FROM SPACE ENVIRONMENT SERVICES CENTER, BOULDER, COLORADO
SDF NUMBER 274
JOINT USAF/NOAA REPORT OF SOLAR AND GEOPHYSICAL ACTIVITY.
ISSUED 2200Z 30 SEP 1988
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM 29/2100Z
TO 30/2100Z:  SOLAR ACTIVITY HAS BEEN MODERATE. REGION 5171
(S25E21) PRODUCED AN M1.7/2N FLARE THAT BEGAN AT 1859Z, REACHED
MAXIMUM AT 1922Z AND ENDED AT 2021Z. THE EVENT WAS ACCOMPANIED
BY A TYPE II SWEEP WITH ESTIMATED SHOCK VELOCITY OF 1700 KM/S
AND A SUBSEQUENT TYPE IV SWEEP. THE REGION WAS A BETA-GAMMA-
DELTA MAGNETIC CLASS FOR THE EARLY PART OF THE DAY BUT MORE
RECENT REPORTS INDICATE THAT THE REGION HAS EVOLVED TO A
SIMPLER, BETA TYPE CLASSIFICATION. REGION 5168 (N19W16)
PRODUCED A C6.0/SF AT 0108Z BUT WAS OTHERWISE FAIRLY STABLE.
SIGNIFICANT SURGE ACTIVITY WAS OBSERVED ON THE EAST LIMB AT
ABOUT S16 AND WAS ASSOCIATED WITH ENHANCED CORONAL YELLOW
LINE EMISSION. THE REMAINDER OF THE SOLAR DISK AND LIMBS
WERE QUIET AND STABLE.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE
AT LOW TO MODERATE LEVELS AS REGIONS 5171 AND 5168 CONTINUE TO
POSE A THREAT FOR ENERGETIC FLARES.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 29/2100Z TO 30/2100Z:
THE GEOMAGNETIC FIELD WAS MOSTLY QUIET UNTIL APPROXIMATELY
1500Z WHEN CONDITIONS BECAME UNSETTLED TO ACTIVE.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO BE MOSTLY UNSETTLED TO ACTIVE. CONDITIONS ON THE
SECOND DAY AND THIRD DAYS MAY BE ENHANCED SOMEWHAT IN RESPONSE
TO THE M5/3B FLARE OF 28 SEPTEMBER: MID-LATITUDES ARE EXPECTED
TO BE UNSETTLED TO ACTIVE AND HIGH-LATITUDES ARE EXPECTED TO
BE AT ACTIVE TO MINOR STORM LEVELS.
III.  EVENT PROBABILITIES 01 OCT-03 OCT
CLASS M    50/50/50
CLASS X    05/05/05
PROTON     05/10/10
PCAF       GREEN
IV.  OTTAWA 10.7 CM FLUX
OBSERVED           30 SEP  172
PREDICTED   01 OCT-03 OCT  172/170/168
90 DAY MEAN        30 SEP  153
V.  GEOMAGNETIC A INDICES
OBSERVED  AFR/AP 29 SEP  002/010
ESTIMATED AFR/AP 30 SEP  008/015
PREDICTED AFR/AP 01 OCT-03 OCT  012/025-018/035-012/030