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Major Solar Flare Alert
Major Solar Flare Alert
13 Jul 2004

SOLAR OUTLOOK: After weeks of quiet, solar activity is increasing. One big sunspot, numbered 649, is emerging over the sun's eastern limb today. Last week this 'spot blasted a coronal mass ejection (CME) in the general direction of the planet Saturn; now it's turning toward Earth.

There's another good-sized sunspot on the back side of the sun; we can "see" it using a technique called helioseismic holography:

If it persists, this 'spot will emerge over the sun's east limb, carried into view by solar rotation, on or about July 17th. Once facing Earth, the active region could direct CMEs toward our planet and spark geomagnetic storms.


ISSUED: 14:30 UTC, 13 JULY 2004


Active Region 646 was responsible for producing two major M-class solar flares during the last 15 hours. The first as a class M6.8 event at 00:17 UTC on 13 July that was followed roughly 9 hours later by a class M5.4 event at 08:48 UTC. The impetus for this activity appears to be the rapid growth of two opposite polarity centers along a sheared east-west oriented neutral line, with negative polarity flux tightly enshrouding the southern and eastern regime of the positive polarity spot. The latest magnetograms indicate some weakening of the positive polarity flux along the eastern flank of the spot group, but moderately strong shear and high gradients are still persisting along the east-west inversion line. Additional minor and/or major M-class flare events appears likely.

The M6.8 event was associated with a weak enhancement of energetic protons at greater than 10 MeV. Another more energetic proton flare cannot be discounted at this time.

New Region 649 (along the southeastern limb) also appears to have energetic flare potential. Although it is still to close to the limb to properly examine, its apparent history of strong backside activity suggests it may be capable of major M and possibly X-class activity. Thus far, it has produced two minor M-class flare events, the most recent occurring at 12:08 UTC on 13 July.

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Last Updated: 13 Jul 2004