Viewing archive of Tuesday, 21 December 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 Dec 21 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 355 Issued at 2200Z on 21 DEC 1999IA. Analysis of Solar Active Regions and Activity from 20-2100Z to 21-2100Z SOLAR ACTIVITY WAS MODERATE. REGION 8806 (N19E24)
PRODUCED AN M1/1N AT 21/1719UT. REGION 8806 IS THE LARGEST REGION ON
THE DISK AND CONTINUES TO BE MAGNETICALLY COMPLEX. REGION 8798
(S13W33), THE SECOND LARGEST REGION ON THE DISK, HAS ONLY PRODUCED
SMALL C FLARES. A CME WAS OBSERVED BY SOHO AROUND 1600UT ON THE
20TH, BUT APPEARED TO BE A BACKSIDE EVENT. THE OBSERVED 10CM RADIO
FLUX REPORTED IN PART IV MAY BE FLARE ENHANCED.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW
TO MODERATE. THERE IS A FAIR CHANCE FOR MAJOR ACTIVITY FROM EITHER
REGION 8798 OR REGION 8806.
IIA. Geophysical Activity Summary 20-2100Z to 21-2100Z
THE GEOMAGNETIC FIELD HAS BEEN BASICALLY QUIET.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO BE QUIET TO UNSETTLED.
III. Event Probabilities 22 DEC to 24 DEC
| Class M | 50% | 50% | 50% |
| Class X | 15% | 15% | 15% |
| Proton | 05% | 05% | 10% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 21 DEC 217 Predicted 22 DEC-24 DEC 200/195/190 90 Day Mean 21 DEC 172
V. Geomagnetic A Indices
OBSERVED AFR/AP 20 DEC 004/003 ESTIMATED AFR/AP 21 DEC 004/005 PREDICTED AFR/AP 22 DEC-24 DEC 007/010-007/007-005/007
VI. Geomagnetic Activity Probabilities 22 DEC to 24 DEC
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 25% | 10% | 10% |
| Minor storm | 10% | 01% | 01% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 25% | 20% | 15% |
| Minor storm | 10% | 05% | 01% |
| Major-severe storm | 01% | 01% | 01% |
All times in UTC
Latest news
Monday, 11 November 2024
Coronal hole faces Earth
Friday, 1 November 2024
X2.0 solar flare
Wednesday, 9 October 2024
X1.8 solar flare, severe geomagnetic storm watch
Latest forum messages
Filaments and prominences 488AR 13901 90Incoming & Unnumbered Active Regions 1245Sunspot Latitudes at or near Solar Maximum 76The Rotations of AR 13780 and AR 13902 1
More topicsSupport SpaceWeatherLive.com!
A lot of people come to SpaceWeatherLive to follow the Sun's activity or if there is aurora to be seen, but with more traffic comes higher server costs. Consider a donation if you enjoy SpaceWeatherLive so we can keep the website online!
Space weather facts
| Last X-flare | 2024/11/06 | X2.39 |
| Last M-flare | 2024/11/20 | M1.1 |
| Last geomagnetic storm | 2024/11/10 | Kp5+ (G1) |
| Spotless days | |
|---|---|
| Last spotless day | 2022/06/08 |
| Monthly mean Sunspot Number | |
|---|---|
| October 2024 | 166.4 +25 |
| November 2024 | 142.7 -23.8 |
| Last 30 days | 155.2 +4.4 |