:Product: 19990818RSGA.txt
:Issued: 1999 Aug 18 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 230 ISSUED AT 2200Z ON 18 AUG 1999
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  17/2100Z
TO 18/2100Z:  SOLAR ACTIVITY WAS LOW. A LONG-DURATION C7 EVENT WAS
THE HIGHLIGHT OF THE PERIOD, BUT THE EVENT WAS NOT OPTICALLY
OBSERVED. REGION 8668 (N22E15) REMAINS THE DOMINANT ACTIVE CENTER IN
WHITE LIGHT AND H-ALPHA. NEWLY ASSIGNED REGION 8672 (N12E01) EMERGED
JUST WEST OF 8668 AND PRODUCED A SUBFLARE AT 1154Z.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE LOW.
HOWEVER, REGION 8668 MAY PRODUCE AN ISOLATED M-CLASS EVENT DURING
THE NEXT THREE DAYS.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 17/2100Z TO 18/2100Z:
THE GEOMAGNETIC FIELD REMAINED AT ACTIVE TO MINOR STORM LEVELS. THIS
DISTURBANCE, RELATED TO A HIGH SPEED SOLAR WIND STREAM, BEGAN IN THE
EARLY PART OF 16 AUGUST. SPEEDS CONTINUED IN THE 600-700 KM/S RANGE
MOST OF TODAY. THE GREATER THAN 2 MEV GEOSYNCHRONOUS ELECTRON FLUX
ATTAINED HIGH LEVELS AROUND 1200Z.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO BE UNSETTLED TO ACTIVE ON 19 AUGUST. SOLAR WIND SPEEDS
SHOULD DIMINISH TO A MORE NORMAL RANGE THEN, AND ACTIVITY SHOULD
DECLINE. UNSETTLED CONDITIONS SHOULD PREVAIL AT THE END OF THE
INTERVAL.
III.  EVENT PROBABILITIES 19 AUG-21 AUG
CLASS M    15/15/15
CLASS X    01/01/01
PROTON     01/01/01
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           18 AUG 131
PREDICTED   19 AUG-21 AUG  140/155/170
90 DAY MEAN        18 AUG 163
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 17 AUG  026/027
ESTIMATED AFR/AP 18 AUG  030/030
PREDICTED AFR/AP 19 AUG-21 AUG  015/020-015/015-015/010
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 19 AUG-21 AUG
A.  MIDDLE LATITUDES
ACTIVE                35/25/20
MINOR STORM           15/10/10
MAJOR-SEVERE STORM    01/01/01
B.  HIGH LATITUDES
ACTIVE                45/40/40
MINOR STORM           30/20/20
MAJOR-SEVERE STORM    05/01/01