NOAA/USAF Report of Solar-Geophysical Activity 27 September 2000

:Product: Report of Solar-Geophysical Activity
:Issued: 2000 Sep 27 2200 UT
# 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 271 ISSUED AT 2200Z ON 27 SEP 2000
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  26/2100Z
TO 27/2100Z:  SOLAR ACTIVITY WAS LOW.  THE LARGEST EVENT THIS PERIOD
WAS A C9/1N EVENT FROM REGION 9167 (N14W69).  NUMEROUS MINOR C-CLASS
FLARES WERE OBSERVED FROM SEVERAL OTHER REGIONS, SUCH AS 9169
(N12W47), 9173 (S13E38) AND NEW REGION 9176 (S10E68).  SEVERAL OF
THE MINOR C-CLASS WERE OPTICALLY UNCORRELATED.  REGION 9169 SHOWED
NO FURTHER DECAY SINCE YESTERDAY.  THE REGION NOW HAS A BETA GAMMA
MAGNETIC CONFIGURATION.  REGION 9170 (S06W51) SHOWED SLIGHT GROWTH
DURING THE PERIOD AND ALSO NOW HAS A BETA GAMMA CONFIGURATION.  NEW
REGIONS 9176, AND 9177 (N28E01) WERE NUMBERED TODAY.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE LOW
TO MODERATE.  CONTINUED MINOR C-CLASS ACTIVITY IS EXPECTED.  REGIONS
9169 AND 9170 ARE THE MOST LIKELY TO PRODUCE AN ISOLATED M-CLASS
EVENT.  HOWEVER, NEW REGION 9176 NEAR THE EAST LIMB MAY ALSO BE
CAPABLE OF M-CLASS ACTIVITY.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY 26/2100Z TO 27/2100Z:
THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED.  THE AFFECTS ASSOCIATED
WITH THE HIGH-SPEED CORONAL HOLE STREAM APPEAR TO BE SLOWLY
DIMINISHING.  THE SOLAR WIND SPEED, NEAR 600 KM/S YESTERDAY, IS
SLOWLY DECREASING AND IS CURRENTLY AVERAGING 500 - 550 KM/S.  THE
GREATER THAN 2 MEV ELECTRONS AT GEOSYNCHRONOUS ORBIT WERE AT HIGH
LEVELS.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO BE MOSTLY QUIET TO UNSETTLED WITH A CHANCE OF ISOLATED
ACTIVE PERIODS POSSIBLE ON THE FIRST DAY.
III.  EVENT PROBABILITIES 28 SEP-30 SEP
CLASS M    50/50/50
CLASS X    10/10/10
PROTON     05/05/05
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           27 SEP 205
PREDICTED   28 SEP-30 SEP  205/200/195
90 DAY MEAN        27 SEP 181
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 26 SEP  017/021
ESTIMATED AFR/AP 27 SEP  012/013
PREDICTED AFR/AP 28 SEP-30 SEP  012/012-010/010-010/010
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 28 SEP-30 SEP
A.  MIDDLE LATITUDES
ACTIVE                25/20/20
MINOR STORM           15/10/10
MAJOR-SEVERE STORM    01/01/01
B.  HIGH LATITUDES
ACTIVE                35/25/25
MINOR STORM           20/10/10
MAJOR-SEVERE STORM    01/01/01