NOAA/USAF Report of Solar-Geophysical Activity 28 Apr 2000

:Product: Report of Solar-Geophysical Activity

:Issued: 2000 Apr 28 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 119 ISSUED AT 2200Z ON 28 APR 2000

IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  27/2100Z

TO 28/2100Z:  SOLAR ACTIVITY WAS LOW. ONLY TWO C-CLASS EVENTS

OCCURRED DURING THE PERIOD, THE LARGEST BEING A C5/1N WITH AN

ACCOMPANYING TYPE II RADIO SWEEP (VELOCITY – 500 KM/S) AT 28/1851UT,

FROM REGION 8967 (N19W60). THREE NEW REGION WERE NUMBERED TODAY:

8976 (S11E03), 8977 (S14W04), AND 8978 (N19E04). ALL THREE NEW

REGIONS SHOWED SIGNS OF ACTIVITY AND FAIRLY STEADY GROWTH DURING THE

DAY.

IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO CONTINUE

TO BE LOW.

IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 27/2100Z TO 28/2100Z:

THE GEOMAGNETIC FIELD WAS MOSTLY QUIET TO UNSETTLED WITH ISOLATED

ACTIVE PERIODS.

IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS

EXPECTED TO BE QUIET TO UNSETTLED.

III.  EVENT PROBABILITIES 29 APR-01 MAY

CLASS M    30/30/30

CLASS X    01/01/01

PROTON     01/01/01

PCAF       GREEN

IV.  PENTICTON 10.7 CM FLUX

OBSERVED           28 APR 183

PREDICTED   29 APR-01 MAY  180/175/175

90 DAY MEAN        28 APR 188

V.  GEOMAGNETIC A INDICES

OBSERVED AFR/AP 27 APR  012/013

ESTIMATED AFR/AP 28 APR  012/018

PREDICTED AFR/AP 29 APR-01 MAY  010/012-010/010-010/010

VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 29 APR-01 MAY

A.  MIDDLE LATITUDES

ACTIVE                20/20/20

MINOR STORM           05/05/05

MAJOR-SEVERE STORM    01/01/01

B.  HIGH LATITUDES

ACTIVE                30/30/30

MINOR STORM           05/05/05

MAJOR-SEVERE STORM    01/01/01