Viewing archive of Wednesday, 22 September 1999

Solar activity report

Report of Solar-Geophysical Activity 1999 Sep 22 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 265 Issued at 2200Z on 22 SEP 1999

IA. Analysis of Solar Active Regions and Activity from 21-2100Z to 22-2100Z

SOLAR ACTIVITY WAS LOW. A C5/1F FLARE FROM REGION 8706 (N19E38) AT 1340Z WAS THE LARGEST EVENT OF THE DAY. NEWLY ASSIGNED REGION 8708 (S09E55) PRODUCED FREQUENT SUBFLARES DURING THE FIRST HALF OF THE INTERVAL. ANOTHER NEW REGION, 8707 (S07W08) HAS BEEN QUIET.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW. IIA. GEOPHYSICAL ACTIVITY SUMMARY FROM 21/2100Z TO 22/2100Z: THE GEOMAGNETIC FIELD WAS AT QUIET TO MINOR STORM LEVELS. A SMALL SUDDEN IMPULSE, MEASURED AT BOULDER TO BE 8 NANOTESLA, OCCURRED AT 1222Z. SATELLITE DATA FROM ACE SHOWED THE PASSAGE OF AN INTERPLANETARY SHOCK JUST PRIOR. SOLAR WIND SPEEDS NEAR 600 KM/S, AND BZ MEASURING NEAR -15 NT ARE NOW OCCURRING. THE SOLAR ORIGIN OF THIS EJECTION IS NOT WELL-ESTABLISHED.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS EXPECTED TO BE AT ACTIVE TO MINOR STORM LEVELS FOR THE NEXT 24 HOURS. SOLAR WIND DATA INDICATE HIGH SPEEDS AND RELATIVELY STRONG SOUTHWARD MAGNETIC FIELDS. UNSETTLED TO ACTIVE CONDITIONS SHOULD PREVAIL THE LAST TWO DAYS.
III. Event Probabilities 23 SEP to 25 SEP
Class M 15%15%15%
Class X 01%01%01%
Proton01%01%01%
PCAFGREEN
IV. Penticton 10.7 cm Flux
  Observed       22 SEP 140
  Predicted    23 SEP-25 SEP  140/135/135
  90 Day Mean        22 SEP 163
V. Geomagnetic A Indices
OBSERVED AFR/AP 21 SEP  010/010
ESTIMATED AFR/AP 22 SEP  020/025
PREDICTED AFR/AP 23 SEP-25 SEP  020/025-015/015-015/012
VI. Geomagnetic Activity Probabilities 23 SEP to 25 SEP
A. Middle Latitudes
Active50%40%40%
Minor storm 20%10%10%
Major-severe storm 05%01%01%
B. High Latitudes
Active60%50%50%
Minor storm 20%10%10%
Major-severe storm 05%01%01%

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