:Product: 19990911RSGA.txt
:Issued: 1999 Sep 11 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 254 ISSUED AT 2200Z ON 11 SEP 1999
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  10/2100Z
TO 11/2100Z:  SOLAR ACTIVITY INCREASED TO LOW LEVELS BY VIRTUE OF AN
OPTICALLY UNCORRELATED C1 X-RAY FLARE AT 11/0631Z. ISOLATED B-CLASS
X-RAY FLARES WERE ALSO DETECTED, ONE OF WHICH WAS ASSOCIATED WITH A
SUBFLARE IN REGION 8690 (N14E06). REGION 8690 DISPLAYED A SMALL
INCREASE IN SPOT COUNT DURING THE PERIOD, BUT WAS OTHERWISE
UNREMARKABLE. NEW REGIONS 8696 (N14W48), 8697 (S20W06), 8698
(S16E64), AND 8699 (N21E29) WERE ASSIGNED TODAY. REGION 8699
APPEARED TO BE GROWING AT A MODERATE PACE AND PRODUCED A SMALL
SUBFLARE LATE IN THE PERIOD.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO REMAIN
AT LOW LEVELS. REGIONS 8690, 8692, AND 8699 MAY PRODUCE C-CLASS
FLARES.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 10/2100Z TO 11/2100Z:
GEOMAGNETIC FIELD ACTIVITY RANGED FROM QUIET TO ACTIVE LEVELS.
UNSETTLED TO ACTIVE LEVELS OCCURRED DURING 11/0100 - 0500Z FOLLOWING
A SOUTHWARD TURNING OF THE BZ COMPONENT OF THE INTERPLANETARY
MAGNETIC FIELD. FIELD ACTIVITY DECLINED TO MOSTLY QUIET LEVELS AFTER
11/0500Z.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  GEOMAGNETIC FIELD ACTIVITY IS
EXPECTED TO VARY FROM QUIET TO ACTIVE LEVELS. INTERMITTENT ACTIVE
PERIODS ARE EXPECTED IN RESPONSE TO RECURRENT CORONAL HOLE EFFECTS.
III.  EVENT PROBABILITIES 12 SEP-14 SEP
CLASS M    25/25/25
CLASS X    01/01/01
PROTON     01/01/01
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           11 SEP 123
PREDICTED   12 SEP-14 SEP  125/125/130
90 DAY MEAN        11 SEP 164
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 10 SEP  012/015
ESTIMATED AFR/AP 11 SEP  010/015
PREDICTED AFR/AP 12 SEP-14 SEP  015/015-015/015-015/015
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 12 SEP-14 SEP
A.  MIDDLE LATITUDES
ACTIVE                35/35/35
MINOR STORM           10/10/10
MAJOR-SEVERE STORM    01/01/01
B.  HIGH LATITUDES
ACTIVE                40/40/40
MINOR STORM           15/15/15
MAJOR-SEVERE STORM    05/05/05