:Product: 19981001RSGA.txt
:Issued: 1998 Oct 01 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 274 ISSUED AT 2200Z ON 01 OCT 1998
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  30/2100Z
TO 01/2100Z:  SOLAR ACTIVITY BECAME LOW. SMALL C-CLASS EVENTS
OCCURRED. MOST WERE NOT OPTICALLY CORRELATED TO ANY SPECIFIC REGION.
REGION 8349 (S26E29) GREW SLIGHTLY AND PRODUCED SEVERAL SUBFLARES.
THE LOOP PROMINENCE SYSTEM, VISIBLE AFTER THE FLARE ON 30 SEP FROM
REGION 8340 (NOW AT N23W106), FADED DURING THE PERIOD. NEW REGION
8350 (N20E79) ROTATED ONTO THE DISK AS A MODERATE SIZE H CLASS SPOT.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY SHOULD REMAIN AT A LOW
LEVEL. ISOLATED C-CLASS EVENTS ARE POSSIBLE.  THERE IS A DIMINISHING
PROBABILITY OF M-CLASS EVENTS FROM DEPARTED REGION 8340.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 30/2100Z TO 01/2100Z:
THE GEOMAGNETIC FIELD RANGED FROM MOSTLY UNSETTLED TO MINOR STORM
LEVELS. THE MOST DISTURBED PERIOD WAS 01/0000-0300Z. SOLAR WIND DATA
SHOW A MODERATELY HIGH VELOCITY FLOW IMPACTING THE EARTH. THE
GREATER THAN 10 MEV PROTON FLUX REACHED A MAXIMUM OF 1200 PFU AT
01/0025Z. FLUXES AT THE END OF THE PERIOD WERE BELOW 40 PFU. THE
GREATER THAN 100 MEV PROTON FLUX DROPPED BELOW THE 1 PFU THRESHOLD
AT 30/2235Z. THE POLAR CAP ABSORPTION EVENT CONTINUED BUT DECAYED AS
THE PROTON FLUX DECREASED. ENERGETIC ELECTRON FLUXES WERE HIGH AT
THE BEGINNING OF THE DAY AND DECREASED THROUGH THE PERIOD.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD SHOULD BE
AT QUIET TO ACTIVE LEVELS ON 02 OCT. IT IS NOW BELIEVED THAT ON
02-03 OCT THE EARTH WILL RECEIVE AN OBLIQUE STRIKE FROM A LARGE CME
ASSOCIATED WITH THE ACTIVITY ON 30 SEP. UNSETTLED TO MINOR STORM
LEVELS ARE POSSIBLE DURING 02-03 OCT WITH ISOLATED MAJOR STORM
PERIODS POSSIBLE AT HIGH LATITUDES. UNSETTLED TO SLIGHTLY ACTIVE
CONDITIONS ARE FORECAST FOR 04 OCT. THE GREATER THAN 10 MEV PROTON
EVENT SHOULD DROP BELOW 10 PFU IN 1-2 DAYS.
III.  EVENT PROBABILITIES 02 OCT-04 OCT
CLASS M    20/10/10
CLASS X    05/01/01
PROTON     10/05/01
PCAF       IN PROGRESS
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           01 OCT 119
PREDICTED   02 OCT-04 OCT  115/113/112
90 DAY MEAN        01 OCT 129
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 30 SEP  006/008
ESTIMATED AFR/AP 01 OCT  017/022
PREDICTED AFR/AP 02 OCT-04 OCT  015/020-018/020-012/015
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 02 OCT-04 OCT
A.  MIDDLE LATITUDES
ACTIVE                20/40/25
MINOR STORM           10/15/10
MAJOR-SEVERE STORM    05/10/05
B.  HIGH LATITUDES
ACTIVE                35/35/30
MINOR STORM           20/20/15
MAJOR-SEVERE STORM    10/10/10