Model output discussion - into July 2020

[johnholmes]

Well I might as well drop this in the mix, it in my view is perhaps the most realistic, at least for the upper air pattern, being reasonably consistent for a few days

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

 

Climate Prediction Center - 6-10 Day 500mb Outlook

WWW.CPC.NCEP.NOAA.GOV

 

 

Based on these then no real signal for a settled dry hot spell, just a mix, one decent day scattered amongst fairly unsettled with the so often NW-SE split.

[mountain shadow]

32 minutes ago, mb018538 said:

Again - the less said about the CFS the better as well.

It forecast a very strong and persistent ridge over the UK/scandi for mid to late July. That turned out well....

I don't know how many millions of dollars is spent on this model, but they would be better spending it on something else. 

 

[ChannelThunder]

1 hour ago, Ice Day said:

Not much change on the overnight runs, showing a real mixed bag for the next 10 days, some good, some bad (the south/south east fairing better - sorry ).  It currently looks like next weekend is going to be pretty awful, wet with depressed temperatures nationwide.  In fact, quite remarkable consistency between the ECM and GFS for 9 days from now 

   

Both go on to promise something better from day 10 but too far out to worry about.

 

 

Yeah, spotted that rare cross-model agreement too a moment ago. It looks like a fairly nice week is on the cards until Friday/the weekend, when the Atlantic comes barreling in on both models.

Still no sign of anything plume-like, meaning we're likely going to end up with it having been over a year since the last one.

Edited July 17, 2020 by Lance M

[mb018538]

46 minutes ago, Lance M said:

Yeah, spotted that rare cross-model agreement too a moment ago. It looks like a fairly nice week is on the cards until Friday/the weekend, when the Atlantic comes barreling in on both models.

Still no sign of anything plume-like, meaning we're likely going to end up with it having been over a year since the last one.

Do 16c uppers and four days of 29-33c maxima not count as a plume? Or just regular hot weather!

[MATTWOLVES 3]

2 hours ago, NApplewhite said:

GFS models agree - very heavy rain over England and Wales for the period 24th July to 27th July 2020 with large precipitation amounts and suppressed temperatures. 

Long range forecasts on the brilliant Accuweather (what models do they use) are indicating a very warm and dry period August 10th to August 31st 2020 across the UK.

 

I posted the EC weeklies last night up til around 11th of August... Just had another gander further a field and it tends to be going for a better August than anything in July... Ridging is more prevalent, especially into England and Wales. This trend is showing right into the backend of the month.. So as it stands... The 46 looks pretty decent for next month... Only time will tell.. But let me just say, this is a much more thorough and efficient model than the CFS.. I hope its onto something. 

[Guest]

8 minutes ago, mb018538 said:

Do 16c uppers and four days of 29-33c maxima not count as a plume? Or just regular hot weather!

I think most people think of the plume ending in fireworks, back in June the highly unstable mid-levels that I think defines a true plume never really reached our shores so would it was just regular hot weather? 

[ChannelThunder]

4 minutes ago, Alderc said:

I think most people think of the plume ending in fireworks, back in June the highly unstable mid-levels that I think defines a true plume never really reached our shores so would it was just regular hot weather? 

Agreed, it was almost a plume. Close, but no cigar.

[mushymanrob]

Theres no getting around this outlook.... its pretty dire, and IF this pattern establishes, then theres no quick way back to anything summery . Whats concerning is the cross model support plus anomaly support.. Autumn starts next weekend?

 

[summer blizzard]

Interestingly enough the Euro 46 suggests a significant rise in AAM..

It will be interesting to see if it transpires however. With the large trade burst currently underway I wonder if it’s picking up too much on the relative rise afterwards.

[Frosty.]

Well, this summer clearly isn’t the best, blah blah etc etc..what’s new?..recent years we are used to crap winters ain’t we?..so let’s deal with what’s in front of us and actually there are some decent signs next week, at least for a time and especially across the south..so, quit moaning and just accept what we have!..and remember, even after July there is still another 4 weeks of the meteorological summer to enjoy / endure!

 

[summer blizzard]

GFS6z is possibly the worst run since 2012.

[mb018538]

47 minutes ago, summer blizzard said:

Interestingly enough the Euro 46 suggests a significant rise in AAM..

It will be interesting to see if it transpires however. With the large trade burst currently underway I wonder if it’s picking up too much on the relative rise afterwards.

I was just going to mention this! Latest ECM has Scandi blocking into the first week of August. Simon Lee has said caution needed though with such a wild swing from a day ago, and the models could be picking this signal up incorrectly. Matt Hugo rightly points out that the Pacific basin is still in a highly suppressed state are forecast to remain that way into August, which would work against any rise in AAM.
 

 

[Skullzrulerz]

Sounding by the looks of things better make the most of this week's weather while you still can 

To be fair it has been quite a nice summer sure it's not been too hot or hasn't broken any records but being nice and cool at times has helped

 

[wellington boot]

1 hour ago, summer blizzard said:

Interestingly enough the Euro 46 suggests a significant rise in AAM..

It will be interesting to see if it transpires however. With the large trade burst currently underway I wonder if it’s picking up too much on the relative rise afterwards.

Last couple of runs follow a similar path, which is nice, but... difficult to ignore the fact that every single run forecasts almost exactly the same rise in AAM, so it's a challenge to take it at all seriously...

[summer blizzard]

The obvious question here is whether anybody can explain what a wave packet is without me having to read a research paper.

