:Product: 20000717RSGA.txt
:Issued: 2000 Jul 17 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 199 ISSUED AT 2200Z ON 17 JUL 2000
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  16/2100Z
TO 17/2100Z:  SOLAR ACTIVITY WAS MODERATE. SEVERAL REGIONS PRODUCED
SMALL M-CLASS FLARES. REGION 9090 (N12E59) PRODUCED AN M1/1N EVENT
AT 16/2147Z; REGION 9077 (N18W46) PRODUCED AN M1/2F AT 17/0004Z; AND
REGION 9087 (S12 E31) GENERATED AN M1/1F AT 17/1344Z AND AN M2/1N AT
17/2027Z WITH A 280 SFU BURST AT 2695 MHZ AND A TYPE II.  REGION
9077 SLOWLY DECLINED DURING THE PERIOD. REGION 9087 EXHIBITED
GROWTH.  THE OTHER SIGNIFICANT REGIONS ON THE DISK WERE
PREDOMINANTLY STABLE.  A LARGE MASS EJECTION WAS OBSERVED OVER THE
EAST LIMB AROUND 17/1100Z.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY SHOULD BE MODERATE TO
HIGH. THE THREE REGIONS MENTIONED ABOVE ARE OBVIOUSLY CAPABLE OF
OCCASIONAL M-CLASS EVENTS.  CONTINUED GROWTH IN REGION 9087 WOULD
INCREASE THE FREQUENCY OF M-CLASS EVENTS FROM THAT LOCATION. THERE
REMAINS A POSSIBILITY OF A MAJOR FLARE FROM REGIONS 9077, 9087, AND
9090.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 16/2100Z TO 17/2100Z:
THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED.  SOLAR WIND VELOCITY
DECLINED DURING THE PERIOD FROM APPROXIMATELY 750 TO 600 KM/S.  THE
GREATER THAN 10 MEV PROTON FLUX BEGAN THE PERIOD AT APPROXIMATELY
180 PFU AND BY ISSUE TIME WERE NEAR 50 PFU.  THE POLAR CAP
ABSORPTION EVENT ENDED AT 17/1943Z.  THE FORBUSH DECREASE REMAINED
IN PROGRESS.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD SHOULD BE
PREDOMINANTLY QUIET TO UNSETTLED FOR THE NEXT THREE DAYS.  ISOLATED
ACTIVE PERIODS ARE POSSIBLE AS LONG AS SOLAR WIND VELOCITY REMAINS
ELEVATED.  THE SOLAR PROTON EVENT SHOULD CONTINUE TO DECAY SLOWLY
AND BE BELOW EVENT THRESHOLD AROUND 19 JULY.  HOWEVER, IT REMAINS
POSSIBLE THAT REGION 9077 COULD PRODUCE ANOTHER MAJOR EVENT THAT
COULD RESULT IN AN ADDITIONAL INJECTION OF ENERGETIC PROTONS.
III.  EVENT PROBABILITIES 18 JUL-20 JUL
CLASS M    75/75/75
CLASS X    25/25/25
PROTON     99/75/40
PCAF       YELLOW
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           17 JUL 228
PREDICTED   18 JUL-20 JUL  230/233/234
90 DAY MEAN        17 JUL 186
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 16 JUL  032/046
ESTIMATED AFR/AP 17 JUL  010/010
PREDICTED AFR/AP 18 JUL-20 JUL  010/008-010/010-012/012
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 18 JUL-20 JUL
A.  MIDDLE LATITUDES
ACTIVE                25/20/20
MINOR STORM           15/10/10
MAJOR-SEVERE STORM    05/05/05
B.  HIGH LATITUDES
ACTIVE                25/20/20
MINOR STORM           15/10/10
MAJOR-SEVERE STORM    05/05/05