:Product: 19991022RSGA.txt
:Issued: 1999 Oct 22 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
: : : : : : : CORRECTED COPY : : : : : : :
SDF NUMBER 295 ISSUED AT 2200Z ON 22 OCT 1999
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  21/2100Z
TO 22/2100Z:  SOLAR ACTIVITY WAS LOW. THE LARGEST EVENT OF THE PERIOD
WAS A C4/SF IN REGION 8732 (N20W89) AT 22/0915Z. TWO TYPE II'S
OCCURRED AT 22/0853Z AND 22/1300Z, LIKELY DUE TO THE CME ACTIVITY IN
THE CLUSTER OF REGIONS TRANSITING THE NORTHWEST LIMB. REGIONS 8737
(S15W26) AND 8739 (S13E43) BOTH EXHIBITED GROWTH THIS PERIOD WITH
REGION 8739 PRODUCING A 1F/SF AT 22/1929Z. NEW REGIONS 8740 (N27W83)
AND 8741 (S25E64) WERE NUMBERED TODAY.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE LOW
TO MODERATE. AN ISOLATED M-CLASS EVENT IS STILL POSSIBLE FROM
REGIONS 8731 (N12W79) AND REGION 8732, AS THEY ROTATE AROUND THE WEST
LIMB. C-CLASS ACTIVITY IS LIKELY FROM REGIONS 8737 AND 8739.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 21/2100Z TO 22/2100Z:
THE GEOMAGNETIC FIELD WAS AT ACTIVE TO SEVERE STORM LEVELS. THIS
STORM WAS ASSOCIATED WITH THE SUDDEN IMPULSE (SI) OBSERVED AT
21/0226Z. A SUSTAINED PERIOD OF RELATIVE CALM FOLLOWED THE SI, BUT
CONDITIONS CHANGED CONSIDERABLY AROUND 21/2240Z. A DRAMATIC CHANGE
IN THE IMF BZ TO A STRONG SOUTHWARD ORIENTATION PRODUCED SEVERE
CONDITIONS AT MID AND HIGH LATITUDES. THE DISTURBANCE BEGAN TO WANE
SOON AFTER 22/1200Z. ACTIVE CONDITIONS HAVE PERSISTED SINCE.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO BE AT ACTIVE TO MINOR STORM LEVELS WITH ISOLATED MAJOR
STORM PERIODS LIKELY AT HIGH LATITUDES. A FAVORABLY POSITIONED
GEOEFFECTIVE CORONAL HOLE SHOULD RESULT IN UNSETTLED TO ACTIVE
CONDITIONS THROUGH ALL THREE DAYS.
III.  EVENT PROBABILITIES 23 OCT-25 OCT
CLASS M    40/35/30
CLASS X    10/05/05
PROTON     10/05/05
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           22 OCT 160
PREDICTED   23 OCT-25 OCT  155/145/140
90 DAY MEAN        22 OCT 158
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 21 OCT  014/015
ESTIMATED AFR/AP 22 OCT  055/090
PREDICTED AFR/AP 23 OCT-25 OCT  025/040-020/030-020/020
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 23 OCT-25 OCT
A.  MIDDLE LATITUDES
ACTIVE                30/30/30
MINOR STORM           40/40/30
MAJOR-SEVERE STORM    10/10/05
B.  HIGH LATITUDES
ACTIVE                30/40/40
MINOR STORM           50/40/40
MAJOR-SEVERE STORM    20/20/10