:Product: 19981227RSGA.txt
:Issued: 1998 Dec 27 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 361 ISSUED AT 2200Z ON 27 DEC 1998
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  26/2100Z
TO 27/2100Z:  SOLAR ACTIVITY WAS LOW. TODAY'S ACTIVITY WAS
CHARACTERIZED BY OCCASIONAL C-CLASS FLARES. THE LARGEST OF THESE WAS
A C7/SF FROM REGION 8419 (N27W27) AT 26/2344Z. REGION 8419 GREW
CONSIDERABLY OVER THE LAST 24 HOURS; THE PENUMBRA IN THE GROUP HAS
DEVELOPED AND MATURED AND OBSERVATIONS TOWARD THE END OF THE DAY
INDICATED THE PRESENCE OF A MAGNETIC DELTA CONFIGURATION IN THE
REGION. REGION 8421 (N27E26) SHOWED A LITTLE GROWTH AND OCCASIONAL
SUBFLARES DURING THE DAY. REGION 8422  (S23E38) PRODUCED A FEW
SUBFLARES BUT WAS ESSENTIALLY STABLE. BACKGROUND FLUX LEVELS FOR
X-RAYS AND 10.7 CM INCREASED DURING THE PAST 24 HOURS IN ASSOCIATION
WITH THE GROWTH OF REGION 8419.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE LOW
TO MODERATE. THERE IS A FAIR CHANCE FOR AN ISOLATED M-CLASS EVENT
FROM REGIONS 8419 AND 8421.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 26/2100Z TO 27/2100Z:
THE GEOMAGNETIC FIELD WAS PREDOMINANTLY QUIET DURING THE PAST 24
HOURS. THERE WERE SOME UNSETTLED CONDITIONS BETWEEN 26/2100UT AND
27/0000UT, BUT THE FIELD HAS BEEN VERY QUIET FROM THE START OF THE
UT DAY (27/0000UT) TO THE END OF THE PERIOD (27/2100UT).
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO BE QUIET TO UNSETTLED FOR THE NEXT THREE DAYS.
III.  EVENT PROBABILITIES 28 DEC-30 DEC
CLASS M    50/50/50
CLASS X    10/10/10
PROTON     10/10/10
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           27 DEC 167
PREDICTED   28 DEC-30 DEC  165/165/160
90 DAY MEAN        27 DEC 134
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 26 DEC  012/016
ESTIMATED AFR/AP 27 DEC  005/007
PREDICTED AFR/AP 28 DEC-30 DEC  005/009-010/011-005/009
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 28 DEC-30 DEC
A.  MIDDLE LATITUDES
ACTIVE                05/10/05
MINOR STORM           01/05/01
MAJOR-SEVERE STORM    01/01/01
B.  HIGH LATITUDES
ACTIVE                05/10/05
MINOR STORM           01/05/01
MAJOR-SEVERE STORM    01/01/01