Viewing archive of Thursday, 21 April 2005

Solar activity report

Report of Solar-Geophysical Activity 2005 Apr 21 2210 UTC
# Prepared jointly by the U.S. Dept. of Commerce, NOAA, #Space Environment Center and the U.S. Air Force. #

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 111 Issued at 2200Z on 21 Apr 2005

IA. Analysis of Solar Active Regions and Activity from 20-2100Z to 21-2100Z

Solar activity was very low. Regions 752 (N03W55) and 755 (S12E21) continue to decay. X-ray flux background is down to approximately A2 level. No new regions were numbered today.
IB. Solar Activity Forecast
Solar activity is expected to be very low.
IIA. Geophysical Activity Summary 20-2100Z to 21-2100Z
The geomagnetic field was quiet to unsettled.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to be quiet to unsettled early on 22 April. A geoeffective coronal hole high speed stream is expected to increase conditions later in the day. Unsettled to active with minor storm periods are possible late on 22 April continuing into early 23 April. Conditions are expected to settle down on 24 April to mostly quiet to unsettled.
III. Event Probabilities 22 Apr to 24 Apr
Class M01%01%01%
Class X01%01%01%
IV. Penticton 10.7 cm Flux
  Observed       21 Apr 077
  Predicted   22 Apr-24 Apr  080/080/080
  90 Day Mean        21 Apr 091
V. Geomagnetic A Indices
  Observed Afr/Ap 20 Apr  012/021
  Estimated     Afr/Ap 21 Apr  005/010
  Predicted    Afr/Ap 22 Apr-24 Apr  015/020-012/020-008/015
VI. Geomagnetic Activity Probabilities 22 Apr to 24 Apr
A. Middle Latitudes
Minor storm15%15%10%
Major-severe storm05%05%01%
B. High Latitudes
Minor storm15%15%15%
Major-severe storm10%10%05%

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