:Product: 19990627RSGA.txt
:Issued: 1999 Jun 27 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 178 ISSUED AT 2200Z ON 27 JUN 1999
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  26/2100Z
TO 27/2100Z:  SOLAR ACTIVITY WAS MODERATE. REGION 8592 (N22W33), A
SIMPLE SINGLE SPOT HSX GROUP, PRODUCED AN M1/2N FLARE TODAY AT
0844Z. THE EVENT WAS ACCOMPANIED BY A TYPE IV RADIO SWEEP. NEW
REGION 8611 (S26E60) EMERGED TODAY AND PRODUCED SOME SUBFLARE
ACTIVITY. REGION 8598 (N23W11) CONTINUES TO BE THE LARGEST REGION ON
THE DISK. THERE IS EVIDENCE OF EMERGING NEGATIVE MAGNETIC FLUX IN
THE MIDDLE OF A STRONG POSITIVE POLARITY FIELD WHICH HAS LED TO THE
FORMATION OF A DELTA SPOT NEAR THE CENTER OF THIS EXTENDED SUNSPOT
REGION. A VERY SLOW, LONG DURATION RISE AND DECAY IN THE X-RAY FLUX
OCCURRED BETWEEN 1815-2030Z, PEAKING AT THE C3 LEVEL; THE EVENT WAS
ASSOCIATED WITH SUBFAINT INTENSITY PLAGE IN REGION 8598. REGION 8602
(N17E22) AND 8603 (S16E29) ARE ALSO OF RESPECTABLE SIZE; BOTH
REGIONS PRODUCED A COUPLE SUBFLARES TODAY.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE
MODERATE. REGION 8598 SHOWS GOOD POTENTIAL FOR PRODUCING M-CLASS
FLARES. REGIONS 8602, 8603, AND 8606 COULD ALSO POSSIBLY CONTRIBUTE
AN M-FLARE. THERE IS A POSSIBILITY FOR A MAJOR FLARE OR PROTON
PRODUCING FLARE FROM 8598.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 26/2100Z TO 27/2100Z:
THE GEOMAGNETIC FIELD RANGED FROM QUIET TO ACTIVE LEVELS, WITH SOME
MINOR STORM INTERVALS AT HIGH LATITUDES. AN INITIALLY QUIET TO
UNSETTLED GEOMAGNETIC FIELD BECAME MORE DISTURBED AFTER 1200Z; AFTER
WHICH MIDDLE LATITUDES WERE MOSTLY ACTIVE AND HIGH LATITUDES WERE AT
ACTIVE TO MINOR STORM LEVELS. ACE OBSERVATIONS SHOW AN OSCILLATING
BZ COMPONENT WHICH BEGAN TO HAVE SOME NEGATIVE INTERVALS AFTER
0900Z.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO PERSIST AT ACTIVE LEVELS FOR THE NEXT 12 HOURS, AFTER
WHICH UNSETTLED LEVELS ARE EXPECTED TO PREVAIL. UNSETTLED WITH A
POSSIBILITY FOR ACTIVE IS FORECAST FOR THE SECOND DAY BECAUSE A NEW
DISTURBANCE IS POSSIBLE ON THE 29TH DUE TO THE PARTIAL HALO CORONAL
MASS EJECTION THAT OCCURRED ON THE 24TH. GENERALLY UNSETTLED
CONDITIONS ARE EXPECTED TO PREDOMINATE ON THE THIRD DAY.
III.  EVENT PROBABILITIES 28 JUN-30 JUN
CLASS M    75/75/75
CLASS X    20/20/20
PROTON     25/25/25
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           27 JUN 207
PREDICTED   28 JUN-30 JUN  200/200/200
90 DAY MEAN        27 JUN 143
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 26 JUN  014/017
ESTIMATED AFR/AP 27 JUN  018/020
PREDICTED AFR/AP 28 JUN-30 JUN  015/015-015/010-010/010
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 28 JUN-30 JUN
A.  MIDDLE LATITUDES
ACTIVE                35/35/20
MINOR STORM           15/15/05
MAJOR-SEVERE STORM    05/05/01
B.  HIGH LATITUDES
ACTIVE                35/35/30
MINOR STORM           20/20/10
MAJOR-SEVERE STORM    10/10/05