MattTarrant

One would conclude that it will be a slow transition to notably sunnier conditions, this change being pronounced when/if a continental feed forms. One certain though is a warming trend with temperatures trending around or just above average and feeling very pleasant indeed.

Elevated storms so not routed in the boundary layer hence sea level temperatures can be ignored.

I will refrain from shouting, though as has been mentioned initiation has been consistently modeled in the late afternoon/early evening in North Wales/North West England due to slow development of convergence zones and as forcing mechanisms increase. An upper level warm nose has capped convection, though this will likely be eroded as heights lower from the west and convergence causes strong uplift.

READ THE UK CONVECTIVE FORECAST

Elevated Storms are not routed to the boundary (surface) layer so insolation is not really a contributing factor.

Convective initiation, as has been mentioned is relying strongly on the 850hpa - 900hpa warm sector being eroded. Euro4 is suggesting sufficient cloud levels to prohibit insolation, hence sporadic development.

You raise a notable point of interest regarding deficiencies within the +1/2 hr time range. This for me constitutes a significant barrier to verification capabilities, observational frameworks do require greater investment to prevent deviation at such short range. These deficiencies represent themselves frequently in warm/hot synoptic episodes, even seen in the most recent cold spell. This rhetoric was indicated somewhat at the Met Office (Visit Day).

It would seem unrealistic to reach such a record, though more pertinent here is the high res models tendency to upscale heat rapidly within the 24 hour range. London is frequently up-scaled as the dynamics of urban heat containment are controlled with greater accuracy! The models ability to locate sea mist formation is an area of interest also, with some coastal regions suffering short notice downturn in weather prospects (for most people).

I bet that comment would be reversed if it was snow being anticipated, just a caution to stop such bold language use.

I never intended to directly define wavelength, my answer was portended to help Mike with his questions. Wavelength in it self is does not require much talk, I intended to discuss around the topic to help promote Mike's wider thinking.

Good Evening Mike , Seasonal Wavelength Change : With regard to the notion of teleconnections, this relates (as you mentioned) to jet stream undulation/amplitude. Winter is characterized through a high poleward temperature gradient, resulting in increased upper atmospheric zonal winds (Jet Stream). High velocity upper atmospheric winds rarely reflect themselves in a meridional (high amplitude) setup, partial reasoning at least why winter weather is dominated by interchangeable surface setups (Unsettled). In summer months, with the considerable weakening of the polar vortex the temperature gradient is far less pronounced, resulting in lower upper atmospheric zonal winds (Jet Stream). This can and usually translates to a more amplified pattern being seen in the upper winds. In short, summer is characterized by short wavelength (increased amplitude) jet stream (Slower Aswell) setups and this is reversed in winter months. A possible approach to this (for beginners), is to consider why blocked surface patterns gain so much interest in the winter period. It will have weak correlation with fanatical hopes of snowmageddon, but on a serious note it provides respite from the broad continuum of strongly zonal conditions. Wavelength changes can change more abruptly on reduced timescales, these being induced by changes in the global wind oscillation (GWO), MJO phases etc. An interesting line of thought, especially since the turn of the millennium regards an ever increasingly undulated jet stream in both winter & summer potentially related to arctic temperature sensitivity. Here are a few links to research papers for you : https://ams.confex.com/ams/94Annual/webprogram/.../Extended Abstract.pdf http://iopscience.iop.org/article/10.1088/1748-9326/10/1/014005/pdf Feel free to message me with any specific queries

Good luck with these extra commitments I will attempt to do the occasional post, though as with you my time will be constrained when back studying next week. I will hopefully formulate a response to Mike in the upcoming days . On a separate note, I will be transferring across a detailed update to the 'Hurricane Tutorial' written back in 2005 in preparation for the upcoming North Atlantic Hurricane Season. It should be fully updated and available on here within two weeks, anyone interested should occasionally check in the Hurricane Tutorial thread and possibly any new thread for the upcoming season where it will likely be added to.

The intensity of this system is impressive. Even very wet and warm surfaces can see snow settle on them given very heavy wet flakes.

Yes Sunday night has some potential, probably a 1 - 3 hour window where some wet snow is possible under evaporate cooling. Obviously Exmoor/Mendips/Chilterns will likely see a transient wet covering before transition to rain.

No unlikely, not sufficient for wintry precipitation anyhow. Its 3.1 here will little bit of sleet, but other than that a very wet afternoon.

Indeed would now expect some wet snow to come down to low levels at times in the next few hours. Temperature here in Wellington now falling and currently around 3.3.

Given sufficient intensity I would assume snow will settle, just devoid of any significant impacts to major travel routes. Considerably transient though with sub surface temperatures too high.

Unlikely now to be anything in Swansea (at least giving decent depth), with limited covering overnight now almost fully melted. Bravo to ARPEGE & EURO4 for its correct predictions. Thhe band is weakening already so HIRLAM looks somewhat wrong.

James you are one of a few who analyse charts instead of hopecasting so please join me in trying to increase that number.

Don't want to be an attention grabber, but the HIRLAM is awesome.

I think for Swansea, It's been an average to decent winter. I think we now be in double figures of days where snow has fallen at some point (rare). It may not have delivered in depth but there is essentially only 1/2 ways Swansea would receive notable depth. These would be from a front from the west engaging with in situ cold, unlike these two cold outbreaks which have & will be to 'clean' for us (Unlikely to see much tonight/tomorrow 1/2 cm).

You saying I have been all talk & no action?

'There is the potential for 5-10 cm of snow to fall quite widely'

Charts? With the exception of forced ascent along the Eastern Brecons (20/25cm), 5 - 10 cm would be the sensible prediction.

How good is Joe's Ice Cream place?