Viewing archive of Tuesday, 19 April 2011

Solar activity report

Report of Solar-Geophysical Activity 2011 Apr 19 2200 UTC
Prepared by the NOAA © SWPC and processed by

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 109 Issued at 2200Z on 19 Apr 2011

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

Solar activity has been at low levels for the past 24 hours. New Region 1195 (S16E68) rotated onto the visible disk, early in the period, as a Dao sunspot group. Before being numbered, Region 1195 produced several C-class events off the east limb, as well as the largest event of the past 24 hours, a C1 flare at 18/0512Z. Region 1193 (N17W08) continues to evolve and has grown into a beta-gamma magnetic classification.
IB. Solar Activity Forecast
Solar activity is expected to be at low levels with a slight chance for M-class activity for the next three days (20-22 April).
IIA. Geophysical Activity Summary 18-2100Z to 19-2100Z
The geomagnetic field has been at quiet levels for the past 24 hours.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to be at quiet to unsettled levels with a chance for isolated active periods for the next three days (20-22 April). Heightened activity levels are expected due to the arrival, early on day 1, of a coronal hole high-speed stream (CH HSS). Effects from the CH HSS are expected to last about 2 days. Late on day 2, a slow-moving CME is expected to become geoeffective with effects lasting through day 3.
III. Event Probabilities 20 Apr to 22 Apr
Class M15%15%15%
Class X01%01%01%
IV. Penticton 10.7 cm Flux
  Observed       19 Apr 111
  Predicted   20 Apr-22 Apr  110/110/110
  90 Day Mean        19 Apr 104
V. Geomagnetic A Indices
  Observed Afr/Ap 18 Apr  008/010
  Estimated     Afr/Ap 19 Apr  005/005
  Predicted    Afr/Ap 20 Apr-22 Apr  010/010-010/010-010/010
VI. Geomagnetic Activity Probabilities 20 Apr to 22 Apr
A. Middle Latitudes
Minor storm10%05%05%
Major-severe storm01%01%01%
B. High Latitudes
Minor storm15%10%10%
Major-severe storm05%01%01%

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