Joint USAF/NOAA Report of Solar and Geophysical Activity 31 May 2011

:Product: Report of Solar-Geophysical Activity
:Issued: 2011 May 31 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 151 Issued at 2200Z on 31 May 2011
IA. Analysis of Solar Active Regions and Activity from 30/2100Z
to 31/2100Z: Solar activity has been low. Region 1226 (S22E27) and
Region 1227 (S18E39) each produced C1 x-ray events in the past 24
hours. Region 1226 was classified as a Dhc group with Beta magnetic
characteristics while Region 1227 was a Dsi group with more complex
Beta-Gamma characteristics. Region 1228 (N17E50) rapidly evolved
into a Cso type group as new trailing spots emerged. New Region
1230 (N19E58) was numbered today. This new region, and the remainng
regions, were generally quiescent, small and magnetically simple.
IB. Solar Activity Forecast: Solar activity is expected to be low,
with a slight chance for M-class events for the next three days (1 –
3 Jun).
IIA. Geophysical Activity Summary 30/2100Z to 31/2100Z:
The geomagnetic field ranged from quiet to active levels over the
past 24 hours. Heliospheric imagery from STEREO-B suggests the
increased activity was the result of a transient, weak CME. 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 unsettled to active on day 1 (01 Jun) , quiet to
unsettled on day 2 (02 Jun), and unsettled to active on day 3 (03
Jun). ENLIL model output indicates the passage of the 29 May CME
early on day 1. A brief return to generally quiet conditions on day
2 is followed by disturbed conditions on day 3 as a recurrent
coronal hole high speed stream begins to influence the
magnetosphere.
III. Event Probabilities 01 Jun-03 Jun
Class M 20/20/20
Class X 01/01/01
Proton 01/01/01
PCAF green
IV. Penticton 10.7 cm Flux
Observed 31 May 112
Predicted 01 Jun-03 Jun 115/115/110
90 Day Mean 31 May 108
V. Geomagnetic A Indices
Observed Afr/Ap 30 May 007/009
Estimated Afr/Ap 31 May 010/012
Predicted Afr/Ap 01 Jun-03 Jun 010/010-007/008-010/010
VI. Geomagnetic Activity Probabilities 01 Jun-03 Jun
A. Middle Latitudes
Active 20/10/20
Minor storm 10/05/10
Major-severe storm 05/01/05
B. High Latitudes
Active 20/15/20
Minor storm 25/10/20
Major-severe storm 10/05/15