Rainfall & Drought Watch - 2019

Oneiric 3

Going through some stats, which I haven't updated in a good while, I was surprised to see how 'dry' this January has been so far across the country and proves that personal perception may not fall in line with the stats all of the time. As this January did not seem particularly dry to me, whereas December, which was statistically wet, did not seem to be all that so.


But, given that the odd rainfall patterns of last year seem to be continuing into this new year, I thought it might be useful to have a dedicated thread to exclusively monitor rainfall and drought patterns that may occur throughout the year, which continues on from the now irrelevant 'Summer Rainfall/Drought Watch' thread opened up last year.


To start it off, here is a graph showing the 28 day running rainfall pattern (expressed as percentages from the 1981-2010 average) for the last 12 months:




Very much swings and roundabouts since early Summer last year, yet overall, this winter so far, despite the unusually dry January, is running close to average regarding totals, due to the very wet December.

Will these wild swings in rainfall patterns continue throughout the coming year, or will they just fall back again within the usual standard deviations as we grow just that bit little older and just a little bit more portly as 2019 wears on?

We shall see...


All data in this post C/O Met Eireann.

blackwave

Just out of curiousity and for my own knowledge is there any website to check the levels of the Irish Water resevoirs? If there isn't do people know how the levels are after the dry summer compared to other years?

prunudo

blackwave wrote: »

Just out of curiousity and for my own knowledge is there any website to check the levels of the Irish Water resevoirs? If there isn't do people know how the levels are after the dry summer compared to other years?

Roundwood has been about as full as it gets the last few weeks. Was full this time last year too. Can only base it from observations/looking back at old photos and not from technical data.

Oneiric 3

Final national rainfall figure for January came in at 66.4mm, or around 60% of average, which is roughly on par with that of 2017, but still places it comfortably within the top 20 driest Januarys since 1900.

Some notably dry Januarys in history:

1963: 25.3mm
1997: 36.3mm
1953: 47.2mm
1935: 47.5mm
1964: 50.6mm.


Edit: May as well throw in MSLP stats as well for the month. Nationally, pressure anomaly came in at above 6.0 hPa above normal, with mean values highest in the SW (1020.4 hPa in both Cork Apt and Valentia) and lowest in the Northwest (1016.8 hPa in Malin Hd)

DOCARCH

Only 28.3mm here in Dublin 16 in January.

Harry Palmr

I'm shocked anyone would be surprised at this news. We've had just one properly wet day since December 15 - Jan 31st.

Mortelaro

Just 18.4mm in January here in Arklow

Oneiric 3

Mortelaro wrote: »

Just 18.4mm in January here in Arklow

May I ask how this compares to your monthly summer totals during 2018?

Looking at some temp stats here and nationally, averaged out over a 4 week period, the temperature anomaly peaked at 2.87 Deg. C during the mid-January period, which was higher than the peak 4 week deviation (2.74 Deg. C) which occurred during the extraordinary warmth of late Spring/early Summer last year, and with both times coinciding with unusually low rainfall totals.

Makes me wonder if the N Atlantic pattern was 'jarred' somewhat after the late Feb/early Mar easterly spell last year that we my still be in recovery from? As another very notable feature of this Winter so far is the lack of wind compared to average. It may have been an Atlantic dominated winter so far, but certainly not in typical way. Far from it in fact.

Any data used in this post is courtesy of Met Éireann.

Abhainn

Began recording Feb 2013 in Wicklow Town
Last 6 Jans

2019 - 22.0mm
2018 - 97.1mm
2017 - 36.2mm
2016 - 111.3mm
2015 - 65.0mm
2014 - 145.3mm

Mortelaro

Off the top of my head,it's more rain than in June and July
November had a whopping in or about 300mm though and December around 150
I'm not near the pc but I'll look it up later
October was also wet
The southeast in general I think had a lot of rain in those 3 months
Using a Davis vantage pro 2

Oneiric 3

Mortelaro wrote: »

Off the top of my head,it's more rain than in June and July
November had a whopping in or about 300mm though and December around 150
I'm not near the pc but I'll look it up later
October was also wet
The southeast in general I think had a lot of rain in those 3 months
Using a Davis vantage pro 2

Thanks. November certainly was wet in the SE, but October looked to be quite dry, relatively speaking? At least according to this map by the Met.



Though those maps are not great at picking up localised quirks, which your region may well have experienced.

