Model Output Discussion - 3rd May Onwards 00z--->

[Gibby]

HERE IS MY LATEST ANALYSIS USING DATA SUPPLIED BY THE NWP OUTPUT COVERING 5 OF THE WORLDS MOST POWERFUL WEATHER COMPUTERS ISSUED AT 08:00 ON TUESDAY MAY 19TH 2015.

 

THE CURRENT GENERAL SITUATION A showery West to Northwest airflow will continue to blow down across the UK today and tonight with a ridge of High pressure moving into Western Britain tomorrow.

 

http://www.wetterzentrale.de/pics/Rtavn001.gif 

 

MODELS-2 WEEK HEADLINE  Slowly becoming drier and brighter especially towards the SW but still rather cool with a little rain at times towards the North and NE.

 

http://www.netweather.tv/index.cgi?action=jetstream 

 

GFS OPERATIONAL The GFS Operational's main theme this morning is for High pressure to lie out to the SW of the UK for some considerable time, tantalisingly close to give the chance of some fine and in places less cool weather especially towards the SW. However, it looks unlikely to fully restrict some ingress of cooler air from the NW at times with troughs crossing SE at times down over the North and East with cloud cover and a little rain at times.

 

http://www.wetterzentrale.de/pics/Rtavn1441.gif

 

http://www.wetterzentrale.de/pics/Rtavn3841.gif 

 

THE GFS CONTROL The GFS Control run also shows strong support for High pressure to become dominant in the shape of a ridge across England and Wales from later this week and lasting well into next. This run then shows the High making it's way across the UK to the East with pressure falling to both the South and East of UK with a somewhat showery and cool end to the run shown in a NE flow. 

 

THE GFS CLUSTERS The GFS Clusters today show a High pressure based pattern to be dominant across the UK in two weeks time. Unfortunately it looks likely to be badly positioned to bring anything other than cool NW or North winds and the threat of some showers at times down over the UK as the High centre lies over the Atlantic to the West or NW.

 

http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000&CONT=euro&MODELL=gefs&MODELLTYP=2&BASE=-&VAR=cpre&HH=372&ZOOM=0&ARCHIV=0&RES=0&WMO=&PERIOD=

 

UKMO UKMO this morning shows a ridge of High pressure lying across the UK from an anticyclone out to the SW of the UK. The best weather looks likely in the SW over the Bank Holiday with the rest of the UK seeing a lot of dry if rather cloudy conditions with the odd shower possible and temperatures less cool than recently though never overly warm.

 

http://www.wetterzentrale.de/pics/Rukm1441.gif 

 

THE FAX CHARTS The Fax Charts show a High pressure ridge from the SW trying desparately hard to build across the UK with some weak fronts moving SE in the flow at times ensuring much cloud cover and temperatures suppressed to average levels at best over the holiday weekend.

 

http://www.weathercharts.org/ukmomslp.htm#t120.

 

GEM GEM too this morning maintains the stance that once established in a few days time High pressure will remain focused out to the SW of the UK with a West or NW flow across the UK. northern areas will see occasional light rain from weak troughs and the remnants of these will bring cloudier skies to the South too at times with the best and warmest weather likely to the SW.

 

http://www.wetterzentrale.de/pics/Rgem2401.gif 

 

NAVGEM NAVGEM is also fully in support of the NW flow down over the UK with high pressure to the SW. the flow will bring rather cloudy skies down across the UK perhaps with a little rain with the highest risk to the North and East of this while the SW will see the driest, brightest and warmest conditions.

 

http://www.wetterzentrale.de/pics/Rnvg1681.gif.

 

ECM ECM today is not quite as good as yesterday morning's run as it holds High pressure just too far out into the Atlantic allowing more influence of a chilly NW flow to be maintained well into next week and including the Bank Holiday weekend. The most likely weather over the UK for the weekend will be rather cloudy for many with a few showers at times especially in the North and East with the best of any brightness towards the SW with this trend being maintained through the working days of next week too.

 

http://www.wetterzentrale.de/pics/Recm2401.gif

 

ECM 10 DAY MEAN The ECM 10 Day Mean Chart  from last night shows rock solid support that High pressure will lie out to the SW of the UK in 10 days time with a light NW drift across the UK with the SW of the UK best for any warmth and sunshine.

 

http://www.wetterzentrale.de/pics/Reem2401.gif 

 

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The model output have become more resigned to the fact that High pressure will remain just too far out to the West or SW of the UK next week to have any real summery effect on the weather across the UK. 

 

31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKM & ECM The current verification statistics for the past 31 days shows ECM leading the way at 3 days with 96.6 pts followed by UKM at 95.8 pts and GFS at 95.1. At 5 days ECM  leads UKMO with 86.1 over UKMO's 83.4pts with GFS at 82.0. At 8 days ECM and GFS are tied today at 51.6 pts each. Then at Day 10 GFS and ECM are again tied at 33.6pts each.

