:Product: 19990907RSGA.txt
:Issued: 1999 Sep 07 2200 UTC
# 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 250 ISSUED AT 2200Z ON 07 SEP 1999
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  06/2100Z
TO 07/2100Z:  SOLAR ACTIVITY WAS LOW. THERE WERE TWO C-CLASS FLARES
WHICH WERE NOT OBSERVED OPTICALLY: A C1.7 AT 06/2112Z AND A C1.2 AT
07/1358Z. REGION 8690 (N13E60) HAS ROTATED MORE FULLY INTO VIEW AND
IS AN 80 MILLIONTHS D-TYPE GROUP. A NEW REGION 8691 EMERGED NEAR
S30W32 DURING THE PAST 24 HOURS. NEW REGIONS 8692 (S25E74) AND 8693
(N12E79) ROTATED INTO VIEW. BOTH OF THESE GROUPS SHOW SPOTS WITH
PENUMBRA.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE LOW.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 06/2100Z TO 07/2100Z:
THE GEOMAGNETIC FIELD RANGED FROM QUIET TO ACTIVE LEVELS. ACE
REAL-TIME SOLAR WIND MEASUREMENTS INDICATE THE ARRIVAL OF A
HIGH-SPEED, LOW DENSITY SOLAR WIND STREAM AT ABOUT 07/0900Z. THE
HIGH VELOCITY AND FREQUENTLY OSCILLATING BZ COMPONENT OF THE
MAGNETIC FIELD RESULTED IN AN INCREASE IN ACTIVITY TO UNSETTLED TO
ACTIVE LEVELS.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO BE MOSTLY UNSETTLED FOR THE NEXT THREE DAYS. THERE IS A
FAIR CHANCE FOR SOME ACTIVE PERIODS DURING THE NEXT 24 HOURS,
HOWEVER, IN RESPONSE TO THE HIGH SPEED SOLAR WIND STREAM.
III.  EVENT PROBABILITIES 08 SEP-10 SEP
CLASS M    05/05/05
CLASS X    01/01/01
PROTON     01/01/01
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           07 SEP 112
PREDICTED   08 SEP-10 SEP  115/115/115
90 DAY MEAN        07 SEP 166
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 06 SEP  004/006
ESTIMATED AFR/AP 07 SEP  015/013
PREDICTED AFR/AP 08 SEP-10 SEP  015/013-012/013-010/010
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 08 SEP-10 SEP
A.  MIDDLE LATITUDES
ACTIVE                50/25/15
MINOR STORM           15/10/10
MAJOR-SEVERE STORM    05/05/05
B.  HIGH LATITUDES
ACTIVE                50/35/20
MINOR STORM           20/15/10
MAJOR-SEVERE STORM    10/05/05