:Product: 19991028RSGA.txt
:Issued: 1999 Oct 28 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 301 ISSUED AT 2200Z ON 28 OCT 1999
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  27/2100Z
TO 28/2100Z:  SOLAR ACTIVITY WAS LOW. THE DEPARTURE OF REGION 8737
NEAR SW13 AND THE SIMPLIFICATION OF REGION 8739 (S11W37) CAUSED
FLARE COUNTS TO FALL OVER THE PAST 24 HOURS. VERY LITTLE ACTIVITY
OCCURRED, THE MOST NOTABLE EVENT BEING A C1/SF FROM 8739 AT 0457Z.
NEWLY ASSIGNED REGION 8747 (N10E59) HAS BRIGHT PLAGE AND DID PRODUCE
A FEW SUBFLARES DURING THE INTERVAL.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE LOW
TO MODERATE. ALTHOUGH SEEMINGLY MORE BENIGN, REGION 8739 MAY STILL
GENERATE AN ISOLATED M-CLASS EVENT.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 27/2100Z TO 28/2100Z:
THE GEOMAGNETIC FIELD VARIED FROM QUIET TO MINOR STORM LEVELS DURING
THE DAY. ABOUT 1200Z, SOLAR WIND PLASMA AND MAGNETIC FIELD
EXPERIENCED A CHANGE AT THE ACE SPACECRAFT, RESULTING IN THE
DISTURBED LEVELS SEEN DURING THE LATTER HALF OF THE PERIOD. THESE
DATA SUGGEST A GLANCING BLOW BY A TRANSIENT AS THE CAUSE OF THE
ELEVATED ACTIVITY. THE GREATER THAN 2 MEV ELECTRON FLUX AT
GEOSYNCHRONOUS ORBIT REACHED HIGH LEVELS FROM 1330-1630Z,
APPROXIMATELY.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO BE AT UNSETTLED TO ACTIVE LEVELS FOR THE NEXT FEW DAYS.
EPISODIC MINOR STORM CONDITIONS ARE DISTINCTLY POSSIBLE DURING LOCAL
NIGHTTIME HOURS. A HIGH SPEED STREAM IS EXPECTED TO PROLONG THE
UNSETTLED CONDITIONS THROUGH OCTOBER 31.
III.  EVENT PROBABILITIES 29 OCT-31 OCT
CLASS M    30/30/30
CLASS X    01/01/01
PROTON     01/01/01
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           28 OCT 184
PREDICTED   29 OCT-31 OCT  175/165/160
90 DAY MEAN        28 OCT 157
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 27 OCT  010/017
ESTIMATED AFR/AP 28 OCT  015/015
PREDICTED AFR/AP 29 OCT-31 OCT  020/020-015/020-015/015
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 29 OCT-31 OCT
A.  MIDDLE LATITUDES
ACTIVE                40/30/30
MINOR STORM           25/20/20
MAJOR-SEVERE STORM    05/01/01
B.  HIGH LATITUDES
ACTIVE                50/40/40
MINOR STORM           30/25/25
MAJOR-SEVERE STORM    05/05/05