Another flare headed our way... Event #49 - 28 October 2003 Issued: 16:30 UTC, 28 October 2003 SOURCE EVENT Class X17.2 Flare in Region 486 at 11:10 UTC on 28 October 2003 Type II: 1250 km/sec Estimated LASCO-derived Plane of Sky Velocity: 2125 km/sec ESTIMATED TIME OF ARRIVAL OF SHOCK AT EARTH Estimated Impact Window: 00:00 UTC on 29 October to 21:00 UTC on 29 October Preferred Predicted Impact Time: 08:00 UTC, 29 October 2003 (3 am EST on 29 October) Estimated Shock Strength (0=Weakest, 9=Strongest): 9 Predicted Behavior of IMF at Shock Impact At Shock Impact, the Interplanetary Magnetic Field is predicted to initially turn: SOUTHWARD IMPORTANT TIME OF ARRIVAL NOTICE FOR NORTH AMERICANS The preferred time of arrival is ***TONIGHT***, TUESDAY NIGHT (before you go to bed that night) near or after 3 am Eastern Standard Time). That's 2 am Central Standard Time on TONIGHT. That's 1 am Mountain Standard Time on TONIGHT. That's MIDNIGHT Pacific Standard Time on TONIGHT. EXPECT RESIDUAL ACTIVITY (LESS INTENSE) TOMMORROW NIGHT (WEDNESDAY, 29 OCT) AS WELL ! EVENT #49 NOTES: This is the most energetic Earthward-directed event of the solar cycle. SEVERE to MAJOR geomagnetic storming is expected to abruptly commence following the arrival of the shock front from this flare. This flare was associated with a Ground-Level Event. It was also associated with very high energy protons at greater than 100 MeV (which are still climbing, over 5 hours after the event began). A magnetic crochet was observed over the daylit sections of the ionosphere. An exceptionally intense shortwave fadeout and polar cap absorption event are in progress. There are reports this event was observed in white-light. Intense radio bursts were associated with this event across the spectrum. The type II shock velocity is not representative of the observed velocity of this CME. The observed velocity as determined by SOHO was 2125 km/sec. This event has the potential to produce the strongest geomagnetic storm since 1989. Auroral activity could become visible into the deep low latitude regions. This one is worth driving a good long distance over to find clear skies. It has better potential to produce low-latitude aurora than almost any other event observed in the past decade. Keep in mind that it is also possible the disturbance may not be nearly as geoeffective as many would like. It all depends on the character of the magnetic fields imbedded within the coronal mass ejection. However, we believe it will either be very large, or only modestly large in terms of its capacity to produce disturbed geomagnetic and auroral activity. We do not expect this disturbance to be small. These predictions may be based on preliminary data and may be revised without warning. The predictions should not be used as a definitive indication of CME impact times or strengths and may frequently be in error. The proprietary methods used to estimate shock impact times are under continual development. Caution is advised.