Viewing archive of Friday, 27 April 2001
Solar activity report
Any mentioned solar flare in this report has a scaling factor applied by the Space Weather Prediction Center (SWPC). Because of the SWPC scaling factor, solar flares are reported as 42% smaller than for the science quality data. The scaling factor has been removed from our archived solar flare data to reflect the true physical units.
Report of Solar-Geophysical Activity 2001 Apr 27 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 117 Issued at 2200Z on 27 Apr 2001IA. Analysis of Solar Active Regions and Activity from 26-2100Z to 27-2100Z
Solar activity was moderate. Region 9433 (N18W39)
produced an M1/1f flare at 27/1915 UTC along with isolated C-class
subflares. Region 9433 began to gradually decay following
yesterday's M7/2b flare with decreased spot count and penumbral
coverage. However, a magnetic delta configuration persisted in the
trailer portion of the region, where most flare activity has
occurred. Region 9441 (N08E38) produced isolated subflares as it
gradually increased in spot count and penumbral coverage, though it
remained a moderate-sized, simply-structured spot group. New Region
9443 (S10E21), a small simple bipole, was numbered.
IB. Solar Activity Forecast
Activity is expected to be at moderate
to high levels. Region 9433 is expected to produce mostly low-level
M-class flares. However, it may produce an isolated major flare
during the period.
IIA. Geophysical Activity Summary 26-2100Z to 27-2100Z
Geomagnetic field activity was at quiet to unsettled levels. The
greater than 10 MeV electron flux became enhanced following
yesterdays M7/2b flare, but did not reach event levels.
IIB. Geophysical Activity Forecast
A geomagnetic disturbance is
expected to commence during the latter half of 28 April and continue
into 29 April following yesterday's M7/2b flare and associated
full-halo CME . Active to major storm levels will be possible during
this disturbance. Mostly unsettled levels are expected during 30
April. The greater than 10 MeV proton flux could increase to event
levels on 28 April. Region 9433 may produce a proton flare during
the period.
III. Event Probabilities 28 Apr to 30 Apr
| Class M | 75% | 75% | 75% |
| Class X | 20% | 20% | 20% |
| Proton | 20% | 20% | 20% |
| PCAF | yellow | ||
IV. Penticton 10.7 cm Flux
Observed 27 Apr 191 Predicted 28 Apr-30 Apr 185/180/175 90 Day Mean 27 Apr 167
V. Geomagnetic A Indices
Observed Afr/Ap 26 Apr 008/007 Estimated Afr/Ap 27 Apr 005/008 Predicted Afr/Ap 28 Apr-30 Apr 015/010-040/040-012/020
VI. Geomagnetic Activity Probabilities 28 Apr to 30 Apr
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 25% | 30% | 40% |
| Minor storm | 20% | 35% | 20% |
| Major-severe storm | 05% | 10% | 05% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 30% | 25% | 45% |
| Minor storm | 25% | 40% | 25% |
| Major-severe storm | 10% | 15% | 10% |
All times in UTC
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