:Product: 19991011RSGA.txt
:Issued: 1999 Oct 11 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 284 ISSUED AT 2200Z ON 11 OCT 1999
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  10/2100Z
TO 11/2100Z:  SOLAR ACTIVITY WAS LOW. TODAY'S ACTIVITY CONSISTED OF A
FEW, LOW LEVEL C-CLASS EVENTS. OF THE 10 SPOTTED REGIONS ON THE
DISK, NEW REGION 8731 (N10E62) WAS THE MOST ACTIVE WITH FREQUENT
POINT BRIGHTENINGS AND PLAGE FLUCTUATIONS. REGION 8728 (N22E38) IS
THE LARGEST GROUP ON THE DISK AT 560 MILLIONTHS AND SHOWS SOME
MAGNETIC COMPLEXITY. THIS GROUP HAS INCREASED SIGNIFICANTLY OVER THE
LAST 24 HOURS.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE
MOSTLY LOW, BUT THERE IS A GOOD CHANCE FOR AN ISOLATED M-CLASS EVENT
SOMETIME OVER THE NEXT THREE DAYS, ESPECIALLY GIVEN THE GROWTH AND
COMPLEXITY OF REGION 8728. REGION 8731 IS EXPECTED TO PRODUCE
OCCASIONAL C-CLASS FLARES OVER THE NEXT THREE DAYS.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 10/2100Z TO 11/2100Z:
THE GEOMAGNETIC FIELD WAS AT QUIET TO ACTIVE LEVELS DURING THE PAST
24 HOURS. ACTIVE LEVELS DOMINATED FROM 0000-1500Z. SOLAR WIND
MEASUREMENTS INDICATED THAT THE ACTIVITY WAS DUE TO A HIGH-SPEED,
LOW-DENSITY CORONAL HOLE ASSOCIATED SOLAR WIND STREAM. THE GREATER
THAN 2 MEV ELECTRONS ATTAINED HIGH FLUX VALUES DURING THE PAST 24
HOURS.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO BE UNSETTLED TO ACTIVE DURING THE NEXT 24 HOURS AS THE
CURRENT DISTURBANCE SUBSIDES. A NEW ENHANCEMENT IN GEOMAGNETIC
ACTIVITY IS EXPECTED ON THE 2ND AND 3RD DAYS AS A NEW SOLAR CORONAL
HOLE WILL BE ROTATING INTO A GEOEFFECTIVE POSITION. MID-LATITUDES
ARE FORECAST TO BE ACTIVE AND HIGH LATITUDES ARE EXPECTED TO BE AT
MINOR STORM LEVELS.
III.  EVENT PROBABILITIES 12 OCT-14 OCT
CLASS M    35/35/35
CLASS X    05/05/05
PROTON     05/05/05
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           11 OCT 167
PREDICTED   12 OCT-14 OCT  170/175/180
90 DAY MEAN        11 OCT 154
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 10 OCT  018/028
ESTIMATED AFR/AP 11 OCT  020/022
PREDICTED AFR/AP 12 OCT-14 OCT  015/020-020/030-020/035
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 12 OCT-14 OCT
A.  MIDDLE LATITUDES
ACTIVE                30/40/40
MINOR STORM           15/20/20
MAJOR-SEVERE STORM    10/10/10
B.  HIGH LATITUDES
ACTIVE                35/40/40
MINOR STORM           15/25/25
MAJOR-SEVERE STORM    05/15/15