Viewing archive of Wednesday, 7 April 1999

Solar activity report

Report of Solar-Geophysical Activity 1999 Apr 07 2200 UTC
Prepared 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 1999

IA. 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 FROM 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 M25%25%25%
Class X05%05%05%
Proton05%05%05%
PCAFGREEN
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
Active30%25%15%
Minor storm20%15%05%
Major-severe storm10%05%01%
B. High Latitudes
Active30%25%15%
Minor storm20%15%05%
Major-severe storm10%10%05%

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