Viewing archive of Monday, 4 October 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 Oct 04 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 277 Issued at 2200Z on 04 OCT 1999IA. Analysis of Solar Active Regions and Activity from 03-2100Z to 04-2100Z SOLAR ACTIVITY REMAINED AT A LOW LEVEL. THE LARGEST
EVENT OF THE PERIOD WAS A MODERATE DURATION C5/SF FROM REGION 8720
(N13E54) AT 04/0816Z. SMALL SUBFLARES WERE ALSO OBSERVED FROM
REGIONS 8719 (S22E37) AND 8721 (S18E46). SEVERAL FILAMENTS AROUND
N35 AND SPANNING CENTRAL MERIDIAN FADED SLOWLY BEGINNING AT
23/2324Z. A SMALL H CLASS SPOT ROTATED AROUND THE LIMB AND WAS
NUMBERED AS NEW REGION 8723 (N18E76).
IB. Solar Activity Forecast
SOLAR ACTIVITY SHOULD CONTINUE AT A
PREDOMINANTLY LOW LEVEL. ISOLATED SMALL M-CLASS EVENTS ARE POSSIBLE
FROM THE ACTIVE REGION COMPLEX 8719/8721 AND TO A LESSER DEGREE FROM
THE 8716 (N19E47)/8720 COMPLEX.
IIA. Geophysical Activity Summary 03-2100Z to 04-2100Z
THE GEOMAGNETIC FIELD WAS PREDOMINANTLY QUIET TO UNSETTLED. SOME
ISOLATED ACTIVE CONDITIONS WERE OBSERVED AT SEVERAL SITES DURING THE
PERIOD. SOLAR WIND VELOCITY INCREASED SLOWLY DURING THE PERIOD TO
NEAR 450 KM/S.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO RANGE FROM QUIET TO ACTIVE LEVELS FOR THE NEXT THREE
DAYS. TWO CORONAL HOLES, WHICH ENLARGED SINCE LAST ROTATION, ARE
MOVING INTO FAVORABLE POSITION FOR THEIR HIGH SPEED STREAMS TO
IMPACT THE EARTH.
III. Event Probabilities 05 OCT to 07 OCT
| Class M | 20% | 20% | 20% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 04 OCT 144 Predicted 05 OCT-07 OCT 145/147/150 90 Day Mean 04 OCT 155
V. Geomagnetic A Indices
OBSERVED AFR/AP 03 OCT 006/010 ESTIMATED AFR/AP 04 OCT 012/015 PREDICTED AFR/AP 05 OCT-07 OCT 012/020-012/015-012/012
VI. Geomagnetic Activity Probabilities 05 OCT to 07 OCT
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 25% | 25% | 25% |
| Minor storm | 15% | 15% | 15% |
| Major-severe storm | 05% | 05% | 05% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 25% | 25% | 25% |
| Minor storm | 15% | 15% | 15% |
| Major-severe storm | 05% | 05% | 05% |
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