Model Output Discussion 31/05/14 onwards.

[95 Degrees]

Truly beautiful GFS run, surely the best of the summer so far with the azores high fully in charge and hot air being pumped from the south and south west, caution must be taken with whats being shown in FI as usual, but certainly some very warm weather coming up next week.

[East_England_Stormchaser91]

Well... July 2006 looks to be repeated if the pub run is speaking sober thoughts!!

Excellent run. And very warm too for the middle to the end if this week. Proper summer charts these are

[summer blizzard]

Think your all getting excited too much about a 3 day FI hot spell. Ignoring the Euro with its data error the GEM, GFS and JMA all have unsettled conditions at day albeit GFS is more of a north/south split.

 

[bluearmy]

Seems to me that CPC NOAA is buying the NAFES idea rather than the ECM idea with still a mean trough over us, on the other hand the mean HP seems to be getting closer so really you can't rule out a July 2013 type of scenario although we need to have persistent runs of HP for that to happen, here we go with the anomolies then:http://www.cpc.ncep.noaa.gov/products/predictions/814day/500mb.phpSee on CFS they upgraded the warmth for July as well.

Erm that probably because at weekends, noaa cpc is raw naefs!looks like yesterdays ecm 12z entire suite was missing some data re the early development of that deep depression. clear from the ens graphs that nw europe was just wrong with no troughing whatsoever. Will be interesting to see how far it kicks back this morning though the day 3 chart comparsion is already stark. Gfs seems to be treading a different route whilst ukmo and gem seem to be in broad agreement. Gem has been consistent on next weekends trough.

[Captain Shortwave]

I would say that the GEM has (like the ECM/GFS did yesterday) toned down the effect of the trough, just a brief affair before the Azores high kicks back in. ECM has a flatter pattern like the UKMO, but the pattern is further north so the southern half of the UK is fine and very warm to end the week which extends into the weekend.

ECM has the cold front moving through on Sunday. Still a good 4 days of really decent weather, especially for the south.

Edited June 29, 2014 by Captain shortwave

[johnholmes]

Erm that probably because at weekends, noaa cpc is raw naefs! 

 

oh come on ba you trot this out every time with no proof that this affects the actual charts at all. I have never noticed anything consistently about charts changing from Friday to Saturday or Sunday to Monday because of this supposed change

[bluearmy]

oh come on ba you trot this out every time with no proof that this affects the actual charts at all. I have never noticed anything consistently about charts changing from Friday to Saturday or Sunday to Monday because of this supposed change

John, the comment was made that the cpc chart yesterday looked like naefs output. i only stated that at weekends it IS naefs output. maybe your point should be how good the naefs model clearly is or that the mean upper ens pattern and anomolys are never that varied in the 8/14 day timeframe re the naefs/ecm modelling.Captain - agree with you re the flatter pattern hanging on longer but the secondary low bringing the upper trough south for next weekend has been on every gem run from my recollection. Gfs has diluted this for a few runs now so maybe worth holding on for another couple of runs before cancelling next saturdays fete! Nothing is clear beyond next weekend imo. Edited June 29, 2014 by bluearmy

[knocker]

Looking at the anomaly charts this morning for next weekend and further afield. NOAA has the trough established over the UK and still there on the on the 8-14 albeit weaker. The GFS more or less agrees for the weekend but thereafter introduces a more influential Atlantic ridge with the weak trough lying east/west north of the UK. The ECM is in rough agreement with both for the weekend.

 

Regarding the weekend the ECM seems to have returned to earth although still quite warm on Saturday.

Edited June 29, 2014 by knocker

[SteveB]

Well the cool wet  Northerly that the models were predicting at day 8 & 9 last week didn't really materialise this weekend, ending up instead with a sunshine and showers set up typical of a British Summer.

 

Shame for the Glasto lot, but it wouldn't  be the same without mud..... yeah.

 

Next week is looking good again (if you like sun and warmth in Summer)

 

[Summer Sun]

Well the cool wet  Northerly that the models were predicting at day 8 & 9 last week didn't really materialise this weekend, ending up instead with a sunshine and showers set up typical of a British Summer.

 

Shame for the Glasto lot, but it wouldn't  be the same without mud..... yeah.

