CRACKLING SUNSPOT: Old sunspot 1039 is crackling with solar flares. Over the past 48 hours, it has produced five M-class eruptions. Click on the image to play a movie of the latest, an M2-blast recorded by STEREO-B at 1756 GMT on Jan. 20th:
The ongoing sequence of flares signals a sharp upturn in solar activity. Before this week, the last time the sun produced even a single M-class solar flare was in March 2008--almost two years ago. M-class solar flares have a moderate effect on Earth. Mainly, they boost the usual ionization of Earth's upper atmosphere, causing short-lived radio blackouts at some frequencies and radio enhancements at others. For an example, scroll down and read the section "Ionospheric Disturbance."
Today, the active region responsible for these fireworks is emerging over the sun's eastern limb where it can be seen from Earth: finder chart. Readers with solar telescopes are encouraged to monitor developments.
:Product: Geophysical Alert Message wwv.txt
:Issued: 2010 Jan 20 2106 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
#
# Geophysical Alert Message
#
Solar-terrestrial indices for 20 January follow.
Solar flux 82 and estimated mid-latitude A-Index 9.
The mid-latitude K-index at 2100 UTC on 20 January was 3 (27 nT).
Space weather for the past 24 hours has been minor.
Geomagnetic storms reaching the G1 level occurred.
Radio blackouts reaching the R1 level occurred.
Space weather for the next 24 hours is expected to be minor.
Radio blackouts reaching the R1 level are expected.
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 020 Issued at 2200Z on 20 Jan 2010
IA. Analysis of Solar Active Regions and Activity from 19/2100Z
to 20/2100Z: Solar activity was moderate. Region 1041 (S25E77)
produced four M-class flares during the past 24 hours, as well as
numerous C-class flares. The largest of these was an M3.4/Sf at
20/1755Z. Region 1041 was classified as a Cso-beta group with six
spots, as it rotated on to the east limb.
IB. Solar Activity Forecast: Solar activity is expected to be low
to moderate. Occasional M-class flares are likely. Frequent C-class
flares are expected.
IIA. Geophysical Activity Summary 19/2100Z to 20/2100Z:
The geomagnetic field was quiet to active, with isolated minor storm
conditions at high latitudes. Solar wind observations from the ACE
spacecraft indicated the onset of a co-rotating interaction region
around 20/0900Z. Solar wind velocity increased from 300 km/s to a
max of 525 km/s at 20/1834 km/s. The interplanetary magnetic field
(IMF) activity showed an enhancement of total field of 19 nT, and
the southern component of the IMF ranged between +15 nT and -17 nT.
Density reached 48 p/cc at 20/1546Z.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be quiet for the next three days (21-23 January).
III. Event Probabilities 21 Jan-23 Jan
Class M 75/75/75
Class X 05/05/05
Proton 05/05/05
PCAF Green
IV. Penticton 10.7 cm Flux
Observed 20 Jan 082
Predicted 21 Jan-23 Jan 083/084/085
90 Day Mean 20 Jan 077
V. Geomagnetic A Indices
Observed Afr/Ap 19 Jan 002/001
Estimated Afr/Ap 20 Jan 007/010
Predicted Afr/Ap 21 Jan-23 Jan 005/005-005/005-005/005
VI. Geomagnetic Activity Probabilities 21 Jan-23 Jan
A. Middle Latitudes
Active 05/05/05
Minor storm 01/01/01
Major-severe storm 01/01/01
B. High Latitudes
Active 05/05/05
Minor storm 01/01/01
Major-severe storm 01/01/01