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 UTC
Prepared 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 1999

IA. 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 M80%80%80%
Class X15%15%15%
Proton10%10%10%
PCAFYELLOW
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
Active20%25%15%
Minor storm40%05%05%
Major-severe storm30%01%01%
B. High Latitudes
Active20%30%20%
Minor storm30%10%05%
Major-severe storm35%05%01%

All times in UTC

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