:Product: Weekly Highlights and Forecasts :Issued: 2002 Jul 23 2212 UTC # Prepared by the US Dept. of Commerce, NOAA, Space Environment Center # Product description and SEC contact on the Web # http://www.sec.noaa.gov/weekly.html # # Weekly Highlights and Forecasts # Highlights of Solar and Geomagnetic Activity 15 - 21 July 2002 Solar activity alternated between low and high levels during the period. Major solar flares occurred on 15, 17, 18, and 20 July from two active regions: Region 30 (N19, L = 012, class/area Fkc/1350 on 16 July) and Region 39 (S12, L = 212, class/area Dac/330 on 22 July). Region 30 produced an X3/3b flare at 15/2008 UTC, an M8/1b at 17/0713 UTC, and an X1/2b at 18/0744 UTC, all of which were associated with Earth-directed coronal mass ejections (CME). Region 30 entered a decay phase on 16 July, though it remained large and magnetically complex with multiple delta magnetic configurations. It rotated out of view on the day of this report. Region 39, which rotated into view on 22 July, was the likely source for an X3 X-ray flare at 20/2130 UTC from beyond the southeast limb. It was also the likely source for multiple far side CME activity observed during the period. On the day of this report, Region 39 produced an X4 X-ray flare associated with a halo CME, which will be summarized in next week’s report. Region 30 was still too close to the limb for a detailed analysis, but appeared to be very large and magnetically complex. Solar wind data were available from the NASA Advanced Composition Explorer (ACE) spacecraft for most of the summary period. A weak high-speed solar wind stream associated with a positive-polarity coronal hole was observed during 15 – 16 July with peak velocities to around 440 km/sec. CME passages occurred during 17 – 18 July and 19 – 21 July following major flare activity from Region 30. The 17 – 18 July passage was relatively weak. It began about 17/1520 UTC and was associated with peak velocities of about 500 km/sec and brief periods of southward IMF Bz with maximum deflections to minus 16 nT (GSM). Multiple CME passages occurred during 19 – 21 July with velocities as high as 920 km/sec detected on 19 and 20 July. IMF Bz was mostly southward from late on 19 July through 21 July with maximum deflections to minus 10 nT (GSM). A greater than 10 MeV proton event began at 16/1750 UTC following the X3/3b flare on 15 July. This event peaked at 234 pfu at 17/1600 UTC, and ended at 18/1550 UTC. Another greater than 10 MeV event began at 19/1050 UTC, reached a peak of 13 pfu at 19/1515 UTC, then ended at 19/1535 UTC. Greater than 10 MeV fluxes remained enhanced and began to gradually increase on 21 July following the X3 flare of 20 July. Greater than 2 MeV electron fluxes at geo-synchronous orbit were at normal to moderate levels through 20 July, then increased to normal to high levels on 21 July. Geomagnetic field activity was at quiet to active levels during 15 – 16 July due to weak coronal hole effects. Quiet to active conditions occurred on 17 July due to a CME passage. Field activity ranged from quiet to minor storm levels during 19 – 21 July due to multiple CME passages. Forecast of Solar and Geomagnetic Activity 24 July - 19 August 2002 Solar activity is expected to range from low to high levels. Isolated low-level M-class flares are expected throughout the period. Region 39 is likely to produce isolated major flares before it rotates out of view on 04 August. Proton events will be possible until Region 39 rotates out of view on 04 August. There will also be a chance for a proton event during the rest of the period with the return of old Region 30 on 06 August. Greater than 2 MeV electron fluxes at geo-synchronous orbit are expected to be at normal to moderate levels for most of the period. Geomagnetic field activity is expected to be at unsettled to minor storm levels during 24 – 26 July due to a CME passage. Active conditions will be possible during 03, 06, and 09 August due to coronal hole effects. Quiet to unsettled conditions are expected for the remainder of the period. .