NOAA/USAF Report of Solar-Geophysical Activity 12 May 2000

Report of Solar-Geophysical Activity

:Issued: 2000 May 12 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 133 ISSUED AT 2200Z ON 12 MAY 2000

IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  11/2100Z

TO 12/2100Z:  SOLAR ACTIVITY WAS LOW.  THERE WERE A NUMBER OF C-CLASS

X-RAY FLARES, ALL OF THEM OPTICALLY UNCORRELATED.  A 32 DEGREE

FILAMENT ERUPTED FROM ROUGHLY S50E50 BETWEEN 11/22 AND 11/23UT.  THE

ERUPTION WAS VISIBLE IN EIT IMAGERY AND LASCO REVEALED A DRAMATIC

CME OFF THE SOUTH POLE.  AT THIS TIME THE CME DOES NOT APPEAR TO BE

EARTH DIRECTED.

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

TO MODERATE.  THERE ARE CURRENTLY A NUMBER OF REGIONS CAPABLE OF

PRODUCING M FLARES.

IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 11/2100Z TO 12/2100Z:

THE GEOMAGNETIC FIELD WAS AT QUIET TO MINOR STORM LEVELS.  ACE DATA

INDICATED THE PASSAGE OF TWO SOLAR TRANSIENTS, ASSUMED TO BE RELATED

TO THE MULTIPLE FILAMENT ERUPTIONS OF 8 MAY.  WHILE THE TRANSIENTS

PRODUCED SUSTAINED PERIODS OF NEGATIVE BZ, THE WIND SPEED REMAINED

VERY LOW INHIBITING A STRONG GEOMAGNETIC RESPONSE.

IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS

EXPECTED TO BE QUIET TO MINOR STORM FOR THE FIRST TWO DAYS OF THE

PERIOD. ON THE FIRST DAY, WE EXPECT TO SEE INCREASES IN THE SOLAR

WIND SPEED DUE TO A SMALL CORONAL HOLE THAT IS NOW FAVORABLY

POSITIONED.  A SHOCK ASSOCIATED WITH THE 10 MAY LONG DURATION FLARE

AND FILAMENT ERUPTION IS ALSO EXPECTED LATE 13 OR EARLY 14 MAY.

III.  EVENT PROBABILITIES 13 MAY-15 MAY

CLASS M    50/50/50

CLASS X    05/05/05

PROTON     05/05/05

PCAF       GREEN

IV.  PENTICTON 10.7 CM FLUX

OBSERVED           12 MAY 190

PREDICTED   13 MAY-15 MAY  195/200/200

90 DAY MEAN        12 MAY 187

V.  GEOMAGNETIC A INDICES

OBSERVED AFR/AP 11 MAY  004/006

ESTIMATED AFR/AP 12 MAY  015/020

PREDICTED AFR/AP 13 MAY-15 MAY  020/020-015/015-008/008

VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 13 MAY-15 MAY

A.  MIDDLE LATITUDES

ACTIVE                40/30/20

MINOR STORM           20/15/05

MAJOR-SEVERE STORM    05/05/01

B.  HIGH LATITUDES

ACTIVE                40/35/25

MINOR STORM           25/20/05

MAJOR-SEVERE STORM    05/05/01