Viewing archive of Friday, 31 July 1998
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 1998 Jul 31 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.comJoint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 212 Issued at 2200Z on 31 JUL 1998
IA. Analysis of Solar Active Regions and Activity from 30-2100Z to 31-2100Z
SOLAR ACTIVITY WAS LOW. THREE NOTABLE FLARES OCCURRED.
THE FIRST WAS A C1 PEAKING AT 31/0345Z AND WAS ASSOCIATED WITH
MODERATE INTENSITY TYPE II/IV SWEEP EVENTS. ALTHOUGH NO OPTICAL
FLARE REPORTS WERE RECEIVED, ENHANCED PLAGE OBSERVED IN REGION 8280
(S24W54) SHORTLY AFTER THIS FLARE MAY SUGGEST ITS ORIGIN. THE SECOND
FLARE OF NOTE WAS A LONG-DURATION C2/2F AT 31/0538Z IN REGION 8283
(N27E16). THIS FLARE WAS ASSOCIATED WITH A 12 DEGREE DSF AND STRONG
TYPE II SWEEP. THE THIRD FLARE WAS A B7 AT 31/1540Z ASSOCIATED WITH
FILAMENT ACTIVATION AND PARTIAL ERUPTION IN REGION 8282 (N30W48).
NEW REGIONS 8289 (N22W63), 8290 (N17E63), AND 8291 (S23E09) WERE
NUMBERED. REGION 8290 PRODUCED THE ONLY OTHER OPTICAL FLARE
REPORTED, A SF (NO X-RAY OUTPUT) AT 31/1605Z.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE VERY
LOW TO LOW. FLARES ARE POSSIBLE IN REGIONS 8280, 8282, AND 8290.
REGION 8282 MAY PRODUCE AN ISOLATED M-CLASS FLARE BEFORE ITS DISK
DEPARTURE.
IIA. Geophysical Activity Summary 30-2100Z to 31-2100Z
THE GEOMAGNETIC FIELD RANGED FROM QUIET TO STORM LEVELS. ACE RTSW
DATA SUGGESTS THAT THE EARTH'S MAGNETOSPHERE IS REACTING TO SEVERAL
HOURS OF SOLAR WIND CHARACTERIZED BY HIGH DENSITY (20-70 P/CC),
SLIGHTLY ENHANCED SPEED (420 KM/S), AND VARIABLE BZ (+/- 12 NT). THE
NATURE OF THIS STRUCTURE (TRANSIENT OR NOT) IS NOT CLEAR FROM THE
AVAILABLE DATA.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO BE UNSETTLED TO ACTIVE FOR THE NEXT 24 HOURS, BECOMING
QUIET TO UNSETTLED BY THE END OF THE FORECAST PERIOD. THE SOLAR
EVENTS WHICH WERE OBSERVED TODAY (DSFS AND TYPE II/IV SWEEPS) MAY
INDICATE THE OCCURRENCE OF CMES WHICH COULD AFFECT ACTIVITY LEVELS
AT THE END, OR JUST OUTSIDE, OF THE 3-DAY FORECAST PERIOD.
III. Event Probabilities 01 AUG to 03 AUG
Class M | 15% | 10% | 05% |
Class X | 01% | 01% | 01% |
Proton | 01% | 01% | 01% |
PCAF | GREEN
|
IV. Penticton 10.7 cm Flux
Observed 31 JUL 114
Predicted 01 AUG-03 AUG 112/110/108
90 Day Mean 31 JUL 110
V. Geomagnetic A Indices
OBSERVED AFR/AP 30 JUL 011/012
ESTIMATED AFR/AP 31 JUL 024/025
PREDICTED AFR/AP 01 AUG-03 AUG 015/015-010/012-010/015
VI. Geomagnetic Activity Probabilities 01 AUG to 03 AUG
A. Middle Latitudes |
Active | 20% | 15% | 15% |
Minor storm | 10% | 01% | 01% |
Major-severe storm | 05% | 05% | 05% |
B. High Latitudes |
Active | 25% | 15% | 15% |
Minor storm | 15% | 05% | 05% |
Major-severe storm | 10% | 05% | 05% |
All times in UTC
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