NOAA SEC Weekly Highlights and Forecasts 22 Feb 2002

Highlights of Solar and Geomagnetic Activity

11 – 17 February 2002

Solar activity was low through the period with isolated to occasional
C-class flares. Sunspot groups of interest included Regions 9825
(N13, L = 206, Fkc/500 on 14 February) and 9830 (S20, L = 135,
Fai/360 on 17 February). Region 9825 produced isolated C-class
flares as it gradually developed during the first half of the
period, then gradually decayed during the second half of the period
(for flare details, please refer to the Optical Flares list) .
Region 9830 produced C-class flares as it gradually increased in
size and complexity during the latter half of the period. By the
close of the period, Region 9830 had become large and magnetically
complex as multiple delta magnetic configurations developed within
its leader spots. One event of note was a partial-halo CME from the
southwest quadrant early on 14 February.

Solar wind data were available from the NASA Advanced Compositions
Explorer (ACE) spacecraft for most of the period. A high-speed
stream associated with a coronal hole was observed during 11 – 13
February. Wind speeds increased to as high as 620 km/sec during 11 –
12 February. This stream subsided by midday on 13 February. A weak
CME passage occurred on 17 February. The passage began at
approximately 17/0210 UTC followed by increased velocities (peaks to
460 km/sec), densities, and a few brief intervals of southward IMF
Bz (maximum deflections to minus 11 nT (GSM)). CME effects began to
subside during the latter half of 17 February.

There were no proton events at geosynchronous orbit during the
period.

The greater than 2 MeV electron flux at geosynchronous orbit was at
normal to moderate levels.

Geomagnetic field activity was at quiet to unsettled levels during
most of the period. However, isolated active conditions occurred on
11 and 17 February. The 11 February activity was due to a high-speed
stream associated with a coronal hole. The 17 February activity was
preceded by a sudden impulse at 17/0257 UTC (13 nT, as measured by
the Boulder USGS magnetometer) and was due to a weak CME passage,
likely associated with the partial-halo observed early on 14
February.

Forecast of Solar and Geomagnetic Activity
20 February – 18 March 2002

Solar activity is expected to be at low to moderate levels. Isolated
low-level M-class flares are likely during the period. Region 9830
could produce a major flare before it crosses the west limb on 27
February.

There is a slight chance for a proton event through the end of
February.

The greater than 2 MeV electron flux at geosynchronous orbit is
expected to be at normal to moderate levels during most of the
period. However, high flux levels are possible during 06 – 08 March.

Geomagnetic field activity is expected to increase to unsettled to
active levels during 04 – 06 March due to recurrent coronal hole
effects. Quiet to unsettled levels are expected for the rest of the
period.