:Product: 19981223RSGA.txt
:Issued: 1998 Dec 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 357 ISSUED AT 2200Z ON 23 DEC 1998
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  22/2100Z
TO 23/2100Z:  SOLAR ACTIVITY WAS MODERATE. A SERIES OF OPTICALLY
UNCORRELATED X-RAY EVENTS OCCURRED THROUGH THE PERIOD. THE FIRST WAS
A C6 AT 22/2351Z. A LONG DURATION M2 OCCURRED AT 23/0659Z WITH AN
ASSOCIATED TYPE II AND TYPE IV RADIO SWEEP. THE TYPE II SHOCK SPEED
WAS 850 KM/S. THIS EVENT WAS FOLLOWED SOON AFTER BY AN M1 AT
23/0816Z. POST FLARE LOOPS OBSERVED AT N24E89 SUGGEST NEW REGION
NUMBERED TODAY AS 8421 (N29E83) WAS THE LIKELY SOURCE REGION FOR ALL
THESE EVENTS. REGION 8421 APPEARS TO BE A LARGE COMPLEX AREA WHICH
HAS PRODUCED STRONG SURGING SINCE BECOMING VISIBLE ON THE LIMB.
OTHER NEW REGIONS NUMBERED TODAY WERE REGION 8419 (N27E25) AND
REGION 8420 (N18E64). TWO DISAPPEARING FILAMENTS WERE REPORTED, ONE
BETWEEN 22/2320Z AND 23/1713Z AT N23W23 WHICH WAS 10 DEGREES LONG
AND THE OTHER BETWEEN 23/1753-1812Z AT N16E37 WHICH WAS 5 DEGREES
LONG.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY SHOULD BE LOW TO
MODERATE. SEVERAL OF THE REGIONS ON THE DISK ARE CAPABLE OF
PRODUCING OCCASIONAL M-CLASS FLARES ESPECIALLY REGION 8421.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 22/2100Z TO 23/2100Z:
THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO BE QUIET TO SLIGHTLY UNSETTLED THROUGH THE FORECAST
PERIOD.
III.  EVENT PROBABILITIES 24 DEC-26 DEC
CLASS M    40/40/40
CLASS X    05/05/05
PROTON     05/05/05
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           23 DEC 140
PREDICTED   24 DEC-26 DEC  145/148/150
90 DAY MEAN        23 DEC 133
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 22 DEC  002/005
ESTIMATED AFR/AP 23 DEC  008/012
PREDICTED AFR/AP 24 DEC-26 DEC  005/009-005/009-005/009
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 24 DEC-26 DEC
A.  MIDDLE LATITUDES
ACTIVE                10/10/10
MINOR STORM           05/05/05
MAJOR-SEVERE STORM    01/01/01
B.  HIGH LATITUDES
ACTIVE                15/15/15
MINOR STORM           05/05/05
MAJOR-SEVERE STORM    05/05/05