A large and active sunspot complex may be gearing up to produce possible major solar flares over the next several days. NOAA active Regions 8673 and 8674 are the most impressive sunspot groups currently visible on the Sun.

They are located just southwest of the central solar meridian and consisttogether of 86 sunspots. Region 8674 is the most complex and has developed into what is known as a beta-gamma-delta magnetic configuration (the most complex magnetic configuration identified). Sunspots classed as "beta" groups are simple bipolar regions. "Beta-gamma" sunspot groups are more complex and consist of an irregular mixture of magnetic polarities.

The "delta" magnetic configuration only occurs when two closely-spaced, opposite polarity umbrae appear within a single penumbra. This characteristic implies that magnetic field gradients are high and that respectable levels of magnetic shear may exist around the two opposite polarity umbral spots. Sunspot regions that possess the "delta" configuration are the most potentially volatile and flare-prone active regions. Some of the most powerful solar flares in recorded history (including the rare white-light flares) have issued forth from complex sunspot regions containing magnetic delta configurations. The intermediate and trailing portions of Region 8674 are the areas containing the magnetic delta configurations. Magnetic analysis of the region shows that moderate levels of magnetic shear exists along a substantial portion of the neutral line (the line separating opposite magnetic polarities) in the trailer spot complex. This ingredient is often (but not always) a precursor to major solar flare activity.

Over the last 24 hours, Region 8674 has produced a minimal major M5.5 solar x-ray flare. But this event lacked significant character and does not appear to have been associated with a coronal mass ejection. This region has the potential to produce much larger activity, even X-class solar flares,particularly if growth continues. Most forecast centers are anticipating major flare activity from this sunspot group over the next 24 to 72 hours. Amateur solar observers are encouraged to keep a close eye on this region, particularly the intermediate and trailer spot complexes of Region8674. There is a fair possibility a large X-class flare could be spawned by this region with possible sympathetic activity in Region 8673 (the spot complex just northwest of Region 8674). These two active regions are merging,which is making it increasingly difficult to determine which region is which.

Observers with hydrogen-alpha filters should be able to spot very frequent point brightenings along with occasional flare activity and associated bright or dark surges. Observers equipped with white-light filters will probably not observe any activity (flare activity is dominantly a chromospheric phenomenon requiring a filter capable of resolving the hydrogen-alpha component of sunlight:). However, the development of sunspots and evolution of existing spot groups is best observed in white-light. There is also a very slight chance that observers may spot rare and brief brightenings in white-light during large solar flares. These white-light solar flares are some of the most extraordinary and powerful classes of solar flares and should definitely be reported. They often occur within the penumbral or umbral regions of spot complexes. Reports of activity can be made by amateurs to our Solar Activity Observation Network at: http://solar.uleth.ca/www/sunobs.html. Click on the Submission link to report your observations. All observations are made publically available within 5 minutes of the posting.

As always, the standard caveat applies to solar observing: don't observe the sun directly without adequate eye protection. Telescopic observations should only be performed with solar filters designed to cover the front end of the telescope and those filters should be securely fastened so they don't accidentally fall off during observations. Do not use solar filters that screw into the inside of eyepieces. They can crack during observations caused by excessive heat. For those without filters, use the projection technique to telescopically project the image of the Sun onto a sheet of paper or a white metal plate behind the eyepiece. Avoid keeping telescopes pointed at the Sun for extended periods during projection. Some optical components may heat excessively if trained on the Sun for prolonged periods. This does not apply to telescopes fitted with full-apeture filters that fully cover the front end of the telescope.

As active Regions 8673 and 8674 approach the southwest solar limb in another 5 to 6 days, observers may witness periods of interesting limb activity, including loop prominence systems following flare activity, bright limb surging and mass ejections.

Observers should keep a close eye on solar x-ray activity, particularly while performing observations to correlate observations with x-ray activity, by referring to the Space Environment Centers x-ray plots at: http://www.sec.noaa.gov/rt_plots/xray_1m.cgi. For serious observers, a sophisticated software package for Windows 95/98/NT4.0/2000 is also available to aid in monitoring solar and space weather conditions at: http://solar.uleth.ca/www/swarm.html.

-- Rickjohn (rickjohn1@yahoo.com), August 28, 1999

Answers

So?

-- R.L. (trubeliever@webtv.net), August 28, 1999.

Official Space Weather Advisory issued by NOAA Space Environment Center

Boulder, Colorado, USA

SPACE WEATHER BULLETIN #99- 6

1999 August 27 at 01:46 p.m. MDT (1999 August 27 1946 UT)

**** MAJOR SOLAR FLARE ****

A major solar flare occurred today, August 27, at 7:07 a.m. MDT (1307 UT). This activity originated from a large active region complex currently positioned near the center of the solar disk. This event was the largest of a number of sizeable x-ray flares from this area in the past 24 hours.

This group continues to grow and change, and more substantial x-ray flare activity is likely. In addition, a significant mass ejection may occur from this site, and, if it erupts, could cause a geomagnetic storm at some point during the next week.

Solar flares are known to affect communications and navigation systems operating on the dayside of the Earth. Electrical power grids and satellite operations can be impacted during large geomagnetic storms.

Data used to provide space weather services are contributed by NOAA, USAF, NASA, NSF, USGS, the International Space Environment Services and other observatories, universities, and institutions. More information is available at SEC's Web site http://sec.noaa.gov or (303) 497-5127. The NOAA Public Affairs contact is Barbara McGehan at bmcgehan@erl.noaa.gov or (303) 497-6286.

-- mabel (mabel_louise@yahoo.com), August 28, 1999.

Any further updates on this?

-- Moore Dinty moore (not@thistime.com), August 28, 1999.

Yes, and this is significant in scope, in that the X class flare just

reported has happened within the highest flux recorded in Solar Cycle

23. The numbers are increasing so rapidly, I have seen two records

set in a matter of hours. Also an update to *high probability* for

Coronal holes has occurred since I opened the net two hours ago!

This in addition to the already high probability of M or X class flares. Because of the position of the regions producing these readings, the probability of geoeffective storming becomes a certainty, but the resulting effects are not threatening, yet!

-- Michael (mikeymac@uswest.net), August 29, 1999.

Michael,

Could you please say that in lingo I understand...I get the idea...getting hot out there..but what are the time parameters you are discussing???

-- Moore Dinty moore (not@thistime.com), August 29, 1999.

Effects from a coronal hole could reach earth within 5 days. Material from a CME is likely to impact earth within 96 hours. There is a possibility of either M or X class flares to reach earth within the next 48 hours.

-- bardou (bardou@baloney.com), August 29, 1999.