Viewing archive of Tuesday, 11 May 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 May 11 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 131 Issued at 2200Z on 11 MAY 1999IA. Analysis of Solar Active Regions and Activity from 10-2100Z to 11-2100Z SOLAR ACTIVITY HAS BEEN LOW. SEVERAL OPTICAL SUBFLARES
HAVE PRODUCED SMALL C-LEVEL X-RAY FLARES FROM REGIONS 8535 (N21E08)
AND 8541 (N22E25).
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW
TO MODERATE.
IIA. Geophysical Activity Summary 10-2100Z to 11-2100Z
THE GEOMAGNETIC FIELD WAS QUIET. THE GREATER THAN 2 MEV ELECTRONS AT
GEOSYNCHRONOUS ORBITS WERE AT MODERATE TO HIGH LEVELS.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO BE UNSETTLED TO ACTIVE DURING THE FIRST AND THIRD DAY IN
THE PERIOD DUE TO CORONAL HOLE INFLUENCES. DAY 2 IS EXPECTED TO BE
ACTIVE WITH A CHANCE OF MINOR STORMING DUE TO A CME OBSERVED EARLY
ON 10 MAY.
III. Event Probabilities 12 MAY to 14 MAY
| Class M | 60% | 60% | 60% |
| Class X | 15% | 15% | 15% |
| Proton | 05% | 10% | 10% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 11 MAY 159 Predicted 12 MAY-14 MAY 157/157/157 90 Day Mean 11 MAY 132
V. Geomagnetic A Indices
OBSERVED AFR/AP 10 MAY 003/005 ESTIMATED AFR/AP 11 MAY 005/005 PREDICTED AFR/AP 12 MAY-14 MAY 015/015-020/025-015/015
VI. Geomagnetic Activity Probabilities 12 MAY to 14 MAY
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 30% | 35% | 35% |
| Minor storm | 15% | 20% | 20% |
| Major-severe storm | 01% | 05% | 05% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 35% | 40% | 35% |
| Minor storm | 20% | 25% | 20% |
| Major-severe storm | 05% | 05% | 05% |
All times in UTC
Latest news
Sunday, 7 December 2025
M8.1 solar flare with earth-directed CME
Monday, 1 December 2025
X1.9 solar flare, Coronal hole faces Earth
Friday, 14 November 2025
X4.0 solar flare
Latest forum messages
AR 4299 112AR4299 M8.1 CME 2025/12/06 83AR4294 / 4296 / 4298 371New paper on the Gannon Storm 10-11 May 2024 2Electron event 10
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 | 2025/12/08 | M2.0 |
| 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 | 167.7 +75.9 |
| Last 30 days | 107.1 +12.4 |