Viewing archive of Thursday, 21 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 21 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 111 Issued at 2200Z on 21 Apr 2005IA. Analysis of Solar Active Regions and Activity from 20-2100Z to 21-2100Z Solar activity was very low. Regions 752 (N03W55) and
755 (S12E21) continue to decay. X-ray flux background is down to
approximately A2 level. No new regions were numbered today.
IB. Solar Activity Forecast
Solar activity is expected to be very
low.
IIA. Geophysical Activity Summary 20-2100Z to 21-2100Z
The geomagnetic field was quiet to unsettled.
IIB. Geophysical Activity Forecast
The geomagnetic field is
expected to be quiet to unsettled early on 22 April. A geoeffective
coronal hole high speed stream is expected to increase conditions
later in the day. Unsettled to active with minor storm periods are
possible late on 22 April continuing into early 23 April.
Conditions are expected to settle down on 24 April to mostly quiet
to unsettled.
III. Event Probabilities 22 Apr to 24 Apr
| Class M | 01% | 01% | 01% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | green | ||
IV. Penticton 10.7 cm Flux
Observed 21 Apr 077 Predicted 22 Apr-24 Apr 080/080/080 90 Day Mean 21 Apr 091
V. Geomagnetic A Indices
Observed Afr/Ap 20 Apr 012/021 Estimated Afr/Ap 21 Apr 005/010 Predicted Afr/Ap 22 Apr-24 Apr 015/020-012/020-008/015
VI. Geomagnetic Activity Probabilities 22 Apr to 24 Apr
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 30% | 30% | 20% |
| Minor storm | 15% | 15% | 10% |
| Major-severe storm | 05% | 05% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 40% | 40% | 30% |
| Minor storm | 15% | 15% | 15% |
| Major-severe storm | 10% | 10% | 05% |
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