:Product: 19990626RSGA.txt
:Issued: 1999 Jun 26 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 177 ISSUED AT 2200Z ON 26 JUN 1999
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  25/2100Z
TO 26/2100Z:  SOLAR ACTIVITY WAS MODERATE. REGION 8598 (N23E02)
PRODUCED AN M2/2N AT 0512Z. THE GROUP CONTINUES TO BE THE DOMINANT
REGION ON THE DISK AND PRODUCED ADDITIONAL C-CLASS FLARES DURING THE
PAST 24 HOURS. REGION 8602 (N17E35) IS ALSO IMPRESSIVE LOOKING WITH
BRIGHT, FLUCTUATING PLAGE BUT COULD ONLY PRODUCE A SUBFLARE. REGION
8596 (N22W12) WAS ALSO ACTIVE A CONTRIBUTED A C4/1N FLARE AT 1650Z.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE
MODERATE. REGIONS 8598 AND 8602 ARE EXPECTED TO BE THE MAIN ACTIVITY
CENTERS FOR THE NEXT THREE DAYS. THERE IS A SLIGHT CHANCE FOR MAJOR
FLARE OR PROTON PRODUCING ACTIVITY FROM REGION 8598.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 25/2100Z TO 26/2100Z:
THE GEOMAGNETIC FIELD WAS QUIET TO ACTIVE. A SHOCK WAS SEEN AT THE
ACE SPACECRAFT AT 0215Z AND WAS FOLLOWED BY A FEW HOURS OF
MODERATELY NEGATIVE SOUTHWARD INTERPLANETARY FIELD. A 16 NT SUDDEN
IMPULSE OCCURRED AT 0326Z AND WAS FOLLOWED BY A 12 HOUR PERIOD OF
UNSETTLED TO ACTIVE GEOMAGNETIC CONDITIONS. A SECOND SHOCK WAS SEEN
AT ACE AT 1925Z, FOLLOWED BY ANOTHER SUDDEN IMPULSE AT 2020Z
WHICH MEASURED 38 NT IN BOULDER. AS OF FORECAST FILE TIME THE
INTERPLANETARY MAGNETIC FIELD WAS ORIENTED NORTHWARDS.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO BE MOSTLY UNSETTLED FOR THE NEXT TWO DAYS. HOWEVER, THE
NATURE OF THE PLASMA AND FIELDS BEHIND THE 20/1925Z SHOCK AT ACE IS
CURRENTLY UNKNOWN AND COULD BE GEOEFFECTIVE. THEREFORE THERE IS A
POSSIBILITY OF DISTURBED CONDITIONS FOR THE NEXT 12 HOURS. AN
INCREASE IN GEOMAGNETIC ACTIVITY IS ALSO POSSIBLE ON THE THIRD DAY
IN RESPONSE TO THE PARTIAL HALO CORONAL MASS EJECTION OF 24/1200Z.
III.  EVENT PROBABILITIES 27 JUN-29 JUN
CLASS M    55/55/55
CLASS X    15/15/15
PROTON     20/20/20
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           26 JUN 200
PREDICTED   27 JUN-29 JUN  205/205/205
90 DAY MEAN        26 JUN 141
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 25 JUN  002/005
ESTIMATED AFR/AP 26 JUN  014/012
PREDICTED AFR/AP 27 JUN-29 JUN  010/012-010/012-015/010
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 27 JUN-29 JUN
A.  MIDDLE LATITUDES
ACTIVE                20/20/30
MINOR STORM           05/05/10
MAJOR-SEVERE STORM    01/01/05
B.  HIGH LATITUDES
ACTIVE                25/25/35
MINOR STORM           10/10/15
MAJOR-SEVERE STORM    01/01/10