Report of Solar-Geophysical Activity 23 Feb

:Product: Report of Solar-Geophysical Activity

:Issued: 2000 Feb 23 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 054 ISSUED AT 2200Z ON 23 FEB 2000

IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  22/2100Z

TO 23/2100Z:  SOLAR ACTIVITY WAS MODERATE DUE TO A SINGLE

UNCORRELATED M1 X-RAY FLARE AT 22/2147Z.  THE FLARE WAS PROBABLY THE

SUPERPOSITION OF THREE EVENTS, A LONG DURATION C9 AND IMPULSIVE M1

AND C7 FLARES, BUT WITHOUT OPTICAL CORRELATION IT IS IMPOSSIBLE TO

BE SURE.  THE REMAINDER OF THE PERIOD SAW NUMEROUS UNCORRELATED

C-CLASS FLARES AMIDST A BACKGROUND X-RAY FLUX AVERAGING NEARLY C2.

THREE NEW REGIONS WERE NUMBERED TODAY, 8884 (S11W74), 8885 (N11W43),

AND 8886 (S14E31).

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

PREDOMINANTLY LOW, WITH ISOLATED M-CLASS FLARES POSSIBLE.  SOLAR

ACTIVITY IS EXPECTED TO BE ON THE RISE BY THE END OF THE PERIOD.

IMAGERY FROM THE YOHKOH SOFT X-RAY TELESCOPE SUGGESTS AT LEAST TWO

LARGE ACTIVE REGIONS WILL SOON BE ROTATING ONTO THE DISK.

IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 22/2100Z TO 23/2100Z:

THE GEOMAGNETIC FIELD WAS PREDOMINANTLY QUIET TO UNSETTLED.  THE

FIELD INCREASED TO ACTIVE BETWEEN 15Z AND 18Z DUE TO THE ARRIVAL OF

A CO-ROTATING INTERACTION REGION (CIR) SEEN IN ACE DATA.  THIS CIR

BROUGHT INCREASED SOLAR WIND VELOCITIES AND MAGNETIC FIELD STRENGTH;

BZ FLUCTUATED WILDLY BETWEEN -15 AND 10 NT.  THE CIR HERALDS THE

EXPECTED RETURN OF A HIGH SPEED CORONAL HOLE STREAM.

IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS

EXPECTED TO BE UNSETTLED TO ACTIVE IN THE MIDDLE LATITUDES AND

UNSETTLED TO MINOR STORM IN THE HIGHER LATITUDES FOR THE FIRST TWO

DAYS OF THE FORECAST PERIOD DUE TO THE EFFECTS OF A RECURRENT

CORONAL HOLE STREAM.  ON THE THIRD DAY ACTIVITY IS EXPECTED TO

DIMINISH.

III.  EVENT PROBABILITIES 24 FEB-26 FEB

CLASS M    30/30/30

CLASS X    05/05/05

PROTON     01/01/01

PCAF       GREEN

IV.  PENTICTON 10.7 CM FLUX

OBSERVED           23 FEB 185

PREDICTED   24 FEB-26 FEB  185/185/190

90 DAY MEAN        23 FEB 164

V.  GEOMAGNETIC A INDICES

OBSERVED AFR/AP 22 FEB  005/005

ESTIMATED AFR/AP 23 FEB  010/012

PREDICTED AFR/AP 24 FEB-26 FEB  020/023-020/018-015/015

VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 24 FEB-26 FEB

A.  MIDDLE LATITUDES

ACTIVE                50/50/35

MINOR STORM           15/15/05

MAJOR-SEVERE STORM    01/01/01

B.  HIGH LATITUDES

ACTIVE                60/60/45

MINOR STORM           20/20/10

MAJOR-SEVERE STORM    05/05/01