Viewing archive of Tuesday, 27 April 1999
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 1999 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 1999IA. Analysis of Solar Active Regions and Activity from 26-2100Z to 27-2100Z SOLAR ACTIVITY WAS LOW DUE TO A C1/SF FLARE AT
27/2026UT IN REGION 8524 (N22E10). GROWTH IN THIS REGION APPEARS TO
BE STABILIZING. REGION 8523 (N32E04) HAS ALSO GROWN SINCE YESTERDAY
BUT HAS NOT PRODUCED ANY SIGNIFICANT FLARES.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE VERY
LOW TO LOW. REGIONS 8523 AND 8524 ARE THE MOST LIKELY AREAS FOR
ISOLATED C-CLASS ACTIVITY.
IIA. Geophysical Activity Summary 26-2100Z to 27-2100Z
THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO BE QUIET TO UNSETTLED.
III. Event Probabilities 28 APR to 30 APR
| Class M | 05% | 05% | 05% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 27 APR 109 Predicted 28 APR-30 APR 110/110/110 90 Day Mean 27 APR 128
V. Geomagnetic A Indices
OBSERVED AFR/AP 26 APR 006/007 ESTIMATED AFR/AP 27 APR 010/010 PREDICTED AFR/AP 28 APR-30 APR 010/015-010/020-015/020
VI. Geomagnetic Activity Probabilities 28 APR to 30 APR
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 10% | 15% | 15% |
| Minor storm | 05% | 10% | 10% |
| Major-severe storm | 01% | 05% | 05% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 15% | 15% | 15% |
| Minor storm | 10% | 10% | 10% |
| Major-severe storm | 01% | 05% | 05% |
All times in UTC
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