NOAA/USAF Report of Solar-Geophysical Activity 22 Apr 00

:Product: Report of Solar-Geophysical Activity

:Issued: 2000 Apr 22 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 113 ISSUED AT 2200Z ON 22 APR 2000

IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  21/2100Z

TO 22/2100Z:  SOLAR ACTIVITY WAS LOW. SEVERAL C-CLASS FLARES OCCURRED

FROM A VARIETY OF ACTIVE REGIONS, INCLUDING 8955 (S21W71), 8963

(N17W44), 8967 (N22E23), 8970 (S15E56), 8971 (N17E54), AND 8972

(N33W10). REGION 8963, A SMALL SLOWLY DECAYING SUNSPOT GROUP, WAS

THE MOST ACTIVE. REGION 8970 IS THE LARGEST SUNSPOT GROUP ON THE

DISK BUT APPEARS MAGNETICALLY SIMPLE. NEW REGION 8973 (N20W12)

EMERGED ON THE DISK.

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

TO MODERATE. C-CLASS ACTIVITY IS EXPECTED TO CONTINUE. REGIONS 8963,

8970, 8971, AND 8972 ARE THE MOST LIKELY SOURCE OF ENERGETIC

FLARES.

IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 21/2100Z TO 22/2100Z:

THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED.

IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS

EXPECTED TO BE QUIET TO UNSETTLED.

III.  EVENT PROBABILITIES 23 APR-25 APR

CLASS M    50/50/50

CLASS X    02/02/02

PROTON     02/02/02

PCAF       GREEN

IV.  PENTICTON 10.7 CM FLUX

OBSERVED           22 APR 202

PREDICTED   23 APR-25 APR  210/215/220

90 DAY MEAN        22 APR 184

V.  GEOMAGNETIC A INDICES

OBSERVED AFR/AP 21 APR  007/010

ESTIMATED AFR/AP 22 APR  006/008

PREDICTED AFR/AP 23 APR-25 APR  005/005-005/008-010/008

VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 23 APR-25 APR

A.  MIDDLE LATITUDES

ACTIVE                15/15/15

MINOR STORM           05/05/05

MAJOR-SEVERE STORM    01/01/01

B.  HIGH LATITUDES

ACTIVE                15/15/15

MINOR STORM           05/05/05

MAJOR-SEVERE STORM    01/01/01