Viewing archive of Friday, 18 May 2012
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 2012 May 18 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 139 Issued at 2200Z on 18 May 2012IA. Analysis of Solar Active Regions and Activity from 17-2100Z to 18-2100Z Solar activity was at low levels. The largest flare
was a C3 at 18/0823Z from old Region 1476 (N10, L=180), which
rotated off the disk. A filament eruption was observed in SDO/AIA
304 imagery beginning at 18/0510Z near Region 1482 (N15W17). An
associated CME was observed in STEREO A COR 2 imagery beginning at
18/0709Z with an estimated plane-of-sky speed of approximately 482
km/s. The majority of the ejecta appeared to be slightly north of
the ecliptic plane, however a glancing blow is likely.
IB. Solar Activity Forecast
Solar activity is expected to be at
low levels with a slight chance for an M-class flare all three days
(19 - 21 May).
IIA. Geophysical Activity Summary 17-2100Z to 18-2100Z
The geomagnetic field was at quiet to unsettled levels. The greater
than 100 MeV proton event at geosynchronous orbit that began at
17/0200Z, reached a maximum of 20.4 pfu at 17/0230Z and ended at
17/1725Z. The greater than 10 MeV proton event is currently
hovering close to the 10 pfu threshold (S1).
IIB. Geophysical Activity Forecast
The geomagnetic field is
expected to be at quiet to unsettled levels with isolated active
periods on day 1 (19 May) due to a possible shock arrival from the
17 May CME. Quiet to unsettled conditions are expected on day 2 (20
May). Mostly quiet conditions are expected on day 3 (21 May).
There is a slight chance for shock enhancement of the greater than
10 MeV protons above 10 pfu on day 1.
III. Event Probabilities 19 May to 21 May
| Class M | 10% | 10% | 10% |
| Class X | 01% | 01% | 01% |
| Proton | 20% | 05% | 01% |
| PCAF | green | ||
IV. Penticton 10.7 cm Flux
Observed 18 May 132 Predicted 19 May-21 May 135/135/130 90 Day Mean 18 May 115
V. Geomagnetic A Indices
Observed Afr/Ap 17 May 005/004 Estimated Afr/Ap 18 May 008/008 Predicted Afr/Ap 19 May-21 May 009/010-008/008-006/005
VI. Geomagnetic Activity Probabilities 19 May to 21 May
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 25% | 10% | 05% |
| Minor storm | 15% | 05% | 01% |
| Major-severe storm | 05% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 30% | 15% | 10% |
| Minor storm | 20% | 10% | 05% |
| Major-severe storm | 05% | 01% | 01% |
All times in UTC
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