:Product: 19991021RSGA.txt
:Issued: 1999 Oct 21 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 294 ISSUED AT 2200Z ON 21 OCT 1999
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  20/2100Z
TO 21/2100Z:  SOLAR ACTIVITY WAS LOW. THERE WERE SEVERAL C-CLASS
SUBFLARES DURING THE DAY. MOST OF THESE WERE FROM REGIONS 8732
(N21W76) AND 8739 (S12E58). REGIONS 8739 AND 8737 (S15W12) BOTH
SHOWED GROWTH DURING THE PAST 24 HOURS. REGION 8731 (N12W68)
CONTINUES TO BE THE LARGEST REGION ON THE DISK BUT WAS RELATIVELY
QUIET AND STABLE.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE LOW
TO MODERATE. REGIONS 8731 AND 8732 CONTINUE TO BE THE MOST LIKELY
SOURCES FOR ENERGETIC FLARES.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 20/2100Z TO 21/2100Z:
THE GEOMAGNETIC FIELD WAS QUIET TO ACTIVE. A SUDDEN IMPULSE WAS
OBSERVED AT 0226Z, WHICH WAS PRECEDED BY A SHOCK OBSERVED AT THE ACE
SPACECRAFT AT 0138Z. THE SHOCK WAS FOLLOWED BY AN INTERPLANETARY
TRANSIENT, BUT THE TRANSIENT WAS NOT VERY GEOEFFECTIVE: ONLY ONE
ACTIVE PERIOD OCCURRED FROM 0300-0600Z. THE REMAINDER OF THE DAY WAS
QUIET TO UNSETTLED. THE GREATER THAN 2 MEV ELECTRON FLUXES EXCEEDED
HIGH LEVELS.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO BE UNSETTLED TO ACTIVE FOR THE NEXT 24 HOURS. THERE IS A
GOOD CHANCE FOR SOME ENHANCED ACTIVITY DURING LOCAL NIGHTTIME HOURS.
CONDITIONS SHOULD SUBSIDE A BIT ON THE SECOND DAY, BUT ANOTHER
INCREASE IS ANTICIPATED ON THE THIRD DAY IN RESPONSE TO A FAVORABLY
POSITIONED CORONAL HOLE.
III.  EVENT PROBABILITIES 22 OCT-24 OCT
CLASS M    40/35/30
CLASS X    10/05/05
PROTON     10/05/05
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           21 OCT 159
PREDICTED   22 OCT-24 OCT  150/145/140
90 DAY MEAN        21 OCT 158
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 20 OCT  004/004
ESTIMATED AFR/AP 21 OCT  012/012
PREDICTED AFR/AP 22 OCT-24 OCT  015/020-015/010-020/015
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 22 OCT-24 OCT
A.  MIDDLE LATITUDES
ACTIVE                40/40/50
MINOR STORM           20/20/30
MAJOR-SEVERE STORM    05/05/10
B.  HIGH LATITUDES
ACTIVE                50/50/40
MINOR STORM           25/25/35
MAJOR-SEVERE STORM    15/15/20