:Product: 19980930RSGA.txt
:Issued: 1998 Sep 30 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 273 ISSUED AT 2200Z ON 30 SEP 1998
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  29/2100Z
TO 30/2100Z:  SOLAR ACTIVITY BECAME MODERATE. REGION 8340 (N19W92)
PRODUCED A LONG DURATION M2/2N FLARE AT 30/1350Z. THIS EVENT WAS
ACCOMPANIED BY STRONG TYPE II/IV SWEPT FREQUENCY EVENTS AND A 490
SFU BURST AT 2695 MHZ. MUCH MATERIAL MOTION WAS VISIBLE ALONG AND
ABOVE THE NORTHWEST LIMB IN THE FORM OF BRIGHT SURGES, ERUPTIVE
PROMINENCES, AND LOOP PROMINENCE SYSTEMS. OTHER REGIONS ON THE DISK
WERE STABLE OR SLOWLY DECAYING.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY SHOULD BECOME VERY LOW
TO LOW AS THE REGIONS AT OR OVER THE NORTHWEST LIMB BECOME LESS
VISIBLE DUE TO SOLAR ROTATION. THERE IS A SLIGHT POSSIBILITY REGION
8340 MAY PRODUCE ANOTHER M-CLASS EVENT FROM BEHIND THE WEST LIMB
BETWEEN NOW AND 02 OCT.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 29/2100Z TO 30/2100Z:
THE GEOMAGNETIC FIELD WAS QUIET TO SLIGHTLY UNSETTLED. THE GREATER
THAN 100 MEV PROTON FLUX CROSSED THE 1 PFU THRESHOLD AT 30/1435Z AND
REACHED A MAXIMUM OF 3 PFU DURING THE PERIOD. THE GREATER THAN 10
MEV FLUX REACHED EVENT THRESHOLD OF 10 PFU AT 30/1520Z. DURING THE
PERIOD, A MAXIMUM FLUX OF 840 PFU WAS OBSERVED. A POLAR CAP
ABSORPTION EVENT ACCOMPANIED THE PROTON EVENT. A MAXIMUM ABSORPTION
OF 4.3 DB WAS OBSERVED AT THE END OF THE PERIOD. ENERGETIC ELECTRON
FLUXES AT GEOSYNCHRONOUS ORBIT WERE AT MODERATE TO HIGH LEVELS.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
FORECAST TO BE QUIET TO UNSETTLED FOR 01-02 OCT. UNSETTLED TO
SLIGHTLY ACTIVE CONDITIONS ARE POSSIBLE ON 03 OCT. THE GREATER THAN
10 MEV PROTON EVENT IS EXPECTED TO SLOWLY DECAY OVER THE NEXT THREE
DAYS.
III.  EVENT PROBABILITIES 01 OCT-03 OCT
CLASS M    20/20/05
CLASS X    05/05/01
PROTON     10/10/01
PCAF       IN PROGRESS
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           30 SEP 122
PREDICTED   01 OCT-03 OCT  110/107/105
90 DAY MEAN        30 SEP 130
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 29 SEP  006/010
ESTIMATED AFR/AP 30 SEP  004/010
PREDICTED AFR/AP 01 OCT-03 OCT  008/012-008/010-010/020
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 01 OCT-03 OCT
A.  MIDDLE LATITUDES
ACTIVE                10/10/10
MINOR STORM           05/05/05
MAJOR-SEVERE STORM    01/01/05
B.  HIGH LATITUDES
ACTIVE                20/20/25
MINOR STORM           10/10/15
MAJOR-SEVERE STORM    05/05/05