Viewing archive of Tuesday, 25 May 1999

Solar activity report

Report of Solar-Geophysical Activity 1999 May 25 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 145 Issued at 2200Z on 25 MAY 1999

IA. Analysis of Solar Active Regions and Activity from 24-2100Z to 25-2100Z

SOLAR ACTIVITY WAS LOW. THE PERIOD WAS CHARACTERIZED BY A NUMBER OF VERY WEAK C-CLASS X-RAY AND OPTICAL FLARES. TWO REGIONS WERE NUMBERED TODAY. THE FIRST, REGION 8553 (N25W02) , BEGAN THE PERIOD AS A SOUTHWEST EXTENSION TO REGION 8551 (N32E10). THE SECOND, REGION 8554 (N27E39), FORMED OVERNIGHT.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO REMAIN LOW WITH A SLIGHT CHANCE FOR AN ISOLATED M-CLASS X-RAY FLARE. IIA. GEOPHYSICAL ACTIVITY SUMMARY FROM 24/2100Z TO 25/2100Z: THE GEOMAGNETIC FIELD RANGED FROM QUIET TO MINOR STORM LEVELS. THE MOST ACTIVE CONDITIONS WERE SEEN OVERNIGHT AND IN THE EARLY MORNING HOURS. THESE CONDITIONS WERE DUE TO THE EFFECT OF A SMALL CORONAL HOLE AS WELL AS THE IMPACT OF A TRANSIENT FEATURE THAT BROUGHT A SUSTAINED PERIOD OF SOUTHWARD BZ.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS EXPECTED TO BE QUIET TO UNSETTLED. AS THE EFFECT OF THE CURRENT CORONAL HOLE DIMINISHES, ANOTHER RECURRENT HOLE IS EXPECTED BY THE SECOND DAY OF THE FORECAST PERIOD.
III. Event Probabilities 26 MAY to 28 MAY
Class M 30%30%30%
Class X 01%01%01%
Proton01%01%01%
PCAFGREEN
IV. Penticton 10.7 cm Flux
  Observed       25 MAY 143
  Predicted    26 MAY-28 MAY  145/145/150
  90 Day Mean        25 MAY 129
V. Geomagnetic A Indices
OBSERVED AFR/AP 24 MAY  011/011
ESTIMATED AFR/AP 25 MAY  015/019
PREDICTED AFR/AP 26 MAY-28 MAY  012/012-010/010-010/010
VI. Geomagnetic Activity Probabilities 26 MAY to 28 MAY
A. Middle Latitudes
Active20%20%20%
Minor storm 05%05%05%
Major-severe storm 01%01%01%
B. High Latitudes
Active25%25%25%
Minor storm 05%05%05%
Major-severe storm 01%01%01%

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