Viewing archive of Friday, 18 February 2011

Solar activity report

Report of Solar-Geophysical Activity 2011 Feb 18 2200 UTC
Prepared by the NOAA © SWPC and processed by

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 049 Issued at 2200Z on 18 Feb 2011

IA. Analysis of Solar Active Regions and Activity from 17-2100Z to 18-2100Z

Solar activity was high during the past 24 hours. Region 1158 (S19W64) produced several C-class events with a C1 at 17/2135Z that was associated with a Type II Sweep and an M1 event at 18/1303Z. Region 1161 (N12W02) grew slightly in area and maintained a beta-gamma magnetic classification. New Region 1162 (N18W06) was numbered today and developed rapidly into a Dai-type sunspot group with a beta-gamma magnetic classification. The bulk of the activity originated from this new region, including two M1 events and an M6 event at 18/1011Z.
IB. Solar Activity Forecast
Solar activity is expected to be moderate with a chance for isolated high level activity for the next three days (19-21 February).
IIA. Geophysical Activity Summary 17-2100Z to 18-2100Z
The geomagnetic field was unsettled to active with an isolated minor storm period at high latitudes. This activity was due to the effects of the CMEs associated with two M-class events and an X-class event observed from 13-15 February. A sudden impulse of 33 nT was observed at 18/0136Z at the Boulder magnetometer in association with this event. The ACE spacecraft indicated solar wind velocities increased to approximately 700 km/s along with a sustained period of southward Bz between -10 and -15 nT from 18/0200-0300Z.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to be quiet to unsettled with a chance for isolated active periods for day one (19 February) due to the residual effects of the recent CMEs. Days two and three (20-21 February) are expected to be mostly quiet.
III. Event Probabilities 19 Feb to 21 Feb
Class M75%75%75%
Class X15%15%15%
IV. Penticton 10.7 cm Flux
  Observed       18 Feb 125
  Predicted   19 Feb-21 Feb  120/120/110
  90 Day Mean        18 Feb 086
V. Geomagnetic A Indices
  Observed Afr/Ap 17 Feb  005/002
  Estimated     Afr/Ap 18 Feb  018/022
  Predicted    Afr/Ap 19 Feb-21 Feb  010/012-005/005-005/005
VI. Geomagnetic Activity Probabilities 19 Feb to 21 Feb
A. Middle Latitudes
Minor storm10%05%01%
Major-severe storm01%01%01%
B. High Latitudes
Minor storm10%05%01%
Major-severe storm01%01%01%

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