Model Output Discussion - Mid Summer Onwards

[Rain All Night]

15 minutes ago, sheikhy said:

Thanks mate!!!Hmmm a pretty strong signal there for high pressure end of october!!im all for it!!keep the rain away lol!sorry!as much as you want it to RainAllNIight!!!

I only want it to rain at night, not during the day, because I hate rain, but I know it has to rain some time for there not to be drought  Plus I like the sound of rain on my window at night, helps me sleep good...

The ECM's idea of "high floats in behind the cold snap" - perhaps propped up by a low in the vicinity of Portugal - has support from the other models this morning:

Also, the ECM ensemble, along with the other two, still seems to think that this high will end up parked over Scandi - I will post the charts showing this from Tropical Tidbits once they have finished loading there.

Edited October 9, 2023 by RainAllNight

[sundog]

Latest gfs and ecm both going for hp to the northeast at day 10.

[Rain All Night]

2 hours ago, RainAllNight said:

I only want it to rain at night, not during the day, because I hate rain, but I know it has to rain some time for there not to be drought  Plus I like the sound of rain on my window at night, helps me sleep good...

The ECM's idea of "high floats in behind the cold snap" - perhaps propped up by a low in the vicinity of Portugal - has support from the other models this morning:

Also, the ECM ensemble, along with the other two, still seems to think that this high will end up parked over Scandi - I will post the charts showing this from Tropical Tidbits once they have finished loading there.

Here you go, my "Frankenstein's ensemble" of charts from Tropical Tidbits.

Day 10 (Thu 19 Oct): ECM, GEFS, GEM

Day 15 (Tue 24 Oct) : ECM, GEFS, GEM

It looks like the GEFS thinks that the high will go further east than the other two models, which (I think) would mean we would be getting rather wet if that were correct.

Edited October 9, 2023 by RainAllNight

[Cambrian]

Keeping the horror theme going…

Friday the 13th : When Two Fronts Collide…

0z UKMO fax charts for 96h and 120h

 

…and for good measure, a moisture-laden low pressure runs up from the southwest, deepening as it does so.

24h precipitation charts for Friday from the 0z UKMO and 6z GFS - 30-50+mm through central Wales, the Midlands to Lincolnshire and Norfolk. 

  

Might not be so bad in the event and move through a bit further north as with the ECM and GEM, but equally, plenty of potential for even more rain with this one, particularly locally. Either way, great weather for frogs. 

[Addicks Fan 1981]

13 hours ago, Metwatch said:

Hopefully Tamara makes another post soon, give us that key vital update of the AAM in tandem with the MJO / tropical convection placement!

Think Tams will post if she is free to do so, she gives very detailed analysis and looks at all the variables involved as well. 

 There are posters though here and I'm not going to name drop who go with their gut instincts on what they think will come off. 

Sometimes gut instincts are the fact, but often they are opinion, think i will have the backing of@Scorcher on this to be honest.  

Anyway it does look like a short lived cooler interlude is on its way, but it won't last for very long.   

[Bats32]

37 minutes ago, Cambrian said:

Keeping the horror theme going…

Friday the 13th : When Two Fronts Collide…

0z UKMO fax charts for 96h and 120h

 

…and for good measure, a moisture-laden low pressure runs up from the southwest, deepening as it does so.

24h precipitation charts for Friday from the 0z UKMO and 6z GFS - 30-50+mm through central Wales, the Midlands to Lincolnshire and Norfolk. 

  

Might not be so bad in the event and move through a bit further north as with the ECM and GEM, but equally, plenty of potential for even more rain with this one, particularly locally. Either way, great weather for frogs. 

To be honest, the last thing the north can do with right now after the weekend is more rain. Warnings out for tomorrow also, could do with this not hitting further North on Friday.

Edited October 9, 2023 by Bats32

[Rain All Night]

2 hours ago, RainAllNight said:

Here you go, my "Frankenstein's ensemble" of charts from Tropical Tidbits.

Day 10 (Thu 19 Oct): ECM, GEFS, GEM

Day 15 (Tue 24 Oct) : ECM, GEFS, GEM

It looks like the GEFS thinks that the high will go further east than the other two models, which (I think) would mean we would be getting rather wet if that were correct.

The GEFS 6z run is even more determined than its predecessor that the ECM and GEM ensembles are giving us the wrong impression about an upcoming Scandi high spell, suggesting instead that we are going to have lows coming in and getting stuck over us due to heights further east, with heights only building further north late in the run, at which point the lows start digging to the southeast.

Edited October 9, 2023 by RainAllNight

[legion_quest]

3 hours ago, sundog said:

Latest gfs and ecm both going for hp to the northeast at day 10.

An Omega pattern again. The GFS and ECM have both loved that pattern recently, and we've seen it come off. 

But, it's also possible they are just presenting a pattern and something else could come along that means that pattern doesnt go that way given the time frames. 

We'll see, but that sort of Southerly draw at the end of October would make me cry. Halloween needs to be cold and misty/foggy. Not warm! 

[Addicks Fan 1981]

29 minutes ago, RainAllNight said:

The GEFS 6z run is even more determined than its predecessor that the ECM and GEM ensembles are giving us the wrong impression about an upcoming Scandi high spell, suggesting instead that we are going to have lows coming in and getting stuck over us due to heights further east, with heights only building further north late in the run, at which point the lows start digging to the southeast.

We will just have to wait and see if NOAA back the GFS op later on with the 6-10 day/8-14 day or whether it turns a blind eye to it.   

[Metwatch]

On 10/09/2023 at 22:10, Metwatch said:

I don't think we are fully out of the woods yet with days where it reaches 25C or above. Looking at the October date records, 25C can be seen well into October. More prolonged high 20s were seen during late September 1895 and early October 1921 as well, but those are exceptional examples.

