Joint USAF/NOAA Report of Solar and Geophysical Activity 24 January 2012

:Product: Report of Solar-Geophysical Activity
:Issued: 2012 Jan 24 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 024 Issued at 2200Z on 24 Jan 2012
IA. Analysis of Solar Active Regions and Activity from 23/2100Z
to 24/2100Z: Solar activity was at low levels. Low-level C-class
events were observed from Region 1401 (N16W53) and Region 1402
(N29W48). Region 1401 indicated slight decay while Region 1402
showed some growth in the trailer spots.
IB. Solar Activity Forecast: Solar activity is expected to be low
during the period (25 – 27 January) with M-class activity likely
from Regions 1401 and 1402.
IIA. Geophysical Activity Summary 23/2100Z to 24/2100Z:
The geomagnetic field was at quiet to active levels with isolated
minor to major storm periods. At 24/1431Z, an interplanetary shock
passage was recorded at the ACE satellite with a corresponding
sudden impulse of 22 nT observed at the Boulder magnetometer at
24/1504Z. At the time of the IP shock passage, Bt reached a maximum
of 37 nT at 24/1439Z while the Bz component of the interplanetary
magnetic field hit a maximum northward extent of 27 nT at 24/1436Z
and a maximum southward extent of -16 nT at 24/1807Z. Wind
velocity, as measured at the SOHO spacecraft, were observed at shock
passage near 750 km/s with post shock passage speeds near 650 km/s.
The greater than 100 MeV proton flux event that began at 23/0445Z,
reached a maximum of 2 pfu at 23/0750Z and ended at 23/2050Z. The
greater than 10 MeV proton flux event that began at 23/0530Z,
reached a new maximum of 6310 pfu at 24/1530Z and was still in
progress at the time of this writing.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at unsettled to minor storm levels, with isolated
major storm intervals, on day one (25 January) as effects from the
arrival of the 23 January CME persist. By day two (26 January), the
field is expected to be at mostly quiet levels as CME effects wane.
Quiet to unsettled levels, with isolated active periods, are
expected on day three (27 January) due to a recurrent coronal hole
high speed stream rotating into a geoeffective position. The
greater than 10 MeV proton flux event is expected to remain above
threshold through 26 January, falling to background levels by 27
January.
III. Event Probabilities 25 Jan-27 Jan
Class M 60/60/60
Class X 10/10/10
Proton 99/99/50
PCAF in progress
IV. Penticton 10.7 cm Flux
Observed 24 Jan 136
Predicted 25 Jan-27 Jan 140/140/135
90 Day Mean 24 Jan 143
V. Geomagnetic A Indices
Observed Afr/Ap 23 Jan 007/011
Estimated Afr/Ap 24 Jan 022/030
Predicted Afr/Ap 25 Jan-27 Jan 018/020-005/005-007/008
VI. Geomagnetic Activity Probabilities 25 Jan-27 Jan
A. Middle Latitudes
Active 35/10/25
Minor storm 20/05/05
Major-severe storm 05/01/01
B. High Latitudes
Active 40/15/35
Minor storm 25/05/15
Major-severe storm 10/01/05