:Product: 19990217RSGA.txt
:Issued: 1999 Feb 17 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 048 ISSUED AT 2200Z ON 17 FEB 1999
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  16/2100Z
TO 17/2100Z:  SOLAR ACTIVITY WAS LOW. OCCASIONAL C-CLASS FLARES MADE
UP THE DAY'S ACTIVITY, THE LARGEST BEING AN UNOBSERVED C6 AT
2029Z.REGION 8462 (N20W27) HAD THE VAST MAJORITY OF THE ASSOCIATED
FLARE ACTIVITY, WITH ITS LARGEST A C5/1N WITH TYPE II SWEEP AT
16/2121Z. REGION 8458 (S23W36) HAD ONLY A FEW C-CLASS FLARES. REGION
8457 (N15W42), ALTHOUGH QUIET, REMAINS BRIGHT IN H-ALPHA. THE
REMAINDER OF THE DISK AND LIMBS WERE QUIET.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE LOW
TO MODERATE. REGIONS 8457, 8458 AND 8462 RETAIN THE POTENTIAL FOR
ISOLATED M-CLASS FLARES.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 16/2100Z TO 17/2100Z:
THE GEOMAGNETIC FIELD WAS AT QUIET TO MINOR STORM LEVELS. A TRANSIENT
STRUCTURE WAS SEEN TO PASS ACE AROUND 0500Z, WITH ELEVATED SPEED AND
PROLONGED SOUTHWARD BZ. CONDITIONS HAVE SINCE STABILIZED WITH
NOMINAL CONDITIONS NOW OCCURRING. THIS TRANSIENT MAY BE AN EFFECT OF
SOLAR ACTIVITY ON FEBRUARY 12.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO BE GENERALLY UNSETTLED FOR THE NEXT THREE DAYS. THERE IS
A CHANCE FOR EPISODES OF ELEVATED ACTIVITY IN THE FIRST TWO DAYS,
DUE TO SOLAR ACTIVITY FROM REGION 8458 EARLY ON FEBRUARY 16.
III.  EVENT PROBABILITIES 18 FEB-20 FEB
CLASS M    50/50/50
CLASS X    10/10/10
PROTON     10/10/10
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           17 FEB 190
PREDICTED   18 FEB-20 FEB  185/175/165
90 DAY MEAN        17 FEB 146
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 16 FEB  003/004
ESTIMATED AFR/AP 17 FEB  015/015
PREDICTED AFR/AP 18 FEB-20 FEB  015/010-015/010-010/008
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 18 FEB-20 FEB
A.  MIDDLE LATITUDES
ACTIVE                40/40/30
MINOR STORM           20/20/10
MAJOR-SEVERE STORM    05/05/05
B.  HIGH LATITUDES
ACTIVE                50/50/40
MINOR STORM           25/25/20
MAJOR-SEVERE STORM    10/10/05