Mortelaro

Yeah roughly 2 weeks of October was wet here,I'll have a look at the daily when I'm back at the pc
Many many days in November had anomalous dregs of coastal rain or showers dragging it's heels clearing
My area got a lot of that, as Villian will testify as he got the almost daily disaster report with video and radar to his carlow weather dm:D
Waterford weather actually had slightly more rain in nov and Dec than I did
Sometimes east wexford missed this as often the line of rain bumped out to sea there and back in near Waterford

Mortelaro

Here's some examples from my Twitter from October

https://twitter.com/Arklowweather/status/1051030221787463680?s=19

https://twitter.com/Arklowweather/status/1051092623543418880?s=19

https://twitter.com/Arklowweather/status/1052195413443264515?s=19

https://twitter.com/Arklowweather/status/1056918091903442945?s=19

Xenji

We had 152mm of rain in Castlebar in January, but it is usually one of our wettest months with 16 out of the last 30 January's here having 200mm plus of rain.

Timmaay

Abhainn wrote: »

Began recording Feb 2013 in Wicklow Town
Last 6 Jans

2019 - 22.0mm
2018 - 97.1mm
2017 - 36.2mm
2016 - 111.3mm
2015 - 65.0mm
2014 - 145.3mm

You don't have a live hourly/daily stream of this data anywhere online? I've been too lazy to get myown proper rain gauge yet ha.

Oneiric 3

Rainfall % of average for the first two months of 2019 for all of the reporting Met Eireann stations:



Data: Met Eireann.

Very apparent east/west split, While most if not all stations are coming in with a rainfall deficit, some stations in the east have only received 50% or less of normal rainfall for the Jan-Feb period.

Fairly widespread, if modest falls across the country on the first day of Spring yesterday, with longer range forecasts suggesting anything between 20 & 50 mm falling over the country over the 7 days or so, so maybe some good news for those looking for some rain.

Latest NWP rainfall total forecast up to the end of the coming working week:

sryanbruen

https://twitter.com/meteireann/status/1103710794057957376?s=21

BlackandGreen

Said it before but the one thing that worries me about our weather after last year is extended drought.
A lot of people got away with it in 2018 but there was entire parishes without water for months here.



I was lucky in that we had water for a few hours every day and managed to be able to get everything done, but i had to seriously curb water consumption as it was off from 6pm to 7am every day and then from 8pm to 7am right up until december because there was such a shortage.


Other places simply had NO water for weeks if not months.


If we were to get a drought like that for another summer or a few in a row it coule be a serious emergency. It made me anxious to be honest, not being able to wash in the morning after sweating all night in bed when it was in the high 20's.
I had to take 2~ minute showers. turning it off in between using soap.


What píssed me off the most was that so many people just refused to conserve water. If I said that a 30 minute shower was too long, or there's no need to do a full 2 hour wash for some underwear and non stained clothes people would just fob me off.

Neighbors went out and make a big point of power washing the entire house right in the middle of the hosepipe ban just because "fúck em".

Oneiric 3

Very wet March so far, with most, if not all stations already surpassing their entire monthly long-term average, despite the fact that we are really just a little over halfway through the month.

This graph shows the running 28 day mean percentage of average rainfall totals (up to yesterday, the 16th) since March last year:



Really spiking up now and as can be seen, we are now in the wettest period, relative to average, in over a year.

Top 5 wettest stations so far this March (mm)

Newport: 194.6
Finner Camp: 176.0
Markee: 175.8
Shannon Apt: 167.8
Knock Apt: 167.1



Top 5 'driest' so far: (or just escaping the very worst)

Phoenix Pk: 82.3
Casement: 83.2
Dublin Apt: 89.9
Roches Pt: 98.4
Mace Hd: 99.3



Mean totals by Province:

Connacht 152.1
Ulster (RoI) 146.7
Munster 130.2
Leinster 104.6


The coming working week does look to be drier as high pressure tries to build in, but when I see a forecast chart like this, which is for the midweek period,



it doesn't convince one that there will be any great drying either after the recent deluges, with northern and western areas, in particular, prone to drizzly damp bursts at times as weak fronts hover just a bit to close for comfort.

All data above from Met Eireann.
Forecast map from AMet (Spanish Met Office)

Mortelaro

'Just' 80.6mm here in Arklow in March so far

pauldry

Definitely going to break the 200mm in Sligo

A lot drier in last 15 days with about 30 or 40mm in NW

Graces7

Non stop deluges out here. how easy is it with home items to measure rain? as opposed to tech stuff.?..would love to try that

west mayo offshore

Oneiric 3

Graces7 wrote: »

Non stop deluges out here. how easy is it with home items to measure rain? as opposed to tech stuff.?..would love to try that

west mayo offshore

If you have a spare coffee mug Grace, that is as good as anything. Though given your windy location, you might want to set it in firm enough in the ground so as not to blow away. Just make sure it is set level and measure any rain collected in the mug (every day at a set time if at all possible, and to the nearest millimeter ) with a ruler and just log in the results in a dedicated school copy or something similar.

