Viewing archive of Friday, 22 October 1999
Solar activity report
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Report of Solar-Geophysical Activity 1999 Oct 22 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
: : : : : : : CORRECTED COPY : : : : : : : SDF Number 295 Issued at 2200Z on 22 OCT 1999IA. Analysis of Solar Active Regions and Activity from 21-2100Z to 22-2100Z SOLAR ACTIVITY WAS LOW. THE LARGEST EVENT OF THE PERIOD
WAS A C4/SF IN REGION 8732 (N20W89) AT 22/0915Z. TWO TYPE II'S
OCCURRED AT 22/0853Z AND 22/1300Z, LIKELY DUE TO THE CME ACTIVITY IN
THE CLUSTER OF REGIONS TRANSITING THE NORTHWEST LIMB. REGIONS 8737
(S15W26) AND 8739 (S13E43) BOTH EXHIBITED GROWTH THIS PERIOD WITH
REGION 8739 PRODUCING A 1F/SF AT 22/1929Z. NEW REGIONS 8740 (N27W83)
AND 8741 (S25E64) WERE NUMBERED TODAY.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW
TO MODERATE. AN ISOLATED M-CLASS EVENT IS STILL POSSIBLE FROM
REGIONS 8731 (N12W79) AND REGION 8732, AS THEY ROTATE AROUND THE WEST
LIMB. C-CLASS ACTIVITY IS LIKELY FROM REGIONS 8737 AND 8739.
IIA. Geophysical Activity Summary 21-2100Z to 22-2100Z
THE GEOMAGNETIC FIELD WAS AT ACTIVE TO SEVERE STORM LEVELS. THIS
STORM WAS ASSOCIATED WITH THE SUDDEN IMPULSE (SI) OBSERVED AT
21/0226Z. A SUSTAINED PERIOD OF RELATIVE CALM FOLLOWED THE SI, BUT
CONDITIONS CHANGED CONSIDERABLY AROUND 21/2240Z. A DRAMATIC CHANGE
IN THE IMF BZ TO A STRONG SOUTHWARD ORIENTATION PRODUCED SEVERE
CONDITIONS AT MID AND HIGH LATITUDES. THE DISTURBANCE BEGAN TO WANE
SOON AFTER 22/1200Z. ACTIVE CONDITIONS HAVE PERSISTED SINCE.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO BE AT ACTIVE TO MINOR STORM LEVELS WITH ISOLATED MAJOR
STORM PERIODS LIKELY AT HIGH LATITUDES. A FAVORABLY POSITIONED
GEOEFFECTIVE CORONAL HOLE SHOULD RESULT IN UNSETTLED TO ACTIVE
CONDITIONS THROUGH ALL THREE DAYS.
III. Event Probabilities 23 OCT to 25 OCT
| Class M | 40% | 35% | 30% |
| Class X | 10% | 05% | 05% |
| Proton | 10% | 05% | 05% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 22 OCT 160 Predicted 23 OCT-25 OCT 155/145/140 90 Day Mean 22 OCT 158
V. Geomagnetic A Indices
OBSERVED AFR/AP 21 OCT 014/015 ESTIMATED AFR/AP 22 OCT 055/090 PREDICTED AFR/AP 23 OCT-25 OCT 025/040-020/030-020/020
VI. Geomagnetic Activity Probabilities 23 OCT to 25 OCT
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 30% | 30% | 30% |
| Minor storm | 40% | 40% | 30% |
| Major-severe storm | 10% | 10% | 05% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 30% | 40% | 40% |
| Minor storm | 50% | 40% | 40% |
| Major-severe storm | 20% | 20% | 10% |
All times in UTC
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