:Product: 19980423RSGA.txt
:Issued: 1998 Apr 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 113 ISSUED AT 2200Z ON 23 APR 1998
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  22/2100Z
TO 23/2100Z:  SOLAR ACTIVITY WAS HIGH. AN OPTICALLY UNCORRELATED X1
X-RAY BURST WAS DETECTED AT 23/0555Z. THIS ACTIVITY WAS ASSOCIATED
WITH A LARGE CORONAL MASS EJECTED OFF THE SE-NE LIMB NOTED BY
SPACE-BASED SENSORS. FURTHER ANALYSIS INDICATED THE FOOT POINTS OF
THE EJECTION APPEARED TO BE LOCATED NEAR RETURNING REGIONS 8190
(S21,L144) AND 8196 (N18,L144). BOTH REGIONS ARE LESS THAN A DAY
BEHIND THE EAST LIMB. THE X-RAY BURST WAS ACCOMPANIED BY A 10.7CM
RADIO BURST OF 430 SFU, MAKING IT A TENFLARE, AND A TYPE IV SWEEP.
POST FLARE LOOPS WERE OBSERVED AS WELL. NEW SWO REGION 8209
(S22W06), A SMALL AXX GROUP, WAS NUMBERED TODAY.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE LOW
TO MODERATE. AN INCREASE IN ACTIVITY IS EXPECTED WITH THE RETURN OF
REGION 8190, ESPECIALLY IN LIGHT OF TODAY'S ACTIVITY.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 22/2100Z TO 23/2100Z:
THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED. A SHOCK WAS NOTED ON
ALL INSTRUMENTS AT ABOUT 23/1800Z, INDICATED BY AN INCREASE IN SOLAR
WIND DENSITY AND SPEED, AN INCREASE IN PARTICLES DETECTED ON ACE AND
GOES, AND A SMALL IMPULSE NOTED EARTH-BASED AND GEOSYNCHRONOUS
MAGNETOMETERS. THE GREATER THAN 10 MEV PROTON EVENT IS STILL IN
PROGRESS. THE EVENT CONTINUES TO DIMINISH AND IS CURRENTLY AT 30
PFU.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO BE MOSTLY UNSETTLED FOR THE NEXT 24 HOURS AT MID
LATITUDES AND UNSETTLED TO ACTIVE FOR THE NEXT 48 HOURS AT HIGH
LATITUDES. THEREAFTER, THE FIELD IS EXPECTED TO BE QUIET TO
UNSETTLED.
III.  EVENT PROBABILITIES 24 APR-26 APR
CLASS M    15/15/15
CLASS X    10/10/10
PROTON     05/05/05
PCAF       IN PROGRESS
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           23 APR 090
PREDICTED   24 APR-26 APR  092/094/094
90 DAY MEAN        23 APR 104
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 22 APR  005/006
ESTIMATED AFR/AP 23 APR  009/015
PREDICTED AFR/AP 24 APR-26 APR  015/020-010/015-010/012
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 24 APR-26 APR
A.  MIDDLE LATITUDES
ACTIVE                20/15/10
MINOR STORM           10/05/05
MAJOR-SEVERE STORM    05/05/05
B.  HIGH LATITUDES
ACTIVE                20/15/10
MINOR STORM           15/10/10
MAJOR-SEVERE STORM    05/05/05