NOAA/USAF Report of Solar-Geophysical Activity 05 Apr 2000

:Product: Report of Solar-Geophysical Activity

:Issued: 2000 Apr 05 2210 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 096 ISSUED AT 2200Z ON 05 APR 2000

IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  04/2100Z

TO 05/2100Z:  SOLAR ACTIVITY WAS LOW, ONLY C-CLASS FLARES WERE

OBSERVED.  THERE ARE 14 SPOTTED REGIONS VISIBLE ON THE DISK, MOST

APPEAR STABLE OR DECLINING.  REGION 8933 (N18W84)  REMAINS

MAGNETICALLY COMPLEX AS IT BEGINS ITS WEST LIMB TRANSIT.  SOHO

SPACECRAFT CORONAL IMAGES INDICATE THAT A CME, WHICH MAY BE

EARTH-DIRECTED, WAS ASSOCIATED WITH THE C9/2F FLARE FROM THIS REGION

ON 4 APRIL.  REGION 8948 (S15E56) APPEARS TO BE A DAO SPOT GROUP

WITH AN EAST-WEST NEUTRAL LINE.  REGIONS 8949 (S18E76) AND 8950

(N18W64) WERE NUMBERED TODAY.

IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE LOW

TO MODERATE.

IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 04/2100Z TO 05/2100Z:

THE GEOMAGNETIC FIELD WAS MOSTLY UNSETTLED TO ACTIVE.  THE PROTON

EVENT WHICH STARTED AT 04/2055T PEAKED AT 55 PFU AT 05/0930UT AND

CONTINUES IN PROGRESS (CURRENT FLUX IS 20 PFU AT >10MEV).  THE

ASSOCIATED PCA BEGAN AT 05/0653UT, REACHED MAXIMUM OF 2.2 DB AT

05/0950UT AND ENDED AT 05/1807UT.

IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS

EXPECTED TO BE QUIET TO UNSETTLED UNTIL 08 APRIL WHEN THE FIELD IS

EXPECTED TO BECOME ACTIVE WITH THE ARRIVAL OF THE DISTURBANCE FROM

THE CME ASSOCIATED WITH THE C9/2F FLARE AT 04/1541UT.  THE SATELLITE

PROTON EVENT IS EXPECTED TO END IN THE NEXT 24 HOURS.

III.  EVENT PROBABILITIES 06 APR-08 APR

CLASS M    50/50/50

CLASS X    05/05/05

PROTON     05/05/05

PCAF       GREEN

IV.  PENTICTON 10.7 CM FLUX

OBSERVED           05 APR 194

PREDICTED   06 APR-08 APR  190/185/180

90 DAY MEAN        05 APR 185

V.  GEOMAGNETIC A INDICES

OBSERVED AFR/AP 04 APR  023/021

ESTIMATED AFR/AP 05 APR  009/012

PREDICTED AFR/AP 06 APR-08 APR  008/010-008/010-025/025

VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 06 APR-08 APR

A.  MIDDLE LATITUDES

ACTIVE                10/10/30

MINOR STORM           05/05/20

MAJOR-SEVERE STORM    01/01/06

B.  HIGH LATITUDES

ACTIVE                15/15/30

MINOR STORM           05/05/20

MAJOR-SEVERE STORM    01/01/11