Viewing archive of Friday, 18 April 2014
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 2014 Apr 18 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 108 Issued at 2200Z on 18 Apr 2014IA. Analysis of Solar Active Regions and Activity from 17-2100Z to 18-2100Z
Solar activity reached high levels. Region 2036 (S16W41,
Dhc/beta-gamma) produced an M7 flare at 18/1303 UTC, which was the
largest flare of the period. It was accompanied by a Tenflare (1000
sfu), a Castelli-U signature, as well as Type II (851 km/s) and Type IV
radio emissions. An asymmetric halo CME was subsequently observed in
SOHO/LASCO C2 coronagraph imagery at 18/1325 UTC. Analysis suggested the
ejecta was moving at approximately 1000 km/s and Earth-directed.
IB. Solar Activity Forecast
Solar activity is likely to be moderate
with a slight chance for an X-class flare on days one, two, and three
(19 Apr, 20 Apr, 21 Apr).
IIA. Geophysical Activity Summary 17-2100Z to 18-2100Z
The geomagnetic
field has been at quiet levels for the past 24 hours. Solar wind speed,
as measured by the ACE spacecraft, reached a peak speed of 540 km/s at
18/1845Z. Total IMF reached 9 nT at 18/0207Z. The maximum southward
component of Bz reached -8 nT at 18/0243Z. Protons greater than 10 MeV
at geosynchronous orbit reached a peak level of 38 pfu at 18/1955Z.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected
to be at quiet to active levels on day one (19 Apr) and quiet to minor
storm levels on days two and three (20 Apr, 21 Apr) with a chance for
major storm levels on day two (20 Apr). Protons are expected to remain
above the 10 pfu threshold on day one (19 Apr), are expected to cross
threshold on day two (20 Apr) and have a chance of crossing threshold on
day three (21 Apr).
III. Event Probabilities 19 Apr to 21 Apr
| Class M | 60% | 60% | 60% |
| Class X | 10% | 10% | 10% |
| Proton | 99% | 75% | 50% |
| PCAF | yellow | ||
IV. Penticton 10.7 cm Flux
Observed 18 Apr 172 Predicted 19 Apr-21 Apr 175/175/175 90 Day Mean 18 Apr 156
V. Geomagnetic A Indices
Observed Afr/Ap 17 Apr 011/011 Estimated Afr/Ap 18 Apr 007/008 Predicted Afr/Ap 19 Apr-21 Apr 009/012-018/025-017/020
VI. Geomagnetic Activity Probabilities 19 Apr to 21 Apr
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 40% | 40% | 40% |
| Minor storm | 15% | 35% | 25% |
| Major-severe storm | 01% | 10% | 05% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 10% | 05% | 05% |
| Minor storm | 25% | 20% | 20% |
| Major-severe storm | 55% | 75% | 60% |
All times in UTC
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