Viewing archive of Monday, 17 July 2000

Solar activity report

Report of Solar-Geophysical Activity 2000 Jul 17 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 199 Issued at 2200Z on 17 JUL 2000

IA. Analysis of Solar Active Regions and Activity from 16-2100Z to 17-2100Z

SOLAR ACTIVITY WAS MODERATE. SEVERAL REGIONS PRODUCED SMALL M-CLASS FLARES. REGION 9090 (N12E59) PRODUCED AN M1/1N EVENT AT 16/2147Z; REGION 9077 (N18W46) PRODUCED AN M1/2F AT 17/0004Z; AND REGION 9087 (S12 E31) GENERATED AN M1/1F AT 17/1344Z AND AN M2/1N AT 17/2027Z WITH A 280 SFU BURST AT 2695 MHZ AND A TYPE II. REGION 9077 SLOWLY DECLINED DURING THE PERIOD. REGION 9087 EXHIBITED GROWTH. THE OTHER SIGNIFICANT REGIONS ON THE DISK WERE PREDOMINANTLY STABLE. A LARGE MASS EJECTION WAS OBSERVED OVER THE EAST LIMB AROUND 17/1100Z.
IB. Solar Activity Forecast
SOLAR ACTIVITY SHOULD BE MODERATE TO HIGH. THE THREE REGIONS MENTIONED ABOVE ARE OBVIOUSLY CAPABLE OF OCCASIONAL M-CLASS EVENTS. CONTINUED GROWTH IN REGION 9087 WOULD INCREASE THE FREQUENCY OF M-CLASS EVENTS FROM THAT LOCATION. THERE REMAINS A POSSIBILITY OF A MAJOR FLARE FROM REGIONS 9077, 9087, AND 9090. IIA. GEOPHYSICAL ACTIVITY SUMMARY FROM 16/2100Z TO 17/2100Z: THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED. SOLAR WIND VELOCITY DECLINED DURING THE PERIOD FROM APPROXIMATELY 750 TO 600 KM/S. THE GREATER THAN 10 MEV PROTON FLUX BEGAN THE PERIOD AT APPROXIMATELY 180 PFU AND BY ISSUE TIME WERE NEAR 50 PFU. THE POLAR CAP ABSORPTION EVENT ENDED AT 17/1943Z. THE FORBUSH DECREASE REMAINED IN PROGRESS.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD SHOULD BE PREDOMINANTLY QUIET TO UNSETTLED FOR THE NEXT THREE DAYS. ISOLATED ACTIVE PERIODS ARE POSSIBLE AS LONG AS SOLAR WIND VELOCITY REMAINS ELEVATED. THE SOLAR PROTON EVENT SHOULD CONTINUE TO DECAY SLOWLY AND BE BELOW EVENT THRESHOLD AROUND 19 JULY. HOWEVER, IT REMAINS POSSIBLE THAT REGION 9077 COULD PRODUCE ANOTHER MAJOR EVENT THAT COULD RESULT IN AN ADDITIONAL INJECTION OF ENERGETIC PROTONS.
III. Event Probabilities 18 JUL to 20 JUL
Class M75%75%75%
Class X25%25%25%
Proton99%75%40%
PCAFYELLOW
IV. Penticton 10.7 cm Flux
  Observed       17 JUL 228
  Predicted   18 JUL-20 JUL  230/233/234
  90 Day Mean        17 JUL 186
V. Geomagnetic A Indices
OBSERVED AFR/AP 16 JUL  032/046
ESTIMATED AFR/AP 17 JUL  010/010
PREDICTED AFR/AP 18 JUL-20 JUL  010/008-010/010-012/012
VI. Geomagnetic Activity Probabilities 18 JUL to 20 JUL
A. Middle Latitudes
Active25%20%20%
Minor storm15%10%10%
Major-severe storm05%05%05%
B. High Latitudes
Active25%20%20%
Minor storm15%10%10%
Major-severe storm05%05%05%

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