IDO

Looking at the GFS in FI it appears that once the low is squeezed out by the blocking HP's to our east and west we will be locked into a possible HP scenario from late September to mid October (onwards)... The slack or absent jet stream modelled by GFS does suggest a less lively zonal influence. Too early for deja vu, but October may again be a settled dryish, average-above average temp month. See if GFS brings some consistency to this.

Just a thought but it looks like the models are picking up on the trough over the UK being stalled by the west to east shift of Hurricane Nadine. Its strength seemingly holding back the southern progress of the trough, by keeping the HP on its current latitude (helpful for south UK). Once Nadine degrades in 5-7 days time the pattern re-establishes, bringing a LP over the whole of the UK, within a blocked pattern thus keeping us in a cool setup. Because of this strong variable, I cant help thinking that FI starts around Wednesday of next week. The GEFS for London certainly highlights the doubts from around the 20th. But the synoptic remains for a trend to a below average temp. scenario, but slowed by upstream developments (for the south at least) for the time being. http://www.evernote.com/shard/s19/sh/1d9be1c0-bc08-4a6f-8c04-3a994865d842/e7280a06cbd8476ab8336d99777e3967 (18th 15.00)

I was looking at the 2m max. temps on the GEFS and they show temps around 20c for the weekend (London) but the following 4/5 days see it rise to around 25c (12z op run). That would be nice, but it looks a bit of an outlier at the moment (at least from Tuesday onwards, eg control run varies by -9c on one day), but hopefully it's trending that way.

Seasonal update of the ECMWF for D/J/F totally diff to last month with a zonal +NAO pattern for the winter as a whole = mild & wet. #winter — Matthew Hugo (@MattHugo81) September 10, 2012 What is the success rate of the ECMW winter forecast from three months out? At the moment it is forecasting a continuation of the zonal mess we have had for a while. (Flipped from last month, so covering all bases) As Matt Hugo suggests, mild wet and windy. Though I suspect the knowleagable will tell that its not worth the paper its printed on. Intertesting to know though, and as this site is pro ECMW, someone may well have the data. Thanks in advance.

The GFS 0z ensembles are very clustered for the next 6-7 days, so high confidence. It looks like a slack northerly for the majority of that time, so in the sun the south may not be far off average temps., though this weekend will be cooler even down here. From T144 the ensembles are varied, with a spread of T850s (London) from +5 to -5c. The cluster at the end of FI suggests a less cool outlook. Fi on this run is again a cooler option with the mean average temps (London) above 10c whilst the Op run hovers around 5c. ECM not dissimilar in the reliable time frame. So not too bad weather for the next week, average/cool with sunshine and showers. I had one 30 second shower yesterday. After that HP edges closer from the SW and the models are struggling with the knock on effect of that battle, but they are consistent with the lows from the west winning out, and on this run they have a low stalling over the UK for 60 odd hours, as it interacts with the HP. Hopefully, as they do, GFS have over egged this. Ditto from T228 to the end of the run, another slow moving low hovering over the UK as HP blocks squeeze it from the east and SW. By the last week of the month HP has a weak hold on the UK.

Yes it does, and again the GFS 0z today suggests a cool April in FI. However looking at the ensembles, both the Op run and to a lesser extent the control run (T850s London) are at the bottom of the cold options. So this run at the moment would appear to be the worse case scenario. The mean suggests a more average set up for April. Looking at the min temps shows how much of a cool outlier the 0z run is. From the 16th the ensembles have min daytime temps between 5-12c till around the 20th, when the range is between 7-15c (+). Yet the Op run is nearer 0c most of the run in that period (till the end when it finishes around 5c). So for the next week it looks like starting average then cooling down to below average April temps, with frosts likely where clear skies persist. There looks like spells of rain, but apart from the 9th they look to be hit and miss events. GFS does not appear to be confident from the 15th and I expect ECM are also going to chop and change as HP tries to edge back in. With the synoptics of the PV at the moment, the cooler Op run may not necessarily be far off the mark. So not very confident of April returning to a settled HP outlook (till the last week, maybe, and then poss transient) so suspect this month's CET will be below average by between 1.5-2.5c, balancing out the March gain.

