Archives for Tony

Solar wind summary


The solar wind field at the ACE spacecraft was relatively unchanged
until about 28/0400 UTC. Wind speed had lingered around 280 km/s and
Phi had been positive (away). Between 28/0400-0549 UTC, wind speed rose
to 363 km/s and Bz approached -6 nT. Bt reached about 7 nT. Phi
briefly shifted to a negative (toward) orientation before becoming
positive around 28/0900 UTC. After 28/0549 UTC, wind speed abruptly
returned to around 270 km/s where it has remained. The low energy
particle flux at ACE continued to rise, suggesting the impending arrival
of the expected transient. Additionally, the greater than 10 MeV
particle flux recorded by the ACe/SIS instrument began rising after the
X1 event mentioned earlier and had reached 3.8 pfu by 28/1030 UTC.

28th October


Solar activity reached high levels when Region 1875 (N07W71,
Fkc/beta-gamma-delta) produced an X1/2N flare at 28/0203 UTC. A Type II
radio emission (451 km/s) was reported at 28/0200 UTC. This event was
followed by an asymmetric halo CME first visible in SOHO/LASCO C2
imagery at 28/0224 UTC. A coarse fit using only SOHO/LASCO C3 imagery
and a preliminary WSA-Enlil model run suggests arrival of ejecta on 30
October. However, the lack of sufficient STEREO COR2 imagery for the
fit means confidence in this solution is low and analysis is ongoing.

An M5/2B from the same region followed at 28/0441 UTC and was
accompanied by a Type II radio emission (508 km/S) at 28/0437 UTC, a
Type IV emission, and a 170 sfu Tenflare at 28/0438 UTC. A CME was
subsequently observed in SOHO/LASCO C2 imagery at 28/0448 UTC. Analysis
of this event suggests the ejecta was directed well westward and the
geoeffective potential low.

Over the past 24 hours, Regions 1875 and 1877 have decreased in area and
1877 lost its delta magnetic configuration. Region 1882 (S09E41,
Dkc/beta-gamma-delta) was relatively stable, losing a few spots but
retaining its beta-gamma-delta configuration. Region 1884 (S14E60,
Dao/beta-gamma-delta) and the remaining regions were relatively stable.
Emerging flux was observed near S15E22 and was being monitored.

Kp5/G1 storm expected tonight (28th Oct)



Kp5/G1 storm expected tonight (28th Oct)

Aurora Borealis tonight!

The SWPC have a Kp5/G1 watch active for tonight. They have had them previously this week which amounted to nothing and left an lot of people disappointed. So we are cautious to get peoples hopes up, as such we have barely covered this event. But this one looks like it might be a bit more accurate. On the graph above, the Protons are rising considerably, which means that something reasonable sized will arrive shortly, probably tonight, as forecast. Although it is cloudy in most of Northern Europe tonight, here included, we will be heading out for a few hours if the solar wind conditions at the ACE satellite show good signs. After the previous week, I will be happy to get even green clouds.

Solar wind summary


A shock passage was observed at 26/2145 UTC. There were distinct
discontinuities in both density and temperature, along with a jump in
wind speeds from 280 km/s to 312 km/s and a rise in Bt from 4 nT to 7
nT. Before shock arrival, wind speed ranged between a high of about 310
km/s to a low of near 275 km/s. The interplanetary magnetic field (IMF)
Bt varied between 2 and 4 nT while the Bz component did not vary much
beyond +/- 2 nT. Phi was in a predominately negative (towards)
orientation through about 26/1630 UTC when it switched to a more
positive (away) orientation through until about 27/0900 UTC.

27th October


Solar activity was at moderate levels. A 27 degree long filament,
centered near S41W32, erupted between 26/0950 – 1310 UTC. LASCO C2
imagery observed a CME at 26/1325 UTC off the SW limb. Newly numbered
Region 1884 (S14E74, Hsx/alpha) produced an M3/Sf flare at 26/1927 UTC
and Region 1882 (S08E27, Dkc/beta-gamma-delta) produced an M1/Sf flare
(R1 Radio Blackout) at 26/1953 UTC. A CME was observed in SOHO/LASCO C2
imagery emerging from the east limb beginning at 26/1912 UTC. A
preliminary analysis suggests the ejecta is moving at about 970 km/s.

At least five other CMEs were observed in C2 imagery exiting the west
limb over the past 24 hours. Examination of SDO/AIA 304 imagery
indicates Regions 1873 (N13W83, Hrx/alpha) and 1875 (N06W56,
Ekc/beta-gamma-delta) as the origin. Where sufficient coronagraph
imagery was available, analysis suggests these events are directed
mostly westward with a slim chance of a significant impact at Earth.
Further analysis will be accomplished when additional STEREO COR2
imagery becomes available.

While Regions 1875 and 1877 (S13W35, Dhi/beta-gamma) remained the
largest spot groups on the visible disk, they only produced a few
C-class flares and changed little over the period. In addition to
Region 1884, two other regions were numbered during the period, Regions
1883 (N04E66, Hsx/alpha) and 1885 (S18E69, Hsx/alpha). Region 1885
appeared to be the origin of an eruption in the southeast visible in
SDO/AIA 304 imagery around 27/0451 UTC.

