Mean 05 Aug 096
V. Geomagnetic A Indices
Observed Afr/Ap 04 Aug 003/004
Estimated Afr/Ap 05 Aug 020/020
Predicted Afr/Ap 06 Aug-08 Aug 035/035-015/018-008/010
VI. Geomagnetic Activity Probabilities 06 Aug-08 Aug
A. Middle Latitudes
Active 20/25/10
Minor storm 40/15/05
Major-severe storm 35/05/00
B. High Latitudes
Active 20/25/15
Minor storm 35/20/05
Major-severe storm 40/15/00

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