Never underestimate the residual warmth to our south from the summer, even into October!

[Addicks Fan 1981]

1 hour ago, Metwatch said:

Never underestimate the residual warmth to our south from the summer, even into October!

I made a thread over autumn 2007 in the historic thread if you are interested in posting in it.   Meanwhile today has reached 26.1 degrees in East malling today with the 3rd consecutive day above 25 degrees centigrade.    

[Rain All Night]

4 hours ago, RainAllNight said:

The GEFS 6z run is even more determined than its predecessor that the ECM and GEM ensembles are giving us the wrong impression about an upcoming Scandi high spell, suggesting instead that we are going to have lows coming in and getting stuck over us due to heights further east, with heights only building further north late in the run, at which point the lows start digging to the southeast.

...whereas the GFS 12z op is on board with it!

Edited October 9, 2023 by RainAllNight

[SunnyG]

3 hours ago, legion_quest said:

An Omega pattern again. The GFS and ECM have both loved that pattern recently, and we've seen it come off. 

But, it's also possible they are just presenting a pattern and something else could come along that means that pattern doesnt go that way given the time frames. 

We'll see, but that sort of Southerly draw at the end of October would make me cry. Halloween needs to be cold and misty/foggy. Not warm! 

 Says who? They celebrate it all over the world (god knows why), even in places where it's sweltering.

[Methuselah]

Is that it?        

It's hardly worth the heating bill! 

 

Edited October 9, 2023 by Methuselah

[ANYWEATHER]

Ouch......

[Quantock]

6 minutes ago, Methuselah said:

Is that it?        

It's hardly worth the heating bill! 

 

I’m not sure what you’re expecting for the middle of October...Snow drifts and ice days?

Below average temps and frosts look likely.

Edited October 9, 2023 by Quantock
Edit

[Addicks Fan 1981]

6 minutes ago, Quantock said:

I’m not sure what you’re expecting for the middle of October...Snow drifts and ice days?

Below average temps and frosts look likely.

The update from Exeter doesn't agree with what you say there as they are going for near average temps and warmer in the south.   

[78/79]

3 hours ago, legion_quest said:

An Omega pattern again. The GFS and ECM have both loved that pattern recently, and we've seen it come off. 

But, it's also possible they are just presenting a pattern and something else could come along that means that pattern doesnt go that way given the time frames. 

We'll see, but that sort of Southerly draw at the end of October would make me cry. Halloween needs to be cold and misty/foggy. Not warm! 

First Mother in law would probably disagree with you, she reckons her broomstick is freezing at that time of year .

[legion_quest]

35 minutes ago, SunnyG said:

 Says who? They celebrate it all over the world (god knows why), even in places where it's sweltering.

Says me! 

[blizzard81]

22 minutes ago, Addicks Fan 1981 said:

The update from Exeter doesn't agree with what you say there as they are going for near average temps and warmer in the south.   

Except the update hasn't updated since yesterday. Still stuck on the 13th Oct to 22nd Oct period with yesterday's date at the bottom. It should now be showing 14th to 23rd Oct. 

[WYorksWeather]

Yep, does look like the models have finally settled on quite a substantial cold spell. I know I was previously sceptical of the idea (mea culpa). To be fair to myself - the models were fairly equivocal about the progression - some failing to push the cold front through at all, or quickly replacing it with milder air.

ECM isn't out yet, but here's UK Met, GFS and GEM at T+72 and T+120:

  

  

  

By T+120, all three models drawn down some sort of northerly airflow. Beyond that, some variation in the length of the cold spell, but all models keep the cooler air in place at least up to T+168, but after that the GFS keeps it cool right out to T+240. The GEM also stays relatively cool,  but by T+240 looks to be setting up another warm southerly, though perhaps mild is a better descriptor by the time we get to the latter stages of October.

A lot to happen before now and I wouldn't put too much stock beyond T+168 or even T+120 - I think the consensus is warm until Wednesday, bit of a battleground until Friday but then cold wins out and most likely stays in place through the weekend, which is probably as far as we can reasonably look with confidence.

Will be interesting to see if ECM follows the same broad pattern out to T+120/168. If so, I think we can call it a cold spell!

[blizzard81]

Amazing how mild and benign the outlook is over the north American continent. Look at Canada. 

[seb]

42 minutes ago, Addicks Fan 1981 said:

The update from Exeter doesn't agree with what you say there as they are going for near average temps and warmer in the south.   

Which really is what model output, taken together, is showing. Probabilities matter in forecasting which is why I really never understood why some here still take individual runs as gospel… regardless of scatter in the ensembles and constant chopping and changing of the op runs.

[Addicks Fan 1981]

3 minutes ago, seb said:

Which really is what model output, taken together, is showing. Probabilities matter in forecasting which is why I really never understood why some here still take individual runs as gospel… regardless of scatter in the ensembles and constant chopping and changing of the op runs.

As I said in my above post it's their gut instincts that kick in and they probably don't entirely understand ensemble mean runs all that well.  I look at things in a similar vein to mushy to be honest and mushy says it like it is pretty much.    

[WYorksWeather]

2 minutes ago, seb said:

Which really is what model output, taken together, is showing. Probabilities matter in forecasting which is why I really never understood why some here still take individual runs as gospel… regardless of scatter in the ensembles and constant chopping and changing of the op runs.

Yeah it is important to take the OP runs with a pinch of salt - as I've been pointing out over the past few days the operational runs have been close to the bottom of the ensemble packs lately. However, tonight it does seem that the 12z runs are mostly singing from the same hymn sheet (pending ECM), and so it does look like there'll be a period of cooler weather.

I also think given the tropical features at this time of year, anything beyond T+120 is iffy, and beyond T+168 is FI. Strictly for fun only.