:Product: 20000523RSGA.txt
:Issued: 2000 May 23 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 144 ISSUED AT 2200Z ON 23 MAY 2000
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  22/2100Z
TO 23/2100Z:  SOLAR ACTIVITY WAS LOW. THE LARGEST EVENT WAS A C9/2F
FROM REGION 9002 (N20W37). THIS REGION, DESPITE OBVIOUS DECAY IN
WHITE LIGHT, EMERGED AS THE MOST ACTIVE REGION ON THE VISIBLE DISK
AND PRODUCED SEVERAL SMALL FLARES DURING THE LATTER HALF OF THE
PERIOD. A SPOTLESS, UNNUMBERED REGION NEAR N07W05 PRODUCED A C5/1N
AT 23/1106Z. REGION 8996 (S20W77) CONTINUES TO BE QUITE ACTIVE, BUT
ALL FLARE ACTIVITY WAS IN THE LOW C-CLASS CATEGORY. REGION 9004
(N12W48) EXHIBITED LITTLE CHANGE IN SIZE BUT DEVELOPED INCREASED
MAGNETIC COMPLEXITY AND PRODUCED A C5/SF AT 23/1945Z.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO CONTINUE
AT LOW TO MODERATE LEVELS. REGIONS 8996, 9002 AND 9004 MAY PRODUCE
AN ISOLATED M-CLASS FLARE.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 22/2100Z TO 23/2100Z:
THE GEOMAGNETIC FIELD WAS AT QUIET TO ACTIVE LEVELS. QUIET TO
UNSETTLED CONDITIONS PRECEDED A WEAK SHOCK OBSERVED AT ACE AT
23/1625Z. THE ACE SIGNATURE WAS CONSISTENT WITH A GEOEFFECTIVE
TRANSIENT THAT LIKELY ORIGINATED FROM THE C7/1N FLARE AND CME AT
20/0535Z. BZ INITIALLY WENT NORTHWARD, BUT QUICKLY TURNED SOUTHWARD
AT 23/1830Z REACHING NEAR -20NT AND RESULTING IN MINOR STORMING AT
HIGH LATITUDES. BZ RETURNED TO MORE NOMINAL CONDITIONS BY END OF
PERIOD.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO BE AT UNSETTLED TO MINOR STORM LEVELS. ACTIVE TO MINOR
STORM LEVELS ARE LIKELY THROUGH DAY ONE FOLLOWING TODAY'S SHOCK
ARRIVAL. MOSTLY QUIET TO UNSETTLED CONDITIONS SHOULD PREVAIL THROUGH
DAYS 2 AND 3.
III.  EVENT PROBABILITIES 24 MAY-26 MAY
CLASS M    50/50/40
CLASS X    10/10/05
PROTON     05/05/01
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           23 MAY 204
PREDICTED   24 MAY-26 MAY  195/185/180
90 DAY MEAN        23 MAY 197
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 22 MAY  008/009
ESTIMATED AFR/AP 23 MAY  017/015
PREDICTED AFR/AP 24 MAY-26 MAY  018/018-015/010-010/010
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 24 MAY-26 MAY
A.  MIDDLE LATITUDES
ACTIVE                50/30/30
MINOR STORM           30/10/10
MAJOR-SEVERE STORM    15/01/01
B.  HIGH LATITUDES
ACTIVE                40/40/40
MINOR STORM           40/15/15
MAJOR-SEVERE STORM    20/05/05