Solar Terrestrial Activity Report

Last major update issued on October 19, 2014 at 06:15 UTC. Updates will be irregular until October 27.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update October 1, 2014)] [Cycle 24 progress (last update October 1, 2014) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update October 1, 2014)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update October 1, 2014)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update October 10, 2014)]

[Noon SDO sunspot count 1K Reference: 4K (large file) (updated daily)]

[POES auroral activity level October 2009 - December 2012]
[Solar polar fields vs solar cycles - updated October 11, 2014]
[Presentations: 3rd SSN Workshop, Tucson, 2013 (pdf) / 4th SSN Workshop, Locarno, 2014]

Recent activity

The geomagnetic field was quiet to unsettled on October 18. Solar wind speed at SOHO ranged between 424 and 483 km/s under the influence of high speed streams.

Solar flux at 20h UTC on 2.8 GHz was 160 (increasing 36.1 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 134.4. The Potsdam WDC planetary A index was 12 (STAR Ap - based on the mean of three hour interval ap indices: 12.3). Three hour interval K indices: 33223323 (planetary), 23223422 (Boulder).

The background x-ray flux is at the class C2 level.

At the time of counting spots (see image time), spots were observed in 7 active regions using 2K resolution (SN: 178) and 6 active regions using 1K resolution (SN: 128) SDO images on the visible solar disk.

Region 12186 [S22W69] was quiet and stable.
Region 12187 [S09W13] was quiet and stable.
Region 12190 [N23E10] decayed slowly and quietly.
Region 12191 [S11E04] decayed slowly and quietly.
Region 12192 [S14E63] has a huge main spot with penumbra that extends nearly 10 degrees longitudinally and 7 degrees latitudinally. That spot has one strong magnetic delta structures and two small ones. The region was the source of a major long duration X1.1 event peaking at 05:03 on October 19. Further X class flaring is likely.

Spotted regions not numbered (or interpreted differently) by SWPC:
New region S3919 [N04E24] emerged early in the day and developed slowly.
New region S3920 [S05W22] emerged with a penumbra spot.

C2+ flares (GOES):

Coronal mass ejections (CMEs)

October 16-18: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.

Coronal holes

[Coronal hole history (since October 2002)]
[Compare today's report to the situation one solar rotation ago: 28 days ago 27 days ago 26 days ago]

A recurrent trans equatorial coronal hole (CH639) was in an Earth facing position on October 17-18. A recurrent trans equatorial coronal hole (CH640) will likely rotate into an Earth facing position on October 19-21.

Propagation

Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over upper middle latitudes is poor. Propagation on long distance northeast-southwest paths is fair to good.

Forecast

The geomagnetic field is expected to be quiet to unsettled on October 19. Quiet to active conditions are likely on October 20-24 due to effects from CH639 and CH640.

1) Effects from a coronal hole could reach Earth within the next 5 days. When the high speed stream has arrived the color changes to green.
2) Effects from a CME are likely to be observed at Earth within 96 hours.
3) There is a possibility of either M or X class flares within the next 48 hours.

Green: 0-30% probability, Yellow: 30-70% probability, Red: 70-100% probability.

Active solar regions

(Click on image for 2K resolution) Compare to the previous day's image. 0.5K image

When available the active region map has a coronal hole polarity overlay where red (pink) is negative and blue is positive.

Data for all numbered solar regions according to the Solar Region Summary provided by NOAA/SWPC. Comments are my own, as is the STAR spot count (spots observed at or inside a few hours before midnight) and data for regions not numbered by SWPC or where SWPC has observed no spots. SWPC active region numbers in the table below and in the active region map above are the historic SWPC/USAF numbers.

Active region	Date numbered detected	Spot count			Location at midnight	Area	Classification		SDO / HMI 4K continuum image with magnetic polarity overlay		Comment
		SWPC	Magnetic (SDO)				SWPC	STAR	Current	Previous
			2K	1K
12186	2014.10.07	1	2	2	S20W70	0110	HSX	HSX			area: 0160 location: S22W69
12187	2014.10.11	10	20	14	S09W12	0210	CSO	CKO			area: 0310
S3893	2014.10.11				N15W51						plage
12189	2014.10.11 2014.10.14				N23W35						plage
S3898	2014.10.12				S20W46						plage
12188	2014.10.13				N18W94
S3900	2014.10.13				N07E07						plage
12191	2014.10.14 2014.10.15		3	2	S14E02	0008		BXO			location: S11E04
12190	2014.10.14		2	1	N22E05	0005		AXX			location: N23E10
S3905	2014.10.15				S15W34						plage
S3908	2014.10.15				N09W35						plage
S3910	2014.10.16				S17E20						plage
12192	2014.10.16 2014.10.17	19	71	43	S13E56	1240	FKC	FKC			beta-gamma-delta location: S14E63 area: 2200
S3912	2014.10.16				S29W37						plage
S3913	2014.10.16				S23W37						plage
S3914	2014.10.16				N05E26						plage
S3915	2014.10.17				S24E18						plage
S3916	2014.10.17				S25E05						plage
S3917	2014.10.17				N18W14						plage
S3918	2014.10.17				N18W14						plage
S3919	2014.10.18		9	6	N04E24	0040		DRO
S3920	2014.10.18		1		S05W22	0003		AXX
Total spot count:		30	108	68
Sunspot number:		60	178	128	(total spot count + 10 * number of spotted regions)
Weighted SN:		50	136	96	(Sum of total spot count + classification weighting for each AR. Classification weighting: X=0, R=3, A/S=5, H/K=10)
Relative sunspot number (Wolf number):		36	62	70	k * (sunspot number). k = 0.6 for SWPC, k = 0.35 for MSN 2K, k = 0.55 for MSN 1K (MSN=Magnetic Sunspot Number)

Monthly solar cycle data

1) Running average based on the daily 20:00 UTC observed solar flux value at 2800 MHz.
2A) Current impact on the monthly sunspot number based on the Boulder (NOAA/SWPC) sunspot number (accumulated daily sunspots / month days). The official WDC-SILSO international sunspot number is typically 30-50% lower. 2B) Boulder SN current month average to date. 2C) STAR SDO 1K Wolf number 30 day average.
3) Running average based on the quicklook and definitive Potsdam WDC ap indices. Values in red are based on the definitive international GFZ Potsdam WDC ap indices.

This report has been prepared by Jan Alvestad. It is based on the analysis of data from whatever sources are available at the time the report is prepared. All time references are to the UTC day. Comments and suggestions are always welcome.

SDO images are courtesy of NASA/SDO and the AIA, EVE, and HMI science teams.