Viewing archive of Saturday, 21 July 2001

Solar activity report

Report of Solar-Geophysical Activity 2001 Jul 21 2200 UTC
Prepared by the NOAA © SWPC and processed by

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 202 Issued at 2200Z on 21 Jul 2001

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

Solar activity has been low. Region 9543 (S23W06) produced today's largest flare, a C6/Sf at 0508 UTC. Region 9543 continues to be the largest group on the disk and is growing slowly. Region 9548 (N16E09) also showed growth but was stable. Region 9545 (N09W43) showed newly emerging magnetic flux in the middle of the old fields, and exhibited occasional plage fluctuations, but no flare-level activity.
IB. Solar Activity Forecast
Solar activity is expected to be predominantly low. There is, however, a slight chance for an isolated M-class event.
IIA. Geophysical Activity Summary 20-2100Z to 21-2100Z
The geomagnetic field was quiet to unsettled. The greater than 2 MeV electron fluxes attained high levels during the past 24 hours.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to be quiet to unsettled for the next three days. There is a possibility for a small increase in activity on the third day in response to a small but favorably positioned coronal hole.
III. Event Probabilities 22 Jul to 24 Jul
Class M25%25%25%
Class X01%01%01%
IV. Penticton 10.7 cm Flux
  Observed       21 Jul 139
  Predicted   22 Jul-24 Jul  140/140/135
  90 Day Mean        21 Jul 157
V. Geomagnetic A Indices
  Observed Afr/Ap 20 Jul  008/008
  Estimated     Afr/Ap 21 Jul  005/008
  Predicted    Afr/Ap 22 Jul-24 Jul  007/008-007/010-012/015
VI. Geomagnetic Activity Probabilities 22 Jul to 24 Jul
A. Middle Latitudes
Minor storm10%10%20%
Major-severe storm05%05%05%
B. High Latitudes
Minor storm10%10%20%
Major-severe storm05%05%10%

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