Viewing archive of Saturday, 23 April 2005
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 2005 Apr 23 2210 UTC# Prepared jointly by the U.S. Dept. of Commerce, NOAA, #Space Environment Center and the U.S. Air Force. #
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 113 Issued at 2200Z on 23 Apr 2005IA. Analysis of Solar Active Regions and Activity from 22-2100Z to 23-2100Z Solar activity continues at very low levels. There are
just a couple of very small and simple sunspot groups on the visible
disk. Occasional bright surges were observed on the southeast limb
late in the period. The associated active region is expected to
rotate into view on 24 April. No other activity of note was
observed.
IB. Solar Activity Forecast
Solar activity is expected to be very
low to low. A new region rotating on the east limb near S05 may
slightly elevate activity levels over the next three days.
IIA. Geophysical Activity Summary 22-2100Z to 23-2100Z
The geomagnetic field was quiet to unsettled with isolated active
conditions late in the period. A coronal hole high speed stream has
rotated into a geoeffective position. Solar wind speed gradually
increased to near 600 km/s. The IMF Bz was generally northward, but
occasional brief southward excursions occurred late in the period.
IIB. Geophysical Activity Forecast
The geomagnetic field is
expected to be quiet to unsettled with isolated active periods on 24
and 25 April. Predominantly quiet levels with isolated unsettled
periods are expected on 26 April as the high speed stream rotates
out of a geoeffective position.
III. Event Probabilities 24 Apr to 26 Apr
| Class M | 01% | 01% | 01% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | green | ||
IV. Penticton 10.7 cm Flux
Observed 23 Apr 079 Predicted 24 Apr-26 Apr 080/085/085 90 Day Mean 23 Apr 090
V. Geomagnetic A Indices
Observed Afr/Ap 22 Apr 007/009 Estimated Afr/Ap 23 Apr 008/015 Predicted Afr/Ap 24 Apr-26 Apr 010/020-008/010-005/008
VI. Geomagnetic Activity Probabilities 24 Apr to 26 Apr
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 30% | 25% | 15% |
| Minor storm | 15% | 10% | 05% |
| Major-severe storm | 05% | 05% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 40% | 35% | 20% |
| Minor storm | 20% | 15% | 05% |
| Major-severe storm | 10% | 05% | 01% |
All times in UTC
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