Polar Maritime's above post is a bit misleading. GFS 0z is showing average April temps through most of the run; with only 4/5 patchy frosts forecast and they were in prone areas, not widespread events, probably dependent on cloud cover. The cooler temps are in the T500s, whereas the T850s remain in the low negatives. Ground temps are therefore tempered compared to the recent warmth but nothing extraordinary. The Easter weekend for the SE has temps between 12-14 (max). The main conclusion from the GFS chart is the potential for rain and minimal sunshine. The ensembles reflect high confidence for the next two weeks; members are clustered for most of the run. Very few members are tempted by > -5 T850s (London) with the majority around 0c so no real upper cold on the horizon for the foreseeable.

HP to the UK's SW most of the GFS 06z run. This block allows a mixture of weather to be thrown at us for the next 2-3 weeks, most of it cool to cold. This was the overall pattern ECM was hinting at the last few days. However ECM have flip flopped with GFS and now show HP back influencing the UK from mid-week, through Easter. A NW'ly flow so rather cool, but nothing as bad as GFS. This is certainly a turnaround, though GFS Ensembles (0z) certainly do not preclude a similar ECM setup potential for Easter (T850's cluster 0 to -5c for London 0z run & 06z is a cold outlier in FI)). Looks like ECM have the south holding cold uppers (t850s) for 36-48 hours from this Wednesday and this is close to the GFS 06z run. However the latter has the cold uppers back in the south 24 hours later for another two days. On the GFS the HP is never far from the west/SW of the UK so they could swing towards the ECM without too much of a side step. So, cooling down, a cold 4-5th April and 50:50 for a wintry Easter or a settled average/cool one, depending on the model you favour.

Summer comes early with the 12z from GFS. The last week of FI, and bucket loads of continuous rain. Low after low squatting over the UK. Can't wait!

Yes. The GFS 06z is more favourable for the south. It flattens out the Atlantic, allowing zonal weather. On this run (in FI) it means the south, advantaged by the positive uppers, get less rain, milder temps and more sun, whilst the north is cooler and wetter (influenced more by the lows barrelling through the Atlantic on the back of the jetstream). Looking at the ensembles the 0z is not an outlier (though is favouring the milder members); so within the bounds of possibilities. Closer to home (GFS 06Z), the south get -8 T850's uppers for about 15 hours from Wednesday (4th) but looks mostly dry down here with HP remaining the dominant pattern for next week. So little precipitation after the front on Tuesday, with 2-3 frosts, but average temps during the days later in the week, following a cold start to the week. Not sure we will see any snow south of the Pennines (Tuesday/Wednesday). The GFS 0z was very similar for next week. The ECM 0z is not too out of kilts with the GFS 06z; again with a zonal look at T240, that is, after a cooler week (similar uppers, do not widely contrast with GFS). Relative inter-model support for the next ten days, and an improvement for the Easter weekend for the South; at the moment a dry Friday, Saturday and Monday, washout Sunday. Up north, washout for three of these days (as per 06z).

The GFS 12z is again a cold outlier. From the 7th April the Op run remains 5-7c below the mean, through to the 15th. It bounces along the -10c T850s when the main cluster of members are between 0c and -6c. So still relatively cool on that basis, but not as cold as the Op run would suggest. However the Control run finishes at +10c (compared to the Op at -8c) so from T168 lots of options. For instance the T500s ensembles for T372, the south of the UK has more than 50% of members showing positive upper temps. In the reliable time scale (next week), the cool spell, on the GFS, is a blink and miss it event for the west/south of the UK. The negative uppers (T850s) dont touch these areas. ECM showing colder uppers but UKMO now closer to GFS than ECM. Nogaps in between UKMO and ECM. CFS cooler than ECMF! The AO ensemble forecast highlights the uncertainty: http://policlimate.com/climate/gens_ao_00.png So low confidence from Tuesday onwards, though cooler temps a no brainer.

