Viewing archive of Saturday, 18 May 2013
Solar activity report
Any mentioned solar flare in this report has a scaling factor applied by the Space Weather Prediction Center (SWPC). Because of the SWPC scaling factor, solar flares are reported as 42% smaller than for the science quality data. The scaling factor has been removed from our archived solar flare data to reflect the true physical units.
Report of Solar-Geophysical Activity 2013 May 18 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 138 Issued at 2200Z on 18 May 2013IA. 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% |
| Proton | 60% | 30% | 30% |
| PCAF | yellow | ||
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 | |||
|---|---|---|---|
| Active | 35% | 30% | 15% |
| Minor storm | 30% | 10% | 05% |
| Major-severe storm | 20% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 05% | 15% | 15% |
| Minor storm | 20% | 30% | 25% |
| Major-severe storm | 75% | 40% | 25% |
All times in UTC
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