Viewing archive of Friday, 23 July 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 Jul 23 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.comJoint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 204 Issued at 2200Z on 23 JUL 1999
IA. Analysis of Solar Active Regions and Activity from 22-2100Z to 23-2100Z
SOLAR ACTIVITY BECAME MODERATE. NEW REGION 8644
(S24E69) PRODUCED AN M1 AT 23/1601Z. THE BIG BEAR OBSERVATORY
REPORTED A FLARE BRIGHT KNOT OF MATERIAL AT THE SOUTHEAST LIMB AT
THE TIME OF THE X-RAY BURST. THERE MAY BE A REGION BEHIND 8644 THAT
WAS THE PRIMARY SOURCE OF THE X-RAY BURST. THIS WOULD BE NEAR THE
LOCATION OF THE RETURN OF OLD REGION 8611 THAT PRODUCED 5 M-CLASS
EVENTS LAST ROTATION. REGION 8636 (N21W02) GREW SLOWLY DURING THE
PERIOD AND SIMPLIFIED. THE WEAK DELTA CONFIGURATION VISIBLE IN THIS
REGION ON 22 JUL FADED. REGION 8636 PRODUCED A VERY LONG DURATION
M1/2F THAT BEGAN AT 23/1832Z AND REACHED MAXIMUM AT 23/2005Z.
SEVERAL MID TO HIGH LEVEL C-CLASS FLARES WERE PRODUCED BY THIS
REGION. REGION 8639 (N38W60) GREW AT A MODERATE PACE AND EXHIBITED
A STRAIGHT BIPOLAR, BUT REVERSE POLARITY, CONFIGURATION.
IB. Solar Activity Forecast
AT A MINIMUM, SOLAR ACTIVITY SHOULD
CONTINUE AT MODERATE LEVELS FOR THE NEXT THREE DAYS. REGIONS 8636,
8639, AND 8644 (OR THE REGION BEHIND IT) ARE CAPABLE OF PRODUCING
M-CLASS EVENTS. REGION 8636 COULD PRODUCE AN X-CLASS EVENT DURING
THE PERIOD.
IIA. Geophysical Activity Summary 22-2100Z to 23-2100Z
THE GEOMAGNETIC FIELD WAS PREDOMINANTLY UNSETTLED WITH BRIEF QUIET
PERIODS. SOLAR WIND VELOCITY BEGAN TO DECREASE DURING THE PERIOD BUT
REMAINED ABOVE NORMAL.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD SHOULD BE
QUIET TO UNSETTLED FOR THE NEXT THREE DAYS. ISOLATED ACTIVE
CONDITIONS ARE POSSIBLE ON 24-25 JUL. SHOULD REGION 8636 PRODUCE A
LARGE FLARE, IT WOULD LIKELY HAVE THE CHARACTERISTICS (LARGE AREA,
LONG DURATION, AND CME CREATION) TO PRODUCE A SOLAR PROTON EVENT AT
THE EARTH.
III. Event Probabilities 24 JUL to 26 JUL
Class M | 90% | 90% | 90% |
Class X | 20% | 20% | 20% |
Proton | 20% | 20% | 20% |
PCAF | YELLOW
|
IV. Penticton 10.7 cm Flux
Observed 23 JUL 194
Predicted 24 JUL-26 JUL 175/178/180
90 Day Mean 23 JUL 155
V. Geomagnetic A Indices
OBSERVED AFR/AP 22 JUL 023/024
ESTIMATED AFR/AP 23 JUL 010/012
PREDICTED AFR/AP 24 JUL-26 JUL 012/012-012/012-008/008
VI. Geomagnetic Activity Probabilities 24 JUL to 26 JUL
A. Middle Latitudes |
Active | 30% | 20% | 20% |
Minor storm | 05% | 05% | 05% |
Major-severe storm | 01% | 05% | 01% |
B. High Latitudes |
Active | 40% | 35% | 30% |
Minor storm | 05% | 05% | 05% |
Major-severe storm | 01% | 05% | 01% |
All times in UTC
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