Viewing archive of Thursday, 27 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 27 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 147 Issued at 2200Z on 27 MAY 1999IA. Analysis of Solar Active Regions and Activity from 26-2100Z to 27-2100Z
SOLAR ACTIVITY WAS LOW. THERE WERE NUMEROUS C-CLASS
X-RAY FLARES THROUGHOUT THE PERIOD; THE LARGEST WAS A C7 OPTICALLY
CORRELATED TO REGION 8545 (N37W85). BEGINNING AT 27/0917Z EIT
IMAGERY SHOWED A SERIES OF SYMPATHETIC FLARES BETWEEN REGIONS 8551
(N32W14) AND 8554 (N26E11). THESE FLARES PRODUCED A NUMBER OF RADIO
EVENTS INCLUDING TYPE II AND IV RADIO SWEEPS AS WELL AS A 16000 SFU
TENFLARE. A CORRESPONDING HALO CME WAS SEEN ON LASCO C3 AT
27/1338Z. REGION 8552 (N20E25) REMAINS THE LARGEST AND MOST COMPLEX
REGION ON THE DISK.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW
WITH A CHANCE FOR ISOLATED MODERATE ACTIVITY.
IIA. Geophysical Activity Summary 26-2100Z to 27-2100Z
THE GEOMAGNETIC FIELD RANGED FROM QUIET TO UNSETTLED. A ENERGETIC
PROTON ENHANCEMENT BEGAN AT APPROXIMATELY 27/1130Z, BUT DID NOT
REACH THRESHOLD LEVELS. AFTER PEAKING AT APPROXIMATELY 27/1230Z THE
PROTONS STEADILY DECREASED.
IIB. Geophysical Activity Forecast
DURING DAY ONE THE GEOMAGNETIC
FIELD IS EXPECTED TO BE MOSTLY QUIET TO UNSETTLED. BRIEF PERIODS OF
ACTIVE CONDITIONS ARE POSSIBLE EARLY DUE TO THE EFFECTS OF A
RECURRENT CORONAL HOLE. BY DAY TWO THE IMPACT OF A CME IS EXPECTED
TO BRING UNSETTLED TO ACTIVE CONDITIONS.
III. Event Probabilities 28 MAY to 30 MAY
| Class M | 30% | 30% | 30% |
| Class X | 01% | 01% | 01% |
| Proton | 05% | 05% | 05% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 27 MAY 155 Predicted 28 MAY-30 MAY 155/165/165 90 Day Mean 27 MAY 129
V. Geomagnetic A Indices
OBSERVED AFR/AP 26 MAY 007/008 ESTIMATED AFR/AP 27 MAY 010/010 PREDICTED AFR/AP 28 MAY-30 MAY 010/012-020/025-015/020
VI. Geomagnetic Activity Probabilities 28 MAY to 30 MAY
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 20% | 50% | 35% |
| Minor storm | 05% | 20% | 10% |
| Major-severe storm | 01% | 05% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 25% | 60% | 40% |
| Minor storm | 05% | 25% | 15% |
| Major-severe storm | 01% | 05% | 01% |
All times in UTC
Current data suggests there is a slight possibility for aurora to appear at the following high latitude regions in the near future
Rovaniemi, SodankyläKirkenes
Murmansk, Norilsk, Vorkuta
Latest news
Friday, 28 March 2025
X1.1 solar flare
Monday, 24 March 2025
Coronal hole faces Earth
Saturday, 22 March 2025
Strong G3 geomagnetic storm watch for 23 March
Latest forum messages
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!
Latest alerts
17:27 UTC - Solar flare
Moderate M1.5 flare
17:03 UTC - Solar flare
Moderate M1.61 flare
16:45 UTC - Radio Blackout
Minor R1 radio blackout in progress (≥M1 - current: M1.61)
02:09 UTC - Solar flare
Moderate M1.54 flare from sunspot region 4048
01:42 UTC - Radio Blackout
Minor R1 radio blackout in progress (≥M1 - current: M1.24)
Space weather facts
| Last X-flare | 2025/03/28 | X1.1 |
| Last M-flare | 2025/03/30 | M1.4 |
| Last geomagnetic storm | 2025/03/27 | Kp5 (G1) |
| Spotless days | |
|---|---|
| Last spotless day | 2022/06/08 |
| Monthly mean Sunspot Number | |
|---|---|
| February 2025 | 154.6 +17.6 |
| March 2025 | 127.5 -27.1 |
| Last 30 days | 127.5 -24.7 |