FI Charts ( T120+ onwards) Spring 2020 **READ MOD NOTE IN FIRST POST**

The models are starting to fall more in line with each other now. The GFS has been particularly disappointing recently getting it wrong several times over the past 10 days with warm and settled spells that none of the other models were showing. The GEM has actually worked out very well recently. It was the first model to show that the break in the settled conditions last Tuesday was more than just a blip hinting at a pattern change. The ECM fell in line fairly quickly but the GFS took it's time and eventually got there only to revert to a warmer and dryer solution again which was binned last night.


All the models are now in agreement that we are going to stay in this rather unsettled period for the foreseeable future. Even the warmer temperatures for this weekend and early next week have been downgraded considerably as the low pressure over us stays here throughout the weekend and into next week.

The next week will be dominated by low pressure in off the Atlantic with bands of rain or showers sweeping across the country in a relatively cool flow.



Heat builds over much of Europe by next weekend, but doesn't get as far as Ireland. We stay under a cool Atlantic setup with bands of rain and average to slightly below average temperatures.



There are hints at the very end of height's rising from the south, but this looks a flimsy attempt at best and the low pressures from the Atlantic remain close to our western coast at all times.



ECM is unsettled right to it's extended range as well with the Atlantic well in control:



GEM keeps the Atlantic going as well with no real sign of things settling down soon.



Next 10 days are looking fairly wet as well with bands of rain or showers most days. June is likely to finish with over 100mm of rain in most places as about 80mm is predicted to fall within the next 10 days. Flooding may become an issue if the second half of June remains unsettled with frequent spells of rain in off the Atlantic.

Cork Boy 53 wrote: »

So basically a repeat of most of June 2019 is on the cards though not quite as cold as then?

yep unless the models do big changes again soon looks like a basic repeat of June 2019. Probably not quite as cold as last year but we've already had a week of temperatures several degree's below average. Most places are already a degree below average, we would need the last week of June in the low to mid 20's to fix that anomaly.

I'm beginning to think there is something not right with the GFS, it has flipped back to a dry and settled solution for the 3rd time in a matter of days, not only that but all 20 runs are returning milder than average values almost identical to each other over the next 8 days, it certainly seems rather odd.

sryanbruen wrote: »

I think the GFS should be ignored altogether until it gets a dramatic performance improvement. Some days recently even the NAVGEM has had better verification than it. UKMO, ECM and GEM have been the best.

yep i'm beginning to think the same, it cannot be relied upon at all at the moment these wild swings from one thing to another all the time is just not workable.

The GEM has been excellent recently as is the UKMO, pity the UKMO is only up to 144 hours.

Farmer2017 wrote: »

What the weather ecm ukmo and gem giving for next 10 days

Until the GFS is fixed, there is not much point issuing forecasts based on that model as it just can't be relied upon as it changes it's tune more than I can keep up with it.

The ECM is similar to how it's been for the past while. We stay mild over the following 10 days with low pressure close to us at all times off to our west.




UKMO is similar, basically low pressure close to or over us next week.



Back to the ECM in terms of rainfall:

Sunday looks fairly wet, plenty of showers or longer outbreaks of rain and possibily thundery in places.



Tuesday again plenty of rain or showers possibly thundery



second half of next week looks dryer with showers in places.

Heavy rain moves in off the Atlantic next Saturday

eon1208 wrote: »

Gonzo.. Explain a little about cold fronts and warm fronts and the way they mingle with ZLP and HP. Just a short basic explanation.
Great updates..

Basically areas of high pressure can block areas of low pressure, but not always.

e.g. if there is high pressure stuck to our east over Europe (which is often the case in the summer), low pressure from the Atlantic can move through Ireland and then head north-eastwards over North-west England, on into Scotland and towards Scandinavia. This is why the Atlantic can have problems getting it's rain into SE England, France and most of the continent during the summer.

If high pressure is over Scandinavia or Greenland in the summer, low pressures can dive below the high pressure which is why we can sometimes get very cool and wet conditions with 'northern blocking' in the summer. This was one of the reasons why June 2019 was awful.

The same northern blocking during winter (high pressure over greenland or Scandinavia) can cause low pressures to sink down over us with winds reversed into the east, rather than from the Atlantic. This is exactly what most of us want to see, but rarely ever get in the winter. It can cause very cold temperatures and heavy snow between mid November and mid March.

High pressure in the mid Atlantic can cause cool and unsettled north-west winds and low pressures to dive north-west to south-east over Ireland and deliver quite a chilly time for us.

For Ireland the best position for high pressure is usually to our south-east in the summer, but close enough that we can tap into it properly, this can help draw up nice gentle warm southeaserlies or southerlies off a hot continent, and in the winter the best position for high pressure if you want snow is one that moves from Scandinavia over to Greenland.

This is only basic to how high pressures can interact and change the flow of low pressures. There are other factors involved such as sea surface temperatures, the polar vortex, the jetstream, El Nino which can also control areas of high pressure and low pressure.

eon1208 wrote: »

Thanks Gonzo. Very informative.. I only have one question. How do the easterlies form in the winter with blocking HP over Greenland and Scandinavia. LP is an anticlockwise flow.. Surely the flow can come in from the atlantic in such a case and not the east leading to wet..

Basically as you know the flow of the jet is west to east. During the autumn the polar vortex over north pole regions powers up which locks in deep cold high up over the polar regions. This big temperature difference between the polar regions and mid latitudes is what drives the jet stream during our winter and is one of the main reasons why our winters usually end in failure from a cold and snowy perspective. Our winter just gone had record breaking strong polar vortex along with record breaking positive AO and NAO, so we had relentless westerlies all through the winter resulting in a very wet autumn and winter. Northern blocking didn't stand a chance all winter because of this strength, but once the polar vortex began to weaken considerably in March (it usually starts decaying from March), we stood a better chance of northern blocking forming.

Since March the jetstream weakened considerably, we've had plenty of northern blocking when we don't really want it. We've had mostly easterlys and northerly's since March which is why we have been very dry for the most part. When northern blocking happens, the jetstream still moves east to west, but the flow of the jet can get shifted away from us, it can dive south through the Atlantic and then flow west to east across southern Spain or Morocco. This places us on the cold side of the jet, the westerlies are cut off and we either get high pressure with winds in from the east, a northerly or low pressures moving north-east to south-west over us. We can also end up in no mans land with neither high pressure or low pressure and just fairly static conditions.

We haven't really had the westerlies here since early March so high pressures have stuck around for ages. We have since had several northerly attacks and more recently a series of very slow moving low pressures moving north to south, these have become stuck over us in a very slack flow and this is why we've had a rather unfair distribution of showers or rain over the past few weeks with the east seeing most of any rain that's been going.

Once we resume the westerlies we should go back to our typical pattern of bands of rain every few days on a constant conveyer belt. At the moment there is a bit of a battle between the Atlantic, the blocking over Scandinavia and the Azores high in the mid Atlantic. The low pressures over us are going nowhere fast because there is nothing to force them out of the way fairly quickly.

It remains to be seen if the Atlantic will barge through over the next week. I think the Azores high will come back but we may have to wait till the end of June or sometime in July for that to happen.

If we do get the westerlies back on steroids over the next few weeks then that could be a very worrying outcome for those of us who want a few weeks of warm and settled conditions during this summer. At the moment all we can do is wait and see what happens over the next few weeks. This battle is one of the reasons why the models have really struggled recently, the GFS in particular wants to bring the Azores high back to us every week but it has failed 2 or 3 times already with it's predictions.