February 2018 had heavy rain at last

Wave cloud photo

Lenticular over Warrabah

Although there were eleven hot days over 35° this month, no days went over 40°. On the average, the second week was just 3.4° above normal, but the first week had been 3.5° below. Through most of the month, the weather was sunny with little rain, making the soil extremely dry. A drought seemed likely.
A violent front on the 25th brought an estimated 54 mm of rain: the heaviest fall in years. There is no official record of this rain event. Nor is there an official record of the only recent events of such a large amount: 47.0 mm on 4 February 2016, and 54.5 mm on 17 June 2015. The latest official readings that were higher were more than five years ago. They were in the record-breaking month of November 2011: 60.8 mm on the 14th, and 62.9 mm on the 27th.

[See note below on “Very wet days at Manilla”.]

Weather log for February 2018

Comparing February months

Compared to last February, this one was not nearly so hot and not so dry. Nights were near normal and days, at 33.9°, only one degree above normal (32.9°). Despite other signs of high moisture, the early morning dew point of 9.9° was very low.
Thanks to the one day of heavy rain, the estimated monthly rainfall total (71 mm) was above the average (67 mm) and at the 65th percentile. Among totals for more than one month, there is just one serious shortage. The 72-month (6-yr) total of 3400 mm is at the 8th percentile (450 mm low).

Climate in February months

Very wet days at Manilla

Log of decade totals of rainfall excess, Manilla, NSWDaily rainfall amounts of over 50 mm (“flooding rains”) are extreme events that feature in several posts on this blog. A graph in the first post on the topic is a log of every very wet day in the 130-year record. In a second post, I graph the pattern of how the total rainfall in very wet days changes decade by decade (Graph copied here.). Very wet days have a curious relation to drought that is analysed in “More Droughts After Heavier Rains”, Parts I, II, and III.

Data. A Bureau of Meteorology automatic rain gauge operates in the museum yard. From 17 March 2017, 9 am daily readings are published as Manilla Museum, Station 55312.  These reports use that rainfall data when it is available, but it is not.  The gauge last reported on 24 September 2017.

All data, including subsoil at 750 mm, are from 3 Monash Street, Manilla.


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