- Press Release
- Jun 7, 2023
Joint USAF/NOAA Report of Solar and Geophysical Activity 23 January 2012
:Product: Report of Solar-Geophysical Activity
:Issued: 2012 Jan 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 023 Issued at 2200Z on 23 Jan 2012
IA. Analysis of Solar Active Regions and Activity from 22/2100Z
to 23/2100Z: Solar activity reached high levels. Region 1402
(N28W36) produced a long-duration M8/2b flare at 23/0359Z.
Associated with this event were multi-frequency radio emissions
spanning 25 MHz through 15.4 GHz including a 5100 sfu Tenflare.
SOHO/LASCO observed an asymmetric, full-halo CME, first observed in
C2 imagery at 27/0412Z as a bright halo over the northern
hemisphere. Model output suggests potential Earth impact midday on
24 January. Region 1402 showed some umbral separation in the large
leader spot. Region 1401 (N16W39) produced a C1/Sf at 23/2011Z.
The remainder of the disk was quiet and stable.
IB. Solar Activity Forecast: Solar activity is expected to be low
during the period (24 – 26 January) with M-class activity likely
from Regions 1401 and 1402.
IIA. Geophysical Activity Summary 22/2100Z to 23/2100Z:
The geomagnetic field ranged from quiet to minor storms levels. The
period began with active to minor storm conditions as the field was
under the influence of the 19 January CME. By 23/0600Z, the field
became mostly quiet to unsettled. Solar wind speeds began the
period at about 450 km/s while the Bz component of the
interplanetary magnetic field (IMF) was at about -10 nT. By about
0630Z, wind speeds dropped sharply to near 300 km/s, density dropped
to near 0 p/cc and IMF Bz turned northward. These signatures were
consistent with a possible reverse shock at the back end of the CME.
The greater than 10 MeV proton flux at greater than or equal to 10
pfu and the greater than 100 MeV proton flux at greater than or
equal to 1 pfu at geosynchronous orbit were above threshold during
the period. The 10 MeV event began at 23/0530Z and reached at
maximum of 3100 pfu at 23/1940Z. The 100 MeV event began at
23/0445Z and reached a maximum of 2.3 pfu at 23/0750Z. Both events
were still in progress at the time of this report.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to range from quiet to isolated severe storm levels on day
one (24 January). Mostly quiet levels are expected through midday
on 24 January when the anticipated arrival of the 23 January CME is
expected to affect the field. Active to major storm levels, with
isolated severe storm periods, are expected for the remainder of day
one. By day two (25 January), field activity is expected to
decrease to unsettled to active levels, with isolated minor storm
periods, as effects from the CME wane. Day three (26 January)
should see a return to mostly quiet conditions.
III. Event Probabilities 24 Jan-26 Jan
Class M 60/60/60
Class X 10/10/10
IV. Penticton 10.7 cm Flux
Observed 23 Jan 144
Predicted 24 Jan-26 Jan 145/145/145
90 Day Mean 23 Jan 143
V. Geomagnetic A Indices
Observed Afr/Ap 22 Jan 022/024
Estimated Afr/Ap 23 Jan 008/009
Predicted Afr/Ap 24 Jan-26 Jan 022/042-018/020-005/005
VI. Geomagnetic Activity Probabilities 24 Jan-26 Jan
A. Middle Latitudes
Minor storm 35/15/01
Major-severe storm 20/01/01
B. High Latitudes
Minor storm 50/25/05
Major-severe storm 30/10/01