 

Next week is looking good again (if you like sun and warmth in Summer)

 

 

Whilst I'd like to agree with the bit in bold GFS is on its own currently (not saying its wrong) but until UKMO and ECM push the low further north I remain cautious. Certainly potential for a pressure rise during W/C 7th but next weekend may be pushing it

 

 

UKMO also shows westerly winds with rain or showers +8 850's are shown to be over the UK next Saturday but how warm it would be on the surface is another thing given the threat of rain / showers

 

 

t120 850's unavailable at the time of posting

Edited June 29, 2014 by Summer Sun

[SteveB]

Going by what we've seen happen this weekend and next week regards the models predicting unsettled conditions, I wouldn't be putting to much faith in what they are showing next weekend.

 

Yes it's been un-settled, but not as bad as what it could have been (if you believe the models at day 8-9)

[knocker]

Looking at the ECM ens sticking to the cold air Canada to the UK with a trough over the latter with the Bermuda/Azores HP in mid Atlantic. giving a W/NW flow over the UK.

 

This gives unsettled conditions over the UK alternating to some extent from Cyclonic to a transient ridge from the SW. Far too early in the day to firm up any dominance of these features but would think the temps hovering around the average.

 

[Yarmy]

Going by what we've seen happen this weekend and next week regards the models predicting unsettled conditions, I wouldn't be putting to much faith in what they are showing next weekend.

 

Yes it's been un-settled, but not as bad as what it could have been (if you believe the models at day 8-9)

 

Been a pretty poor weekend here to be fair, although not a complete washout. I'd argue the outcome is worse than was modelled 7 days ago:

 

Actual:

 

 

ECM was not far out, but had weak heights over us with the trough pushed further east:

 

GFS was far too optimistic:

[Milhouse]

Very summerlike end to the GEM.

 

[Summer Sun]

Very summerlike end to the GEM.

 

 

Yep GEM living up-to its name with a lovely end to its run turning things increasingly warmer maybe even hot for some parts

 

[draztik]

Going by what we've seen happen this weekend and next week regards the models predicting unsettled conditions, I wouldn't be putting to much faith in what they are showing next weekend.

 

Yes it's been un-settled, but not as bad as what it could have been (if you believe the models at day 8-9)

 

that is a rather simplistic and dare I say folly way to look at things. If we went by that rationale, we'd be forgiven for believing we lived in a utopia of sun and warmth. What we are having at current is pretty bog standard British summer. Putting faith in any model output is risky.... no matter what is being shown. Looking at the ecm ensembles, we see the main player being a trough to our N and NE influencing conditions into the mid term..(w/ support from GEFS) so, not wall to wall sunshine & heat, but certainly no rainfest either, esp for Southern and SW parts. Pretty standard British summer weather.... July 2013 has clearly spoiled a lot.

 

ecm ens height anom days 5-10 8-13

 

yes, this may change... and most likely will. But there is no signal, none, for a July 2006/13 to develop, as was suggested last night, based on one run from the GFS. We need to be realistic.

 

GEFS temp anom days 1-16 0z suite.

[Tamara]

The Pacific jetstream forecasts hint at a second jet streak of energy to be transported eastwards in the further outlook. It is on this basis that we see renewed predictions for further unsettled weather to head from the NW later next week/weekend after a drier interlude once the showery weekend/ early week trough exits into NE Europe

 

This second peak of energy arriving on the west coast of the US is indicated as spiked on the red line on the PNA forecasts and has good cross model agreement for this timeframe.

 

Although the pattern over the Pacific has good enough agreement once again in the models, there is yet again considerable medium/longer term disagreement how the next phase of energy transport is handled downstream across the US and across the atlantic. The ECM (currently) sends more energy NE from the US east coast and creates a deeper low towards Greenland which although it verifies in further unsettled weather, the low, being a deeper feature, is taken further north and there is a longer window for a ridge across the UK from midweek before further wet weather arrives around the next weekend.

 

The ECM also splits energy in the atlantic and creates a cut-off low which underpins the ridge for a little longer. A reasonable number of ECM ensemble members reflect this - just f.e, the deterministic and control

 

<snip> a replica synoptic repeat of this weekend seems unlikely. However this is not certain by any means, and it will be a case of how the models handle the next burst of energy in the closer timeperiod.

 

Working on this caveated assumption - this is not a pattern for heat (if that is what one is looking for) but should give average conditions and feel pleasant at least in the drier interludes, especially perhaps towards the SW.

