Armagh Observatory stories that July 2023 was a lot wetter than common, and cooler than June. It was additionally duller than common, and had an exceptionally low imply atmospheric stress for July.
Whole precipitation was 138.75 mm (5.46 inches) together with three hint values, that’s, 138.6 mm if hint values are ignored. That is almost 90% greater than the 183-year long-term (1838-2020) common July precipitation at Armagh (73.4 mm) and barely greater than twice the latest (1991-2020) 30-year July common (69.0 mm).
Following an unusually dry July final yr (2022), this was the wettest July at Armagh for 87 years, that’s, since July 1936 (149.4 mm). If hint values are ignored, this July was the equal-fifth wettest July on file at Armagh in a day by day instrumental file extending again 185 years to 1838. There was measurable precipitation larger than or equal to 0.1 mm on 26 days, and of the remaining 5 days solely two have been utterly dry.
The six wettest Julys at Armagh at the moment are July 1896 (180.4 mm), July 1936 (149.4 mm), July 1880 (147.9 mm), July 1931 (146.3 mm), and July 2023 and 1895 (each 138.6 mm if hint values are ignored).
The wettest day was the twenty second, with 40.2 mm (1.6 inches) of rainfall, adopted by the 14th (15.3 mm) and the 4th (12.5 mm). The twenty second was the fourth-wettest July day on file at Armagh and the wettest July day at Armagh for 68 years, that’s, since third July 1955 (43.7 mm).
The 5 wettest July days at Armagh at the moment are the eighth of July 1896 (53.6 mm), twenty seventh July 1888 (46.4 mm), third July 1955 (43.7 mm), fifteenth July 2023 (40.2 mm), and thirteenth July 1908 (38.5 mm).
There was no thunder or lightning this month nor have been any rainbows or named storms recorded. It’s fascinating, nevertheless, {that a} gull was seen chasing a buzzard on the fifth and once more on the seventh, and roughly 25 swifts have been seen on the morning of the eleventh.
The imply temperature this month was 15.4 levels Celsius (59.7 Fahrenheit). That is roughly 0.5 C hotter than the 225-year long-term (1796-2020) common July temperature at Armagh (14.87 C) and 0.35 C cooler than the latest (1991-2020) 30-year July common (15.72 C). This was the best July at Armagh for 3 years, that’s, since a imply temperature of 14.6 C was recorded in July 2020.
Simply because the warmest a part of the day often (however not at all times) happens after noon, so too the warmest month of the yr often happens after June. At Armagh, the warmest or equal warmest month of the yr is both July (54% of the time) or August (42% of the time). June is hotter than July solely 8% of the time.
This yr the mix of a record-breaking heat June along with July cooler than the latest 30-year common meant that 2023 was one such yr, giving a June minus July temperature distinction of two.0 C. This equals the file for such a temperature distinction at Armagh, a file that was set 83 years in the past in July 1940.
The month’s warmest day was 23.3 C on the seventh, adopted by 22.6 C on the eighth and 21.9 C on the twenty seventh. The warmest day (23.3 C) was considerably cooler than the 28.5 C achieved on thirteenth June 2023. This due to this fact holds its place because the warmest day of the yr thus far. Against this, the best day (lowest most air temperature) was 15.5 C on the 14th, adopted by 16.4 C on the twenty first and 16.8 C on the 2nd.
The warmest evening (highest minimal air temperature) was 15.3 C, which was attributed to the twenty seventh though unusually the minimal occurred across the time of observations the day past. This was adopted by 14.4 C and 14.3 C, attributed to the eighth and thirty first respectively though these minimal air temperatures additionally occurred after the time of observations the day past. The good evening (lowest minimal air temperature) was 8.5 C within the small hours of the twenty fifth, adopted by 8.9 C on the thirteenth and 9.4 C on the third. There have been no air or floor frosts this month, the bottom grass-minimum temperatures being 2.2 C on the twenty fifth adopted by 2.3 C on the thirteenth.
The moist July 2023 was dominated by frequent showers or longer durations of rain accompanied by a wide range of troughs and frontal depressions crossing the nation. This month the typical stress, which displays the frequency of high- and low-pressure techniques in the course of the month and the consequences of a robust or weak jet stream, was unusually low for July, that’s, 1008 mbar decreased to imply sea stage.
This was the bottom common July atmospheric stress at Armagh for 162 years, that’s, since July 1861 (imply stress 1006 mbar), and the second-lowest imply July stress at Armagh in a day by day collection extending again to 1850. The 170-year (1851-2020) long-term common July stress at Armagh, decreased to imply sea stage, is 1015 mbar.
The Observatory’s long-term stress file is supported by handbook observations taken with a Kew sample barometer. Outcomes from this historic instrument haven’t been calibrated precisely in opposition to the extra trendy digital devices in use, however they do allow the long-term handbook file to be prolonged constantly to the current day. The Observatory additionally information minute-by-minute adjustments in atmospheric stress by way of its Computerized Climate Station (AWS), with outcomes from completely different barometers usually agreeing to higher than 1 or 2 mbar.
This month the observer recorded an exceptionally low atmospheric stress on the time of observations, 09:00 GMT, on the fifteenth of July. Right now, the Kew sample barometer gave 986.6 mbar decreased to imply sea stage, the second-lowest July atmospheric stress ever recorded at Armagh and the bottom since 985.0 mbar was recorded 144 years in the past on 1st July 1879.
The AWS offers additional info. It recorded 985.4 mbar at 09:00 GMT, roughly 1.2 mbar under the worth calculated from the much less correct Kew sample instrument. In keeping with the AWS, the bottom atmospheric stress that day was 984.6 mbar decreased to imply sea stage, 0.8 mbar under the 09:00 GMT worth, a lowest studying that occurred for roughly half an hour between 10:41 and 11:12 GMT because the exceptionally deep (for July) low-pressure system moved throughout the nation.
With a complete of 123.9 hours of robust sunshine, July 2023 was barely duller than common, with roughly 91% of the 140-year long-term (1881-2020) July common (135.9 hours) at Armagh and 92% of the latest (1991-2020) 30-year common (134.8 hours). The sunniest day was the twenty ninth with simply 10.0 hours of robust sunshine, adopted by the ninth with 9.3 hours and the eighth with 8.9 hours.
These information check with observations at Armagh Observatory, which has been recording the climate at Armagh since 1795.
For additional info, 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
