:Product: 19990527RSGA.txt
:Issued: 1999 May 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 147 ISSUED AT 2200Z ON 27 MAY 1999
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  26/2100Z
TO 27/2100Z:  SOLAR ACTIVITY WAS LOW.  THERE WERE NUMEROUS C-CLASS
X-RAY FLARES THROUGHOUT THE PERIOD; THE LARGEST WAS A C7 OPTICALLY
CORRELATED TO REGION 8545 (N37W85).  BEGINNING AT 27/0917Z EIT
IMAGERY SHOWED A SERIES OF SYMPATHETIC FLARES BETWEEN REGIONS 8551
(N32W14) AND 8554 (N26E11).  THESE FLARES PRODUCED A NUMBER OF RADIO
EVENTS INCLUDING TYPE II AND IV RADIO SWEEPS AS WELL AS A 16000 SFU
TENFLARE.  A CORRESPONDING HALO CME WAS SEEN ON LASCO C3 AT
27/1338Z.  REGION 8552 (N20E25) REMAINS THE LARGEST AND MOST COMPLEX
REGION ON THE DISK.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE LOW
WITH A CHANCE FOR ISOLATED MODERATE ACTIVITY.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 26/2100Z TO 27/2100Z:
THE GEOMAGNETIC FIELD RANGED FROM QUIET TO UNSETTLED.  A ENERGETIC
PROTON ENHANCEMENT BEGAN AT APPROXIMATELY 27/1130Z, BUT DID NOT
REACH THRESHOLD LEVELS.  AFTER PEAKING AT APPROXIMATELY 27/1230Z THE
PROTONS STEADILY DECREASED.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  DURING DAY ONE THE GEOMAGNETIC
FIELD IS EXPECTED TO BE MOSTLY QUIET TO UNSETTLED.  BRIEF PERIODS OF
ACTIVE CONDITIONS ARE POSSIBLE EARLY DUE TO THE EFFECTS OF A
RECURRENT CORONAL HOLE.  BY DAY TWO THE IMPACT OF A CME IS EXPECTED
TO BRING UNSETTLED TO ACTIVE CONDITIONS.
III.  EVENT PROBABILITIES 28 MAY-30 MAY
CLASS M    30/30/30
CLASS X    01/01/01
PROTON     05/05/05
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           27 MAY 155
PREDICTED   28 MAY-30 MAY  155/165/165
90 DAY MEAN        27 MAY 129
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 26 MAY  007/008
ESTIMATED AFR/AP 27 MAY  010/010
PREDICTED AFR/AP 28 MAY-30 MAY  010/012-020/025-015/020
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 28 MAY-30 MAY
A.  MIDDLE LATITUDES
ACTIVE                20/50/35
MINOR STORM           05/20/10
MAJOR-SEVERE STORM    01/05/01
B.  HIGH LATITUDES
ACTIVE                25/60/40
MINOR STORM           05/25/15
MAJOR-SEVERE STORM    01/05/01