:Product: 19980923RSGA.txt
:Issued: 1998 Sep 23 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 266 ISSUED AT 2200Z ON 23 SEP 1998
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  22/2100Z
TO 23/2100Z:  SOLAR ACTIVITY WAS HIGH DUE TO AN M6.9/3B FLARE THAT
OCCURRED IN REGION 8340 (N20W02) AT 23/0713UT. THIS WAS A LONG
DURATION EVENT THAT ALSO PRODUCED A TYPE II AND A TYPE IV SWEEP.
THERE IS A FAIR POSSIBILITY THAT A PROTON EVENT WAS ALSO GENERATED
DURING THIS ACTIVITY. REGION 8340 ALSO PRODUCED A C2 X-RAY FLARE AND
3 OPTICAL SUBFLARES DURING THE PERIOD. OTHER ACTIVE REGIONS WERE
8344 (S20E09) WHICH PRODUCED A C9/SF AT 23/0038UT AND REGION 8343
(N38E13) WHICH PRODUCED A SINGLE OPTICAL SUB FLARE DURING THE
PERIOD. THE REST OF THE REGIONS WERE STABLE AND MOSTLY QUIET.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE LOW
TO MODERATE. REGION 8340 CAN BE EXPECTED TO PRODUCE CONTINUED
C-CLASS FLARES AND A POSSIBLE M-CLASS EVENT.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 22/2100Z TO 23/2100Z:
GEOMAGNETIC ACTIVITY WAS QUIET TO UNSETTLED.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO BE QUIET TO UNSETTLED WITH POSSIBLE ACTIVE PERIODS AT
HIGH LATITUDES. THERE IS A FAIR CHANCE OF A PROTON EVENT RESULTING
FROM THE M6 FLARE AND THE ASSOCIATED TYPE II AND IV SWEEPS THAT
OCCURRED ON 23/0713. PROJECTED ARRIVAL OF THE PROTON EVENT IS EARLY
ON 24 SEPT AT AROUND 0300UT.
III.  EVENT PROBABILITIES 24 SEP-26 SEP
CLASS M    30/30/25
CLASS X    05/05/01
PROTON     05/05/01
PCAF       YELLOW
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           23 SEP 143
PREDICTED   24 SEP-26 SEP  150/150/155
90 DAY MEAN        23 SEP 129
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 22 SEP  006/010
ESTIMATED AFR/AP 23 SEP  012/012
PREDICTED AFR/AP 24 SEP-26 SEP  020/020-040/040-020/020
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 24 SEP-26 SEP
A.  MIDDLE LATITUDES
ACTIVE                30/50/30
MINOR STORM           15/30/15
MAJOR-SEVERE STORM    05/10/05
B.  HIGH LATITUDES
ACTIVE                50/65/50
MINOR STORM           10/30/10
MAJOR-SEVERE STORM    01/05/01