NOAA/USAF Report of Solar-Geophysical Activity 13 September 200

:Product: Report of Solar-Geophysical Activity
:Issued: 2000 Sep 13 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 257 ISSUED AT 2200Z ON 13 SEP 2000
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  12/2100Z
TO 13/2100Z:  SOLAR ACTIVITY WAS LOW. AN OPTICALLY UNCORRELATED C2
X-RAY BURST OCCURRED AT 13/1434Z. NEW REGIONS 9164 (S15W13), AND
9165 (N12E30) WERE NUMBERED TODAY. NEW SPOTS RE-EMERGED IN REGIONS
9156 (S27W40) AND 9158 (N31W08). A NEW ACTIVE REGION IS ROTATING ON
THE EAST LIMB.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO CONTINUE
AT LOW LEVELS. OCCASIONAL LOW C-CLASS FLARES ARE EXPECTED.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY 12/2100Z TO 13/2100Z:
THE GEOMAGNETIC FIELD WAS QUIET TO ACTIVE. UNSETTLED TO ACTIVE
CONDITIONS OCCURRED EARLY IN THE PERIOD, BUT MOSTLY QUIET CONDITIONS
PERSISTED SINCE 13/0600Z. THE >10 MEV PROTON EVENT THAT BEGAN AT
12/1555Z IS STILL IN PROGRESS. A MAXIMUM VALUE OF 321 PFU OCCURRED
AT 13/0340Z. THE EVENT HAS BEEN IN SLOW DECAY SINCE THE MAXIMUM AND
IS CURRENTLY AT 93 PFU. THE >100 MEV ENHANCEMENT NEVER REACHED EVENT
THRESHOLD AND IS ALSO SLOWLY RETURNING TO BACKGROUND. THE PCA THAT
BEGAN NEAR 12/1830Z REMAINS IN PROGRESS. PEAK ABSORPTION OBSERVED AT
THULE, GREENLAND WAS 4.6DB AT 13/0603Z. CURRENT ABSORPTION IS
APPROXIMATELY 3DB.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO REMAIN AT QUIET TO UNSETTLED LEVELS THROUGH EARLY DAY
ONE. STORMING IN RESPONSE TO THE CME OBSERVED ON 12 SEP IS EXPECTED
TO BEGIN DURING THE LATTER HALF OF DAY ONE AND CONTINUE THROUGH DAY
TWO. EXPECT CONDITIONS TO RETURN TO UNSETTLED BY DAY THREE. THE >10
MEV PROTON EVENT IS EXPECTED TO END ON DAY ONE.
III.  EVENT PROBABILITIES 14 SEP-16 SEP
CLASS M    10/10/15
CLASS X    01/01/05
PROTON     99/30/05
PCAF       IN PROGRESS
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           13 SEP 133
PREDICTED   14 SEP-16 SEP  130/135/135
90 DAY MEAN        13 SEP 178
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 12 SEP  011/020
ESTIMATED AFR/AP 13 SEP  010/013
PREDICTED AFR/AP 14 SEP-16 SEP  040/045-040/040-015/015
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 14 SEP-16 SEP
A.  MIDDLE LATITUDES
ACTIVE                20/20/35
MINOR STORM           40/40/15
MAJOR-SEVERE STORM    40/40/05
B.  HIGH LATITUDES
ACTIVE                10/10/40
MINOR STORM           45/45/20
MAJOR-SEVERE STORM    45/45/05