:Product: 19980828RSGA.txt
:Issued: 1998 Aug 28 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 240 ISSUED AT 2200Z ON 28 AUG 1998
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  27/2100Z
TO 28/2100Z:  SOLAR ACTIVITY HAS BEEN LOW.  REGION 8307 (N32W39)
CONTINUES TO SIMPLIFY.  IT APPEARS TO STILL BE CAPABLE OF PRODUCING
AN ISOLATED CLASS M EVENT.  REGION 8319 (N19W15) CONTINUES TO GROW
AND SHOW SIGNS OF FURTHER DEVELOPMENT WITH AN ACTIVE ARCH-FILAMENT
SYSTEM EXTENDING THE LENGTH OF THE REGION.  YOHKOH REPORTS THAT A
POTENTIAL-LIKE LOOP STRUCTURE IS WELL DEVELOPED.  SMALL GROUPS OF
NEW SPOTS CONTINUE TO APPEAR ACROSS THE FACE OF THE VISIBLE DISK.
OLD REGION 8293 APPEARS TO BE RETURNING AT S21 ON THE EAST LIMB.
FILAMENTS HAVE DISAPPEARED IN THE SOUTH CENTRAL AREA OF THE DISK.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE LOW
TO MODERATE.  FREQUENT FLARES CLASS C TO CLASS M ARE EXPECTED IN
REGION 8319 AND AN ISOLATED CLASS M FLARE MAY OCCUR IN REGION 8307.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 27/2100Z TO 28/2100Z:
GEOPHYSICAL ACTIVITY HAS BEEN UNSETTLED TO ACTIVE.  THE GEOMAGNETIC
STORM HAS DECLINED RAPIDLY AND K-INDICES OF 3 AND 4 ARE PREVALENT AT
MID-LATITUDE.  THE REAL TIME SOLAR WIND DATA FROM ACE SHOWS A
REGULAR WAVE-LIKE STRUCTURE IN THE BZ COMPONENT WITH A PERIOD OF
ABOUT 30 MINUTES.  THE STRUCTURE HAS BEEN QUIRE REGULAR FOR THE LAST
20 HOURS.  THE ENERGETIC PARTICLES WITH ENERGY GREATER THAN 10 MEV
HAVE DECLINED AND ARE HOVERING AT ABOUT 10 PFU.  AN END TO THE EVENT
IS LIKELY TO BE PRONOUNCED IN THE NEXT FEW HOURS.  THE NEUTRON
MONITOR FLUXES HAVE RETURNED TO NEAR-NORMAL LEVELS.  GREATER THAN 2
MEV ELECTRONS AT GOES ARE NOW EXCEEDING A FLUX OF 1.0 E4, A LEVEL 10
TIMES THE ALERT THRESHOLDS.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO BE UNSETTLED TO ACTIVE FOR THE NEXT DAY OR SO.  THE
DISAPPEARANCE OF FILAMENTS IN THE SOUTHERN CENTRAL PORTION OF THE
SUN MAY BE ASSOCIATED WITH CORONAL MASS EJECTIONS THAT COULD BRING
ENHANCED ACTIVITY TO EARTH ON AUGUST 30 AND 31.
III.  EVENT PROBABILITIES 29 AUG-31 AUG
CLASS M    20/20/20
CLASS X    05/05/05
PROTON     25/25/25
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           28 AUG 139
PREDICTED   29 AUG-31 AUG  135/135/135
90 DAY MEAN        28 AUG 118
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 27 AUG  077/112
ESTIMATED AFR/AP 28 AUG  022/030
PREDICTED AFR/AP 29 AUG-31 AUG  010/015-015/015-015/015
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 29 AUG-31 AUG
A.  MIDDLE LATITUDES
ACTIVE                20/20/20
MINOR STORM           01/10/10
MAJOR-SEVERE STORM    01/01/01
B.  HIGH LATITUDES
ACTIVE                25/50/25
MINOR STORM           10/15/15
MAJOR-SEVERE STORM    01/01/01