Viewing archive of Wednesday, 20 October 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 Oct 20 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 293 Issued at 2200Z on 20 OCT 1999IA. Analysis of Solar Active Regions and Activity from 19-2100Z to 20-2100Z SOLAR ACTIVITY WAS MODERATE. REGION 8731 (N14W55)
PRODUCED AN M1/1F FLARE AT 20/0622Z ACCOMPANIED BY A TYPE II SWEEP.
THIS REGION CONTINUES TO SLOWLY DECAY AS IT APPROACHES THE WEST
LIMB. REGION 8732 (N22W64) HAS STABILIZED SINCE PRODUCING A C8/SF
LATE LAST PERIOD AND A C7/1F AT 19/2204Z. NEW REGIONS 8738 (N16E28)
AND 8739 (S13E81) WERE NUMBERED TODAY:
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW
TO MODERATE. REGIONS 8731 AND 8732 ARE IN DECAY BUT POSSESS
POTENTIAL FOR AN ISOLATED M-CLASS EVENT.
IIA. Geophysical Activity Summary 19-2100Z to 20-2100Z
THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO REMAIN QUIET TO UNSETTLED FOR DAYS ONE AND TWO. ACTIVE
CONDITIONS ARE EXPECTED WITH THE RETURN OF A GEOEFFECTIVE CORONAL
HOLE BY DAY THREE.
III. Event Probabilities 21 OCT to 23 OCT
| Class M | 45% | 40% | 30% |
| Class X | 10% | 10% | 05% |
| Proton | 10% | 10% | 05% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 20 OCT 159 Predicted 21 OCT-23 OCT 165/160/150 90 Day Mean 20 OCT 159
V. Geomagnetic A Indices
OBSERVED AFR/AP 19 OCT 005/007 ESTIMATED AFR/AP 20 OCT 006/008 PREDICTED AFR/AP 21 OCT-23 OCT 010/010-010/012-015/020
VI. Geomagnetic Activity Probabilities 21 OCT to 23 OCT
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 20% | 20% | 40% |
| Minor storm | 10% | 10% | 20% |
| Major-severe storm | 01% | 01% | 10% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 25% | 25% | 50% |
| Minor storm | 15% | 15% | 30% |
| Major-severe storm | 05% | 05% | 15% |
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