Weather Events throughout History

Danno

Looking at the Met Eireann page: Weather Extreme Records for Ireland - Met Éireann - The Irish Meteorological Service

In the driest months on record, the year 1942 pops up for three mentions: April at Abbeyleix (1.3mm); June at Lambay Isle (0.8mm); and November at Edenderry (3.5mm).

An interesting feat for one year to achieve. This webpage which documents quite a few years in weather: Weather in History 1900 to 1949 AD (weatherweb.net) has no mention of anything for 1942 across these islands.

So, the question begs - what happened to weather patterns to keep so much of 1942 dry?

sryanbruen

Whatever about the background drivers, of course the primary reason would be blocking patterns setting up over Ireland and keeping the Atlantic at bay for prolonged periods of time.

Both June and November 1942 featured ridging close to Ireland but centred slightly to our west whilst April was the opposite way round with ridging close to us but centred over Norway with a mean southeasterly airflow.

Looking at daily reanalysis, April 1942 got off to quite an unsettled start with deep areas of low pressure pushing in from the west before high pressure then became a theme through most of the month thereafter.

As mentioned, June 1942 featured ridging from the Atlantic into Ireland which meant there was often a northwesterly feed of air so not an especially warm month despite being exceptionally dry after a pretty warm opening including a max of 27.2C at Birr on the 5th June, the Birr mean temperature for the month was around 13.6C which was basically average for 1971-2000 (the last full 30 year average for Birr before it closed).

November 1942 was much the same story and mid-month in particular was blocked with very stubborn area of high pressure, highly unusual for November. This brought frost and fog with numerous cases of inversions including a -0.5C max observation at Birr on 22nd. Mean temperatures were some 2 to 3C below modern November averages but significantly short of the exceptional cold November in 1919 which brought heavy snow to low lying areas mid-month and severe frosts. Markree had 12 air frosts during Nov 1942 including 5 days of -5C or less, quite notable for November.

These notably dry months of 1942 were of a sequence of very blocked years from 1940 to 1942 which were all cold winters with 1940-41 being the coldest for Ireland and 1939-40 being the coldest for Britain including January 1940 being the coldest month since February 1895. These cold winters were obviously driven by persistent high latitude blocking and reanalysis confirms this. January 1940 500mb height anomaly shown below with anomalously positive heights over Greenland and similarly anomalously negative heights through central and southern Europe with the zonal flow completely reversed.

June 1940 was widely the sunniest on record until June 1957 and still holds station records to the current day including Valentia Observatory, and holds the national highest monthly sunshine record for Northern Ireland too. For the Central England region, April/May 2020 were the coldest April/May since 1941.

Danno

Looking at Markree's historical data here: https://www.met.ie/cms/assets/uploads/2021/09/Markree_1850-1968.csv

They reported 33.3c on June 28th 1851 which ties with Kilkenny's 33.3c a few decades later (June 26th 1887).

500hPa re-analysis for that day.

850hPa re-analysis.

One wonders if Markree was able to hit 33.3c that day, were other locations hotter? Obviously there was no where near the level of observations around Ireland in those days. Also of note - this heat wasn't a once-off day which would raise suspicions, Markree recorded 32.9c on June 26th, 33.1c on June 27th and 32.2c the day after on the 29th of June.

Some four-day blast of heat!

odyboody

must have been the global warming caused by transport and cattle, couldn't possibly be a natural cycle thing😉

Orion402

https://www.boards.ie/discussion/comment/119145196#Comment_119145196

From experience, it is far more enjoyable to do the forensics of specific weather events, like The Night Of The Big Wind in 1839, than try to railroad weather events into planetary climate. I assume that more than a few are enamoured by forensics in the absence of a true picture of these events and thanks to the other contributors for supplying graphics as to the weather conditions present in 1851 and 1942.

Nabber

it was sustained heat in 1887.

The average temp for 1887 was lower than the the average of 22years preceding.

Gael23

In Livy g memory winter 1982 and summer 2006