Joint USAF/NOAA Report of Solar and Geophysical Activity 23 May 2012

:Product: Report of Solar-Geophysical Activity
:Issued: 2012 May 23 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 144 Issued at 2200Z on 23 May 2012
IA. Analysis of Solar Active Regions and Activity from 22/2100Z
to 23/2100Z: Solar activity was low. Region 1484 (N11W56) produced
a C1/Sf flare at 23/0027Z. Region 1484 decayed slightly in its
leader and intermediate spots. Slight growth was observed in Region
1483 (S24W79) as it approached the west limb. New Region 1489
(S30E40) was numbered today. The rest of the spotted regions showed
no significant changes. No earth directed CMEs were observed during
the reporting period.
IB. Solar Activity Forecast: Solar activity is expected to be very
low to low with a slight chance for an M-class flare for the
forecast period (24 – 26 May).
IIA. Geophysical Activity Summary 22/2100Z to 23/2100Z:
The geomagnetic field ranged from quiet to minor storming. Early on
23 May, solar wind speed at the ACE spacecraft increased from
approximately 430 km/s to 630 km/s while the interplanetary magnetic
field (IMF) fluctuated between +/- 10 nT. The geomagnetic field
responded with active to minor storm periods between 23/0000 –
0900Z. By about 23/0600Z, total field strength decreased to
approximately 4 – 5 nT while the Bz component remained mostly
positive. Solar wind speed remained fairly steady around 580 km/s
to 600 km/s through the end of the reporting period.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be quiet to unsettled with a chance for further active
periods on day 1 (24 May). Mostly quiet conditions are expected on
day 2 (25 May). On day 3 (26 May), quiet to unsettled conditions
are expected with a chance for isolated active periods around
mid-day as a glancing blow from the 22 May CME is possible.
III. Event Probabilities 24 May-26 May
Class M 10/10/10
Class X 01/01/01
Proton 01/01/01
PCAF green
IV. Penticton 10.7 cm Flux
Observed 23 May 117
Predicted 24 May-26 May 115/115/110
90 Day Mean 23 May 116
V. Geomagnetic A Indices
Observed Afr/Ap 22 May 015/018
Estimated Afr/Ap 23 May 012/018
Predicted Afr/Ap 24 May-26 May 010/010-005/005-008/008
VI. Geomagnetic Activity Probabilities 24 May-26 May
A. Middle Latitudes
Active 25/05/25
Minor storm 15/01/10
Major-severe storm 05/01/01
B. High Latitudes
Active 30/10/30
Minor storm 20/05/15
Major-severe storm 05/01/05