WETTEST OCTOBER ON RECORD AT ARMAGH, SUNNIER THAN AVERAGE AND VERY MILD
Armagh Observatory stories that October 2023 was very a lot wetter than common, and each sunnier and hotter than common. This was the wettest October at Armagh since day by day rainfall data started on the Observatory in 1838, making this the wettest October, and certainly the wettest calendar month at Armagh, for at the least 185 years.
Whole precipitation was 195.35 mm (7.69 inches) together with 9 hint values, that’s, 194.9 mm (7.67 inches) if hint values are ignored. That is greater than 2.4 occasions each the 183-year long-term (1838-2020) common October precipitation at Armagh (80.4 mm) and the latest (1991-2020) 30-year common (81.0 mm). The half-dozen wettest Octobers at Armagh are actually 2023 (195.35 mm), 1870 (193.75 mm), 2011 (182.75 mm), 2002 (158.1 mm), 1865 (150.0 mm), and 2022 (149.45 mm). 4 of those six wettest Octobers since 1838 have occurred within the final 20 years.
The half-dozen wettest calendar months at Armagh are actually 2023 October (193.35 mm), 1870 October (193.75 mm), 1852 November (188.4 mm), 2015 December (186.1 mm), 2011 October (182.75 mm), and 1914 December (181.35 mm). Three of those wettest months have additionally occurred within the final 20 years.
The wettest day was the thirtieth with a complete rainfall of 30.8 mm, adopted by the twenty ninth with 29.0 mm and the nineteenth with 28.0 mm. Though this month was exceptionally moist, there have been nonetheless solely 20 days with measurable precipitation. This means that, fairly than rainfall turning into extra frequent, when it falls it is available in bigger quantities. This month, the excessive cumulative rainfall complete may be largely attributed to 2 very moist days related to the passage and aftermath of storm Babet (20.0 mm and 28.0 mm of precipitation on the 18th and nineteenth of October respectively) and to a really moist spell on the finish of the month with 5 consecutive days from the twenty seventh to the thirty first every with excessive day by day rainfall totals.
The moisture-laden storm Babet, which had arrived from the Bay of Biscay on the sixteenth, was noteworthy in bringing sturdy winds and really heavy rainfall to central and jap areas of Britain from the 18th to the twentieth. Predominantly excessive stress throughout the first half of the month modified to low stress with the arrival of this storm, which produced an exceptionally low atmospheric stress at Armagh of roughly 978 mbar (diminished to imply sea stage) on the nineteenth. This was the bottom October atmospheric stress recorded at 09:00 GMT at Armagh for 23 years, that’s, since 970 mbar was recorded on each the eleventh and thirtieth of October 2000.
The 5 very moist days from the twenty seventh to the thirty first on the finish of the month produced respective rainfall totals at Armagh of 27.8 mm, 8.2 mm, 29.0 mm, 30.8 mm, and 15.4 mm, totalling 111.2 mm. That is practically 40% greater than the typical complete precipitation for the entire of the month. As was extensively reported, this led to vital flooding throughout Northern Eire together with County Armagh, a end result exacerbated by additional mild rainfall on the first of November.
Northern Eire was lucky find itself situated practically centrally between two very deep areas of low stress throughout the first two days of November, resulting in comparatively quiet circumstances and solely restricted precipitation on the 2nd. Thus, Northern Eire escaped the worst results of the violent storm Ciaran on the first and 2nd of November. This third named storm of the season precipitated havoc to northern France and southern Britain because it moved into the English Channel from the southwest approaches earlier than swinging north and weakening because it handed into the North Sea.
Whereas the 2022/2023 storm season offered solely two named storms (in August 2023), the 2023/2024 season starting in September has already offered three. Rainbows had been seen at Armagh on two days, the morning of the third and the afternoon of the twenty eighth.
