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Model Output Discussion - 31/10/2014 and Beyond


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heres a great way of seeing the direction of travel on the ecm ens two weeks away.

 

two charts showing the probability of SLP > 1030mb.

 

todays 00z                                                yesterdays 12z

 

attachicon.gifeps_mslp_1030o_nh_59.png                          attachicon.gifeps_mslp_1030o_nh_61.png

 

 

 

 

one can see the movement west of the russian high. it may change in twelve hours. note the complete lack of any chance of a strong block directly to our north due to the likely direction of the northern split/or main jet towards svaalbard.

 

I'm no doubt being a bit thick here ba perhaps because "the movement west of the russian high" is open to different interpretations. I'm taking that as the Russian HP moving east and the block becoming less effective. Do i need some more espresso?.

Edited by knocker
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Generally the trend over the last few days has been for the models to strengthen the block to the NE in the timeframe T+96 to T+144. Beyond 144 models have generally eroded the block, some quite dramatically but each day the back track has continued and it is now looking likely that we will end up with an anticyclonic spell. Warm air aloft being sucked up from the SE could lead to a low level inversion with chilly misty conditions at the surface in an east or southeasterly drift from cooling continent.       

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I'm no doubt being a bit thick here ba perhaps because "the movement west of the russian high" is open to different interpretations. I'm taking that as the Russian HP moving east and the block becoming less effective. Do i need some more espresso?.

 

Open the second image fist (yesterdays run) :)

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Oh no the Azores !!!! Well Azores is our friend and for one it settles things down under clear sky's frosty. Then it makes its move retrogression to Scandinavia or even Atlantic Greenland !! Oh let's not forget the heights and the weak vortex. I've not posted for awhile because I don't see any kind of massive change in the models just yet.

I'm watching for the split and where the heights settle there self but one thing is for certain the Scandinavia euro heights are hold ground but we need lower height in Europe or even heights into the North Atlantic into Greenland and lower heights to our East. Even a omega block would be a step in the right direction. But recent days post by chiono and Steve ba ect ect really put things into perspective. Nick Sussex as always puts up the fight for a cold perspective but in all honesty we are in the start of what is a very rapid changing northern hemisphere, Either way it's not a touch on last year and is extremely frustrating but interesting.

Let battle commence. For the much new forum fans don't be disheartened by the repeated postings of mild mild mild because we need the mild to aid us towards cold. 09/10 was the same if not worse than this but look what happened that's why we need what's happening in future runs up to the reliable time frame to happen even with the differences in ideas.

So take the mild charts and see how it could benefit us and in any case most mild charts that are posted over and over each day are European look. Keep an eye on hemispheric charts lot less disheartening.

Edited by Polar Maritime
Edited to reduce all the gaps between the lines.
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A stalemate seems the more likelier option today from the models, you'll see from the outputs that the constant phasing of troughing to the west of the UK and associated low heights from the PV just drives energy over the top of the high.

 

The best you can do in this situation is to get the high over Europe far enough west and north to bring some surface cold by way of a se/e flow, at least its dry and although not that exciting its preferable IMO to slow moving troughing stuck too close to the UK.

 

If you look at the ECM ensemble graphs you can see some colder options appearing for De Bilt:

 

post-1206-0-30236100-1416050648_thumb.pn

 

Those more likely to be an inversion type scenario, however a small number bring in some deeper cold but that needs the below scenario.

 

The only route to a chance of real cold needs a shortwave to cut se from upstream troughing, this could happen in conjunction with a ridge being forced north ahead of a more amplified mid Atlantic troughing, high pressure to the ne then acts in tandem to help force a shortwave to clear se.

 

The ECM suggested this possibility a few days back but dropped that scenario by the next morning, the window of opportunity for this to happen is closing because the upstream pattern is expected to de-amplify, the UKMO at T144hrs is probably the best upstream at that timeframe:

 

post-1206-0-57497700-1416051746_thumb.gi

 

You can see its more amplified over the mid west USA, downstream as that wave moves east you're  likely to see more dig south of troughing in the Atlantic, the ECM is flatter at that point:

 

post-1206-0-92838600-1416051981_thumb.gi

 

If you just look at the means they show a very slow moving pattern with Atlantic troughing edging slowly east but still with high pressure close by.

