Viewing archive of Sunday, 4 April 1999

Solar activity report

Report of Solar-Geophysical Activity 1999 Apr 04 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 094 Issued at 2200Z on 04 APR 1999

IA. Analysis of Solar Active Regions and Activity from 03-2100Z to 04-2100Z

SOLAR ACTIVITY WAS HIGH. REGION 8508 (N18E62) PRODUCED AN M5/1F X-RAY EVENT AT 04/0528Z. THIS EVENT HAD A 190 SFU RADIO BURST AT 2695 MHZ. ADDITIONAL DATA SHOW ACTIVITY OCCURRING AT THE SAME TIME IN NEARBY REGION 8507 (N10E44). REGION 8508 ALSO PRODUCED AN M4/1F EVENT EARLIER DURING THE PERIOD WITH AN ASSOCIATED TYPE II SWEEP AND A SPEED OF 500 KM/S AT 03/2310Z. REGIONS 8504 (S28W03), 8506, (S26W15), 8507, AND 8508 ALL SHOWED MINOR TO MODERATE GROWTH. ALL OF THESE REGIONS HAVE EXHIBITED NEAR CONTINUOUS SURGING AND BRIGHTENING.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE MODERATE TO HIGH. SEVERAL REGIONS ARE NOW CAPABLE OF CONTINUED M-CLASS EVENT PRODUCTION. REGION 8506 APPEARS THE MOST POTENT WITH AN INCREASE IN THE NUMBER OF SPOTS AND MAGNETIC COMPLEXITY. IIA. GEOPHYSICAL ACTIVITY SUMMARY FROM 03/2100Z TO 04/2100Z: THE GEOMAGNETIC FIELD RANGED FROM QUIET TO ACTIVE. THE GREATER THAN 2 MEV ENERGETIC ELECTRONS AT GEOSYNCHRONOUS ORBIT REACHED HIGH LEVELS AT 04/1420Z THEN DECREASED TO MODERATE LEVELS AFTER 04/1800Z.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS EXPECTED TO BE QUIET TO UNSETTLED. ISOLATED ACTIVE TO MINOR STORM LEVELS ARE POSSIBLE DURING THE FIRST DAY OF THE PERIOD DUE TO AN ELONGATED CORONAL HOLE IN THE SOLAR SOUTHWEST QUADRANT.
III. Event Probabilities 05 APR to 07 APR
Class M 50%50%50%
Class X 05%05%05%
Proton05%05%05%
PCAFGREEN
IV. Penticton 10.7 cm Flux
  Observed       04 APR 116
  Predicted    05 APR-07 APR  125/135/140
  90 Day Mean        04 APR   134
V. Geomagnetic A Indices
OBSERVED AFR/AP 03 APR  012/008
ESTIMATED AFR/AP 04 APR  014/012
PREDICTED AFR/AP 05 APR-07 APR  012/015-012/010-012/010
VI. Geomagnetic Activity Probabilities 05 APR to 07 APR
A. Middle Latitudes
Active30%30%25%
Minor storm 10%10%05%
Major-severe storm 01%01%01%
B. High Latitudes
Active35%35%30%
Minor storm 15%15%10%
Major-severe storm 01%01%02%

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