Viewing archive of Friday, 28 May 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 May 28 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 148 Issued at 2200Z on 28 MAY 1999IA. Analysis of Solar Active Regions and Activity from 27-2100Z to 28-2100Z SOLAR ACTIVITY HAS BEEN LOW. REGIONS 8558 (N14E68) AND
8559 (N21E20) WERE NUMBERED TODAY. REGION 8559 IS NOW A
LARGE ALPHA-TYPE SPOT GROUP WHICH TRAILS REGION 8552 (N21E11).
REGIONS 8558 AND 8557 (S26E60) PRODUCED C2 XRAY FLARES AT 28/0553UT
AND 28/1212UT, RESPECTIVELY. REGION 8552 CONTINUES TO GROW IN
COMPLEXITY.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW
TO MODERATE.
IIA. Geophysical Activity Summary 27-2100Z to 28-2100Z
THE GEOMAGNETIC FIELD HAS BEEN QUIET TO UNSETTLED.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO BE QUIET TO ACTIVE WITH ISOLATED PERIODS OF MINOR STORM
AT HIGH LATITUDES FOR THE FIRST DAY OF THE PERIOD DUE TO RECURRENT
CORONAL HOLE EFFECTS AND POSSIBLE CME INFLUENCE. THE SECOND AND
THIRD DAYS ARE EXPECTED TO BE QUIET TO UNSETTLED WITH ISOLATED
ACTIVE PERIODS AT HIGH LATITUDES.
III. Event Probabilities 29 MAY to 31 MAY
| Class M | 50% | 50% | 50% |
| Class X | 10% | 10% | 10% |
| Proton | 05% | 05% | 05% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 28 MAY 152 Predicted 29 MAY-31 MAY 158/163/170 90 Day Mean 28 MAY 130
V. Geomagnetic A Indices
OBSERVED AFR/AP 27 MAY 007/010 ESTIMATED AFR/AP 28 MAY 010/012 PREDICTED AFR/AP 29 MAY-31 MAY 020/025-012/020-012/010
VI. Geomagnetic Activity Probabilities 29 MAY to 31 MAY
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 50% | 35% | 20% |
| Minor storm | 20% | 10% | 05% |
| Major-severe storm | 05% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 60% | 40% | 30% |
| Minor storm | 30% | 15% | 10% |
| Major-severe storm | 10% | 05% | 01% |
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