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

Report of Solar-Geophysical Activity

:Issued: 2000 May 13 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 134 ISSUED AT 2200Z ON 13 MAY 2000

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

TO 13/2100Z:  SOLAR ACTIVITY WAS MODERATE.  TWO M1 X-RAY FLARES

OCCURRED, ONE OPTICALLY UNCORRELATED AT 13/0144UT, THE OTHER AN SF

FLARE FROM 8998 (S13E66) AT 12/2329UT.  A WEAK TYPE II RADIO SWEEP

(581 KM/S)  PRECEDED THE OPTICAL FLARE.  A LARGE CME WAS SEEN

ERUPTING FROM THE NE LIMB IN LASCO C2 AT 12/2325UT.  EIT IMAGERY

INDICATES THAT THIS CME ORIGINATED BEHIND THE LIMB AND IS NOT EARTH

DIRECTED.  REGION 8996 (S22E57) MORE THAN DOUBLED IN SIZE TO AN AREA

OF 1210 MILLIONTHS. TWO NEW REGIONS WERE NUMBERED TODAY, 8999

(S13E66) AND 9000 (N10E14).

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

TO MODERATE.  A NUMBER OF REGIONS ON THE DISK ARE CAPABLE OF

PRODUCING M FLARES AND X-RAY IMAGERY INDICATES ANOTHER STRONG REGION

IS ROTATING OVER THE NE LIMB.

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

THE GEOMAGNETIC FIELD WAS QUIET TO ACTIVE.  DATA FROM THE ACE

SPACECRAFT INDICATE THE PRESENCE OF A WEAK HIGH SPEED STREAM FROM A

SMALL CORONAL HOLE.

IIB.  GEOPHYSICAL ACTIVITY FORECAST:  ON THE FIRST DAY THE

GEOMAGNETIC FIELD IS EXPECTED TO BE QUIET TO ACTIVE WITH A CHANCE

FOR MINOR STORMING.  THE CURRENT HIGH SPEED STREAM SHOULD DIMINISH

EARLY, BUT A SHOCK ASSOCIATED WITH THE FLARE OF 10 MAY IS EXPECTED.

BY THE SECOND AND THIRD DAYS THE FIELD SHOULD RECOVER TO

PREDOMINANTLY QUIET TO UNSETTLED CONDITIONS.

III.  EVENT PROBABILITIES 14 MAY-16 MAY

CLASS M    60/60/60

CLASS X    05/05/05

PROTON     05/05/05

PCAF       GREEN

IV.  PENTICTON 10.7 CM FLUX

OBSERVED           13 MAY 217

PREDICTED   14 MAY-16 MAY  225/225/230

90 DAY MEAN        13 MAY 187

V.  GEOMAGNETIC A INDICES

OBSERVED AFR/AP 12 MAY  019/022

ESTIMATED AFR/AP 13 MAY  015/018

PREDICTED AFR/AP 14 MAY-16 MAY  018/018-008/010-010/015

VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 14 MAY-16 MAY

A.  MIDDLE LATITUDES

ACTIVE                40/15/15

MINOR STORM           20/05/05

MAJOR-SEVERE STORM    05/01/01

B.  HIGH LATITUDES

ACTIVE                50/25/30

MINOR STORM           25/10/10

MAJOR-SEVERE STORM    05/01/05