Status Report

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

By SpaceRef Editor
June 5, 2011
Filed under , , ,

:Product: Report of Solar-Geophysical Activity
:Issued: 2011 Jun 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 156 Issued at 2200Z on 05 Jun 2011
IA. Analysis of Solar Active Regions and Activity from 04/2100Z
to 05/2100Z: Solar activity was at very low levels with only a
single B3 x-ray event recorded at 05/0214Z from Region 1226
(S21W38). New Region 1233 (S18W29) was numbered as a unipolar spot
group. No significant changes were observed with the remaining
regions on the disk. During the period, LASCO C3 and STEREO-B COR2
imagery observed three separate CMEs. The first two CME’s were
back-sided, and appeared to originate from the vicinity of old
Region 1222 (N17, L=160) which rotated off the visible disk on 31
May. CME number one was first observed in STEREO Ahead EUVI 195
imagery at 04/0645Z and later in LASCO C3 imagery at 04/2212Z as a
partial-halo CME lifting of the east limb. The plane-of-sky speed
was estimated at about 1380 km/s. CME number two was first observed
in STEREO Ahead EUVI 195 imagery at 04/2145Z and later in LASCO C3
imagery at 05/0733ZZ as an asymmetric full-halo CME lifting off the
east limb. The plane-of-sky speed for this CME was estimated at
about 2160 km/s. A third CME originated from an eruptive, 16 degree
filament centered near N34E37. The filament was first observed
lifting off in SDO/AIA 193 imagery at 05/0341Z, with the
partial-halo CME first visible in STEREO Behind COR2 imagery at
05/0733Z. The plane-of-sky speed for the third CME was estimated at
490 km/s.
IB. Solar Activity Forecast: Solar activity is expected to be low
with a slight chance for an M-class event all three days (06 – 08
IIA. Geophysical Activity Summary 04/2100Z to 05/2100Z:
The geomagnetic field was at quiet to major storm levels. The
increase in activity was in response to the arrival of the 02 June
CME, coupled with a recurrent coronal hole high speed wind stream.
After the ACE spacecraft detected the initial interplanetary shock
at 04/1958Z, wind velocities rose steadily for the next four hours
and reached a peak during the period of 560 km/s at 05/0020Z. Bt
reached a maximum of 28 nT at 05/0053Z while the Bz component of the
interplanetary magnetic field (IMF) reached a maximum southward
value of -19 nT at 04/2157Z. The Bz component remained strongly
southward through about 05/0000Z where it turned strongly northward
to about +18 nT through 05/0700Z. Thereafter, and through the
balance of the period, the Bz component of the IMF did not vary much
beyond +/- 7 nT. Associated with the first two CMEs, observed off
the east limb, was a greater than 10 MeV proton enhancement that
reached a maximum of 3.9 pfu at 05/0050Z. Proton flux values decayed
to below 1 pfu after 05/0205Z and remained below through the
remainder of the period. The greater than 2 MeV electron flux at
geosynchronous orbit reached high levels during the period.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be quiet to unsettled, with isolated high latitude
active periods, on day one (06 June) due to lingering effects from
the CME and recurrent coronal hole high speed stream. On days two
and three (07 – 08 June), mostly quiet conditions are expected as
the activity subsides. Other than the brief proton ehnhancement
observed early on 05 June, no other effects are expected from the
three CMEs observed on 04 and 05 June.
III. Event Probabilities 06 Jun-08 Jun
Class M 10/10/10
Class X 01/01/01
Proton 01/01/01
PCAF green
IV. Penticton 10.7 cm Flux
Observed 05 Jun 103
Predicted 06 Jun-08 Jun 100/098/096
90 Day Mean 05 Jun 106
V. Geomagnetic A Indices
Observed Afr/Ap 04 Jun 011/015
Estimated Afr/Ap 05 Jun 020/020
Predicted Afr/Ap 06 Jun-08 Jun 008/010-005/005-005/005
VI. Geomagnetic Activity Probabilities 06 Jun-08 Jun
A. Middle Latitudes
Active 15/05/05
Minor storm 05/01/01
Major-severe storm 01/01/01
B. High Latitudes
Active 20/05/05
Minor storm 10/01/01
Major-severe storm 01/01/01

SpaceRef staff editor.