The ensembles for the GFS 0z indicated the Op run was a modest cold outlier (from T192) so its no surprise the 06z tames down the Easter cold PM excursion. It also pushes the trough further east and flattens things. Still the outlook cannot be ignored as there will be a large dip in max temps. compared to the last week. The GFS ensembles have little inter-model support; for instance the T850's in London have a scatter of over 10c from about the 7th April, so confidence is low for the Easter weekend as to how cool it will be, and the 6z run is more hopeful of the south having a couple of good days. ECM has now pushed back the cold uppers again (T850's), this time by 24 hours (was 2nd-4th previous run), now from the 3rd, and this is close to the GFS, though their (GFS) influence is for less time (c.36 hours). For the south this weekend is still influenced by HP but with temps tempered to only 2-3c above average, away from the cloud. Still low confidence for any significant rain for the south in the short to medium term. We will see if this cold FI eye candy of the GFS 0z is yet another false dawn for cold lovers; the potential is there but lots of uncertainty at the moment.

GFS 0z sticking to its guns this morning with regard to the cold pool coming from our north, and again this weekend avoids the cooler uppers. ECM have also come on board with the HP still maintaining its grip at the weekend: http://policlimate.com/weather/ecmwf/2012032712/ec_gfs_z_panel.html ECM now suggests this cooler outlook will hit us Monday for circa 72 hours. However bearing in mind their backtrack I would still favour the GFS, which has the HP just holding off the cooler PM shot early next week. GFS has HP pretty much all the way through to the end of FI (13th April). The PM shot that showed up in yesterday's output for the Easter weekend has gone, as HP continues to be the dominant pattern. Temps. are however significantly below this weeks marks, going from average to 2-3c above, by the end of FI. The OP run according to the ensembles is similar to the mean plot, tempering recent colder outlier Op runs. However the T850's (London) have a 10c spread at the end of FI, so the second week of April still very uncertain. The Op run (London) has precipitation at around zero for the whole of the 0z run! GFS steadfastness with the HP keeping hold over this weekend, looks to now be the most likely scenario, now ECM has followed suit. Still some divergence early next week but by the end both models are on the HP bandwagon again, though with cooler T850s and T500s always close by, temps will remain subdued compared to the last 10 days.

Yes, the anomaly charts were showing the difference yesterday: http://policlimate.c...fs_z_panel.html Subtle differences modelled upstream give us two different outcomes. I favour GFS, especially as: MattHugo81 Latest EC 32 showing a more settled and slightly warmer opening week to April, than earlier expected, but still cooler/unsettled thereafter 27/03/2012 10:17 Seems the EC32 going against the OP run? Should come closer tomorrow, probably.

The GFS 12z keeps HP right through to 8th April over the majority of the UK. Temps overall down 4-6c on this week but still relatively mild. The cooler uppers forecast for this weekend are kept to our east, though glancing blows to the Eastern coasts are possible. Nothing really cold though. Around the 8th the OP run has another PM excursion. However, looking at the GFS 12z ensembles (London) the OP is in the bottom 10% of cooler members (around -5c to -7c at T850) and as the ensemble mean (London) stays above 0c for most of the latter part of FI, it looks like the odds are (currently) against any wintry stuff . The main ensemble cluster is between 0 and -5 so a cooling does look a strong contender from the second week in April (troughs in the Atlantic and US mainland disrupt the jet-stream). Precipitation flat lines on the ensembles (London) for most of the 12z run, though there are a couple of small spikes, but nothing like what is needed. So HP hangs on, and the forecast pattern change has been pushed further back, to possibly around the 8th April onwards. We will have to wait though, as this may change again, that is, knowing the reluctance of the Azores High to move away.

As per most of the last three months, PM shots forecast in FI, have ended up mostly being tame non-events. Next weekend, as we near the reliable time frame, appears to be a case in point. HP hanging on meaning a cooler settled period for the south with the north having cooler temps. No sign of anything unseasonal. The Op run is also at the bottom 20% of cooler ensembles, so in reality, as the week progresses this may reflect in a milder outlook. GFS 0z also indicates a possible PM shot the following weekend (Easter), however again the Op run is right at the bottom of the colder runs. ECM (0z) is similar to GFS with a very glancing blow of cooler weather next weekend. I suspect the really warm weather of late will end later this week but as that was around 7c over the average that is no surprise. It should still say average/mild for the foreseeable. The CET anomaly for Feb 2012 is at the moment +2.3 so no sign of wintry weather in Feb the last two years. The promise of changes globally this year due to El Nino should be interesting as the weather pattern this last eight months has been surprising. Obviously it has other importance, Olympics et al?

