:Product: 19980824RSGA.txt
:Issued: 1998 Aug 24 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 236 ISSUED AT 2200Z ON 24 AUG 1998
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  23/2100Z
TO 24/2100Z:  SOLAR ACTIVITY BECAME LOW. REGION 8307 (N31E10)
PRODUCED A C1/SF AT 24/1525Z. REGION 8307 CONTINUED ITS DECLINE IN
WHITE LIGHT AREA AND BECAME MORE BIPOLAR MAGNETICALLY. PENUMBRAL
DECAY IN THE NORTHERN PORTION OF THE REGION CAUSED THE DELTA
CONFIGURATION TO FADE. REGION 8309 (N16W38) GREW SLIGHTLY AND
EXHIBITED MINOR MIXING OF POLARITIES.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY SHOULD REMAIN
PREDOMINANTLY LOW FOR THE NEXT THREE DAYS. REGION 8307 RETAINS THE
CAPABILITY OF PRODUCING AN ISOLATED M-CLASS EVENT BUT THAT
POSSIBILITY IS DECREASING AS THE REGION DECAYS.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 23/2100Z TO 24/2100Z:
THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED. SOME HIGH LATITUDE
SITES EXPERIENCED BRIEF ACTIVE PERIODS. SOLAR WIND VELOCITY
DECREASED TO APPROXIMATELY 430 KM/S FROM A HIGH OF NEAR 600 KM/S ON
23 AUG. THE GREATER THAN 10 MEV PROTON ENHANCEMENT CONTINUED TO
DECAY SLOWLY. FLUXES WERE NEAR 1 PFU.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO BE GENERALLY UNSETTLED TO ACTIVE FOR 25-26 AUG IN
RESPONSE TO AN M9 FLARE AND SUSPECTED CME EARLY ON 22 AUG. DURING
THE DISTURBANCE, MINOR STORM PERIODS ARE POSSIBLE AT MIDDLE
LATITUDES AND ISOLATED MAJOR STORMING IS POSSIBLE AT HIGH LATITUDES.
THE FIELD SHOULD BECOME PREDOMINANTLY UNSETTLED ON 27 AUG AS THE
DISTURBANCE SUBSIDES. THE PROTON ENHANCEMENT SHOULD CONTINUE TO
SLOWLY DECLINE.
III.  EVENT PROBABILITIES 25 AUG-27 AUG
CLASS M    35/30/25
CLASS X    10/10/10
PROTON     10/10/10
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           24 AUG 121
PREDICTED   25 AUG-27 AUG  120/120/120
90 DAY MEAN        24 AUG 116
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 23 AUG  014/023
ESTIMATED AFR/AP 24 AUG  010/014
PREDICTED AFR/AP 25 AUG-27 AUG  025/027-025/025-018/020
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 25 AUG-27 AUG
A.  MIDDLE LATITUDES
ACTIVE                30/30/30
MINOR STORM           30/30/15
MAJOR-SEVERE STORM    15/15/05
B.  HIGH LATITUDES
ACTIVE                30/30/30
MINOR STORM           30/30/15
MAJOR-SEVERE STORM    20/20/05