:Product: 19990407RSGA.txt
:Issued: 1999 Apr 07 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 097 ISSUED AT 2200Z ON 07 APR 1999
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  06/2100Z
TO 07/2100Z:  SOLAR ACTIVITY WAS LOW. REGION 8508 (N22E25) PRODUCED A
C1/SF AT 07/0924Z. THIS REGION WAS STABLE BUT RETAINED MIXED
MAGNETIC POLARITIES. A LONG DURATION C1 EVENT OCCURRED BETWEEN
06/2335-07/0115Z. THIS EVENT WAS MOST LIKELY ASSOCIATED WITH A LARGE
CORONAL MASS EJECTION FROM THE SOUTHEAST LIMB AS SEEN IN SOHO
CORONAGRAPH DATA. REGION 8506 (S26W55) DECAYED AND SIMPLIFIED DURING
THE PERIOD.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY SHOULD BE PREDOMINANTLY
LOW FOR THE NEXT THREE DAYS. REGION 8508 REMAINS CAPABLE OF
PRODUCING AN OCCASIONAL M-CLASS EVENT.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 06/2100Z TO 07/2100Z:
THE GEOMAGNETIC FIELD RANGED FROM QUIET TO ACTIVE LEVELS. THE MOST
DISTURBED PERIOD WAS FROM 07/0000-0300Z. AT THAT TIME, SOLAR WIND
DATA DID NOT INDICATE A CME LIKE SIGNATURE. THIS SLIGHT DISTURBANCE
APPEARED TO BE RELATED TO A CONSISTENTLY SOUTHWARD ORIENTED
INTERPLANETARY MAGNETIC FIELD. ENERGETIC ELECTRON FLUXES AT
GEOSYNCHRONOUS ORBIT REACHED HIGH LEVELS DURING THE PERIOD.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD SHOULD
REMAIN AT QUIET TO ACTIVE LEVELS FOR 08-09 APR. A WEAK DISTURBANCE
IS EXPECTED ON 08 APR FROM MULTIPLE MASS EJECTIONS OBSERVED ON 04
APR. QUIET TO UNSETTLED CONDITIONS ARE EXPECTED ON 10 APR. THE
ENERGETIC ELECTRON ENHANCEMENT AT GEOSYNCHRONOUS ORBIT SHOULD DECAY
TO NORMAL LEVELS IN THE NEXT 1-2 DAYS.
III.  EVENT PROBABILITIES 08 APR-10 APR
CLASS M    25/25/25
CLASS X    05/05/05
PROTON     05/05/05
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           07 APR 141
PREDICTED   08 APR-10 APR  142/143/139
90 DAY MEAN        07 APR 134
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 06 APR  006/009
ESTIMATED AFR/AP 07 APR  010/010
PREDICTED AFR/AP 08 APR-10 APR  015/012-010/012-010/010
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 08 APR-10 APR
A.  MIDDLE LATITUDES
ACTIVE                30/25/15
MINOR STORM           20/15/05
MAJOR-SEVERE STORM    10/05/01
B.  HIGH LATITUDES
ACTIVE                30/25/15
MINOR STORM           20/15/05
MAJOR-SEVERE STORM    10/10/05