:Product: 19990828RSGA.txt
:Issued: 1999 Aug 28 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 240 ISSUED AT 2200Z ON 28 AUG 1999
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  27/2100Z
TO 28/2100Z:  SOLAR ACTIVITY REMAINED HIGH.  REGION 8674 PRODUCED AN
IMPULSIVE X1/ AT 28/1805Z. THIS EVENT WAS ACCOMPANIED BY A 1000 SFU
BURST AT 2695 MHZ, STRONG TYPE II EMISSION, AND MAUNA LOA OBSERVED A
CORONAL MASS EJECTION AT SW60. REGION 8674 ALSO PRODUCED AN M1/1F AT
28/0102Z WITH A 290 SFU BURST AT 2695 MHZ. THIS REGION WAS STABLE IN
AREA AND MAGNETICALLY COMPLEX, ESPECIALLY IN THE TRAILER WHERE A
DELTA CONFIGURATION AND HIGH GRADIENTS EXISTED. RECENT VECTOR
MAGNETOGRAPH DATA SHOWED SIGNIFICANT SHEAR ONLY IN THAT AREA. OTHER
REGIONS WERE GENERALLY STABLE WITH THE EXCEPTION OF NEW REGION 8681
(N21E09). THIS REGION EMERGED RAPIDLY DURING THE PERIOD AND CONSISTS
OF BRIGHT PLAGE AND MANY SMALL SPOTS. SEVERAL CORONAL MASS EJECTIONS
WERE OBSERVED DURING THE PERIOD.  AT THIS TIME, NONE APPEAR TO BE
DIRECTED SQUARELY AT THE EARTH.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY SHOULD BE MODERATE TO
HIGH. REGION 8674 WILL CONTINUE TO PRODUCE M-CLASS EVENTS AND
OCCASIONAL X-CLASS EVENTS. SEVERAL OTHER REGIONS POSSESS THE
CAPABILITY OF PRODUCING ISOLATED M-CLASS EVENTS - CONTINUED GROWTH
IN NEW REGION 8681 WOULD PUT IT IN THAT CATEGORY AS WELL.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 27/2100Z TO 28/2100Z:
THE GEOMAGNETIC FIELD REMAINED AT QUIET TO ACTIVE LEVELS. THE EARTH
CONTINUED TO EXPERIENCE A HIGH SPEED LOW DENSITY SOLAR WIND STREAM.
ENERGETIC ELECTRON FLUXES AT GEOSYNCHRONOUS ORBIT REACHED HIGH
LEVELS NEAR 28/1200Z.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD SHOULD BE
AT QUIET TO SLIGHTLY ACTIVE LEVELS FOR MOST OF THE 29-30 AUG PERIOD.
ON 31 AUG, A WEAK DISTURBANCE IS EXPECTED AS A RESULT OF THE X1/CME
EVENT MENTIONED ABOVE. HOWEVER, IT IS EXPECTED THAT THE EARTH WILL
RECEIVE ONLY AN OBLIQUE HIT FROM THIS EVENT AND ISOLATED ACTIVE
CONDITIONS ARE EXPECTED ON THAT DAY. ENERGETIC ELECTRON FLUXES
SHOULD REMAIN AT HIGH LEVELS FOR AT LEAST THE NEXT 2-3 DAYS. THERE
IS A MODERATE POSSIBILITY OF AN ENERGETIC PROTON EVENT DURING THE
PERIOD FROM REGION 8674.
III.  EVENT PROBABILITIES 29 AUG-31 AUG
CLASS M    80/80/80
CLASS X    50/50/50
PROTON     40/40/40
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           28 AUG 248
PREDICTED   29 AUG-31 AUG  240/238/225
90 DAY MEAN        28 AUG 168
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 27 AUG  009/013
ESTIMATED AFR/AP 28 AUG  013/010
PREDICTED AFR/AP 29 AUG-31 AUG  010/010-010/010-012/012
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 29 AUG-31 AUG
A.  MIDDLE LATITUDES
ACTIVE                10/20/20
MINOR STORM           05/10/10
MAJOR-SEVERE STORM    01/05/05
B.  HIGH LATITUDES
ACTIVE                10/25/25
MINOR STORM           05/15/15
MAJOR-SEVERE STORM    01/05/05