:Product: 19990827RSGA.txt
:Issued: 1999 Aug 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 239 ISSUED AT 2200Z ON 27 AUG 1999
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  26/2100Z
TO 27/2100Z:  SOLAR ACTIVITY WAS HIGH. REGION 8674 (S24W16) PRODUCED
AN M5/2N FLARE AT 1307Z. THIS REGION ALSO HAD AN M3/2N AT 1635Z, AND
WAS THE LIKELY SITE OF THE M3 EVENT EARLIER AT 0137Z. THE CENTER OF
THE DISK IS DOMINATED BY THE MERGING OF REGIONS 8674 AND 8673
(S19W24), AND THE TWO ARE NOW NEARLY INDISTINGUISHABLE. ALTHOUGH THE
X-RAY OUTPUT OF TODAY'S EVENTS WAS SUBSTANTIAL, THE RADIO EMISSION
WAS SMALL, AND NO SWEEP FREQUENCY EVENTS WERE DETECTED. ONE NEW
REGION WAS NUMBERED, REGION 8680 (N22W87).
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE
MODERATE TO HIGH. REGIONS 8673 AND 8674 ARE LARGE, MAGNETICALLY
COMPLEX, AND DYNAMIC. WATCH FOR ADDITIONAL M-CLASS, AND ISOLATED
X-CLASS, ACTIVITY DURING THE NEXT THREE DAYS.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 26/2100Z TO 27/2100Z:
THE GEOMAGNETIC FIELD WAS QUIET TO MILDLY ACTIVE. SOLAR WIND SPEEDS
IN EXCESS OF 600 KM/S ARE STILL OCCURRING, LIKELY ORIGINATING FROM A
WELL- POSITIONED CORONAL HOLE WEST OF CENTRAL MERIDIAN. THE GREATER
THAN 2 MEV ELECTRON FLUX AT GEOSYNCHRONOUS ORBIT APPROACHED HIGH
LEVELS AT APPROXIMATELY 1500Z.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO BE UNSETTLED THE NEXT THREE DAYS. THERE IS A GOOD CHANCE
FOR ISOLATED ACTIVE CONDITIONS DURING LOCAL NIGHTTIME HOURS. A
GREATER THAN 10 MEV PROTON EVENT IS ALSO POSSIBLE DURING THE PERIOD,
PENDING FURTHER ACTIVITY FROM REGIONS 8673 AND 8674.
III.  EVENT PROBABILITIES 28 AUG-30 AUG
CLASS M    80/80/80
CLASS X    40/40/40
PROTON     40/40/40
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           27 AUG 223
PREDICTED   28 AUG-30 AUG  225/220/220
90 DAY MEAN        27 AUG 167
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 26 AUG  010/013
ESTIMATED AFR/AP 27 AUG  010/012
PREDICTED AFR/AP 28 AUG-30 AUG  010/010-010/010-010/010
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 28 AUG-30 AUG
A.  MIDDLE LATITUDES
ACTIVE                30/30/20
MINOR STORM           10/10/05
MAJOR-SEVERE STORM    01/01/01
B.  HIGH LATITUDES
ACTIVE                40/40/30
MINOR STORM           15/15/10
MAJOR-SEVERE STORM    01/01/01