Model discussion - Warm spell ending as Spring begins

[Derecho]

1 hour ago, Mattwolves said:

Interesting thoughts about April and pointing out how cold it currently is in Greenland. Apperantly summers in Greenland have been cooling in recent years as well. In 2017 a new July low of - 33c was recorded at the summit. 2018 was also the coolest summer for the area in 20 years. Frequent snowfall increased the surface mass budget of the ice cap by nearly 150bn tonnes, slightly less than 2016/2017 for 6th highest on record. A cold may in which summit temps of - 46.3c was recorded, this marking a new may record for Greenland and delayed the melt season till June. Temperatures in both August and September got within 1-2c of the monthly cold records. In August the temp dropped to - 39c. And in September it hit - 44c.In October the temp dropped to - 55.4c,this surpassing the previous record October record of - 55.2c.So all in all a quite interesting last year in Greenland, and like you mention, some very cold conditions spilling out of there right now. 

Colder air over Greenland during Summer months often coincides with warmer weather over here. In these such scenarios we are likely to see low heights to our NW and high pressure over here or over Scandinavia. This is exactly what happened last year so I would think record cold over Greenland would actually increase our chances of warmth here quite dramatically. The cooler weather from 2007-2012 over here during the summer often coincided with record warmth over Greenland.

So far this March Greenland has been pretty cold but I think if this persists we will get a very warm April with SW winds or high pressure dominating. April 2011 for example was cold over Greenland yet warm records were absolutely smashed here.

For reference here are the monthly anomalies from May to October last year:

   

 

Meanwhile there are records of temperature over Greenland (modelled data from GFS can be questionable over this region) going back to the 1780s which can be viewed through the following link, they are focused on SW Greenland though:

https://crudata.uea.ac.uk/cru/data/greenland/

A graph of the summer temperatures can be seen below back to 1840 (before this the data coverage gets patchy):

2018 was the coldest summer over SW Greenland Greenland since 1996 so this adds weight to the theory that cold summers over Greenland equate to warmer summers here. Such trends may be harder to interpret from earlier data though due to the fact the arctic is now far warmer which may affect how temperature responds to atmospheric circulation patterns. There has been a drop in temperatures since 2012 as you say.

So record cold over Greenland? As unlikely as it sounds it wouldn't be a bad thing if it's warmth and settled weather we are chasing!

 

Edited March 24, 2019 by Quicksilver1989

[MATTWOLVES 3]

Great Post QS, thanks for that very insightful and in depth summary.

[Frosty.]

Put a note in your diaries folks, the Gfs 18z operational  says it's going to snow  early on thursday 4th april..maybe anyweather has a point!

Edited March 24, 2019 by Frosty.

[MATTWOLVES 3]

6 minutes ago, Frosty. said:

Put a note in your diaries folks, the Gfs 18z operational  says it's going to snow  early on thursday 4th april..maybe anyweather has a point!

It would only be a northern high ground event though surely Karl, the uppers don't look cold enough, the 18s not even bringing that Nthly the ECM is going for. Come to think of it the entire run is never cold enough for snow away from the highest parts of scotland. 

[Frosty.]

3 minutes ago, Mattwolves said:

It would only be a northern high ground event though surely Karl, the uppers don't look cold enough, the 18s not even bringing that Nthly the ECM is going for. Come to think of it the entire run is never cold enough for snow away from the highest parts of scotland. 

The 18z kind of goes with Exeter's update indicating short colder interludes, mainly in the north..nothing unusual for early april. 

[MATTWOLVES 3]

These NWtly air streams still packing a punch from the GFSP. One thing for sure its quite a bit more unsettled at this stage. 

Edit... Massive differences between GFSP and ECM at 240 on the northern hemisphere profiles. 

 

Edited March 24, 2019 by Mattwolves

[Frosty.]

Interesting parallel 18z on 7th April..for parts of the north.

Edited March 24, 2019 by Frosty.

[knocker]

Outlook - Put simplistically the Upper trough is stationed to the north west with the ridge to the southwest pushing north east over the UK in the reasonable time frame. With the upper flow tracking north east between Greenland and the UK the latter will remain very dry apart from the north west as the odd system impinges there.

The Atlantic 500mb and surface analysis for midnight and the 0500 UK chart

A fairly benign start to the day as the center of the high cell is now just south of Ireland and yesterday's front is now a very weak affair. However it will pep up a tad later as it swivels and pushes back east, courtesy of a low tracking into Iceland, so some cloud and showery rain effecting the north west during the afternoon. Elsewhere over much of England and Wales it will a pretty good day with plenty of sunshine with temps around average.

During this evening and overnight It will remain generally cloudy in the north with the odd shower but elsewhere there could be some frost patches with the clearer skies

So after a touch of frost to begin Tuesday it will be sunny and quite warm for most with temps a tad above average, The exception being the far north where it will remain cloudy with some patchy rain, courtesy of some fronts that are quite adjacent.

Over Tuesday night and through Wednesday little change

Over Wednesday night and through Thursday the pressure relating to the scenario mentioned earlier is making some inroads and the wind picks up over Scotland with some cloud and patchy rain associated with the odd stray front

Over Thursday night and through Friday the emery continues to suppress the ridge but still warm in the UK south of the cold front winch is edging southeast down the country

Edited March 25, 2019 by knocker

[knocker]

Continuing with the gfs As the upper trough moves away to the east there is a brief resurgence of the high from the south west but there is another trough exiting Canada tracking east over Iceland and phasing with the vortex lobe near Franz Joseph Island. .

And from this point it almost mirrors last evening's ecm output as it has the subtropical high in mid Atlantic amplifying into Greenland and the trough plunging south over the UK introducing much colder air, Clearly the models are still struggling in the 5-10 period

 

[knocker]

The ecm certainly nods in the same direction with a brief transient ridge post Saturday and them an upper trough tracking east past Iceland and then the subtropical high pushing north in mid atlantic with colder air advecting south east over the UK by the end of the run. Still a work i progress

 

[Frosty.]

Looking good folks

[Paul]

Locking this, new thread is open here: