Remove ads from site

NickR
04 February 2016 12:07:18


 


Increasingly there is the suggestion of a slight negative tilt to the developing secondary feature for Saturday. The significance of this is that it leads to a longer-lived stalling out of the frontal boundary across S/SE England. Where exactly is not yet sorted out, with the range of locations currently being shown spread out from the eastern reaches of Devon to the Thames Estuary.


The 00z ARPEGE shows us how some particularly intense rain rates (for the time of year) push up from the SW as the secondary disturbance begins to exert its force upon the occluded airmass associated with the Friday eve/early Sat rainfall (which this model actually makes little of across the S/SE regions).


9 hours later, the still quite active feature is only just starting to move out of CS England. 


 


The resulting accumulations between 00z Sat and 00z Sun are shown below.


 


So 25-40 mm across quite a wide area. A Met Office yellow warning has been issued that talks of 20-30 mm quite widely across the S/SE regions, with locally 40-60 mm possible on south-facing slopes. That part reflects the strong winds expected, driving the air up against higher terrain. "Localised flooding and perhaps some disruption to travel" are the stated hazards to be aware of.


The possibility of intense rainfall is also mentioned so very much in line with ARPEGE (as an example from an array of many models).


 


The GFS 06z has produced an even longer stall-out and again across CS England (the 00z though was more toward the SE).


The totals change from 00z Sat to 00z Sun as follows:


 Modele GFS - Carte prévisions


Similar to ARPEGE despite the slightly lower-resolution which limits the capturing of convective features, though to my eyes it has done reasonably well with the general totals since that upgrade last winter. Relative to expectations, that is, which is to be within around 10 mm of the actual values - the modelling of convection still has a little way to go before it can produce reliably more accurate results than that on small scales.


 


Sunday essentially brings showers from the W/NW during the day, then perhaps some kind of frontal features to contend with as a vigorous disturbance sweeps through. That system might take until sometime on Monday though, based on recent trends.


For what it's worth, here's what the GFS totals look like with the Sun/Mon event added on top of Saturday's event:


Modele GFS - Carte prévisions


Considerable for a 72 hour period. Not exceptional, but given the already saturated ground and a fair bit more rain to come during the rest of next week, I expect some river flooding will be on the cards before long.


 


Oh alright then, here's GFS to the end of next week:


 


Not a pretty picture!


Originally Posted by: Stormchaser 


 


Good post, SC.


Reminds me that this bit of the NE really is very lucky! I've lost count of the number of times I've seen charts like that where we escape more than pretty much everyone else on account of the Pennine rain shadow.


Nick
Durham
[email protected]
Charmhills
04 February 2016 12:11:28


 


The 850s look far higher than I was expecting from that chart:


 


http://modeles.meteociel.fr/modeles/gfs/runs/2016020406/gfsnh-1-234.png?6


 


Originally Posted by: Rob K 


That's it because its a warm sector.


Loughborough, EM.

Knowledge is power, ignorance is weakness.

Duane.
turbotubbs
04 February 2016 15:06:56

Lack of posts is the best guide yet that no snow is  on the way. I kind of agree with IF about this - many of us seem to be very one track at this time year, and end up ignoring some potentially interesting stormy weather in the next few days.

Fothergill
04 February 2016 15:52:46

12z APERGE looks quite wet down here with up to 100mm over next few days. Looks like Feb could be the 4th notably wet month in a row. I think is even a longer wetter spell than 13/14.


Gooner
04 February 2016 16:27:04


It cant decide lol..................not good though


Remember anything after T120 is really Just For Fun



Marcus
Banbury
North Oxfordshire
378 feet A S L


Stormchaser
04 February 2016 17:06:01

Damn it there is just no consistency with respect to the period Sat-Mon; the GFS 12z has made a fair bit more of the Saturday feature with stronger wind gusts, but the Monday system doesn't travel as efficiently toward us and is on the wane before it makes it across:


No chart available for the selected hour. Many charts start at 3 hours ahead, so if you have 0 hours selected try stepping forward or selecting a later hour. No chart available for the selected hour. Many charts start at 3 hours ahead, so if you have 0 hours selected try stepping forward or selecting a later hour.


...yet UKMO has jumped into the vicious storm boat for Sunday, having held the system back to the west on the 00z:


 Modele UKMO - Carte prévisions


 


Then for the 4-5 day period, we see some pretty big differences with the arrival and evolution of the LP that's just about sneaking into the above-left chart (bottom-left of it). It's stronger, resulting in a track further north from both UKMO and GFS. It therefore merges with a shortwave west of Iceland on the UKMO run and comes close on the GFS run.


