:Product: 19980506RSGA.txt
:Issued: 1998 May 06 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 126 ISSUED AT 2200Z ON 06 MAY 1998
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  05/2100Z
TO 06/2100Z:  SOLAR ACTIVITY WAS HIGH. REGION 8210 (S15W75) PRODUCED
AN X2/1N FLARE AT 0809Z WHICH HAD VERY STRONG ASSOCIATED RADIO
BURSTS AND A TYPE IV RADIO SWEEP. THE X2 WAS JUST PRECEDED BY AN M2
FROM THE SAME REGION AT 0725Z. REGION 8210 ALSO PRODUCED AN M2/2N
FLARE AT 05/2346Z WHICH HAD ASSOCIATED TYPE II AND TYPE IV SWEEPS.
LASCO OBSERVERS REPORTED THREE CORONAL MASS EJECTIONS DURING THE
TIME PERIOD: THE FIRST WAS A PARTIAL HALO AT 0002Z AND COULD BE
REASONABLY ASSOCIATED WITH THE M2/2N. THE SECOND WAS AT 0228Z FROM
THE NORTH EAST AND APPEARS TO BE AN EVENT BEHIND THE LIMB. THE
THIRD, SEEN AT 0829Z WAS A LARGE AND RELATIVELY FAST EVENT THAT APPEARS
TO BE ASSOCIATED WITH THE X2 FLARE. REGION 8214 (N28W34) HAS NOT
BEEN IMPRESSIVE IN TERMS OF FLARE PRODUCTION, BUT IT CONTINUES TO
GROW IN COMPLEXITY AND CONTINUES TO DISPLAY VERY HOT PLAGE. SOME
OPPOSITE POLARITY FLUX IS EMERGING JUST WEST OF THE LEADER SPOT, AND
THIS PART OF THE GROUP APPEARS TO BE THE 'HOT SPOT' IN THE REGION.
REGION 8210 (S15W75) IS APPROACHING WEST LIMB, MAKING ANALYSIS MORE
DIFFICULT. THERE MAY BE SOME REFORMING OF THE DELTA CONFIGURATION IN
THE LEADER SPOT. A 10 DEGREE FILAMENT NEAR N20W46
DISAPPEARED BETWEEN 05/1130Z AND 06/0657Z.NEW REGION 8218 (S23E74)
WAS ASSIGNED TODAY AND IS A SIMPLE AXX SPOT GROUP.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE
MODERATE. THERE CONTINUES TO BE A FAIR CHANCE FOR MORE MAJOR FLARES,
PARTICULARLY FROM REGION 8210. REGION 8214 ALSO HAS A GOOD CHANCE OF
PRODUCING M-CLASS EVENTS AND SOME POSSIBILITY FOR MAJOR FLARES OR
PROTON EVENTS.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 05/2100Z TO 06/2100Z:
THE GEOMAGNETIC FIELD HAS BEEN QUIET TO UNSETTLED. A GREATER THAN 10
MEV PROTON EVENT BEGAN AT 0835Z AND QUICKLY REACHED A MAXIMUM OF 210
PFU AT 0945Z. THE GREATER THAN 100 MEV PROTONS WERE ALSO ENHANCED
AND REACHED EVENT LEVEL (GREATER THAN 1 PFU)  AT 0830Z. THE GREATER
THAN 100 MEV PROTONS REACHED A MAXIMUM OF 2.9 PFU AT 0840 AND
DROPPED BELOW THRESHOLD AT 1335Z. THIS PROTON EVENT SHOWED SPECTRAL
CHARACTERISTICS THAT ARE TYPICAL OF WELL-CONNECTED EVENTS. THE FLUX
LEVELS WERE STEADILY DECLINING AT FORECAST ISSUE TIME.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD SHOULD BE
MOSTLY UNSETTLED UNTIL THE POSSIBLE ARRIVAL OF EFFECTS FROM THE
LEADING EDGE OF TODAY'S CME EVENTS ASSOCIATED WITH REGION 8210. THE
LATER CME WAS SUFFICIENTLY FAST THAT IT WILL VERY LIKELY OVERTAKE THE
EARLIER CME. ARRIVAL OF THE SHOCK IS EXPECTED VERY LATE ON THE 7TH
OR EARLY ON THE 8TH, AND A PERIOD OF STRONG ACTIVITY IS LIKELY
SHORTLY THEREAFTER. MID-LATITUDES ARE EXPECTED TO BE AT MINOR TO
MAJOR STORM LEVELS AND HIGH LATITUDES COULD HAVE PERIODS OF
SEVERE STORM LEVELS. CONDITIONS ARE LIKELY TO  PERSIST AT ACTIVE TO
MINOR STORM LEVELS THROUGH 09/1200Z, AFTER WHICH ACTIVITY SHOULD
CALM DOWN TO MOSTLY UNSETTLED CONDITIONS. THE PROTON EVENT IS
EXPECTED TO END WITHIN THE NEXT 12 HOURS.
III.  EVENT PROBABILITIES 07 MAY-09 MAY
CLASS M    75/75/65
CLASS X    20/20/15
PROTON     20/20/15
PCAF       YELLOW
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           06 MAY 130
PREDICTED   07 MAY-09 MAY  130/125/125
90 DAY MEAN        06 MAY 106
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 05 MAY  023/036
ESTIMATED AFR/AP 06 MAY  007/010
PREDICTED AFR/AP 07 MAY-09 MAY  010/020-045/050-020/025
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 07 MAY-09 MAY
A.  MIDDLE LATITUDES
ACTIVE                20/10/20
MINOR STORM           20/25/20
MAJOR-SEVERE STORM    15/45/15
B.  HIGH LATITUDES
ACTIVE                20/10/20
MINOR STORM           20/20/30
MAJOR-SEVERE STORM    15/50/35