Solar activity report

Viewing archive of Friday, 30 April 1999

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 30 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 120 Issued at 2200Z on 30 APR 1999

IA. Analysis of Solar Active Regions and Activity from 29-2100Z to 30-2100Z

SOLAR ACTIVITY WAS LOW. CONTINUING DEVELOPMENT IN REGION 8524 (N21W28) RESULTED IN ITS MERGER WITH NEARBY REGION 8522, FORMING ONE LARGE BIPOLE. REGION 8524 PRODUCED A NUMBER OF C-CLASS EVENTS, THE LARGEST BEING A C8/1F FLARE AT 1221Z. ONE NEW REGION, 8527 (N27E68), ROTATED FULLY INTO VIEW NEAR EAST LIMB, WHERE ANOTHER REGION MAY BE SOON TO APPEAR NEAR S10. REGION 8525 (N16E59), ALTHOUGH QUIET, HAS PATCHES OF BRIGHT PLAGE.

IB. Solar Activity Forecast

SOLAR ACTIVITY IS EXPECTED TO BE LOW TO MODERATE. REGION 8524 IS THE MOST PROMISING SITE OF M-CLASS ACTIVITY. REGION 8525 MAY ALSO CONTRIBUTE SHOULD FURTHER DEVELOPMENT OCCUR.

IIA. Geophysical Activity Summary 29-2100Z to 30-2100Z

THE GEOMAGNETIC FIELD WAS GENERALLY ACTIVE. A HIGH SPEED SOLAR WIND STREAM, AT TIMES REACHING MORE THAN 650 KM/S AT THE ACE SPACECRAFT, DROVE THE FIELD TO EPISODES OF MINOR STORM ACTIVITY DURING THE PERIOD. THE GREATER THAN 2 MEV ELECTRON FLUX AT GEOSYNCHRONOUS ORBIT ATTAINED HIGH LEVELS FROM ABOUT 1300 TO 2100Z.

IIB. Geophysical Activity Forecast

THE GEOMAGNETIC FIELD IS EXPECTED TO BE AT ACTIVE TO MINOR STORM LEVELS FOR THE NEXT THREE DAYS. THE HIGH SPEED STREAM SHOULD ABATE BY THE LATTER PART OF THE PERIOD. A CME, RELATED TO YESTERDAY'S M1 EVENT, MAY IMPACT THE FIELD AT THE END OF THE FORECAST INTERVAL.

III. Event Probabilities 01 MAY to 03 MAY

Class M	30%	30%	30%
Class X	05%	05%	05%
Proton	05%	05%	05%
PCAF	GREEN

IV. Penticton 10.7 cm Flux

  Observed       30 APR 124
  Predicted   01 MAY-03 MAY  130/135/140
  90 Day Mean        30 APR 128

V. Geomagnetic A Indices

OBSERVED AFR/AP 29 APR  018/019
ESTIMATED AFR/AP 30 APR  023/025
PREDICTED AFR/AP 01 MAY-03 MAY  015/030-015/030-015/025

VI. Geomagnetic Activity Probabilities 01 MAY to 03 MAY

A. Middle Latitudes
Active	30%	30%	30%
Minor storm	10%	10%	10%
Major-severe storm	01%	01%	01%

B. High Latitudes
Active	40%	40%	40%
Minor storm	15%	15%	15%
Major-severe storm	01%	01%	01%

All times in UTC

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G1 - Minor geomagnetic storm

Observed Kp: 5
Threshold reached: 22:46 UTC

The solar wind speed is currently moderately high (581.6 km/sec.)

The strength of the interplanetary magnetic field is moderate (18.2nT), the direction is slightly South (-3.85nT).

The Disturbance Storm Time index predicts moderate storm conditions right now (-52nT)

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