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The 6-hourly intervals are centred on the main synoptic hours (00, 06, 12 and 18 UTC) as described in Table 8.
Table 8 - Definition of the 6-hourly aggregation intervals. The defined time limits (note that 21UTC in the 00 interval refers to the previous day) are applied to the observation time (t) as specified in the NWP monitoring reports. It should be noted that only the observations that were made available in time for each of the NWP assimilation systems are included in the NWP reports.Anchor Table8 Table8
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The daily aggregation refers to the union of the four 6-hourly intervals as defined in Table 8, therefore is the 24-hour period within the interval 21 UTC ≤ t < 21 UTC, where t is the observation time and the lower “21UTC” limit is the day before.
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The alert maps represent a 5-day moving average, therefore rely on daily values for a 5 day period as described in Table 9.
Table 9 - 5-day moving averageAnchor Table9 Table9
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