Update

 

Todays modelling confirms that the suspected slower solution with the ridge holding much better through this week is the correct one and many will be pleased to see a better week indicated than might have appeared the case during the splits in the models a few days back.

 

Good agreement across the EPS ensemble members for the south and central of the UK at least to hold on to fine conditons throughout the majority of the working week with any breakdown only arriving from the north west at the end of it.

 

The upstream Pacific jetstreak engineering a fairly deep downsteam summertime low is consistently on target however to arrive through next weekend to bring further unsettled weather to the UK in general. The precise degree of amplification of the atlantic pattern will determine the inroads of the troughing as this passes to the north of the UK, and in turn will measure how far south the most unsettled conditions dig south through the UK as a whole. It looks good for those further south west to see the best chance for fastest recovery as head into week 2 - which maintains previous thoughts of a NE/SW split at this time, as suggested in the last post. In any case, although all areas will see further rain and showers through next weekend and into the start of the following week - it looks like areas further south (in relative terms) will see the lesser surface effects from the rather unseasonal low.

 

This in contrast to this weekends slow moving shallow low pressure area that has brought so many thundery downpours to the south of the UK whilst northern regions have deservedly enjoyed the drier weather  Assuming one has been looking for drier weather of course and not instead hoping for the livelier conditions to be more extensive

 

Its then a case of whether pressure in the atlantic ridges across as a classic summer feature much as the GEM suggests this morning. This is for sure the most optimistic scenario, but does it have any credence?

 

The signal for the main upper High to be maintained in the central/western atlantic and a corresponding intermittent returning downstream trough is a stubborn one, and only further FI modelling tools advertise hints of a change. It is these that the GEM is likely picking up on - and it is quite a good model for picking out such pattern changes in my opinion.

 

So while the outlook in the shorter term looks rather better than perhaps anticipated (we have the deep low programmed to leave Canada to thank for this by slowing the atlantic pattern down and developing the downstream ridge better) its still advisable, just for the time being, to exercise caution as to the extent of inrodes of any ridging eastwards in the much longer term.

 

Such ridging, for now, continues to look vulnerable to being eroded on its N flank, as further potential upstream jet pulses from the eastern Pacific phase with temperature gradients over US and Canada and send developing lows east across southern Greenland and Iceland and then slide around its perimeter close to N UK. On this basis, something of a N/S split remains the overall percentage call for the 10 to 15 day period at least.

 

This is evidenced by the Pacific jet stream forecasts which continue to show such possible peaks of activity into the first 10 days of July with something of a continuing mobile sequence on the US west coast which hinders downstream upper ridging in the western/central atlantic from heading east properly towards the UK.

 

 

Cautious signs though, just perhaps, that this signal may fade somewhat, with a change as we head through towards the end of the second week of July with more settled conditions trying to extend further into the UK from the SW and the jetstream edging a little further north as we approach midmonth.

Edited June 29, 2014 by Tamara תָּמָר

[TonyH]

Going by what we've seen happen this weekend and next week regards the models predicting unsettled conditions, I wouldn't be putting to much faith in what they are showing next weekend.

 

Yes it's been un-settled, but not as bad as what it could have been (if you believe the models at day 8-9)

Agreed, this weekend not too bad at all, especially today, and I am wondering whether the same may happen next weekend regards a dilution to less unsettled warmer conditions, as this seems to be a trend on recent runs:

http://forum.netweather.tv/blog/309/entry-4805-weather-guide-monday-30th-june-to-sunday-6th-july-2014/

[knocker]

Depending on ones definition of settled I wouldn't have thought this week was settled. Monday low to the SW with fronts SW of  Ireland and Cornwall. Generally showery. Tuesday low in Biscay. Wednesday azores ridge effecting southern parts with a deep low over Iceland and fronts and rain approaching NW Scotland. Thursday fronts and rain now over N. Ireland and Scotland with England  in a showery unstable westerly flow. Friday similar with a low developing NW of Ireland. Saturday low 998mb over Scotland bringing wet conditions to most of the UK. On the plus side some fairly robust temps and in fact quite hot for a couple of days.

