:Product: 20000719RSGA.txt
:Issued: 2000 Jul 19 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 201 ISSUED AT 2200Z ON 19 JUL 2000
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  18/2100Z
TO 19/2100Z:  SOLAR ACTIVITY BECAME HIGH.  REGION 9087 (S12W00)
PRODUCED A LONG DURATION M6/3N FLARE AT 19/0726Z.  MINOR RADIO
BURSTS, INCLUDING A WEAK TYPE IV, ACCOMPANIED THIS EVENT.  NO
CORONAGRAPH DATA WERE AVAILABLE FROM SOHO BUT IT IS ASSUMED THAT
THERE WAS A SIGNIFICANT MASS EJECTION WITH THIS EVENT BECAUSE OF
SOFT X-RAY DURATION AND INTERPLANETARY PARTICLE FLUXES.  REGION 9087
CONTINUED TO EMERGE RAPIDLY IN ITS NEW LEADER AREA AND TO THE SOUTH
OF THE PREEXISTING SPOTS.  THE DELTA CONFIGURATION REMAINED.  REGION
9097 (N05E67) SHOWED ITSELF AS A MODERATELY LARGE CLASS D SUNSPOT
REGION AND PRODUCED OCCASIONAL SUBFLARES.  REGION 9077 (N19W72)
CONTINUED TO DECLINE AND PRODUCED ONLY INFREQUENT SUBFLARES.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BECOME
GENERALLY HIGH.  THE CONTINUED GROWTH IN AREA AND MAGNETIC
COMPLEXITY IN REGION 9087 MAKES IT THE PRIME CANDIDATE FOR A MAJOR
EVENT.  LESSER FLARES MAY COME FROM REGIONS 9077 AND 9097.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY 18/2100Z TO 19/2100Z:
THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED FOR MOST OF THE PERIOD.
A SHOCK WAS OBSERVED AT ACE AT 19/1450Z AND A SUDDEN IMPULSE WAS
OBSERVED AT THE EARTH AT 19/1526Z.  UNSETTLED TO ACTIVE CONDITIONS
FOLLOWED THE SHOCK PASSAGE.  SOLAR WIND VELOCITY JUMPED FROM
APPROXIMATELY 450 KM/S TO OVER 600 KM/S.  THE LIKELY SOURCE OF THIS
DISTURBANCE WAS A MASS EJECTION ON 17 JULY THAT APPEARED TO BE
DIRECTED OFF THE EAST LIMB OF THE SUN.  THE GREATER THAN 10 MEV FLUX
BEGAN THE PERIOD NEAR 20 PFU AND DECAYED TO NEAR 10 PFU AT THE END
OF THE PERIOD.  A SLIGHT INCREASE IN FLUX WAS OBSERVED AROUND
19/1500Z WHICH MAY HAVE BEEN RELATED TO THE M6 FLARE MENTIONED
ABOVE.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD SHOULD
RANGE BETWEEN QUIET AND ACTIVE LEVELS FOR 20 JULY.  ACTIVE TO MAJOR
STORM LEVELS ARE EXPECTED ON 21 JULY IN RESPONSE TO TODAY'S
SUSPECTED MASS EJECTION. UNSETTLED TO ACTIVE LEVELS SHOULD RETURN ON
22 JULY.  THE CURRENT SOLAR PROTON EVENT COULD END ON 20 JULY.
HOWEVER, THE LARGE FLARES EXPECTED FROM REGION 9087 WILL LIKELY
CAUSE NEW INJECTIONS OF ENERGETIC PROTONS DURING THE PERIOD.
III.  EVENT PROBABILITIES 20 JUL-22 JUL
CLASS M    90/90/90
CLASS X    50/50/50
PROTON     50/50/50
PCAF       YELLOW
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           19 JUL 250
PREDICTED   20 JUL-22 JUL  252/245/235
90 DAY MEAN        19 JUL 188
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 18 JUL  008/013
ESTIMATED AFR/AP 19 JUL  012/014
PREDICTED AFR/AP 20 JUL-22 JUL  020/015-050/040-020/015
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 20 JUL-22 JUL
A.  MIDDLE LATITUDES
ACTIVE                40/25/40
MINOR STORM           15/25/15
MAJOR-SEVERE STORM    10/30/10
B.  HIGH LATITUDES
ACTIVE                40/25/40
MINOR STORM           15/25/15
MAJOR-SEVERE STORM    10/30/10