26th October


Solar activity was high. At 25/1503 UTC, Region 1882 (S08E54,
Dao/beta-gamma-delta) produced an X2 flare that was associated with
Types II (2078 km/s) and IV radio emissions with another Castelli U
radio signature including a 370 sfu Tenflare. SOHO/LASCO C2 coronagraph
imagery depicted a partial-halo CME emerging from the east limb
beginning at 25/1512 UTC. WSA-Enlil model output suggest this CME will
merge with the ejecta from the 24 October M9 flare and arrive on the
28th.

Region 1882 also produced six M-class events, including an M1 flare at
26/0937 UTC. A Type II (1275 km/s) radio sweep was reported with this
flare, beginning at 26/0931 UTC and dimming was apparent in SDO/AIA 193
imagery south of the region. This event has yet to be observed in
available coronagraph imagery. Region 1882 continued to evolve in both
area, spot count and magnetic complexity.

Regions 1875 (N07W44, Ekc/beta-gamma-delta) and 1877 (S13W23,
Dhi/beta-gamma) remained the largest on the visible disk. Region 1875
grew slightly while 1877 was relatively stable. Between 26/0442-0747
UTC, EUV dimming was observed in SDO/AIA 193 imagery south of and
between Regions 1875 and 1877. A CME was subsequently observed in
SOHO/LASCO C2 imagery emerging from the west beginning at 26/0700 UTC.
This event has not yet been modeled, but a preliminary analysis using
available coronagraph imagery suggests it was moving at approximately
400 km/s and may have an Earth-directed component.

A second dimming event was observed between 26/0827-1015 UTC in the same
vicinity and brightening was evident in Regions 1875 and 1877 around the
same time as the M1 flare from Region 1882. This event has not yet been
observed in coronagraph imagery. Finally, a filament eruption was in
progress in the southwestern quadrant at the time of this writing.

27th October


Level 1 – Quiet

Forecast:
Auroral activity will be at quiet levels. Weather permitting, aurora displays may be visible overhead or on the horizon in Tromsø (Norway) and Utsjoki (Finland).

Comments:
Calm before the storm? Tomorrow is predicted to reach Kp4 with maybe brief G1/Kp5 spells due to ejecta from the M9 flare a couple days ago, plus some slight residual impact from the X class flare. I think this is much more likely than the previous Kp5 alert that was a dud a couple days ago. So tonight is expected to remain pretty quiet until the events of tomorrow unfold. All eyes are on this event. Surely the SWPC and NASA can’t get another event so wrong?

Solar wind summary


The solar wind environment at the ACE spacecraft was nominal. Wind
speed remained in the mid 300 km/s range. The interplanetary magnetic
field (IMF) Bt ranged between 2 to 6 nT with the Bz component did not
vary much beyond +/- 4 nT. The phi angle was in a predominately positive
(towards) orientation through the period. A small discontinuity was
observed around 25/0350 UTC when small increases were observed in
temperature, density and wind speed.

26th October


Tonight’s estimated aurora level:

Level 2 – Low (with a chance of Kp4)

Forecast:
Auroral activity will be at low levels. Weather permitting, aurora displays may be visible overhead or on the horizon in Bodø (Norway), Sodankylä (Finland), Kiruna (Sweden) and Reykjavík (Iceland).

Comments:
With the disappointment of many CME’s missing recently, we don’t hold out much hope for the other one which is due to arrive today. We are not going to complain about NOAA SWPC or NASA because they do a really great job, but for whatever reason their computer models have been way off recently. So really, your best bet is just to enjoy your weekend, sign up to our text alerts, and we will text you if there is any significant activity!

25th October


Solar activity was high. Region 1882 (S08E67, Dso/beta) produced an
impulsive X1 flare (R3 Strong Radio Blackout), with no corresponding
optical report, at 25/0801 UTC. It was accompanied by Type II (1240
km/s) and IV radio emissions and a Tenflare (610 sfu). SOHO/LASCO C2
coronagraph imagery depicts a coronal mass ejection (CME) emerging from
the east limb beginning at 25/0824 UTC.

Earlier, this same region produced an M2 x-ray flare (R1 Minor Radio
Blackout) at 25/0302 UTC as well as Type II (711 km/s) and Type IV radio
emissions. A relatively narrow CME, believed to be associated with this
flare, was observed in SOHO/LASCO C2 coronagraph imagery emerging from
the east limb at 25/0424 UTC. Later, Region 1882 produced an M1/Sf
flare at 25/1012 UTC.

A 25 degree filament eruption in the northeast which occurred between
25/0004-0258 UTC produced a CME visible in SOHO/LASCO C2 imagery
beginning 25/0436 UTC. None of these CMEs are expected to be
geoeffective. Another filament liftoff from the southeast quadrant was
observed in SDO AIA 304 imagery 25/0600-1000 UTC.

Regions 1875 (N08W30, Ekc/beta-gamma-delta) and 1877 (S12W10, Dhi/beta)
remained the largest regions during the past 24 hours. Region 1875
ended Oct 24th with an area of 720 millionths and by the time of this
report had four C-class events to its credit. Region 1877 ended the 24th
at 440 millionths and was responsible for three C-class events so far,
including a C5 at 24/2210 UTC.