NOAA/USAF Report of Solar-Geophysical Activity 15 Apr 2000

:Product: Report of Solar-Geophysical Activity
:Issued: 2000 Apr 15 2200 UT
# 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 106 ISSUED AT 2200Z ON 15 APR 2000
IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  14/2100Z
TO 15/2100Z:  SOLAR ACTIVITY INCREASED TO MODERATE LEVELS. REGION
8955 (S22E20) SHOWED A GRADUAL INCREASE IN MAGNETIC COMPLEXITY
DURING THE PERIOD AND PRODUCED SEVERAL FLARES, TWO OF WHICH REACHED
M-CLASS. THE FIRST WAS AN M4/SF AT 15/1018Z ASSOCIATED WITH A 570
SFU TENFLARE AND A PARTIAL-HALO CME. THE SECOND WAS AN M2/1N AT
15/1448Z. ANOTHER FLARE OF NOTE FROM REGION 8955 WAS A C7/1N AT
15/1905Z ASSOCIATED WITH A SMALL FILAMENT DISAPPEARANCE. MINOR
GROWTH WAS REPORTED IN REGION 8951 (N12W31). REGION 8948 (S16W76)
PRODUCED ISOLATED LOW-LEVEL C-CLASS FLARES AS IT CONTINUED TO DECAY.
THE REMAINING REGIONS WERE STABLE. NO NEW REGIONS WERE ASSIGNED.
IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE AT
LOW TO MODERATE LEVELS. REGION 8955 MAY PRODUCE ADDITIONAL M-CLASS
FLARES.
IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 14/2100Z TO 15/2100Z:
GEOMAGNETIC FIELD ACTIVITY WAS AT QUIET LEVELS. THE GREATER THAN 2
MEV ELECTRON FLUX AT GEOSYNCHROUNOUS ORBIT REMAINED AT MODERATE TO
HIGH LEVELS.
IIB.  GEOPHYSICAL ACTIVITY FORECAST:  GEOMAGNETIC FIELD ACTIVITY IS
EXPECTED TO INCREASE TO UNSETTLED TO ACTIVE LEVELS DURING 16 APRIL
IN RESPONSE TO A PARTIAL-HALO CME OBSERVED LATE ON 13 APRIL. ACTIVE
LEVELS ARE ALSO POSSIBLE ON 18 APRIL DUE TO THE PARTIAL-HALO CME
OBSERVED EARLIER TODAY. THE GREATER THAN 2 MEV ELECTRON FLUX IS
EXPECTED TO RANGE FROM NORMAL TO HIGH LEVELS DURING THE PERIOD.
III.  EVENT PROBABILITIES 16 APR-18 APR
CLASS M    50/50/50
CLASS X    10/10/10
PROTON     05/05/05
PCAF       GREEN
IV.  PENTICTON 10.7 CM FLUX
OBSERVED           15 APR 164
PREDICTED   16 APR-18 APR  165/165/165
90 DAY MEAN        15 APR 184
V.  GEOMAGNETIC A INDICES
OBSERVED AFR/AP 14 APR  002/005
ESTIMATED AFR/AP 15 APR  007/008
PREDICTED AFR/AP 16 APR-18 APR  018/020-010/012-015/018
VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 16 APR-18 APR
A.  MIDDLE LATITUDES
ACTIVE                40/25/30
MINOR STORM           20/10/15
MAJOR-SEVERE STORM    05/01/01
B.  HIGH LATITUDES
ACTIVE                45/30/40
MINOR STORM           25/15/20
MAJOR-SEVERE STORM    10/05/05