Viewing archive of Monday, 19 April 1999

Solar activity report

Report of Solar-Geophysical Activity 1999 Apr 19 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 109 Issued at 2200Z on 19 APR 1999

IA. Analysis of Solar Active Regions and Activity from 18-2100Z to 19-2100Z

SOLAR ACTIVITY REMAINED AT VERY LOW LEVELS. MINOR GROWTH OCCURRED IN REGIONS 8517 (N22W63) AND 8518 (S14E40), BOTH OF WHICH PRODUCED ISOLATED SUBFLARES. THE REMAINING REGIONS WERE EITHER STABLE OR DECLINING. NEW REGIONS 8520 (N20E12) AND 8521 (N34W07) WERE NUMBERED.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE VERY LOW TO LOW. REGIONS 8517 AND 8518 MAY PRODUCE C-CLASS FLARES. IIA. GEOPHYSICAL ACTIVITY SUMMARY FROM 18/2100Z TO 19/2100Z: GEOMAGNETIC FIELD ACTIVITY RANGED FROM QUIET TO ACTIVE LEVELS DURING THE PERIOD. ACTIVE LEVELS WERE DETECTED AT ALL LATITUDES DURING 19/0900 - 1000Z. QUIET TO UNSETTLED LEVELS OCCURRED DURING THE REMAINING HOURS.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS EXPECTED TO BE AT UNSETTLED TO MINOR STORM LEVELS DURING THE FIRST TWO DAYS IN RESPONSE TO A PARTIAL-HALO CME OBSERVED ON 17 APRIL. FIELD ACTIVITY IS EXPECTED TO DECLINE TO QUIET TO UNSETTLED LEVELS ON THE FINAL DAY.
III. Event Probabilities 20 APR to 22 APR
Class M10%10%10%
Class X01%01%01%
Proton01%01%01%
PCAFGREEN
IV. Penticton 10.7 cm Flux
  Observed       19 APR 110
  Predicted   20 APR-22 APR  110/110/105
  90 Day Mean        19 APR 133
V. Geomagnetic A Indices
OBSERVED AFR/AP 18 APR  005/006
ESTIMATED AFR/AP 19 APR  008/008
PREDICTED AFR/AP 20 APR-22 APR  020/014-020/030-010/015
VI. Geomagnetic Activity Probabilities 20 APR to 22 APR
A. Middle Latitudes
Active40%40%25%
Minor storm20%20%10%
Major-severe storm05%05%01%
B. High Latitudes
Active45%45%30%
Minor storm25%25%15%
Major-severe storm05%05%01%

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