Viewing archive of Friday, 15 October 1999
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 1999 Oct 15 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 288 Issued at 2200Z on 15 OCT 1999IA. Analysis of Solar Active Regions and Activity from 14-2100Z to 15-2100Z SOLAR ACTIVITY DECREASED TO LOW LEVELS. REGION 8731
(N12E10) STABILIZED AS A MODERATE-SIZED, MAGNETICALLY-COMPLEX REGION
AND IT APPEARED TO HAVE LOST THE MAGNETIC DELTA CONFIGURATION NEAR
REGION CENTER. IT PRODUCED NUMEROUS FLARES, THE LARGEST OF WHICH WAS
A C7/SF AT 15/0115Z. NEW REGION 8734 (N16E20) WAS NUMBERED TODAY.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW
TO MODERATE. REGION 8731 IS LIKELY TO PRODUCE M-CLASS FLARES AND MAY
ALSO PRODUCE ANOTHER MAJOR FLARE.
IIA. Geophysical Activity Summary 14-2100Z to 15-2100Z
GEOMAGNETIC FIELD ACTIVITY RANGED FROM UNSETTLED TO MINOR STORM
LEVELS DUE TO CONTINUING CORONAL HOLE EFFECTS. THE GREATER THAN 2
MEV ELECTRON FLUX REACHED HIGH LEVELS DURING THE PERIOD.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO BE MOSTLY ACTIVE ON DAY ONE AS THE CURRENT DISTURBANCE
CONTINUES. QUIET TO ACTIVE LEVELS ARE EXPECTED DURING THE REMAINDER
OF THE PERIOD AS CORONAL HOLE EFFECTS GRADUALLY SUBSIDE.
III. Event Probabilities 16 OCT to 18 OCT
| Class M | 60% | 60% | 60% |
| Class X | 20% | 20% | 20% |
| Proton | 10% | 15% | 20% |
| PCAF | YELLOW | ||
IV. Penticton 10.7 cm Flux
Observed 15 OCT 198 Predicted 16 OCT-18 OCT 200/200/195 90 Day Mean 15 OCT 156
V. Geomagnetic A Indices
OBSERVED AFR/AP 14 OCT 017/024 ESTIMATED AFR/AP 15 OCT 028/025 PREDICTED AFR/AP 16 OCT-18 OCT 020/020-015/015-015/015
VI. Geomagnetic Activity Probabilities 16 OCT to 18 OCT
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 30% | 25% | 25% |
| Minor storm | 15% | 10% | 10% |
| Major-severe storm | 05% | 05% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 35% | 30% | 25% |
| Minor storm | 20% | 15% | 15% |
| Major-severe storm | 10% | 10% | 05% |
All times in UTC
Latest news
Monday, 1 December 2025
X1.9 solar flare, Coronal hole faces Earth
Friday, 14 November 2025
X4.0 solar flare
Tuesday, 11 November 2025
X5.1 solar flare, G4 geomagnetic storm watch
Latest forum messages
AR4294 / 4296 / 4298 294Unspecified geomagnetic activity 40Current Farside Activity 235Space Weather Memes 760AR 4299 23
More topicsSupport SpaceWeatherLive.com!
A lot of people come to SpaceWeatherLive to follow the Solar activity or if there is a chance to see the aurora, but with more traffic comes higher costs to keep the servers online. If you like SpaceWeatherLive and want to support the project you can choose a subscription for an ad-free site or consider a donation. With your help we can keep SpaceWeatherLive online!
Space weather facts
| Last X-flare | 2025/12/01 | X1.9 |
| Last M-flare | 2025/12/04 | M6.0 |
| Last geomagnetic storm | 2025/12/04 | Kp5 (G1) |
| Spotless days | |
|---|---|
| Last spotless day | 2022/06/08 |
| Monthly mean Sunspot Number | |
|---|---|
| November 2025 | 91.8 -22.8 |
| December 2025 | 186 +94.2 |
| Last 30 days | 106.3 +12.6 |