Viewing archive of Thursday, 23 April 1998
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 1998 Apr 23 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 113 Issued at 2200Z on 23 APR 1998IA. Analysis of Solar Active Regions and Activity from 22-2100Z to 23-2100Z SOLAR ACTIVITY WAS HIGH. AN OPTICALLY UNCORRELATED X1
X-RAY BURST WAS DETECTED AT 23/0555Z. THIS ACTIVITY WAS ASSOCIATED
WITH A LARGE CORONAL MASS EJECTED OFF THE SE-NE LIMB NOTED BY
SPACE-BASED SENSORS. FURTHER ANALYSIS INDICATED THE FOOT POINTS OF
THE EJECTION APPEARED TO BE LOCATED NEAR RETURNING REGIONS 8190
(S21,L144) AND 8196 (N18,L144). BOTH REGIONS ARE LESS THAN A DAY
BEHIND THE EAST LIMB. THE X-RAY BURST WAS ACCOMPANIED BY A 10.7CM
RADIO BURST OF 430 SFU, MAKING IT A TENFLARE, AND A TYPE IV SWEEP.
POST FLARE LOOPS WERE OBSERVED AS WELL. NEW SWO REGION 8209
(S22W06), A SMALL AXX GROUP, WAS NUMBERED TODAY.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW
TO MODERATE. AN INCREASE IN ACTIVITY IS EXPECTED WITH THE RETURN OF
REGION 8190, ESPECIALLY IN LIGHT OF TODAY'S ACTIVITY.
IIA. Geophysical Activity Summary 22-2100Z to 23-2100Z
THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED. A SHOCK WAS NOTED ON
ALL INSTRUMENTS AT ABOUT 23/1800Z, INDICATED BY AN INCREASE IN SOLAR
WIND DENSITY AND SPEED, AN INCREASE IN PARTICLES DETECTED ON ACE AND
GOES, AND A SMALL IMPULSE NOTED EARTH-BASED AND GEOSYNCHRONOUS
MAGNETOMETERS. THE GREATER THAN 10 MEV PROTON EVENT IS STILL IN
PROGRESS. THE EVENT CONTINUES TO DIMINISH AND IS CURRENTLY AT 30
PFU.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO BE MOSTLY UNSETTLED FOR THE NEXT 24 HOURS AT MID
LATITUDES AND UNSETTLED TO ACTIVE FOR THE NEXT 48 HOURS AT HIGH
LATITUDES. THEREAFTER, THE FIELD IS EXPECTED TO BE QUIET TO
UNSETTLED.
III. Event Probabilities 24 APR to 26 APR
| Class M | 15% | 15% | 15% |
| Class X | 10% | 10% | 10% |
| Proton | 05% | 05% | 05% |
| PCAF | IN PROGRESS | ||
IV. Penticton 10.7 cm Flux
Observed 23 APR 090 Predicted 24 APR-26 APR 092/094/094 90 Day Mean 23 APR 104
V. Geomagnetic A Indices
OBSERVED AFR/AP 22 APR 005/006 ESTIMATED AFR/AP 23 APR 009/015 PREDICTED AFR/AP 24 APR-26 APR 015/020-010/015-010/012
VI. Geomagnetic Activity Probabilities 24 APR to 26 APR
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 20% | 15% | 10% |
| Minor storm | 10% | 05% | 05% |
| Major-severe storm | 05% | 05% | 05% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 20% | 15% | 10% |
| Minor storm | 15% | 10% | 10% |
| Major-severe storm | 05% | 05% | 05% |
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