Edited July 17, 2020 by summer blizzard

[Tamara]

58 minutes ago, summer blizzard said:

Interestingly enough the Euro 46 suggests a significant rise in AAM..

It will be interesting to see if it transpires however. With the large trade burst currently underway I wonder if it’s picking up too much on the relative rise afterwards.

This ties in with the suggestions made yesterday about intra-seasonally driven "wane" periods within the default tropical > extra tropical circulation

The strong trade wind surge during the third week of this month is what is driving NWP at the moment and they are going to struggle to "see" past it. Most especially the GFS which invariably overreacts to robust signals and then goes to town extrapolating it outwards in time.  A poor period of weather is quite likely during this time, but its worth waiting and watching for what happens thereafter.

The powerful intra-seasonal MJO related kelvin wave driving this strong upstream signal will be followed by strong convective suppression in the area where the low frequency walker cell has been strongest and dominant so far this summer. This is tied into those longer range atmospheric angular momentum forecasts and the rebound associated with the lull in easterly inertia that will occur as a result of the convective suppression across Africa and the Equatorial Atlantic - and westerly wind propagation occurring (increasing wind shear across the main development region or MDR of the Equatorial Atlantic) as the  convectively coupled kelvin wave (CCKW) heads eastwards across the tropics. The velocity potential anomalies depict this sequence with the blue shading (active convection) during the coming week and into the following week being replaced by the orange (suppressed shading) as the convective envelope heads into the Maritime continent region of the tropics by the end of July

Little point in looking for clues for this in deterministic and 10 day ensemble NWP this early for quite a while yet because they will be churning out a suppressed downstream flat jet-stream for this period, but while the actual strength of the EC weekly bounce in AAM ,as reflected by the distinct downstream anticyclonic wave-break heading into August on the synoptic level may be open to debate - the evolution it shows is very credible based on the passage of this intra-seasonal phenomena which could well shake up the NH pattern from the default tedium  - at least for a time.

So caution is advised to assumptions about the Pacific heading into August by over extrapolating the suppression there which occurs due to the convective signal across Africa and the Indian ocean. On the other hand instead, an extended watching brief on that default low frequency "wane" (suppression) arriving as August arrives and how much it can create a change of pattern for a little while.

[MATTWOLVES 3]

So some signs of perhaps an increase in AAM  through August, going on the ECM ectended last night, perhaps Tams could shed some light on this at some point. It was quite a different run from the Monday one though. More prevalent ridging and a decrease in rainfall amounts.. 

The general situation for anyone wanting to get away for a break abroad is a very positive one.. Central and Southern Spain remaining hot with loads of Summer conditions there. No surprises there really! Italy and Greece much the same, also some very warm conditions for the low countries at times through next month being flagged up. Plenty of warmth in France, and very warm/hot conditions in Southern France.. Over to the USA and there is lots of heat towards the Eastern Seaboard and out to the mid west, this very warm air also effecting the Eastern Seaboard at times.. Some warmth also to be found into Southern Canada also at times. Not sure to many folk would want to travel to the USA currently anyway with the Covid situation. 

I think Tamara as now posted so I'll see what she as to say.

[Relativistic]

28 minutes ago, summer blizzard said:

The obvious question here is whether anybody can explain what a wave packet is without me having to read a research paper.

In physics contexts a wave packet is a waveform which is enveloped by a second function whose profile decays away from a point in space, thus resulting in a "pulse". This wiki page gives more detail and contains some animations which describe what I mean:

Wave packet - Wikipedia

EN.WIKIPEDIA.ORG

However, as someone with a physics background I find jargon we often use in physics can be used slightly differently (or more loosely) in meteorological settings, so whether this is useful information or not is best left for someone else to clarify.

Edited July 17, 2020 by Relativistic

[mb018538]

2 hours ago, Relativistic said:

In physics contexts a wave packet is a waveform which is enveloped by a second function whose profile decays away from a point in space, thus resulting in a "pulse". This wiki page gives more detail and contains some animations which describe what I mean:

Wave packet - Wikipedia

EN.WIKIPEDIA.ORG

However, as someone with a physics background I find jargon we often use in physics can be used slightly differently (or more loosely) in meteorological settings, so whether this is useful information or not is best left for someone else to clarify.

Nope - the same principle applies in weather terms. This is a good illustration of how they act on the weather.

[Zak M]

Now this is pretty decent from the 12z GFS 

   

Shame it's into the unreliable timeframe...

[Djdazzle]

One post on the 12z’s, which is a GFS FI chart. No need to even look at the models as this tells me all I need to know!

[Mark wheeler]

56 minutes ago, Djdazzle said:

One post on the 12z’s, which is a GFS FI chart. No need to even look at the models as this tells me all I need to know!

It’s a bit Meh , but no washout on the Ukmo .

Edited July 17, 2020 by Mark wheeler
Spelling

[MATTWOLVES 3]

55 minutes ago, Mark wheeler said:

It’s a bit Meh , but no washout in the Ukmo .

Yes Mark.. I pointed out last night from the weeklies about perhaps not a washout.. Tonight's ECM brings a decent week for the whole before trending more unsettled.. But it looks far from a washout.. Quite a slack pattern infact.. So perhaps some areas drier while others could get some big downpours. 

Bit of a ridge by day 9.

Edited July 17, 2020 by MATT☀️

[Zak M]

Nice end to the 12z ECM for the south

@240

[mb018538]

4 minutes ago, Zak M said:

Nice end to the 12z ECM for the south

@240

Looks ok - big low isn’t really there at all! I’m not convinced just yet, but the 00z wasn’t bad either at day 10.