Viewing archive of Monday, 21 December 1998
Geophysical 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.
Solar and Geophysical Activity Summary 1998 Dec 21 0245 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Solar and Geophysical Activity Summary
SGAS Number 355 Issued at 0245Z on 21 DEC 1998 This report is compiled from data received at SWO on 20 DECA. Energetic Events
Begin Max End Rgn Loc Xray Op 245MHz 10cm Sweep 0849 0900 0903 8415 N21E46 M1.8 1N 28
B. Proton Events
None
C. Geomagnetic Activity Summary
THE GEOMAGNETIC FIELD WAS
PREDOMINANTLY UNSETTLED. DURING THE PERIOD, SOLAR WIND VELOCITY
INCREASED, DENSITY DECREASED, AND SEVERAL INTERVALS OF PROLONGED
SOUTHWARD BZ WERE OBSERVED.
D. Stratwarm
STRATWARM ALERT/SUNDAY/STRATWARM EXISTS.
MAJOR WARMING EXISTS. THE MAIN ANTICYCLONE IS LOCATED OVER NORWEGIAN
SEA AND A SECOND ANTICYCLONE OVER ALASKA, TODAY. THE INTENSE WARMING
OVER SIBERIAN ARCTIC FURTHER SLIGHTLY WEAKENING. THE TWO CENTERS OF
THE VORTEX ARE OVER WESTERN SIBERIA AND OVER HUDSON BAY. MEAN ZONAL
WIND AT 60 N IS FURTHER FROM FAST AT 10 HPA AND ABOVE IN THE UPPER
STRATOSPHERE. TEMPERATURE GRADIENT REVERSED BETWEEN 60 N AND THE
POLE IN THE WHOLE STRATOSPHERE BELOW THE UPPERMOST LEVEL.
E. Daily Indices: (real-time preliminary/estimated values)
10 CM 135 SSN 098 AFR/AP 009/011 X-RAY BACKGROUND B6.1 DAILY PROTON FLUENCE (FLUX ACCUMULATION OVER 24 HRS) GT 1 MEV 4.4E+05 GT 10 MEV 1.9E+04 P/(CM2-STER-DAY) (GOES-8 SATELLITE SYNCHRONOUS ORBIT W75 DEGREES) DAILY ELECTRON FLUENCE GT 2 MEV 2.40E+06 E/(CM2-STER-DAY) (GOES-8 SATELLITE SYNCHRONOUS ORBIT W75 DEGREES) 3 HOUR K-INDICES: BOULDER 2 3 3 3 3 3 1 1 PLANETARY 2 3 3 3 3 3 2 2
F. Comments
None
All times in UTC
Latest news
Sunday, 1 February 2026
Complex sunspot region 4366
Monday, 19 January 2026
CME impact! S4 solar radiation storm
Sunday, 18 January 2026
X1.9 solar flare with earth-directed CME
Latest forum messages
AR4392 9CH 31 HSS 3Unspecified geomagnetic activity 115Current Farside Activity 411Comet C/2026 A1 (MAPS) for the southern hemisphere 17
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 | 2026/02/04 | X4.21 |
| Last M-flare | 2026/03/13 | M1.2 |
| Last geomagnetic storm | 2026/03/13 | Kp6- (G2) |
| Spotless days | |
|---|---|
| Last 365 days | 3 days |
| 2026 | 3 days (4%) |
| Last spotless day | 2026/02/24 |
| Monthly mean Sunspot Number | |
|---|---|
| February 2026 | 78.2 -34.3 |
| March 2026 | 83.5 +5.3 |
| Last 30 days | 58.3 -70.3 |