Edited June 29, 2014 by knocker

[Summer Sun]

Not much change from UKMO still looks like turning more unsettled later in the week with rain or showers affecting most parts at times

 

[Captain Shortwave]

Depending on ones definition of settled I wouldn't have thought this week was settled. Monday low to the SW with fronts SW of  Ireland and Cornwall. Generally showery. Tuesday low in Biscay. Wednesday azores ridge effecting southern parts with a deep low over Iceland and fronts and rain approaching NW Scotland. Thursday fronts and rain now over N. Ireland and Scotland with England  in a showery unstable westerly flow. Friday similar with a low developing NW of Ireland. Saturday low 998mb over Scotland bringing wet conditions to most of the UK. On the plus side some fairly robust temps and in fact quite hot for a couple of days.

Shower activity looks very limited given the set-up. Breezy tropical maritime flows tend to bring low level cloud more than anything else. Given the time of year though then this will also be rather limited away from exposed coasts in the west. Pretty much bang on the week ahead forecast which pretty much says dry and settled for most. So a question of where any weather fronts will lie and hence who will receive any rain. Again though this set up usually struggles to bring any significant rain to the majority of the UK, as fronts weaken as they spread south east.

The GFS hi res output is such a typical summer profile for the UK, jet straddling the UK, warm/cool sectors but more of a bias towards warmer than average conditions. UKMO probably a little more unsettled but still decent until the weekend. Looks like a cold front will spread south east on Saturday. 

 

As for the other models, GEM is doing it's usual trying to develop a UK trough by having a much more amplified Atlantic (compared to both the GFS and UKMO). NAVGEM has gone mental and has a heatwave from Wednesday

Edited June 29, 2014 by Captain shortwave

[Summer Sun]

A warm update from NAVGEM this afternoon certainly different to the rest with no deep low for the weekend

 

Edited June 29, 2014 by Summer Sun

[Thundery wintry showers]

I think it looks more like being a transitional week with the high pressure slowly relaxing its grip over the British Isles as the ridge collapses south-eastwards and Atlantic weather systems start pushing in over the top, but as often happens following anticyclonic spells with the high located mainly to the west, many southern and eastern parts of England will probably have their hottest and sunniest weather near the end of the spell, meaning early to mid next week.  However, the far south of England and Ireland may need to watch out for a slow-moving frontal system on Monday and Tuesday which will give cloudy skies and maybe some light rain clipping the English Channel coastline.

 

The change towards a more unsettled type will start to spread south-eastwards through northern and western parts of Britain on the 2nd/3rd and will probably not reach southern and central England until the 4th, although I think most of England and Wales will have a cloudier day on the 3rd thanks to the strengthening westerly flow.  Where the sun stays out for significant periods, though, the 3rd will probably produce the highest temperatures of the week.

 

The NOAA 8-14 day outlook is persistent in showing an anomalous ridge to the west of Britain into week 2.

http://www.cpc.ncep.noaa.gov/products/predictions/814day/500mb.php

 

In general my feelings about how things will probably progress from there are similar to what Tamara posted above.  I think that the high to the north of the Azores will often be flattened by depressions moving around its northern flank in the second week of July, especially the 7th/8th, and that while rainfall totals probably won't be large to the south of the Scottish border, it will probably be fairly cool, especially in Scotland, and and sunshine will probably be variable rather than plentiful.  But towards midmonth I expect that the high will increasingly ridge eastwards and bring warmer and sunnier conditions to most of the country.  How strong the eastward ridging will be is hard to pinpoint at this range but I would earmark the middle part of July as most likely to produce a widespread warm dry sunny spell.

Edited June 29, 2014 by Thundery wintry showers

[damianslaw]

Quite a traditional set of charts for the time of year, with the atlantic jet firing itself up meaning a typical N-S split developing, but until mid week, all parts should stay settled with good spells of sunshine and becoming warm or locally very warm in SE and E parts by mid week. By Wednesday a westerly flow will be ensconsed over northern parts meaning dull drizzly skies before we see the longwave trough anchor itself to the north of the country bringing rain and cool conditions by the weekend away from the far south.

 

Looking further ahead, no real sign the azores high will fight off the power of the atlantic at least for now, so probably driest and sunniest conditions reserved for the south west, wettest for the north west as further trough action rides over the top of the azores high.

 

I do agree with others there is a good chance come mid July, the azores high will ridge sufficiently NE to kill off the advances of the atlantic, but whether this heralds the start of a major pattern or not is unknown, the advances of the atlantic are usually a much greater force by late July than at any stage since March...

[Milhouse]

The warmth building all week across the south mostly with Thursday looking a very warm day. Friday sees a breakdown coming into northern and western parts whilst the warmth hangs on across the south.