:Product: 19990908RSGA.txt
:Issued: 1999 Sep 08 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 251 ISSUED AT 2200Z ON 08 SEP 1999
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  07/2100Z
TO 08/2100Z:  SOLAR ACTIVITY WAS MODERATE. REGION 8690 (N13E47)
PRODUCED AN M1/1B AT 1217Z. THE REGION PRODUCED ADDITIONAL
SUBFLARES, BUT IS RATHER SMALL (50 MILLIONTHS) AND IS SHOWING ONLY
SLOW GROWTH. REGION 8692 (S27E60) HAS ROTATED INTO VIEW AS AN E-TYPE
REGION AND IS CURRENTLY THE LARGEST GROUP ON THE DISK AT 230
MILLIONTHS. THE GROUP WAS QUIET AND STABLE DURING THE PAST 24 HOURS.
NEW REGION 8694 (S14W14) EMERGED ON THE DISK TODAY. AN ERUPTIVE
PROMINENCE WAS OBSERVED ON THE SOUTHWEST LIMB (S34W90) FROM
1126-1220Z.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE LOW.
THERE IS A SLIGHT CHANCE, HOWEVER, FOR AN ISOLATED M-CLASS EVENT
FROM REGION 8690 OR 8692.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 07/2100Z TO 08/2100Z:
THE GEOMAGNETIC FIELD WAS QUIET TO ACTIVE. INITIALLY ACTIVE
CONDITIONS WERE SEEN IN RESPONSE TO A HIGH-SPEED SOLAR WIND STREAM
ASSOCIATED WITH A CORONAL HOLE. CONDITIONS TURNED MARKEDLY QUIET
AFTER 0300Z IN RESPONSE TO A NORTHWARD TURNING OF THE BZ COMPONENT
OF THE INTERPLANETARY MAGNETIC FIELD. UNSETTLED CONDITIONS RETURNED
AFTER 12Z AS BZ TURNED STEADILY SOUTH FOR JUST OVER AN HOUR. QUIET
CONDITIONS PREVAILED FOR THE LAST THREE HOURS OF THE REPORTING
PERIOD.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO BE MOSTLY UNSETTLED FOR THE NEXT THREE DAYS, BUT THERE
IS A FAIR CHANCE FOR SOME ACTIVE PERIODS, ESPECIALLY AT HIGH
LATITUDES. THE ENHANCED ACTIVITY IS POSSIBLE DUE TO ADDITIONAL
CORONAL HOLES THAT WILL BE ROTATING INTO FAVORABLE POSITIONS.
III.  EVENT PROBABILITIES 09 SEP-11 SEP
CLASS M    25/25/25
CLASS X    01/01/01
PROTON     01/01/01
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           08 SEP 106
PREDICTED   09 SEP-11 SEP  105/105/100
90 DAY MEAN        08 SEP 166
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 07 SEP  012/017
ESTIMATED AFR/AP 08 SEP  010/010
PREDICTED AFR/AP 09 SEP-11 SEP  012/012-012/020-010/015
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 09 SEP-11 SEP
A.  MIDDLE LATITUDES
ACTIVE                25/20/20
MINOR STORM           05/05/05
MAJOR-SEVERE STORM    01/01/01
B.  HIGH LATITUDES
ACTIVE                35/25/25
MINOR STORM           10/10/10
MAJOR-SEVERE STORM    05/05/05