Viewing archive of Tuesday, 18 July 2000

Solar activity report

Report of Solar-Geophysical Activity 2000 Jul 18 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 200 Issued at 2200Z on 18 JUL 2000

IA. Analysis of Solar Active Regions and Activity from 17-2100Z to 18-2100Z

SOLAR ACTIVITY REMAINED AT A MODERATE LEVEL. DECAYING REGION 9077 (N18W57) PRODUCED AN M1/2B FLARE AT 18/0515Z WITH WEAK TYPE II AND IV BURSTS. REGION 9087 (S12E12) GENERATED AN M3/2N FLARE AT 18/1419Z. THIS REGION ALSO GENERATED A LONG DURATION M3/2N AT 18/1945Z. IN THE LAST 24 HOURS, THIS REGION EXHIBITED SIGNIFICANT GROWTH JUST AHEAD OF THE PREEXISTING LEADER SPOTS. IT IS LIKELY THAT A DELTA CONFIGURATION FORMED ALSO INDICATING THE PRESENCE OF STRONG MAGNETIC GRADIENTS. SEVERAL NEW REGIONS WERE NUMBERED. THE MOST SIGNIFICANT WAS REGION 9097 (N06E76) THAT ROTATED ONTO THE DISK WITH BRIGHT COMPACT PLAGE, A MODERATE SIZE D CLASS SUNSPOT GROUP, AND FREQUENT SUBFLARES.
IB. Solar Activity Forecast
SOLAR ACTIVITY SHOULD BE MODERATE TO HIGH. A POSSIBILITY REMAINS OF A DECAY PHASE MAJOR FLARE FROM REGION 9077. HOWEVER, REGION 9087 SHOULD BEGIN TO PRODUCE MORE FREQUENT M-CLASS EVENTS DUE TO NEARBY FLUX EMERGENCE. IF THE AREA OF NEW FLUX BEGINS TO MERGE WITH THE PREEXISTING FIELDS, MAJOR FLARES WILL BECOME LIKELY. IIA. GEOPHYSICAL ACTIVITY SUMMARY FROM 17/2100Z TO 18/2100Z: THE GEOMAGNETIC FIELD WAS QUIET TO SLIGHTLY UNSETTLED. SOLAR WIND VELOCITY REMAINED ELEVATED, AT TIMES EXCEEDING 600 KM/S. THE GREATER THAN 10 MEV FLUX BEGAN THE PERIOD AT APPROXIMATELY 50 PFU AND DECLINED SLOWLY TO NEAR 20 PFU AT THE END OF THE PERIOD. AN INTERMITTENT FORBUSH DECREASE WAS IN PROGRESS DURING THE DAY.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD SHOULD BE PREDOMINANTLY QUIET TO UNSETTLED FOR THE NEXT THREE DAYS. OCCASIONAL ACTIVE PERIODS ARE POSSIBLE DURING THAT TIME. BASED UPON THE CURRENT DECAY RATE OF THE GREATER THAN 10 MEV PROTON FLUX, THIS EVENT SHOULD DECREASE BELOW THRESHOLD LATE ON 19 JUL.
III. Event Probabilities 19 JUL to 21 JUL
Class M 90%90%90%
Class X 40%40%40%
Proton99%50%40%
PCAFYELLOW
IV. Penticton 10.7 cm Flux
  Observed       18 JUL 249 (ESTIMATED)
  Predicted    19 JUL-21 JUL  255/260/255
  90 Day Mean        18 JUL 187
V. Geomagnetic A Indices
OBSERVED AFR/AP 17 JUL  008/009
ESTIMATED AFR/AP 18 JUL  008/008
PREDICTED AFR/AP 19 JUL-21 JUL  010/010-012/012-012/012
VI. Geomagnetic Activity Probabilities 19 JUL to 21 JUL
A. Middle Latitudes
Active20%25%25%
Minor storm 10%10%10%
Major-severe storm 05%05%05%
B. High Latitudes
Active20%30%30%
Minor storm 10%15%15%
Major-severe storm 05%05%05%

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