NOAA/USAF Report of Solar-Geophysical Activity 27 Apr 2000

:Product: Report of Solar-Geophysical Activity

:Issued: 2000 Apr 27 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 118 ISSUED AT 2200Z ON 27 APR 2000

IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  26/2100Z

TO 27/2100Z:  SOLAR ACTIVITY WAS LOW. INTERMITTENT C-CLASS EVENTS

OCCURRED, WITH REGIONS 8967 (N23W42) AND 8970 (S14W10) THE PRIMARY

CONTRIBUTORS. ALL REGIONS ON THE DISK WERE, IN GENERAL, EITHER

STABLE OR DECAYING. A PROMINENCE ERUPTED FROM THE NW LIMB AT

APPROXIMATELY 1500Z.

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

AT THE LOW LEVEL.

IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 26/2100Z TO 27/2100Z:

THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED.

IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS

EXPECTED TO BE UNSETTLED TO ACTIVE ON 28 APRIL, AS A HIGH SPEED

STREAM MAY HAVE A MINIMAL IMPACT ON THE FIELD. UNSETTLED CONDITIONS

SHOULD PREVAIL FOR THE FINAL TWO DAYS OF THE INTERVAL.

III.  EVENT PROBABILITIES 28 APR-30 APR

CLASS M    30/30/30

CLASS X    01/01/01

PROTON     01/01/01

PCAF       GREEN

IV.  PENTICTON 10.7 CM FLUX

OBSERVED           27 APR 184

PREDICTED   28 APR-30 APR  180/175/175

90 DAY MEAN        27 APR 188

V.  GEOMAGNETIC A INDICES

OBSERVED AFR/AP 26 APR  003/004

ESTIMATED AFR/AP 27 APR  010/011

PREDICTED AFR/AP 28 APR-30 APR  010/018-010/012-010/010

VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 28 APR-30 APR

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