FROM SPACE ENVIRONMENT SERVICES CENTER, BOULDER, COLORADO
SDF NUMBER 200
JOINT USAF/NOAA REPORT OF SOLAR AND GEOPHYSICAL ACTIVITY.
ISSUED 2200Z 18 JUL 1988
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM 17/2100Z
TO 18/2100Z:  SOLAR ACTIVITY HAS BEEN LOW. REGION 5075 (S21W13)
CONTINUES TO PRODUCE SMALL FLARES INCLUDING A C6.3/1F AT 1608Z
AND A C4.6/1F AT 1625Z. THE LATTER OF THESE WAS CORRELATED WITH
A STRONG TYPE IV RADIO SWEEP AND INTENSE DISCRETE FREQUENCY
BURSTS. THE REGION APPEARS TO BE DECAYING SLIGHTLY BUT IS ALSO
UNDERGOING SOME ROTATION WHICH IS LIKELY TO BE INCREASING
MAGNETIC FIELD SHEARING AND HENCE THE STRENGTH AND FREQUENCY OF
THE FLARES. REGIONS 5071 (N25W68) AND 5073 (N29W84) ALSO PRO-
DUCED SOME SMALL FLARES AS THEY APPROACHED THE WEST LIMB. NEW
REGION 5079 (S16W33) EMERGED TODAY AS A SIMPLE BIPOLAR GROUP
AND NEW REGION 5080 (S18E61) ROTATED INTO VIEW AS A SIMPLE UNI-
POLAR GROUP. RADIO NOISE STORMS WERE IN PROGRESS THROUGHOUT THE
DAY ON 245 AND 410 MHZ WITH OCCASIONAL INTENSE BURSTS WHICH WERE
FREQUENTLY ASSOCIATED WITH TODAY'S SUBFLARE ACTIVITY. THE
REMAINDER OF THE SOLAR DISK AND LIMBS WERE QUIET AND STABLE.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE
GENERALLY LOW. NONETHELESS REGION 5075 CONTINUES TO POSE SOME-
WHAT OF A THREAT FOR MODERATE LEVELS AND MAY PRODUCE AN ISOLATED
M-CLASS FLARE SOMETIME OVER THE NEXT THREE DAYS AS IT CONTINUES
TO DECAY.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 17/2100Z TO 18/2100Z:
THE GEOMAGNETIC FIELD WAS GENERALLY UNSETTLED WITH A PERIOD
OF ACTIVE CONDITIONS AT MIDDLE LATITUDES AND ACTIVE TO STORM
CONDITIONS AT HIGH LATITUDES FROM APPROXIMATELY 0300-1200Z.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS
EXPECTED TO BE UNSETTLED AT MIDDLE LATITUDES AND ACTIVE AT
HIGH LATITUDES. A CORONAL HOLE LOCATED JUST SOUTHWEST OF
REGION 5075 MAY INCREASE LEVELS SLIGHTLY ON THE SECOND AND
THIRD DAYS.
III.  EVENT PROBABILITIES 19 JUL-21 JUL
CLASS M    35/35/30
CLASS X    05/05/05
PROTON     05/05/05
PCAF       GREEN
IV.  OTTAWA 10.7 CM FLUX
OBSERVED           18 JUL  148
PREDICTED   19 JUL-21 JUL  147/145/148
90 DAY MEAN        18 JUL  131
V.  GEOMAGNETIC A INDICES
OBSERVED  AFR/AP 17 JUL  008/017
ESTIMATED AFR/AP 18 JUL  012/025
PREDICTED AFR/AP 19 JUL-21 JUL  010/022-012/025-012/025