:Product: 19990113RSGA.txt
:Issued: 1999 Jan 13 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 013 ISSUED AT 2200Z ON 13 JAN 1999
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  12/2100Z
TO 13/2100Z:  SOLAR ACTIVITY HAS BEEN LOW FOR THE PAST 24 HOURS. NINE
C-CLASS EVENTS OCCURRED PRIMARILY ASSOCIATED WITH REGIONS 8439
(S24E66) AND NEW REGION 8440 (N21E71). THESE REGIONS APPEAR TO BE
FLARING SYMPATHETICALLY.  A BRIGHT SURGE OUT TO 0.19R FROM N23E90
(BEHIND REGION 8440) WAS REPORTED BETWEEN 1914-1936 UT. ADDITIONAL
SURGING ON THE EAST LIMB NEAR N20 MAY BE SIGNALING THE RETURN OF ANY
OF SEVERAL REGIONS EXPECTED OVER THE NEXT 3 DAYS. THE REMAINDER OF
THE LIMBS AND DISK WERE QUIET.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE LOW
TO MODERATE BASED ON THE FLARE POTENTIAL IN REGIONS 8439 AND 8440,
AND THE LIKLIHOOD OF THE RETURN OF ACTIVE REGIONS OVER THE NORTHEAST
LIMB OF THE SUN.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 12/2100Z TO 13/2100Z:
GEOMAGNETIC ACTIVITY HAS BEEN AT QUIET TO MINOR STORM LEVELS FOR THE
PAST 24 HOURS. ACTIVITY INCREASED AFTER A SUDDEN IMPULSE AT 1055 UT.
SOLAR WIND DATA FROM THE ACE SPACECRAFT SHOWED THE PASSAGE OF A
SHOCK AT 0959 UT THAT WAS FOLLOWED BY ENHANCED, SOUTHWARD
INTERPLANETARY MAGNETIC FIELDS (-20 NT). THIS DISTURBANCE MAY HAVE
ORIGINATED ON 9 JANUARY IN ASSOCIATION WITH A FILAMENT DISAPPEARANCE
IN THE NORTH CENTER OF THE SUN AND/OR A LONG-DURATION C1 X-RAY
EVENT. THE GREATER THAN 2 MEV ELECTRON FLUX LEVELS AT GEOSYNCHRONOUS
ORBIT, WHICH ATTAINED HIGH LEVELS ON 12 JANUARY, FELL BELOW EVENT
THRESHOLD AT 12/1835 UT.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO BE PRIMARILY UNSETTLED TO ACTIVE FOR THE NEXT THREE DAYS
WITH THE POSSIBILITY OF OCCASIONAL MINOR STORM CONDITIONS TOMORROW
AS TODAY'S TRANSIENT SOLAR WIND EVENT COMPLETES ITS PASSAGE BEYOND
EARTH.
III.  EVENT PROBABILITIES 14 JAN-16 JAN
CLASS M    30/30/30
CLASS X    10/10/10
PROTON     01/01/05
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           13 JAN 119
PREDICTED   14 JAN-16 JAN  130/140/150
90 DAY MEAN        13 JAN 138
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 12 JAN  003/006
ESTIMATED AFR/AP 13 JAN  015/020
PREDICTED AFR/AP 14 JAN-16 JAN  015/015-010/012-010/009
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 14 JAN-16 JAN
A.  MIDDLE LATITUDES
ACTIVE                30/20/10
MINOR STORM           10/05/01
MAJOR-SEVERE STORM    05/01/01
B.  HIGH LATITUDES
ACTIVE                30/20/10
MINOR STORM           20/10/05
MAJOR-SEVERE STORM    05/05/01