 

In terms of any reset, IMO given the upstream pattern expected this would just be a wet mild affair so I think its a case of uneventful Euro high or that, the low probability option is an undercut.

Edited by nick sussex
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A weaker Atlantic pattern seems the outlook for the next week with low pressure close by being held back by the stubborn high over S,Scandinavia.

The fax for Tuesday shows the expected picture by then

post-2026-0-55533000-1416052882_thumb.gi

A slow moving set up and frustrating in many ways as we know the weaker vortex and continuing wave action holds promise but not yet.

The block ensures a mild feed for much of W.Europe and the UK for a while yet until we have a change in the wave pattern.

Edited by phil nw.
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Interesting output..

 

Firstly at day 5 and 6 we have the Euro and UKMO in agreement rejecting the Atlantic with pressure near 1025mph. It's a southerly flow so warm uppers, without surface charts though i can't tell whether the high pressure will compensate.

 

Rukm1441.gif

 

Moving into FI and the Parallel once again puts up a brick wall to the Atlantic. Unfortunately the center is too far east to be anything other than mild.

 

Rpgfs2401.gif

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post-1206-0-66213300-1416053390_thumb.pn

 

To elaborate on Steves post the above is the NAVGEM T144hrs, you'll see how more amplified the upstream pattern is.

 

The progression from there if things went well would be as follows, the high moves east, the troughing near the UK disrupts ejecting the shortwave se. The high then joins forces with higher pressure to the ne, at the same time low heights near Greenland go more north rather than ne.

 

After this you look to the ne to wait the incoming cold pool!!!

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I just feel that the majority on here are interpreting this so wrongly (and very recent events support this). With a lobe of the PV over N.America bringing cold weather there this is the ideal set up for a conveyor of low systems to develop over NW Atlantic and head for the NE Atlantic where the temperature differential across the N.Atlantic is accelerating the Jet Stream and this will deepen any lows. Something the models proved last December / January that they cannot see very well. There is a slight blocking pattern; but this will be overwhelmed by the low altitude effect of the heat of the N.Atlantic (where SST are anomalously 5C higher than average over Nova Scotia) driving the creation of low pressure systems under the anomalously low temps at high altitude. Its stormy weather not snowy!

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Just 24hrs ago the ECM ens mean was showing this for the 24th.

 

EDM1-240_fti5.GIF

Now    EDM1-216_lrj6.GIF      

 

Unusual for the ECM ens to swing so much so quickly.. so the models are clearly in a mess at the moment.

 

A lot of uncertainty with the situation to our W/NW... LP dominance vs HP dominance? NAEFS spreads

 

naefsnh-6-0-252_vsx7.png

That's a great post and ties in with what Fergie said yesterday with regards to MOGREPS trending to higher pressure building more,

especially over the south.

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I just feel that the majority on here are interpreting this so wrongly (and very recent events support this). With a lobe of the PV over N.America bringing cold weather there this is the ideal set up for a conveyor of low systems to develop over NW Atlantic and head for the NE Atlantic where the temperature differential across the N.Atlantic is accelerating the Jet Stream and this will deepen any lows. Something the models proved last December / January that they cannot see very well. There is a slight blocking pattern; but this will be overwhelmed by the low altitude effect of the heat of the N.Atlantic (where SST are anomalously 5C higher than average over Nova Scotia) driving the creation of low pressure systems under the anomalously low temps at high altitude. Its stormy weather not snowy!

Yes this will eventually likely happen as it normally does but for the next week or so high pressure over Europe and Scandinavis looks more likely to be influential. 

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I just feel that the majority on here are interpreting this so wrongly (and very recent events support this). With a lobe of the PV over N.America bringing cold weather there this is the ideal set up for a conveyor of low systems to develop over NW Atlantic and head for the NE Atlantic where the temperature differential across the N.Atlantic is accelerating the Jet Stream and this will deepen any lows. Something the models proved last December / January that they cannot see very well. There is a slight blocking pattern; but this will be overwhelmed by the low altitude effect of the heat of the N.Atlantic (where SST are anomalously 5C higher than average over Nova Scotia) driving the creation of low pressure systems under the anomalously low temps at high altitude. Its stormy weather not snowy!

