Report of Solar-Geophysical Activity 20 Feb

:Product: Report of Solar-Geophysical Activity

:Issued: 2000 Feb 20 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 051 ISSUED AT 2200Z ON 20 FEB 2000

IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  19/2100Z

TO 20/2100Z:  SOLAR ACTIVITY WAS LOW.  NUMEROUS C-CLASS X-RAY EVENTS

WERE OBSERVED WITH THE LARGEST BEING A C8/1N FROM REGION 8869

(S20W61).  REGIONS 8875 (S22W13) AND 8869 BOTH DISPLAYED SOME GROWTH

DURING THE PERIOD.  REGION 8869 MAINTAINED A BETA-GAMMA MAGNETIC

CLASSIFICATION WITH APPROXIMATELY 41 SUNSPOTS.  NEW REGION 8880

(S08W69) WAS NUMBERED TODAY AND IS CURRENTLY A BETA GROUP WITH 3

SPOTS.

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

TO MODERATE WITH THE POSSIBILITY OF AN ISOLATED M-CLASS EVENT FROM

REGION 8869.

IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 19/2100Z TO 20/2100Z:

THE GEOMAGNETIC FIELD WAS QUIET.

IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS

EXPECTED TO REACH UNSETTLED TO MINOR STORM LEVELS DURING THE FIRST

DAY OF THE PERIOD WITH POSSIBLE MAJOR STORM CONDITIONS AT HIGHER

LATITUDES.  THESE CONDITIONS WILL BE DUE TO A FULL-HALO CME PRODUCED

BY AN EVENT ON 17 FEBRUARY.  THE SECOND AND THIRD DAY OF THE PERIOD

ARE EXPECTED TO BE QUIET TO UNSETTLED.

III.  EVENT PROBABILITIES 21 FEB-23 FEB

CLASS M    35/35/35

CLASS X    05/05/05

PROTON     01/01/01

PCAF       GREEN

IV.  PENTICTON 10.7 CM FLUX

OBSERVED           20 FEB 153

PREDICTED   21 FEB-23 FEB  150/145/135

90 DAY MEAN        20 FEB 165

V.  GEOMAGNETIC A INDICES

OBSERVED AFR/AP 19 FEB  003/004

ESTIMATED AFR/AP 20 FEB  010/010

PREDICTED AFR/AP 21 FEB-23 FEB  030/050-015/030-010/010

VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 21 FEB-23 FEB

A.  MIDDLE LATITUDES

ACTIVE                50/35/25

MINOR STORM           30/15/05

MAJOR-SEVERE STORM    15/05/01

B.  HIGH LATITUDES

ACTIVE                20/40/30

MINOR STORM           60/25/15

MAJOR-SEVERE STORM    15/10/05