Taken as face value the GFS 0z looks good for rain this weekend in the South/SE. However if you look at the ensembles the Op run is an outlier for precipitation for London. 80% of members have very little rain for these areas. Looking at the T850's on the ensembles, again the Op run is an outlier from about the 25th. Again over 75% of members have the uppers at 4-10c. Good confidence this working week will be settled and mild where the sun shines. GFS has max's of 17c the next five days for the SE. Interestingly many of the ensemble members have highs over 15c (some 20c) from the 23rd till the 27th suggesting a high chance of HP coming back for the last ten days of March. Shows the Op run is an outlier late in FI: http://nwstatic.co.uk/viewimage.pbx?type=ens;date=20120312;time=00;file=tmaxLondon;sess=bc7694369aa6136d6922d09324ec6746 ECM is similar, in that they also incorporate a break off low before HP edges back in (slower than GFS). So the cooler potentially wetter weekend is still low confidence as to specifics but a 2-3 day cooler interlude in the HP domination is now looking at inter-model support.

Interesting development on the 12z GFS run. The PM excursion never really gets going, as the resolute HP to our SE holds firm. The cut off low then straddles the west of the UK allowing East and SE England to have a mild weekend (17th & 18th). By T186 a developing HP to the SW pushes the low through the UK, clearing the south in a hurry and by early Wednesday 21st has cleared the UK. From T240, HP back in charge and temps gradually climb, with the HP drawing in milder southerly winds. Back to 16c by Saturday week in the south. By this time the PV is weakening. As per most of this winter, FI modelling the UK to miss any escaping cold uppers, and instead Europe in entombed in a massive HP, with 21c just across the Channel in France and the UK having max's of 17c. The low in 8-10 days looks the best chance for the south to get some rain, otherwise little around. At the end of FI plenty of lows to our NW/W and with the jetstream being weakened, the change to a more mobile pattern is certainly a good possibility.

According to the GFS 0z ensembles, FI starts around the 17th. Prior to that 90% of the members are in agreement with HP in charge and a mild setup for most of the UK with little rain. From next weekend the ensembles T850's scatter from -4 to +8, with a 50:50 split between mild and cool. The control run stays mild right through to the end of FI, apart from a dip around 20-22nd. The OP run apears to be reflective of the ensembles showing a cooler few days around T154, with a buried low that clings to the UK for a few days with a track that at the moment favours the south, with the promise of a few wet days (GFS chop and change with this feature, so low confidence). From T216 to T276 it is zonal, so average in the south for temps and cooler up north. HP back in charge from then, with temps slowly moving above average. Looking at the PV, it is still in tact by the end of FI so any long term pattern change remains on the back burner according to this run. However the 18z last night was showing a weakening of the PV so it maybe only a matter of time, especially as the jetstream appears to not be as potent through this run (from T144). The ECM is similar to the GFS, pattern wise, but is less messy, with no low in the mix. The trough encroaches on Friday, after a mild HP dominated week, and has left our shores by Monday, with a HP taking charge from then, with the north maybe more unsettled. This ties in with their EC 32 run, suggesting HP close by for most of March. So a mild settled week ahead with less confidence from then.

No surprise that the 12z GFS has sent the messy low of the 0z run packing. Much flatter on the latest run with the cooler uppers passing through the south very fleetingly. Still, compared to the proceeding week, next weekend will be cooler for all, but nothing you could call cold. We then have two HP's joining forces to give us a settled picture from T177. The HP then slowly pushes east and temps pick up to around average. A bit messy again from GFS at T276 when it has potential cooler and wetter weather spreading in from the west, probably due to the PV weakening. Still 16c showing up at the end of FI for the SE, but cooler to the west, but still close to average. This potential pattern change in FI threatens a more unsettled period with lows moving in from the east giving the end of March a wetter outlook, adding credence to CFS's forecast for a predominantly wet & cool April and May.