The UKMO solution is better going forward, as it takes away the chance that the shortwave will merge with the next trough coming off the U.S. and give it the excuse needed to just power on east rather than disrupt as per the ECM 00z for example.


In the chart below, there's enough of a wedge of higher heights toward Greenland that the trough complex could have performed a slide SE, however that low exiting Canada via Newfoundland tips the balance the other way instead. 


- but very notably, the further reaches of the run manage to show it going the right way instead. 


No chart available for the selected hour. Many charts start at 3 hours ahead, so if you have 0 hours selected try stepping forward or selecting a later hour.  No chart available for the selected hour. Many charts start at 3 hours ahead, so if you have 0 hours selected try stepping forward or selecting a later hour.


 


GFS has been more amplified in lower-res compared to recent days, and a look at the MJO plots reveals why:



Finally, GEFS have picked up on the MJO progression through to phase 5 and beyond, and this is now feeding into the GFS runs with added amplification as the AAM is boosted.


I should like to see less dithering about in phase 4 beforehand, but beggars can't be choosers... 


 


 


If you have any problems or queries relating to TWO you can Email [email protected]

https://twitter.com/peacockreports 
2023's Homeland Extremes:
T-Max: 30.2°C 9th Sep (...!) | T-Min: -7.1°C 22nd & 23rd Jan | Wettest Day: 25.9mm 2nd Nov | Ice Days: 1 (2nd Dec -1.3°C in freezing fog)
Keep Calm and Forecast On
Shropshire
04 February 2016 17:21:03

Horrific 12z runs thus far, as is usually the case with this pattern, the jet ends up further North when the events come within T120.


From December 27th 2020, zonality will be banned from mixing with the UK. We appreciate that this may come as a shock to younger people and old Uncle Barty. This ban will last for a minimum of ten days.
Brendon Hills Bandit
04 February 2016 17:40:52
I have become interested in the Atlantic SST pattern, and what effect this might be having.

I know that the 'tripole' pattern is the ideal pattern for cold in UK, but foregoing that, would the inverse of what we have now be better for cold prospects ? so by inverse I mean warm where the cold 'blob' is now, and cold to the south towards the equator.

Another thing that is interesting about the Atlantic is that the cold anomalies seem more prevalent than about a month ago, seem to remember it was forecast to be warming up through the winter.
220m asl, edge of Brendon Hills
The Beast from the East
04 February 2016 18:04:41


Horrific 12z runs thus far, as is usually the case with this pattern, the jet ends up further North when the events come within T120.


Originally Posted by: Shropshire 


Indeed. just when even I was thinking we might get something interesting, the jet veers north again. You couldn't make it up. It torture for cold weather fans!


 


"We have some alternative facts for you"
Kelly-Ann Conway - special adviser to the President
Nordic Snowman
04 February 2016 18:07:22

A definite upturn towards milder/unsettled weather from GEFS:-


http://www.wetterzentrale.de/pics/MT8_London_ens.png


Bjorli, Norway

Website 
Charmhills
04 February 2016 18:57:32



A snow risk for some from the ECM 12z.


Loughborough, EM.

Knowledge is power, ignorance is weakness.

Duane.
pdiddy
04 February 2016 19:05:20




A snow risk for some from the ECM 12z.


Originally Posted by: Charmhills 


Agreed.  i see the Siberian high making an appearance  - I won't be bothering my arse to track October snow cover this year as that was a waste of time....

pdiddy
04 February 2016 19:10:08

Looking at the GFS ensembles for Aberdeen, at the 12th Feb on the 0z, just about every member was below the 30yr average, and that had been a trend for a while.  on the 12z nearly all are above.  I suggest this run will not be particularly helpful, esp as so different to ECM.


 

Nordic Snowman
04 February 2016 19:31:22


Looking at the GFS ensembles for Aberdeen, at the 12th Feb on the 0z, just about every member was below the 30yr average, and that had been a trend for a while.  on the 12z nearly all are above.  I suggest this run will not be particularly helpful, esp as so different to ECM.


 


Originally Posted by: pdiddy 


This is the key issues though. Of course, it is easier to pay less attention to an isolated op run but GFS has literally done a major flip and therefore CANNOT be ignored.


Are the Euros going to play catch up?


Is GFS now reacting to the effects of the SSW and has adjusted the trend first?


Is GFS being too progressive?


