Viewing archive of Saturday, 18 May 2013

Solar activity report

Report of Solar-Geophysical Activity 2013 May 18 2200 UTC
Prepared by the NOAA © SWPC and processed by

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 138 Issued at 2200Z on 18 May 2013

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

Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C6 event observed at 18/0345Z from Region 1748 (N12E11). There are currently 9 numbered sunspot regions on the disk.
IB. Solar Activity Forecast
Solar activity is likely to be moderate with a chance for X-class flares on days one, two, and three (19 May, 20 May, 21 May).
IIA. Geophysical Activity Summary 17-2100Z to 18-2100Z
The geomagnetic field has been at quiet to minor storm levels for the past 24 hours. Solar wind speed, as measured by the ACE spacecraft, reached a peak speed of 476 km/s at 18/0911Z. Total IMF reached 13 nT at 18/0244Z. The maximum southward component of Bz reached -13 nT at 18/0146Z. Protons greater than 10 MeV at geosynchronous orbit reached a peak level of 32 pfu at 17/2245Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 131 pfu.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to be at quiet to major storm levels on day one (19 May), quiet to active levels on day two (20 May) and quiet to unsettled levels on day three (21 May). Protons are likely to cross threshold on day one (19 May) and have a chance of crossing threshold on days two and three (20 May, 21 May).
III. Event Probabilities 19 May to 21 May
Class M 65%65%65%
Class X 40%40%40%
IV. Penticton 10.7 cm Flux
  Observed       18 May 132
  Predicted    19 May-21 May 135/135/130
  90 Day Mean        18 May 121

V. Geomagnetic A Indices
  Observed Afr/Ap 17 May  009/010
  Estimated     Afr/Ap 18 May  018/020
  Predicted     Afr/Ap 19 May-21 May  017/035-014/015-007/008

VI. Geomagnetic Activity Probabilities 19 May to 21 May
A. Middle Latitudes
Minor storm 30%10%05%
Major-severe storm 20%01%01%
B. High Latitudes
Minor storm 20%30%25%
Major-severe storm 75%40%25%

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