damianslaw

Back to the grey darkness of earlier in the week.. intermittent drizzle and low cloud and never feeling particularly mild under a strong breeze. Out on the fells and it was preety miserable.. typical late October fayre.. history shows this time of year is usually unsettled and mild in the Lake District. Still waiting for those first crisp fine days of the season. Hopefully will arrive in the first half of November.. can't wait for the first lingering frost and walking on hard not squelch ground!

Last year we had a La Nina which was moderate and it didn't override Strat warming I think resulting in a cold April and May, and the cold early in Feb which didn't sustain itself though.. there was a WQBO which possibly had some effect on developments in Feb.. and MJO.. key factors. We have an EQBO this year and Strat warming is an unknown...many forecasts seem to be allowing forecast of a strong La Nina as a key overriding factor.. yet we don't know how strong La Nina may become and other factors can easily override.. weather is complex.. no magic formula.

Quite a rapid expanse westward especially into Scandi. One theory goes if their is a sudden expanse in late October westward this can have feedbacks for promoting large Siberian highs which can help increase chance if cold in northern hemisphere mid latitudes but either for N America or Europe sometimes both sometimes just for one. Also perhaps more important for us is coverage in Scandi. Last time their was early good snow cover build up their was 2009... it's just one of many factors though and the coming days could see it nibbled away by warmer air from the south...

Reading between the lines.. the Met Office appear to see the signal for mid Atlantic heights throwing in frontal incursions around NE flank perhaps more suppressed at first but ridging in more strongly as the month wears on hence driest conditions in the south and west and more frontal showery activity for the north and east with a NW airstream. Quite a normal pattern for November under a La Nina base state. Not a bad pattern for those wanting a cooler more late autumnal feel with limited deep low pressure systems and associated bouts of heavy rain and gales that often occur with flooding, nor the sustained moist dank south westerly airstreams as we are about to endure in the coming week and their associated overcast low cloud very mild conditions. Hopefully we can see the return of drier sunnier conditions with some fog and frost through November, at a time when light levels are low.. weak late autumn sunshine always welcomed and much needed.

Signs have been there for days but far beyond reliable timeframe . Now creeping into semi-reliable. The rest if the month forecast unsettled mild or very mild to start trending cooler by next weekend. A lot more rain for northern and western parts. Very typical late October fayre.. but no storms or gales indicative of a rather weak Atlantic overall. Into November look to the north and north west for where weather will be coming.

Yes direction of travel is for the Atlantic trough to shift east and dig deep into Scandi allowing for mid Atlantic heights and a flow from the NW, and a cold one to boot.

ECM still doesn't look right to me. Holds low pressure in the same place to the south of Iceland for days. Also those uppers shown in above look too high. There is a very fine margin between alot of cold to the north of the polar front jet and these are not shown. UK looks primed to fall on the boundary of tropical maritime and increasingly cold polar air.. at first we sit firmly on the south side.. but all the signs we will quickly shift places to the north side.

Long way off bit the GFS late timeframe shows a very southerly positioned jet.

Lovely day thanks to polar air. Clear skies excellent visibility lots of sunshine and a chill in the air. More of this please.. alas we are heading straight back to the dank murky fest of early in the week from Saturday onwards.

Weve weak zonal winds now and an Atlantic ruling the roost.. not sure these tell us anything about what will be happening on the ground.

Warm air advection in the vicinity of West Greenland and Labrador is something I'm always looking out for.. a link up as you say often results in a colder trough digging in from the NW here and airstream predominantly between west and north. You need to look at upstream developments over east Pacific as well.. aleutian low, west Canada high, deep central north Canada trough which send warm air advection into saud region on eastern flank. Aleutian low is critical.. aleutuan high usually means the opposite. These are wavelengths for November to March.. models are showing an eventual cold trough scenario as we enter November.

Autumn generally is the least interesting season - Spring the most interesting. Thankfully we are just edging out of the doldrums when UK weather is most benign..

SSTs over Atlantic throughout are uniformly high. This I think should weaken the jet theoretically and promote ridging over mid Atlantic..

Please no November 2009! Extensive flooding! We had a strong El Nino that year.. not the same base state.

What helps drive MJO?

Mild Halloween weekend. Cold Bonfire Night weekend. Become used to both being mild. Will be good to see one colder than normal.

The key is getting the trough further east into Scandi.. the models are heading in this direction. Indeed there is evidence now this is where the eventual direction of travel is.. with a northerly more amplified flow.. knock on implications upstream will have domino effect I.em deepening aleutian low/trough creating more amplification over USA and as you say resulting in warm air advection west Greenland, enabling the azores high to build northwards.. classic text book meridional flow.. until then it's a watch and wait.

Mmm not sure about the dry.. plenty of weather fronts thrown in the mix and dank moist SW flow. Lots of low cloud and drizzle could be the order of the day.. very unappealing.. and a kick in the teeth given it's the last week before clocks go back and half term week. Miserable! Need to store today's sunshine.. make the most of it as we won't see many if any like it for the rest of October, well at least here in the NW!

There is a flip as we enter November.. those heights to the south pushed aside by the deep Atlantic trough which importantly shifts east into scandi and allows cooling into Europe including UK with azores high affected out west and mid Atlantic heights pushing north.. this is a more typical La Nina pattern for late autumn compared to now.

Any frost last night. Think we had a very light ground frost. No frost on the horizon for a while.. still waiting for that proper first frosty morning where frost lingers until about 10am.

The default yearly pressure pattern.. always the safest bet...

Turning into a fairly forgettable October.. roll on November please!

Signs the trough will dig down and through the UK eventually meaning colder and unsettled rather than milder and unsettled.

Goes against the Met forecast. Suggests more southerly tracking jetstream and heights over N Europe which would bring cold dry weather to UK with little Atlantic activity. Going back to the met forecast mentioned nearly every met contingency forecast I've ever read has gone mild or very mild.. for so long now it's a foregone conclusion. Last year only the Beijing climate model was going for something nearer average at least. Last year we had La Nina, and ended up near average and a bit colder in the north especially. It is just one factor. SSW's are an unknown and we are in chaotic times weatherwise and I would urge people to take any forecast with a massive room for high margins of error.

2012 brought a rapid advance in the last week of October. Some years though see a early advance that stutters as it reaches the Urals. A positive is the early snow cover over Scandi. 2009 did this..