Viewing archive of Wednesday, 7 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 07 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 097 Issued at 2200Z on 07 APR 1999IA. Analysis of Solar Active Regions and Activity from 06-2100Z to 07-2100Z SOLAR ACTIVITY WAS LOW. REGION 8508 (N22E25) PRODUCED A
C1/SF AT 07/0924Z. THIS REGION WAS STABLE BUT RETAINED MIXED
MAGNETIC POLARITIES. A LONG DURATION C1 EVENT OCCURRED BETWEEN
06/2335-07/0115Z. THIS EVENT WAS MOST LIKELY ASSOCIATED WITH A LARGE
CORONAL MASS EJECTION FROM THE SOUTHEAST LIMB AS SEEN IN SOHO
CORONAGRAPH DATA. REGION 8506 (S26W55) DECAYED AND SIMPLIFIED DURING
THE PERIOD.
IB. Solar Activity Forecast
SOLAR ACTIVITY SHOULD BE PREDOMINANTLY
LOW FOR THE NEXT THREE DAYS. REGION 8508 REMAINS CAPABLE OF
PRODUCING AN OCCASIONAL M-CLASS EVENT.
IIA. Geophysical Activity Summary 06-2100Z to 07-2100Z
THE GEOMAGNETIC FIELD RANGED FROM QUIET TO ACTIVE LEVELS. THE MOST
DISTURBED PERIOD WAS FROM 07/0000-0300Z. AT THAT TIME, SOLAR WIND
DATA DID NOT INDICATE A CME LIKE SIGNATURE. THIS SLIGHT DISTURBANCE
APPEARED TO BE RELATED TO A CONSISTENTLY SOUTHWARD ORIENTED
INTERPLANETARY MAGNETIC FIELD. ENERGETIC ELECTRON FLUXES AT
GEOSYNCHRONOUS ORBIT REACHED HIGH LEVELS DURING THE PERIOD.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD SHOULD
REMAIN AT QUIET TO ACTIVE LEVELS FOR 08-09 APR. A WEAK DISTURBANCE
IS EXPECTED ON 08 APR FROM MULTIPLE MASS EJECTIONS OBSERVED ON 04
APR. QUIET TO UNSETTLED CONDITIONS ARE EXPECTED ON 10 APR. THE
ENERGETIC ELECTRON ENHANCEMENT AT GEOSYNCHRONOUS ORBIT SHOULD DECAY
TO NORMAL LEVELS IN THE NEXT 1-2 DAYS.
III. Event Probabilities 08 APR to 10 APR
| Class M | 25% | 25% | 25% |
| Class X | 05% | 05% | 05% |
| Proton | 05% | 05% | 05% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 07 APR 141 Predicted 08 APR-10 APR 142/143/139 90 Day Mean 07 APR 134
V. Geomagnetic A Indices
OBSERVED AFR/AP 06 APR 006/009 ESTIMATED AFR/AP 07 APR 010/010 PREDICTED AFR/AP 08 APR-10 APR 015/012-010/012-010/010
VI. Geomagnetic Activity Probabilities 08 APR to 10 APR
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 30% | 25% | 15% |
| Minor storm | 20% | 15% | 05% |
| Major-severe storm | 10% | 05% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 30% | 25% | 15% |
| Minor storm | 20% | 15% | 05% |
| Major-severe storm | 10% | 10% | 05% |
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