Viewing archive of Wednesday, 30 September 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 Sep 30 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 273 Issued at 2200Z on 30 SEP 1998IA. Analysis of Solar Active Regions and Activity from 29-2100Z to 30-2100Z SOLAR ACTIVITY BECAME MODERATE. REGION 8340 (N19W92)
PRODUCED A LONG DURATION M2/2N FLARE AT 30/1350Z. THIS EVENT WAS
ACCOMPANIED BY STRONG TYPE II/IV SWEPT FREQUENCY EVENTS AND A 490
SFU BURST AT 2695 MHZ. MUCH MATERIAL MOTION WAS VISIBLE ALONG AND
ABOVE THE NORTHWEST LIMB IN THE FORM OF BRIGHT SURGES, ERUPTIVE
PROMINENCES, AND LOOP PROMINENCE SYSTEMS. OTHER REGIONS ON THE DISK
WERE STABLE OR SLOWLY DECAYING.
IB. Solar Activity Forecast
SOLAR ACTIVITY SHOULD BECOME VERY LOW
TO LOW AS THE REGIONS AT OR OVER THE NORTHWEST LIMB BECOME LESS
VISIBLE DUE TO SOLAR ROTATION. THERE IS A SLIGHT POSSIBILITY REGION
8340 MAY PRODUCE ANOTHER M-CLASS EVENT FROM BEHIND THE WEST LIMB
BETWEEN NOW AND 02 OCT.
IIA. Geophysical Activity Summary 29-2100Z to 30-2100Z
THE GEOMAGNETIC FIELD WAS QUIET TO SLIGHTLY UNSETTLED. THE GREATER
THAN 100 MEV PROTON FLUX CROSSED THE 1 PFU THRESHOLD AT 30/1435Z AND
REACHED A MAXIMUM OF 3 PFU DURING THE PERIOD. THE GREATER THAN 10
MEV FLUX REACHED EVENT THRESHOLD OF 10 PFU AT 30/1520Z. DURING THE
PERIOD, A MAXIMUM FLUX OF 840 PFU WAS OBSERVED. A POLAR CAP
ABSORPTION EVENT ACCOMPANIED THE PROTON EVENT. A MAXIMUM ABSORPTION
OF 4.3 DB WAS OBSERVED AT THE END OF THE PERIOD. ENERGETIC ELECTRON
FLUXES AT GEOSYNCHRONOUS ORBIT WERE AT MODERATE TO HIGH LEVELS.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
FORECAST TO BE QUIET TO UNSETTLED FOR 01-02 OCT. UNSETTLED TO
SLIGHTLY ACTIVE CONDITIONS ARE POSSIBLE ON 03 OCT. THE GREATER THAN
10 MEV PROTON EVENT IS EXPECTED TO SLOWLY DECAY OVER THE NEXT THREE
DAYS.
III. Event Probabilities 01 OCT to 03 OCT
| Class M | 20% | 20% | 05% |
| Class X | 05% | 05% | 01% |
| Proton | 10% | 10% | 01% |
| PCAF | IN PROGRESS | ||
IV. Penticton 10.7 cm Flux
Observed 30 SEP 122 Predicted 01 OCT-03 OCT 110/107/105 90 Day Mean 30 SEP 130
V. Geomagnetic A Indices
OBSERVED AFR/AP 29 SEP 006/010 ESTIMATED AFR/AP 30 SEP 004/010 PREDICTED AFR/AP 01 OCT-03 OCT 008/012-008/010-010/020
VI. Geomagnetic Activity Probabilities 01 OCT to 03 OCT
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 10% | 10% | 10% |
| Minor storm | 05% | 05% | 05% |
| Major-severe storm | 01% | 01% | 05% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 20% | 20% | 25% |
| Minor storm | 10% | 10% | 15% |
| Major-severe storm | 05% | 05% | 05% |
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