With a median temperature of 11.7 Celsius (53.0 Fahrenheit) this was one other very gentle October, solely barely cooler than the 2 earlier Octobers, particularly 2022 (imply temperature 11.9 C) and 2021 (12.0 C). This October was 2.20 C hotter than the 183-year long-term (1796-2020) common October temperature at Armagh (9.48 C) and 1.31 C hotter than the latest (1991-2020) 30-year common (10.37 C).
The month-to-month common of the day by day most temperatures was 15.1 C. That is roughly 1.4 C hotter than the corresponding most up-to-date (1991-2020) 30-year common (13.7 C) and the ninth warmest such file at Armagh. The month-to-month common of the day by day minimal temperatures was 8.2 C, roughly 1.2 C hotter than the corresponding most up-to-date 30-year common (7.0 C).
The three warmest days (highest day by day most air temperatures) had been 21.7 C on the ninth, bracketed by 20.9 C on the eighth, and 19.2 C on the tenth. Every of as of late was hotter by greater than 5 levels Celsius than the corresponding most up-to-date (1991-2020) 30-year common (13.7 C), suggesting that these very heat October days had been an instance of a uncommon October warmth wave, which in Northern Eire could also be outlined as three or extra consecutive days with day by day temperature maxima exceeding 19.0 C. Such October warmth waves happen at Armagh roughly as soon as each 25 years on common, the latest examples being the durations ninth to eleventh October 1969 and the first to fifth October 1959.
The 2 warmest days this October, particularly the ninth and eighth, had been respectively the third and ninth warmest October days on file at Armagh in a 180-year day by day sequence of temperature maxima and minima extending again to 1844. The ninth (most temperature 21.7 C) was the warmest October day at Armagh for 97 years, that’s, since 22.3 C occurred on the third of October 1926.
The few warmest October days at Armagh are actually 1908 October 3 (22.7 C), 1926 October 3 (22.3 C), 2023 October 9 (21.7 C), 1908 October 1 (21.6 C), and 1959 October 4 (21.6 C).
In contrast, the good days (lowest most day by day temperatures) at Armagh this month had been the thirtieth (10.5 C), adopted by the twenty first (11.3 C) and the 14th (11.4 C).
The very best day by day minimal temperatures, that are normally the warmest nights, had been 15.2 C on the seventh adopted by 15.1 C, which occurred across the time of observations on the eighth and once more shortly after midnight on the night time of the ninth/tenth October (and so related to the tenth). These heat nights had been respectively the eighth and equal ninth warmest October nights on file at Armagh. The good nights (lowest minimal air temperatures) had been 0.9 C on the seventeenth, 1.4 C on the fifteenth, and 1.9 C on the twelfth.
There have been 9 floor frosts (minimal grass temperatures lower than or equal to zero Celsius) this month, of which the three coolest had been -5.4 C on the twelfth, -4.5 C on the fifteenth and -4.3 C on the seventeenth. With a lowest minimal air temperature of 0.9 C there have been no nights with air frost.
This 12 months’s Halloween, as with thirty first October final 12 months (2022), was very moist with 15.4 mm of precipitation, virtually no sunshine, and a imply temperature of roughly 9.9 C.
The entire variety of hours of sturdy sunshine this October, particularly 98.4 hours, was roughly 12% greater than the 140-year (1881-2020) long-term October common at Armagh (87.3 hours) and seven% greater than the latest (1991-2020) 30-year common (92.0 hours). The sunniest day was the twelfth with 9.3 hours of sturdy sunshine, adopted by the 14th with 9.1 hours and the twenty second with 8.7 hours.
These knowledge check with observations at Armagh Observatory, which has been recording the climate at Armagh since 1795.
For additional data, please contact:
Professor Mark E. Bailey
Emeritus Director of Armagh Observatory
Armagh Observatory and Planetarium
School Hill
Armagh
BT61 9DG
Tel: 028-3752-2928
E-mail: mark.bailey@armagh.ac.uk
