:Product: 19990804RSGA.txt
:Issued: 1999 Aug 04 2200 UTC
# Prepared jointly by the U.S. Dept. of Commerce, NOAA,
# Space Environment Center and the U.S. Air Force.
#
JOINT USAF/NOAA REPORT OF SOLAR AND GEOPHYSICAL ACTIVITY
SDF NUMBER 216 ISSUED AT 2200Z ON 04 AUG 1999
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  03/2100Z
TO 04/2100Z:  SOLAR ACTIVITY REMAINED AT HIGH LEVELS. REGION 8647
(S18W75) PRODUCED AN M6/1N FLARE AT 04/0557Z ASSOCIATED WITH A WEAK
TYPE II RADIO SWEEP (EST. SHOCK VELOCITY 400 KM/SEC) AND A 230 SFU
TENFLARE. IT ALSO PRODUCED AN M1/SF FLARE AT 04/1607Z. THIS REGION
SHOWED LITTLE CHANGE DURING THE PERIOD AND WAS OF MODERATE SIZE AND
MAGNETIC COMPLEXITY. REGION 8651 (N25W31) REMAINED A LARGE F-TYPE
GROUP OF MODERATE MAGNETIC COMPLEXITY, BUT APPEARED TO BE SLOWLY
DECAYING. IT PRODUCED TWO SUBFLARES DURING THE PERIOD. REGION 8645
(S26W66) REMAINED MODERATE IN SIZE AND MAGNETIC COMPLEXITY AND
SHOWED LITTLE CHANGE AS IT PRODUCED ISOLATED SUBFLARES. NEW REGION
8660 (S34W25), A SMALL B-TYPE GROUP, WAS NUMBERED TODAY.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE
MODERATE. ISOLATED M-CLASS FLARES ARE POSSIBLE FROM REGIONS 8645,
8647, AND 8651. THERE IS ALSO A CHANCE FOR ANOTHER MAJOR FLARE FROM
REGION 8647.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 03/2100Z TO 04/2100Z:
THE GEOMAGNETIC FIELD WAS AT QUIET TO ACTIVE LEVELS. A SUDDEN IMPULSE
OCCURRED AT 04/0225Z (25 NT, AS MEASURED BY THE BOULDER USGS
MAGNETOMETER). FIELD ACTIVITY INCREASED FOLLOWING THE IMPULSE WITH
ACTIVE LEVELS DETECTED DURING THE 04/0300 - 0600Z INTERVAL. ACTIVITY
DECREASED TO QUIET TO UNSETTLED LEVELS DURING THE REMAINDER OF THE
PERIOD.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO BE AT QUIET TO UNSETTLED LEVELS THROUGH THE PERIOD.
THERE APPEARED TO BE NO EARTH-DIRECTED CORONAL MASS EJECTIONS
ASSOCIATED WITH THE MAJOR FLARES OF 02 AND 04 AUGUST.
III.  EVENT PROBABILITIES 05 AUG-07 AUG
CLASS M    80/70/50
CLASS X    20/15/10
PROTON     10/10/05
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           04 AUG 200
PREDICTED   05 AUG-07 AUG  195/185/175
90 DAY MEAN        04 AUG 165
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 03 AUG  005/008
ESTIMATED AFR/AP 04 AUG  012/015
PREDICTED AFR/AP 05 AUG-07 AUG  012/015-010/010-005/008
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 05 AUG-07 AUG
A.  MIDDLE LATITUDES
ACTIVE                25/20/15
MINOR STORM           05/05/01
MAJOR-SEVERE STORM    01/01/01
B.  HIGH LATITUDES
ACTIVE                25/25/15
MINOR STORM           10/10/05
MAJOR-SEVERE STORM    01/01/01