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                     POTENTIAL GEOMAGNETIC STORM WARNING

                       ISSUED: 02:00 UTC, 15 JULY 2000

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               (See Appended Comments for Synoptic Information)

                      *** SIGNIFICANT EVENT WARNING ***

  VALID BEGINNING AT: 18:00 UTC, 15 JULY

    HIGH RISK PERIOD: 15 - 16 JULY (UTC days)
MODERATE RISK PERIOD: 15 - 17 JULY

POTENTIAL LOW-MIDDLE LATITUDE STORM INTENSITY:  SEVERE
      POTENTIAL HIGH LATITUDE STORM INTENSITY:  SEVERE

      POTENTIAL DURATION OF GEOMAGNETIC STORM:  APPROX 24 TO 36 HOURS
            DURATION OF MAIN BELT OF ACTIVITY:  APPROX 18-24 HOURS

POTENTIAL PEAK LOW-MIDDLE LATITUDE K-INDEX VALUES:  8-9
      POTENTIAL PEAK HIGH LATITUDE K-INDEX VALUES:  9

  EXPECTED DOMINATING LOW-MIDDLE LATITUDE K-INDEX:  7
        EXPECTED DOMINATING HIGH LATITUDE K-INDEX:  7-8

   POTENTIAL FOR LOW LATITUDE HF DEGRADATION:  HIGH
        POTENTIAL SEVERITY OF HF DEGRADATION:  MINOR
          EXPECTED HF PROPAGATION CONDITIONS:  FAIR

POTENTIAL FOR MIDDLE LATITUDE HF DEGRADATION:  HIGH
        POTENTIAL SEVERITY OF HF DEGRADATION:  MAJOR
          EXPECTED HF PROPAGATION CONDITIONS:  VERY POOR TO USELESS

  POTENTIAL FOR HIGH LATITUDE HF DEGRADATION:  HIGH
        POTENTIAL SEVERITY OF HF DEGRADATION:  MAJOR
          EXPECTED HF PROPAGATION CONDITIONS:  USELESS (BLACKOUT CONDITIONS)

POTENTIAL RISK FOR GEOSYNCHRONOUS MAGNETOPAUSE CROSSINGS: 80%

SUSPECTED SOURCE OF OBSERVED/EXPECTED ACTIVITY:

     Large and potentially significant Earthward directed coronal mass
ejection.


---------------------------------       ---------------------------------
EST. POTENTIAL GEOMAGNETIC IMPACT       EST. POTENTIAL IONOSPHERIC IMPACT
---------------------------------       ---------------------------------
       SEVERE STORM : 50 %                 LOW LATITUDES : MINOR
        MAJOR STORM : 40 %              MIDDLE LATITUDES : MAJOR
        MINOR STORM : 10 %                HIGH LATITUDES : MAJOR
     ACTIVE OR LESS :  0 %               POLAR LATITUDES : MAJOR
---------------------------------       ---------------------------------
 PROBABLE SI ASSOCIATION : 95%    ESTIMATED GLOBAL IMPACT: MAJOR

ESTIMATED FORECAST PEAK PLANETARY 24-HOUR A-INDEX DURING STORM: 90-140
                   ----           ---------------

COMMENTS:

     This is a serious event and may have the potential of being one of the
largest geomagnetic storms to be observed this solar cycle. Satellite
operators, hydro operators, pipeline owners and radio communicators may be
affected by this event.


**  End of Warning  **