Or..... has Maunder Minimum's proclaimed GFS flip now happened... only to go the way that nobody wanted?


Bjorli, Norway

Website 
PFCSCOTTY
04 February 2016 20:24:48

Looks like winter is getting ready to pack it's bags on that latest run.

Originally Posted by: Sinky1970 


 


cant believe some even believe the bags were ever opened? ...u certainly wouldn't need your hat and gloves! 

Gusty
04 February 2016 20:39:36

The ECM 192 hour 500 Hpa chart at face value looks loaded with potential.



Overlay the 850Hpa temps and the lack of deep cold now to our east and north is telling.



 


Steve - Folkestone, Kent
Current conditions from my Davis Vantage Vue
https://www.wunderground.com/dashboard/pws/IFOLKE11 
Join Kent Weather on Facebook.
https://www.facebook.com/stevewall69/ 



JACKO4EVER
04 February 2016 20:59:35


The ECM 192 hour 500 Hpa chart at face value looks loaded with potential.



Overlay the 850Hpa temps and the lack of deep cold now to our east and north is telling.



 


Originally Posted by: Gusty 


indeed and that's the fear, if we do tap into a decent set up then just how much cold is left to play with? Perhaps cold zonality is the best we can now hope for with barely three weeks of winter left. 

doctormog
04 February 2016 21:12:13
To be fair the sub 520dam air up here would do the job in the first half of February. Whether it comes to fruition is a different matter.

There will never be a lack of cold air to the far north of the U.K. In February - whether the flow can get it here is also a different issue!
Saint Snow
04 February 2016 22:00:44


There will never be a lack of cold air to the far north of the U.K. In February - whether the flow can get it here is also a different issue!

Originally Posted by: doctormog 


 


Exactly. It was only 5 (and a bit) years ago that the right set-up in late November brought air cold enough to give us one of the best winter spells in living memory. It didn't take long - a few days tops - for the freezing air to advect southwards. Just need that right set-up...


 


 



Martin
Home: St Helens (26m asl) Work: Manchester (75m asl)
A TWO addict since 14/12/01
"How can wealth persuade poverty to use its political freedom to keep wealth in power? Here lies the whole art of Conservative politics."
Aneurin Bevan
Gooner
04 February 2016 22:18:29



LP pulling colder air in, wintry ppn will be around


Remember anything after T120 is really Just For Fun



Marcus
Banbury
North Oxfordshire
378 feet A S L


Gooner
04 February 2016 22:22:25


Could be some decent wintry ppn for Northern areas


Remember anything after T120 is really Just For Fun



Marcus
Banbury
North Oxfordshire
378 feet A S L


tallyho_83
04 February 2016 22:22:43
JFF - A week today....- Just north of Marcus if this materialises:

http://max.nwstatic.co.uk/gfsimages/gfs.20160204/18/150/prectypeuktopo.png 
Home Location - Kellands Lane, Okehampton, Devon (200m ASL)
---------------------------------------
Sean Moon
Magical Moon
www.magical-moon.com


Solar Cycles
04 February 2016 22:43:01

JFF - A week today....- Just north of Marcus if this materialises:

Originally Posted by: tallyho_83 

THE">http://max.nwstatic.co.uk/gfsimages/gfs.20160204/18/150/prectypeuktopo.png

 The NW mild sector is in full force there.😁

David M Porter
04 February 2016 23:11:14

It'll likely count for nothing in the end as it's in deepest FI in the GFS op runs just now, but I've noticed during today's runs that GFS seems to be lessening the extent of the dark blues & purples over the Greenland region as we go into the second half of February.


As I say it very probably won't materialise that way when the time actually comes, but it will be interesting to see whether or not GFS FI still goes with this in tomorrow's runs.


Lenzie, Glasgow

"Let us not take ourselves too seriously. None of us has a monopoly on wisdom, and we must always be ready to listen and respect other points of view."- Queen Elizabeth II 1926-2022
Stormchaser
04 February 2016 23:30:14
GFS, like ECM, now sees the MJO propagation to phase 5, which corresponds to height rises over Greenland.

So your observations are well placed David 🙂
If you have any problems or queries relating to TWO you can Email [email protected]

https://twitter.com/peacockreports 
2023's Homeland Extremes:
T-Max: 30.2°C 9th Sep (...!) | T-Min: -7.1°C 22nd & 23rd Jan | Wettest Day: 25.9mm 2nd Nov | Ice Days: 1 (2nd Dec -1.3°C in freezing fog)
Keep Calm and Forecast On

Remove ads from site

Ads