:Product: 19980723RSGA.txt
:Issued: 1998 Jul 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 204 ISSUED AT 2200Z ON 23 JUL 1998
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  22/2100Z
TO 23/2100Z:  SOLAR ACTIVITY HAS BEEN LOW. THREE C-CLASS FLARES WERE
OBSERVED DURING THE PAST 24 HOURS: A C1 FROM REGION 8280 (S21E54) AT
1605Z, A C1 FROM REGION 8281 (N18E45) AT 1630Z, AND A C1 FROM REGION
8282 (N33E56) AT 1745Z. REGIONS 8281 AND 8282 ARE BOTH RELATIVELY
SMALL, BUT ARE GROWING. REGION 8280 CONTINUES TO BE IMPRESSIVE IN
SIZE AND APPEARS TO BE GROWING SLOWLY. NEVERTHELESS, THE REGION IS
REMARKABLY STABLE.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE
PREDOMINANTLY LOW. THERE IS A CHANCE, HOWEVER, FOR AN ISOLATED
M-CLASS EVENT FROM REGION 8280 SOMETIME IN THE NEXT 3-4 DAYS.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 22/2100Z TO 23/2100Z:
THE GEOMAGNETIC FIELD WAS AT ACTIVE TO MINOR STORM LEVELS, WITH SOME
MAJOR STORM PERIODS AT HIGH LATITUDES. THE PERIOD FROM 0300-1500Z
WAS PARTICULARLY DISTURBED AND ATTAINED MAXIMUM  FROM 09-12Z WITH AN
ESTIMATED KP OF 6. THE ACTIVITY WAS ASSOCIATED WITH A HIGH SPEED
STREAM WITH VELOCITIES UP TO 700 KM/S OBSERVED BY ACE. THE
INTERPLANETARY MAGNETIC FIELD COMPONENT, BZ, SHOWED REGULAR, STRONG
FLUCTUATIONS VARYING BETWEEN +10 NT TO -10NT. THIS WAVE ACTIVITY WAS
MANIFESTED IN THE GROUND BASED MAGNETOMETER SIGNATURE AS FREQUENTLY
FLUCTUATING FIELD VARIATIONS. DURING THE LATTER PART OF THE DAY FROM
1500-2100Z THE WAVE ACTIVITY CONTINUED BUT WAS WEAKER (+/- 5 NT),
AND THIS WAS ALSO REFLECTED IN A WEAKENED MAGNETIC DISTANCE:
MID-LATITUDES WERE ACTIVE AND HIGH LATITUDES WERE MOSTLY ACTIVE TO
MINOR STORM. AFTER THE FACT SOLAR ANALYSIS SUGGESTED THAT THE HIGH
SPEED STREAM IS DUE TO AN EXTENSION OF THE NORTHERN POLAR CORONAL
HOLE.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO BE ACTIVE FOR THE NEXT 12 HOURS. THERE MAY BE SOME
ISOLATED STORM LEVEL ACTIVITY AT HIGH-LATITUDES. CONDITIONS ARE
EXPECTED TO RETURN TO PREDOMINANTLY UNSETTLED LEVELS FOR THE LATTER
PART OF TOMORROW AND THROUGH THE REMAINDER OF THE FORECAST PERIOD.
III.  EVENT PROBABILITIES 24 JUL-26 JUL
CLASS M    25/25/25
CLASS X    05/05/05
PROTON     05/05/05
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           23 JUL 115
PREDICTED   24 JUL-26 JUL  115/112/110
90 DAY MEAN        23 JUL 108
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 22 JUL  008/008
ESTIMATED AFR/AP 23 JUL  025/036
PREDICTED AFR/AP 24 JUL-26 JUL  015/015-012/015-010/010
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 24 JUL-26 JUL
A.  MIDDLE LATITUDES
ACTIVE                40/20/15
MINOR STORM           15/05/05
MAJOR-SEVERE STORM    05/01/01
B.  HIGH LATITUDES
ACTIVE                40/25/20
MINOR STORM           20/15/05
MAJOR-SEVERE STORM    10/05/05

THE FOLLOWING CHANGES WILL OCCUR ON MONDAY, 27 JULY:
GOES-9 WILL BE TAKEN OUT OF OPERATIONAL STATUS
GOES-8 WILL BECOME THE PRIMARY SATELLITE
FOR SWO DATA AND PRODUCTS.
GOES-10 WILL BE THE SECONDARY SATELLITE
(THIS NOTICE SUPERCEDES THE EARLIER
DECISION THAT HAD ASSIGNED GOES-10 AS PRIMARY)