:Product: 19991013RSGA.txt
:Issued: 1999 Oct 13 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 286 ISSUED AT 2200Z ON 13 OCT 1999
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  12/2100Z
TO 13/2100Z:  SOLAR ACTIVITY WAS LOW. REGIONS 8731 (N11E38) AND 8732
(N20E30) PRODUCED MOST OF TODAY'S OCCASIONAL C-CLASS SUBFLARES. BOTH
GROUPS ARE SHOWING GROWTH AND INCREASING MAGNETIC STRENGTH. REGION
8728 (N22E12) CONTINUES TO BE LARGE BUT SEEMED TO BE SIMPLIFYING
MAGNETICALLY AND WAS MOSTLY STABLE DURING THE DAY. A 27 DEGREE
FILAMENT NEAR N45E15 ERUPTED BETWEEN 0000Z AND 0914Z ON THE 13TH.
X-RAY AND CORONAGRAPH OBSERVATIONS CONFIRM THAT THE DISAPPEARANCE
WAS ASSOCIATED WITH A CORONAL MASS EJECTION.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE LOW.
THERE IS A CHANCE, HOWEVER, FOR AN ISOLATED M-CLASS EVENT FROM
REGION 8728, 8731 OR 8732.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 12/2100Z TO 13/2100Z:
THE GEOMAGNETIC FIELD RANGED FROM UNSETTLED TO MINOR STORM LEVELS
DURING THE PAST 24 HOURS. LOCAL NIGHTTIME HOURS EXPERIENCED ACTIVE
TO MINOR STORM LEVELS AND THE DAYTIME HOURS WERE UNSETTLED TO
ACTIVE. THE ENHANCED ACTIVITY IS BEING CAUSED BY THE PRESENCE
HIGH-SPEED CORONAL WIND STREAM AS INDICATED BY SOLAR WIND
OBSERVATIONS. THE GREATER THAN 2 MEV ELECTRON FLUXES ATTAINED HIGH
LEVELS TODAY.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO BE AT MOSTLY ACTIVE LEVELS DURING THE NEXT TWO DAYS,
WITH OCCASIONAL MINOR STORM PERIODS AT HIGH LATITUDE, DUE TO
CONTINUED EFFECTS FROM THE HIGH-SPEED STREAM. A DECREASE TO
UNSETTLED TO SLIGHTLY ACTIVE IS EXPECTED BY THE THIRD DAY.
III.  EVENT PROBABILITIES 14 OCT-16 OCT
CLASS M    30/30/30
CLASS X    05/05/05
PROTON     05/05/05
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           13 OCT 191
PREDICTED   14 OCT-16 OCT  195/200/200
90 DAY MEAN        13 OCT 156
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 12 OCT  021/034
ESTIMATED AFR/AP 13 OCT  020/028
PREDICTED AFR/AP 14 OCT-16 OCT  025/030-025/025-010/020
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 14 OCT-16 OCT
A.  MIDDLE LATITUDES
ACTIVE                45/45/10
MINOR STORM           15/15/05
MAJOR-SEVERE STORM    10/10/01
B.  HIGH LATITUDES
ACTIVE                40/40/10
MINOR STORM           20/20/05
MAJOR-SEVERE STORM    10/10/01