Normal rainfall in November
Rainfall in November 2019 (40.2 mm) was near normal. That reduced shortages at durations from 2-months to 5-months. Otherwise it had little effect: fifteen of twenty longer durations remained extreme shortages.
Values plotted in the 0.1th percentile
For simplicity, the bottom line is labelled with the 0.1th percentile value, and percentile values below 0.1% are plotted on the line. As there are 1600 months of record, both the 2nd-driest month (percentile value 0.063%) and the driest month, (percentile value 0.000%, by convention), which would plot below the line, are plotted on it.
Driest records have again been broken at durations of 12-months (270 mm), 24-months (611 mm), 30-months (834 mm), 72-months (2927 mm), and 96-months (4205 mm). The 96-month record had stood at 4405 mm since November 1919.
A value that equals an earlier record occurs at 84-months (3555 mm).
Values that are 2nd-driest occur at 36-months (1129 mm) and at 240-months (11816 mm). The 240-month (20-year) total is now only 50 mm more than the lowest-ever value of 11766 mm set in February 1931.
How to read the graph
This graph shows all the present rainfall shortages at Manilla, short term and long term, as percentile values. The latest values, as at the end of October 2019, are shown by a thick black line with large circles. Those from one month earlier are shown by a thinner line with small diamonds. [The method is described in “Further Explanation” below.]
The following notes explain aspects of this work under these listed headings:
Cumulative rainfall totals
Severity of rainfall shortages
Limitations of this analysis
Monthly rainfalls form a single population
Observations are not retrospective
The rain gauge failed