Sorry about that. Fair telling off. Yes I was referring to the south. I did mention it in the second paragraph, probably should have been earlier. GFS Thursday Average temps are very seasonal as I stated ("starting average"): http://nwstatic.co.u...1b0c08762a8e27; The whole of the UK isn't under the influence of the HP till T150, but between T96 and then is when it moves over us! For the record I went through the rain charts on the GFS and there are 2/3 spells of rain in that 12 day period but it is relatively settled for March in the South. Scotland (from T96) is relatively dry (again 2/3 spells) right up to T264, then late in FI they are modelled to get more significant rain. The average monthly rain days in Scotland is around 17 (March) and I suspect that the GFS output tends it to significantly lower than that. My post was more focused on pointing out the pattern, that is HP influence rather than earlier more zonal output. It is difficult to mention all the specifics in FI. Anyway that was the 06z so it could all be rather inconsequential by the time the 12z rolls out. Just noted the 06z ensembles and the Op run is, as suspected, at the mild end of the T850's. However, the HP dominated outlook is getting more support: MattHugo81 Definite signal evident now within the GFS and EC ENS for pressure to rise towards mid-month heralding settled/spring-like weather... 04/03/2012 14:09 MattHugo81 Latest EC 32 day forecast backs this up with a subsequent rise in temps to 2C to 4C above average by approx mid-March onwards #onetowatch 04/03/2012 14:11

GFS 06z from T96 to T384 high pressure all the way. Starting average temps. but ending 16c+ by 20th March: http://nwstatic.co.uk/viewimage.pbx?type=gfs;date=20120304;time=06;ext=372;file=ukmaxtemp;sess=6b683c10fb970e0c99e66efbb491e22f; http://nwstatic.co.uk/viewimage.pbx?type=gfs;date=20120304;time=06;ext=372;file=npst850;sess=6b683c10fb970e0c99e66efbb491e22f; It looks like, based on this run, after this weekend, the south can tick winter off their calendar. The only caveat being, as the 0z was in the cold spectrum of ensembles, the 06z is probably in the mild end, though it does appear that the sun is rising on Spring.

The GFS 00z has a mixed 5-7 days coming, with a bit of everything. Then from about the 9th till the 17th HP takes charge and we get settled, mild weather. Though it must be said that the 9th is when the GEFS start to scatter, so a couple of options still possible (as per previous posts): http://nwstatic.co.uk/viewimage.pbx?type=ens;date=20120304;time=00;file=t850London;sess=98412b3d7d45ffdb3cf5c175875c1f56 Late in FI the 0z offers what at the moment looks like another PM excursion: http://nwstatic.co.uk/viewimage.pbx?type=gfs;date=20120304;time=00;ext=384;file=h500slp;sess=533fe73d200bf9617205eab0d5eb7e11; As with this type of troughing its location, location, location and too early to be hopeful, especially as the Op run, from about T324, although not an outlier, is definetly within the 10% of colder outcomes. This end run is because the Jetstream is being modelled south of the UK, from about T348, after being to our North much of the run. The ECM to T240 is similar to the GFS in that HP takes over late next week and is with us till the end of the run: http://cdn.nwstatic.co.uk/ecmimages/20120304/00/ecm500.240.png The GFS at this stage has a flatter pattern. So the March forecast is now becoming more refined; little sign of any prolonged cold, alternating the menu between zonal and HP dishes, so a bit for everyone.

After Monday GFS 12z has south of Birmingham under HP right through till 19th March, apart from about 36 hours! Very mild at times: http://nwstatic.co.uk/viewimage.pbx?type=gfs;date=20120303;time=12;ext=300;file=ukmaxtemp;sess=4b6cba4f46459bf2e23c30788f4b80d9; But average (+) the majority of the run after Monday. Pretty flat pattern: http://nwstatic.co.uk/viewimage.pbx?type=gfs;date=20120303;time=12;ext=168;file=h500slp;sess=4b6cba4f46459bf2e23c30788f4b80d9; With the Jetstream tending to be well to the UK's North: http://nwstatic.co.uk/viewimage.pbx?type=gfs;date=20120303;time=12;ext=252;file=npsjet;sess=4b6cba4f46459bf2e23c30788f4b80d9; No sign of PV split all the way through and at the end of FI: http://nwstatic.co.uk/viewimage.pbx?type=gfs;date=20120303;time=12;ext=384;file=npst850;sess=4b6cba4f46459bf2e23c30788f4b80d9; Very little rain in the SE apart from Sunday/Monday and maybe two other spells, throughout the run.

It should be zonal next week so a good chance of some wintry stuff (transitional?) the further north and to higher ground. But we really need a PV lobe to visit us to get anything interesting for us down south, otherwise it is just frontal stuff that goes as quickly as it arrived.