Viewing archive of Monday, 18 July 2011
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 2011 Jul 18 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 199 Issued at 2200Z on 18 Jul 2011IA. 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. Region 1254 (S22E11) produced the largest event of the
period, a C1/Sf flare at 18/1028Z. Two new regions were numbered
today: Region 1258 (N11W37) emerged on the disk and is magnetically
classified as a beta and Region 1259 (N26E69) rotated on the disk as
a Dao-beta group. Early in the period, two CMEs were observed in
LASCO C2 and C3 imagery but neither appear to be Earth directed.
IB. Solar Activity Forecast
Solar activity is expected to be at
very low to low levels for the next two days (19-20 July). Activity
is expected to decrease to very low levels on day three (21 July) as
Region 1257 (N20W69) rotates off the west limb.
IIA. Geophysical Activity Summary 17-2100Z to 18-2100Z
The geomagnetic field was at quiet to unsettled levels for the past
24 hours. Measurements by the ACE spacecraft indicated a solar
sector boundary crossing (from positive to negative) at around
18/0230Z. Following the crossing, coronal hole high-speed stream
characteristics were monitored, with solar wind speeds increasing
from 370 km/s to around 460 km/s.
IIB. Geophysical Activity Forecast
The geomagnetic field is
expected to be at quiet to unsettled levels on day one (19 July),
and at quiet to active levels on days two and three (20-21 July), as
another coronal hole high-speed stream becomes geoeffective.
III. Event Probabilities 19 Jul to 21 Jul
| Class M | 10% | 10% | 10% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | green | ||
IV. Penticton 10.7 cm Flux
Observed 18 Jul 102 Predicted 19 Jul-21 Jul 102/100/096 90 Day Mean 18 Jul 097
V. Geomagnetic A Indices
Observed Afr/Ap 17 Jul 003/005 Estimated Afr/Ap 18 Jul 006/008 Predicted Afr/Ap 19 Jul-21 Jul 010/010-012/012-012/012
VI. Geomagnetic Activity Probabilities 19 Jul to 21 Jul
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 25% | 30% | 30% |
| Minor storm | 01% | 05% | 05% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 30% | 35% | 35% |
| Minor storm | 01% | 10% | 10% |
| Major-severe storm | 01% | 01% | 01% |
All times in UTC
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