:Product: Report of Solar-Geophysical Activity
:Issued: 2000 Apr 04 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 095 ISSUED AT 2200Z ON 04 APR 2000
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  03/2100Z
TO 04/2100Z:  SOLAR ACTIVITY WAS MODERATE.  AN M1 FLARE OCCURRED AT
04/0132UT.  THIS EVENT WAS NOT REPORTED BY GROUND BASED
OBSERVATORIES, BUT IS COINCIDENT WITH ACTIVITY FROM REGION 8948
(S15E70) AS SEEN BY THE SOHO SPACECRAFT.  REGION 8948 CONTAINS A CSO
SPOT GROUP AND IS IN THE AREA OF RETURNING REGION 8906.  REGION 8933
(N17W70) PRODUCED A C9/2F FLARE AT 04/1541UT.  THIS EVENT WAS
ACCOMPANIED BY A DSF AND IS PROBABLY THE SOURCE OF THE INCREASE OF
ENERGETIC PARTICLES SEEN AT THE GOES SPACECRAFT STARTING AROUND
04/1700UT.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE LOW
TO MODERATE.  THERE IS A CHANCE OF M FLARES FROM REGIONS 8933, 8936,
AND 8948.  REGION 8910 (N11 L=069) IS DUE TO RETURN TO THE EAST LIMB
ON 7 APRIL AND COULD INCREASE THE LEVEL OF ACTIVITY.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 03/2100Z TO 04/2100Z:
THE GEOMAGNETIC FIELD HAS RANGED FROM QUIET TO MAJOR STORM.  A K=6
WAS OBSERVED AT BOULDER FOR THE 0300UT TIME PERIOD.  THE FIELD
RETURNED TO QUIET LEVELS BY 0900UT ONLY TO BECOME ACTIVE AGAIN BY
1500UT.  SOLAR WIND DATA FROM THE ACE SPACECRAFT INDICATE THAT THIS
ACTIVITY WAS ASSOCIATED WITH CHANGES IN THE INTERPLANETARY MAGNETIC
FIELD.  BZ BEGAN THE DAY AROUND -7NT, TURNED POSITIVE (10NT) AROUND
0200UT AND RETURNED NEGATIVE (-7NT) AFTER 1100UT.  FLUXES  OF >10MEV
PROTONS BEGAN TO INCREASE AFTER 04/1700UT, AND REACH 10PFU AT
04/2030UT.  THIS INCREASE IS PROBABLY RELATED TO THE C9 FLARE FROM
REGION 8933 AS REPORTED IN PART 1A.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO BE QUIET TO ACTIVE.
III.  EVENT PROBABILITIES 05 APR-07 APR
CLASS M    50/50/50
CLASS X    05/05/05
PROTON     05/05/05
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           04 APR 207
PREDICTED   05 APR-07 APR  205/200/200
90 DAY MEAN        04 APR 184
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 03 APR  012/012
ESTIMATED AFR/AP 04 APR  022/020
PREDICTED AFR/AP 05 APR-07 APR  010/015-008/012-008/010
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 05 APR-07 APR
A.  MIDDLE LATITUDES
ACTIVE                25/10/10
MINOR STORM           10/05/05
MAJOR-SEVERE STORM    01/01/01
B.  HIGH LATITUDES
ACTIVE                30/15/15
MINOR STORM           15/05/05
MAJOR-SEVERE STORM    01/01/01