:Product: 19981230RSGA.txt
:Issued: 1998 Dec 30 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 364 ISSUED AT 2200Z ON 30 DEC 1998
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  29/2100Z
TO 30/2100Z:  SOLAR ACTIVITY WAS MODERATE. REGION 8421 (N26W14)
PRODUCED ALL OF TODAY'S FLARES, INCLUDING THE ONLY M-CLASS EVENT: AN
M1/SF AT 0546Z. THE GROUP SHOWED SLOW GROWTH TODAY, PRIMARILY BY
MEANS OF CONSOLIDATION OF THE LEADER PART OF THE GROUP INTO A
SINGLE, LARGE PENUMBRAL REGION. THE REGION PRODUCED FREQUENT
SUBFLARES THROUGHOUT THE DAY, 7 OF WHICH WERE LOW-LEVEL C-CLASS
EVENTS. IT WOULD APPEAR THAT THE STORAGE OF NON-POTENTIAL MAGNETIC
ENERGY IN THE REGION IS PROMPTLY DISSIPATED BY THESE FREQUENT SMALL
EVENTS. REGION 8419 (N26W65) DECREASED SLOWLY TODAY AND WAS VERY
STABLE. NEW REGION 8425 (S26E50) WAS ASSIGNED TODAY AND IS A SIMPLE,
SMALL, BIPOLAR SUNSPOT GROUP.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE
MODERATE. REGION 8421 IS EXPECTED TO BE THE SOURCE FOR ANY M-CLASS
ACTIVITY OVER THE NEXT THREE DAYS. THERE CONTINUES TO BE A CHANCE
FOR AN ISOLATED MAJOR FLARE EVENT FROM THIS REGION.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 29/2100Z TO 30/2100Z:
THE GEOMAGNETIC FIELD WAS MOSTLY QUIET TO UNSETTLED. THE FIRST THREE
HOURS OF THE REPORTING PERIOD BEGAN WITH MOSTLY UNSETTLED CONDITIONS
WITH A FEW HIGH LATITUDE STATIONS REPORTING ACTIVE CONDITIONS.
CONDITIONS CALMED SLIGHTLY BETWEEN 0000-0700Z WITH ACTIVITY ON THE
BORDERLINE BETWEEN QUIET AND UNSETTLED. SINCE 0700Z, HOWEVER, THE
FIELD HAS BEEN VERY QUIET AT ALL LATITUDES. AN EXAMINATION OF THE
INTERPLANETARY MAGNETIC FIELD COMPONENT BZ SHOWED A NORTHWARD
TURNING OF THE FIELD TO ABOUT +5 NT AT 0500Z.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO BE UNSETTLED TOMORROW IN RESPONSE TO EFFECTS FROM A
FAVORABLY POSITIONED CORONAL HOLE. UNSETTLED CONDITIONS MAY LINGER
INTO THE EARLY PART OF THE SECOND DAY, BUT QUIET CONDITIONS SHOULD
PREVAIL FOR MOST OF THE SECOND AND THIRD DAYS.
III.  EVENT PROBABILITIES 31 DEC-02 JAN
CLASS M    65/65/65
CLASS X    15/15/15
PROTON     15/20/20
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           30 DEC 179
PREDICTED   31 DEC-02 JAN  172/165/160
90 DAY MEAN        30 DEC 136
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 29 DEC  010/016
ESTIMATED AFR/AP 30 DEC  004/010
PREDICTED AFR/AP 31 DEC-02 JAN  010/010-007/010-005/007
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 31 DEC-02 JAN
A.  MIDDLE LATITUDES
ACTIVE                15/15/10
MINOR STORM           05/05/05
MAJOR-SEVERE STORM    01/01/01
B.  HIGH LATITUDES
ACTIVE                15/15/10
MINOR STORM           10/10/05
MAJOR-SEVERE STORM    05/05/01