Viewing archive of Wednesday, 21 July 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 Jul 21 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 202 Issued at 2200Z on 21 JUL 1999IA. Analysis of Solar Active Regions and Activity from 20-2100Z to 21-2100Z SOLAR ACTIVITY WAS LOW. SEVERAL MINOR C-CLASS X-RAY
EVENTS WERE OBSERVED OVER THE PAST 24 HOURS. REGION 8639 (N38W38)
EXHIBITED SIGNIFICANT GROWTH, AND IS NOW A CLASS D SUNSPOT GROUP
WITH APPROXIMATELY 15 SPOTS. REGION 8636 (N21E25) EXHIBITED SLIGHT
GROWTH DURING THE PERIOD AND HAS MAINTAINED A BETA GAMMA MAGNETIC
CONFIGURATION WITH 35 SPOTS . REGION 8641 (N30W73), AND REGION 8642
(S18E66) WERE NUMBERED TODAY.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW
TO MODERATE. REGION 8636 REMAINS CAPABLE OF PRODUCING C-CLASS AND
ISOLATED M-CLASS EVENTS.
IIA. Geophysical Activity Summary 20-2100Z to 21-2100Z
THE GEOMAGNETIC FIELD WAS QUIET TO ACTIVE. ACTIVE CONDITIONS WERE
OBSERVED DURING THE 21/1500-1800Z PERIOD.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO BE PREDOMINATELY QUIET TO UNSETTLED WITH PERIODS OF
ACTIVE CONDITIONS DURING THE FIRST DAY OF THE PERIOD. THE UNSETTLED
TO ISOLATED ACTIVE CONDITIONS MAY BE THE RESULT OF A CME EARLY ON
THE 19TH. EXPECT QUIET TO UNSETTLED CONDITIONS DURING DAY TWO AND
THREE.
III. Event Probabilities 22 JUL to 24 JUL
| Class M | 50% | 50% | 50% |
| Class X | 05% | 05% | 05% |
| Proton | 01% | 01% | 01% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 21 JUL 147 Predicted 22 JUL-24 JUL 155/165/170 90 Day Mean 21 JUL 154
V. Geomagnetic A Indices
OBSERVED AFR/AP 20 JUL 005/006 ESTIMATED AFR/AP 21 JUL 012/016 PREDICTED AFR/AP 22 JUL-24 JUL 014/015-010/010-008/007
VI. Geomagnetic Activity Probabilities 22 JUL to 24 JUL
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 30% | 20% | 20% |
| Minor storm | 05% | 05% | 05% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 40% | 25% | 25% |
| Minor storm | 15% | 10% | 10% |
| Major-severe storm | 01% | 01% | 01% |
All times in UTC
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