NOAA/USAF Report of Solar-Geophysical Activity 13 June 2000

Report of Solar-Geophysical Activity

:Issued: 2000 Jun 13 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 165 ISSUED AT 2200Z ON 13 JUN 2000

IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  12/2100Z

TO 13/2100Z:  SOLAR ACTIVITY CONTINUED AT A LOW LEVEL.  THE LARGEST

EVENT OF THE PERIOD WAS A LONG DURATION C4/SF AT 13/1350Z FROM

REGION 9041 (N18W35).  GROWTH IN THIS REGION SLOWED BUT SOME RECENT

FLARE ACTIVITY HERE WAS SHARED WITH NEARBY REGION 9033 (N24W22).

FREQUENT SUBFLARES WERE OBSERVED FROM REGION 9042 (N19E69).  THIS

REGION SHOWED ITSELF AS A MODERATE SIZE E CLASS GROUP.  REGION 9026

(N23W74) CONTINUED A SLOW DECAY.

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

TO MODERATE.  REGIONS 9026, 9033/9041, AND 9042 APPEAR CAPABLE OF

PRODUCING ISOLATED M-CLASS EVENTS. THE POSSIBILITY FOR MAJOR FLARES

FROM THESE REGIONS IS DECREASING SLOWLY.

IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 12/2100Z TO 13/2100Z:

THE GEOMAGNETIC FIELD WAS PREDOMINANTLY UNSETTLED TO ACTIVE.  A SHOCK

PASSED THE ACE SPACECRAFT AT 12/2140Z AND CREATED A SUDDEN IMPULSE

OF 28 NT AT THE EARTH AT 12/2210Z.  SOLAR WIND VELOCITY INCREASED

FROM 450 KM/S TO OVER 600 KM/S.  HOWEVER, SINCE THAT TIME, VELOCITY

SLOWLY DECREASED AND AT THE END OF THE PERIOD WAS BACK BELOW 450

KM/S.  THIS SHOCK IS BELIEVED RELATED TO THE FULL HALO CORONAL MASS

EJECTION ON 10 JUN.  THE LEVEL OF DISTURBANCE IN THE GEOMAGNETIC

FIELD FOLLOWING THE SHOCK WAS BELOW EXPECTATION.

IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS

EXPECTED TO BE QUIET TO UNSETTLED FOR THE NEXT THREE DAYS.  VERY

ISOLATED ACTIVE PERIODS ARE POSSIBLE. NO RECENT MASS EJECTIONS

APPEAR TO BE EARTH-DIRECTED.

III.  EVENT PROBABILITIES 14 JUN-16 JUN

CLASS M    50/50/50

CLASS X    10/10/10

PROTON     10/10/10

PCAF       GREEN

IV.  PENTICTON 10.7 CM FLUX

OBSERVED           13 JUN 199

PREDICTED   14 JUN-16 JUN  200/195/192

90 DAY MEAN        13 JUN 188

V.  GEOMAGNETIC A INDICES

OBSERVED AFR/AP 12 JUN  012/015

ESTIMATED AFR/AP 13 JUN  016/016

PREDICTED AFR/AP 14 JUN-16 JUN  010/012-010/012-008/010

VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 14 JUN-16 JUN

A.  MIDDLE LATITUDES

ACTIVE                20/15/10

MINOR STORM           05/05/05

MAJOR-SEVERE STORM    01/01/01

B.  HIGH LATITUDES

ACTIVE                20/15/10

MINOR STORM           05/05/05

MAJOR-SEVERE STORM    01/01/01