This is what the models were showing up until a couple of days ago but they have backtracked somewhat and the block to our east

is much more resilient than they were originally forecasting. This is why the stormy atlantic is not a feature so much now in the forecasts.

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Smiler when is this cold shot coming ? Even though things are looking a little more settled there is still a lot of low pressure to the NW which I think is where we don't want it !

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Smiler when is this cold shot coming ? Even though things are looking a little more settled there is still a lot of low pressure to the NW which I think is where we don't want it !

It's not that there showing any real cold at the moment, it's the fact that some show high pressure over Europe and Russia, with the way the models are chopping and changing it wouldn't take much of a shift to put us under one of these blocks, but also we could stay where we are now which is wedged between high pressure and low pressure.

The point I'm getting across is not to get to hung up on current outputs. The building blocks are there we just need them all to fit together and fall into place where we get the cold. Last winter the uk was stuck under mild westerly yet just across the North Sea Scandinavia was in the freezer, hopefully this year we end up on the right side of the cold

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Smiler when is this cold shot coming ? Even though things are looking a little more settled there is still a lot of low pressure to the NW which I think is where we don't want it !

 

 Hi Kimb

 

A genuine cold shot is unlikely to arrive before December, there are plenty of things happening in the arctic with the polar vortex which suggest that cold will get to us but these things have a lag time between them happening  up there and their consequences down the line for us.

Edited by mcweather
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Im pretty sure when a Cold shot arrives it will be out first one.. The GFSP shows nothing cold until the last few frames, Even then it's cool at best, Where maybe Pm shots are possible. But these are way out in the run. The Models continue to show average if not mild conditions for the South, With bands of rain trying to push in from the West continuing to bump into the block to our East. As said this morning we are not even into winter yet, There is no real cold yet to tap into so members are going to have to be patient, As it's not just going to simply arrive overnight..  For what it's worth looking at the Models, I do think our first Wintry shot will be from the N/W Months end.

 

But there's a lot of water to run under the bridge yet, As the Models work out what to do with the block to our East. So an interesting period of Model watching coming up, As they figure out what happens next!

Edited by Polar Maritime
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I just feel that the majority on here are interpreting this so wrongly (and very recent events support this). With a lobe of the PV over N.America bringing cold weather there this is the ideal set up for a conveyor of low systems to develop over NW Atlantic and head for the NE Atlantic where the temperature differential across the N.Atlantic is accelerating the Jet Stream and this will deepen any lows. Something the models proved last December / January that they cannot see very well. There is a slight blocking pattern; but this will be overwhelmed by the low altitude effect of the heat of the N.Atlantic (where SST are anomalously 5C higher than average over Nova Scotia) driving the creation of low pressure systems under the anomalously low temps at high altitude. Its stormy weather not snowy!

I'm a bit surprised to see how much criticism this post has received. I personally think the sceuro high is not just going to fold under the Atlantic attack, having seen months of model output attempt and fail the same, but the Atlantic isn't without ammunition right now, as the poster quite rightly says, and surely any reasoned post should be treated respectfully, regardless of whichever weather preference one has?

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I just feel that the majority on here are interpreting this so wrongly (and very recent events support this). With a lobe of the PV over N.America bringing cold weather there this is the ideal set up for a conveyor of low systems to develop over NW Atlantic and head for the NE Atlantic where the temperature differential across the N.Atlantic is accelerating the Jet Stream and this will deepen any lows. Something the models proved last December / January that they cannot see very well. There is a slight blocking pattern; but this will be overwhelmed by the low altitude effect of the heat of the N.Atlantic (where SST are anomalously 5C higher than average over Nova Scotia) driving the creation of low pressure systems under the anomalously low temps at high altitude. Its stormy weather not snowy!

 

Don't be put off David by the reactions you have got. Your view will not be popular with those wanting to see cold in the charts. Your view may be a touch simplistic but there is truth in some of the points you make. A bit late but welcome to Net Wx in spite of a fairly hostile reception!

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