Viewing archive of Friday, 30 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 30 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 211 Issued at 2200Z on 30 JUL 1999IA. Analysis of Solar Active Regions and Activity from 29-2100Z to 30-2100Z SOLAR ACTIVITY WAS MODERATE. REGION 8649 (S15W30)
PRODUCED AN M1/1B FLARE AT 30/1520Z WITH MINOR CENTIMETRIC BURSTS.
THIS REGION CONTINUES TO DEVELOP SLOWLY. REGION 8651 (N24E36) WAS
THE MOST ACTIVE REGION THIS PERIOD PRODUCING FREQUENT LOW-MID
C-CLASS FLARES. DRAMATIC GROWTH OCCURRED IN THIS REGION OVER THE
PAST 24 HOURS AND NOW MEASURES OVER 500 MILLIONTHS IN WHITE LIGHT
AREA. REGION 8645 (S25W03) STABILIZED EARLY IN THE PERIOD AS A
F-TYPE GROUP COVERING 600 MILLIONTHS OF WHITE LIGHT AREA. REMAINING
REGIONS WERE MOSTLY STABLE.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO REMAIN
AT MODERATE LEVELS. REGIONS 8645, 8649, AND 8651 WILL CONTINUE TO
PRODUCE C-CLASS FLARES AND WILL BE THE LIKELY SOURCE FOR ISOLATED
M-CLASS EVENTS.
IIA. Geophysical Activity Summary 29-2100Z to 30-2100Z
THE GEOMAGNETIC FIELD WAS AT QUIET TO UNSETTLED LEVELS EARLY IN THE
PERIOD BUT DISTURBANCES ASSOCIATED WITH RECENT CORONAL MASS
EJECTIONS FIRST IMPACTED THE MAGNETIC FIELD AROUND 30/1000Z. ACTIVE
TO MINOR STORMING LASTED THROUGH LATE IN THE PERIOD BUT MINOR TO
MAJOR STORM CONDITIONS WERE EXPERIENCED AT MOST STATIONS FOLLOWING
AN INTERPLANETARY SHOCK ARRIVAL AT 30/1948Z. THE SUDDEN IMPULSE (SI)
MEASURED 89 NANOTESLA AND THE GOES-8 SATELLITE UNDERWENT A
MAGNETOPAUSE CROSSING BETWEEN 30/2007Z - 2052Z.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO BE AT MINOR TO MAJOR STORM LEVELS WITH PERIODS OF SEVERE
STORMING AT HIGH LATITUDES ON 31 JULY. CONDITIONS ARE EXPECTED TO
IMPROVE TO ACTIVE CONDITIONS BY MID PERIOD.
III. Event Probabilities 31 JUL to 02 AUG
| Class M | 80% | 80% | 80% |
| Class X | 15% | 15% | 15% |
| Proton | 10% | 10% | 10% |
| PCAF | YELLOW | ||
IV. Penticton 10.7 cm Flux
Observed 30 JUL 206 Predicted 31 JUL-02 AUG 205/205/200 90 Day Mean 30 JUL 161
V. Geomagnetic A Indices
OBSERVED AFR/AP 29 JUL 006/010 ESTIMATED AFR/AP 30 JUL 025/024 PREDICTED AFR/AP 31 JUL-02 AUG 040/040-015/015-008/008
VI. Geomagnetic Activity Probabilities 31 JUL to 02 AUG
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 20% | 25% | 15% |
| Minor storm | 40% | 05% | 05% |
| Major-severe storm | 30% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 20% | 30% | 20% |
| Minor storm | 30% | 10% | 05% |
| Major-severe storm | 35% | 05% | 01% |
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