:Product: 19980430RSGA.txt
:Issued: 1998 Apr 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 120 ISSUED AT 2200Z ON 30 APR 1998
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  29/2100Z
TO 30/2100Z:  SOLAR ACTIVITY WAS VERY LOW. REGION 8210 (S16E03)
PRODUCED ONLY MINOR FLUCTUATIONS. THIS REGION MAINTAINED SOME MIXED
POLARITIES AND OVERALL WAS STABLE. THE TYPE IV RADIO BURST
ASSOCIATED WITH THE M6/3B FLARE ON 29 APR REMAINED IN PROGRESS
THROUGH THE LAST 24 HOURS.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY SHOULD BE GENERALLY LOW
WITH OCCASIONAL C-CLASS FLARES FROM REGION 8210. AN ISOLATED M-CLASS
EVENT IS POSSIBLE. THIS REGION COULD PRODUCE ANOTHER X-CLASS EVENT
BEFORE WEST LIMB TRANSIT BUT THAT POSSIBILITY IS BECOMING LESSENED
AS THE REGION SIMPLIFIES MAGNETICALLY.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 29/2100Z TO 30/2100Z:
THE GEOMAGNETIC FIELD WAS QUIET UNTIL A 31 NT SUDDEN IMPULSE WAS
OBSERVED AT 30/0933Z. THIS WAS PRECEDED BY A SHOCK PASSAGE AT THE
ACE SPACECRAFT AT 30/0845Z. AFTER THE SUDDEN IMPULSE, UNSETTLED TO
ACTIVE CONDITIONS WERE OBSERVED. THIS DISTURBANCE IS BELIEVED TO BE
RELATED TO THE X1/HALO CME OBSERVED ON 27 APR. A WEAK ENERGETIC
PROTON (GT 10 MEV) ENHANCEMENT BEGAN AT 30/0405Z. MAXIMUM FLUX WAS 2
PFU. THIS ENHANCEMENT IS ATTRIBUTED TO THE M6/HALO CME OBSERVED ON
29 APR. ENERGETIC ELECTRON FLUXES AT GEOSYNCHRONOUS ORBIT WERE
PREDOMINANTLY HIGH.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD SHOULD BE
UNSETTLED TO ACTIVE FOR 01 MAY. ISOLATED MINOR STORMING IS POSSIBLE
DURING THAT TIME. A LARGER DISTURBANCE IS FORECAST FOR 02-03 MAY AS
A RESULT OF M6/HALO CME OBSERVED YESTERDAY. ACTIVE TO MINOR STORM
LEVELS ARE EXPECTED WITH PERIODS AT MAJOR STORM POSSIBLE. THE
CURRENT PROTON ENHANCEMENT SHOULD DECAY TO BACKGROUND LEVELS IN THE
NEXT TWO DAYS.
III.  EVENT PROBABILITIES 01 MAY-03 MAY
CLASS M    25/25/25
CLASS X    10/10/10
PROTON     10/10/10
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           30 APR 103
PREDICTED   01 MAY-03 MAY  104/106/108
90 DAY MEAN        30 APR 104
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 29 APR  005/006
ESTIMATED AFR/AP 30 APR  012/012
PREDICTED AFR/AP 01 MAY-03 MAY  020/018-030/030-015/015
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 01 MAY-03 MAY
A.  MIDDLE LATITUDES
ACTIVE                30/20/30
MINOR STORM           30/40/15
MAJOR-SEVERE STORM    15/20/05
B.  HIGH LATITUDES
ACTIVE                30/20/30
MINOR STORM           40/45/15
MAJOR-SEVERE STORM    15/20/05