Viewing archive of Wednesday, 28 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 28 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 118 Issued at 2200Z on 28 APR 1999IA. Analysis of Solar Active Regions and Activity from 27-2100Z to 28-2100Z SOLAR ACTIVITY WAS LOW DUE TO A C3 X-RAY FLARE AT
28/2032UT. NO OPTICAL FLARE REPORTS CORRELATED TO THIS C-FLARE WERE
RECEIVED. REGION 8524 (N22W02) CONTINUED TO GROW BUT APPEARS TO BE
MATURING AS A MODERATE-SIZED E-TYPE GROUP. OTHER DISK REGIONS HAVE
CHANGED LITTLE.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW.
C-CLASS ACTIVITY IS POSSIBLE IN REGIONS 8523 (N32W09) AND 8524
(N22W02).
IIA. Geophysical Activity Summary 27-2100Z to 28-2100Z
THE GEOMAGNETIC FIELD WAS QUIET TO ACTIVE. MOST ACTIVITY OCCURRED
DURING THE 06-12UT PERIODS.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO BE QUIET TO UNSETTLED. ISOLATED ACTIVE PERIODS ARE
POSSIBLE. ACTIVITY LEVELS MAY INCREASE BY THE END OF THE FORECAST
PERIOD DUE TO CORONAL HOLE EFFECTS.
III. Event Probabilities 29 APR to 01 MAY
| Class M | 05% | 05% | 05% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 28 APR 110 Predicted 29 APR-01 MAY 110/110/115 90 Day Mean 28 APR 128
V. Geomagnetic A Indices
OBSERVED AFR/AP 27 APR 009/014 ESTIMATED AFR/AP 28 APR 012/018 PREDICTED AFR/AP 29 APR-01 MAY 010/025-015/025-015/030
VI. Geomagnetic Activity Probabilities 29 APR to 01 MAY
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 15% | 15% | 15% |
| Minor storm | 10% | 10% | 10% |
| Major-severe storm | 05% | 05% | 05% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 15% | 15% | 15% |
| Minor storm | 10% | 10% | 10% |
| Major-severe storm | 05% | 05% | 05% |
All times in UTC
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