You might be surprised at what an interesting hobby this could turn out to be.

Graces7

Oneiric 3 wrote: »

If you have a spare coffee mug Grace, that is as good as anything. Though given your windy location, you might want to set it in firm enough in the ground so as not to blow away. Just make sure it is set level and measure any rain collected in the mug (every day at a set time if at all possible, and to the nearest millimeter ) with a ruler and just log in the results in a dedicated school copy or something similar.

You might be surprised at what an interesting hobby this could turn out to be.

Does the width/size of the receptacle not matter?

Gaoth Laidir

Graces7 wrote: »

Does the width/size of the receptacle not matter?

It doesn't matter if it is totally cylindrical and the bottom is flat. Some cups have wider rims than bottoms so they won't do.

If you're using a ruler to measure the depth just make sure to account for the blank offset at the end of it. Better instead to dip something square into the water and then measure the length of its wetness.

Another method is to weight the water each time, but for this you will need to know the exact diameter of the mug to calculate its area. 1 mm of rain is 1 litre per square metre. 1 ml weighs 1.0 g.

John mac

heres a handy one..


https://www.wikihow.com/Make-a-Rain-Gauge-out-of-a-Plastic-Bottle

Graces7

John mac wrote: »

heres a handy one..


https://www.wikihow.com/Make-a-Rain-Gauge-out-of-a-Plastic-Bottle

neat! Thankyou

sryanbruen

March 2019 rainfall totals up to the 21st show it has been the wettest March on record at several stations including long-term stations of Shannon Airport and Mullingar.



Data from Met Éireann.

pauldry

Casement Claremorris Malin and Mace will be in or near record territory by 31st March. Thanks for that info Sryan. Is there a website where you get that info. When I look at Met Eireann website I only see data for past couple of years

Id say Markree has defintely had its wettest March for many years based on Finner and fact the most Ive recorded since 2005 is 164mm

sryanbruen

pauldry wrote: »

Casement Claremorris Malin and Mace will be in or near record territory by 31st March. Thanks for that info Sryan. Is there a website where you get that info. When I look at Met Eireann website I only see data for past couple of years

Id say Markree has defintely had its wettest March for many years based on Finner and fact the most Ive recorded since 2005 is 164mm

I get the data from the historical database on met.ie: https://www.met.ie/climate/available-data/historical-data

A weird thing with this database is that on the new met.ie, you cannot access closed station data (like old Oak Park manual station, Kilkenny, Birr, Clones etc) or some long-term stations' data like Valentia Observatory which you need to go to archive.met.ie for. I let Met Éireann know about this bug but got no response.

I download the excel files of each station - monthly ones for this data above and use the filter function in excel making the data go from largest to smallest. I also use the filter function then to only include Marches.

Danno

Graces7 wrote: »

Non stop deluges out here. how easy is it with home items to measure rain? as opposed to tech stuff.?..would love to try that

west mayo offshore

Might be worth contacting Met Eireann directly if you were in a position to take readings every day. They supply and install the equipment, namely the metal gauge, the measuring beaker and the report cards which are freepost back to Dublin every month.

Interestingly there is a station out on Innishboffin

sryanbruen

Any update on this? May was another very dry month alongside some unusually dry months in the past year {May 2018, June 2018, July 2018, January 2019, February 2019}. June wasn't very wet but relatively wetter than average and so far, July is looking quite dry.

Top 20 driest months of the decade for Ireland using the 11-station grid (Ballyhaise, Casement, Claremorris, Cork Apt, Malin Head, Mullingar, Belmullet, Johnstown Castle, Oak Park, Valentia, Shannon Apt):

1. Apr 2017 - 22.6mm
2. Sep 2014 - 22.9mm
3. Jun 2018 - 27.4mm
4. Mar 2012 - 29.3mm
5. Mar 2011 - 40.2mm
6. May 2019 - 40.6mm
7. Jun 2010 - 42.4mm
8. Jun 2015 - 44.4mm
9. Aug 2010 - 44.6mm
10. May 2010 - 46.1mm
11. Feb 2012 - 48.0mm
12. Apr 2011 - 48.6mm
13. Sep 2013 - 49.3mm
14. Jul 2018 - 50.6mm
15. Apr 2015 - 51.7mm
16. Jul 2014 - 51.9mm
17. Feb 2010 - 52.7mm
17b. May 2018 - 52.7mm
18. Jul 2011 - 52.8mm
19. Jun 2014 - 54.3mm
20. May 2012 - 55.7mm

sryanbruen

To continue from the above, here's the monthly rainfall anomalies (using the same 11-station grid) for the Republic of Ireland from September 2015 to June 2019. The unusually dry weather of late 2016/early 2017 and the Summer 2018 drought very evident here.