 

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day3_PMSL_MSL_G2NHX.png 

 

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day5_PMSL_MSL_G2NHX.png

 

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day8_PMSL_MSL_G2NHX.png

 

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day10_PMSL_MSL_G2NHX.prig

 

 

MY THOUGHTS I detect a slight overall backtrack from the models this morning in the extent of the ridge to the SW and how much effect that has over the UK over the weekend and next week. Though the pattern shown between the models is rock solidly the same across all output including the ensembles and clusters the difficulty lies in them determining how far the ridge is going to build across the UK and whether it is sufficient enough to prevent troughs of Low pressure to feed down across the UK from the NW and as a result make things cool and cloudy as opposed to bright and somewhat warmer. The main message is that while the High remains out to the SW whether a ridge is present or not there is unlikely to be a heatwave as the NW flow will be feeding air across the UK from seas to the NW which have temperatures somewhat below average for this time of year. In addition cloud cover will be quite large at times especially towards the North and East with the SW seeing the best of the conditions through most of the period. So my best description of conditions in the next two weeks on a UK wide basis is 'benign'. There should be a reduction over the rest of the month in the amounts of rain that the UK has seen so far but I suppose what most people would like to see is the High to drift NE across and to the East of the UK sending us warm continental air up and across us and bringing our first taste of real summer but there seems little indication of that happening over the next few weeks so high Summer must remain on hold for a few more weeks if this morning's output is to be believed.

 

Next update from 08:00 Wednesday May 20th 2015

[BLAST FROM THE PAST]

The scourge of winter is the scourge of late Spring, HP to WSW. 

 

Today

 

 

and ten days time

 

Edited May 19, 2015 by BLAST FROM THE PAST

[coldcomfort]

The scourge of winter is the scourge of late Spring, HP to WSW. 

 

Today

 

 

and ten days time

 

Indeed BFTP....quite why the models often want to build pressure eastwards from this initial set up is baffling, because they all seem to do it at some stage, only to backtrack later and hold things out west. It's seems to be the equivalent of our T+144hr and beyond direct winter northerlies, which almost always get shunted ever further eastwards as time goes by - but we still fall for them too time after time

[BLAST FROM THE PAST]

Indeed CC, I haven't seen such an omnipresent feature like this.....if it carries on forecasting will become 'easy' 

 

BFTP

[summer blizzard]

The NOAA 500mb anomaly charts (the 6 to 10 day and the 8 to 14 day versions - issued 18th May) maintain a similar theme to previous versions of keeping areas of High Pressure close-by over Western and South-Western areas of the UK (in a way, quite similar to the 500mb mean charts Knocker posted yesterday). I would perhaps says it has trended the higher than average heights to the West of the UK a touch further East compared to the NOAA's previous anomaly charts. It has also certainly lost some of the influence of Low Pressure areas affecting Eastern areas of the UK, which was evident on the anomaly charts a few days ago. However, I think as someone pointed out earlier on, there still doesn't seem to be much of a signal (yet) to suggest the Azores High Pressure will ridge over to the East of the UK. And it's possible some of the troughing the NOAA shows to the East of the UK could help keep the Azores High Pressure locked away to the West or South-West of the UK (though doesn't mean it can't happen at some point and things could always possibly change for the better for those wanting to see an Eastern UK High Pressure set-up). Does, however, still look to be the case that High Pressure and the higher heights towards Western/South-Western UK could stay close enough to keep the British Isles free from much wet weather - although, again, the best of the driest and brightest conditions would probably be over Western and South-Western areas. While nothing particularly warm, especially with a flow at the 500mb height from the North-West, some reasonably warm conditions could still be achieved via longer sunnier breaks. This perhaps again especially true towards Western areas of the UK.

image.jpgimage.jpg

The anomaly charts above also have support from the ECMWF 12Z 500mb and Surface Pressure Ensemble Mean chart - keeps ridging close by over South-Western UK with the strongest of the highest heights out to our West in the Southern Atlantic. Also has the lower than average heights around the Greenland area to our North like the NOAA anomaly charts have.

image.jpgimage.jpgimage.jpg

Be interesting to see whether the 00Z ECMWF sticks to a similar theme (but I suspect there won't be much difference).

In the meantime, the models show a cool Polar Maritime flow bringing some sunshine and showers for places both today

image.jpgimage.jpgimage.jpg

...and tomorrow

image.jpgimage.jpgimage.jpgimage.jpg

...as Low Pressure tracks towards North-Eastern Scotland drags a cool and showery flow down from the North-West. Temperatures slowly starting to rise tomorrow as well, as the charts above show a ridge of High Pressure towards the South-West of the UK terminating the showery activity. Remaining showers getting pushed off to our East. Temperatures looking to get up to around 14 - 17*C for some Eastern spots.

Both tonight and tomorrow night look to be on the chilly side for most places, too:

image.jpgimage.jpg

Thursday will see the ridge of High Pressure settle over Southern areas of the UK with the best of the brightest and warmest conditions towards the East and South of the Beitish Isles. Low Pressure to the North, though, could bring a spell of rain over Scotland. Will be cooler over North-Western areas, especially to those towards Western Scotland exposed to the wet conditions.

image.jpgimage.jpgimage.jpg

While detail is still liable to change somewhat for the next few days after, does looks as though High Pressure will settle over South-Western and Southern areas with the best of the driest conditions and warmest conditions in these areas. But one or two odd spells of rain could spill over the top of the High Pressure and affect Eastern or North-Eastern areas at times.

image.jpgimage.jpgimage.jpg

And should the anomaly charts be correct with their ideas (although it does have similar support from operational models, such as the 0Z GFS, then High Pressure could remain somewhere close by to the West or South-Western areas of the UK for a little while.

 

Anomaly chart still removing the western US trough which should precipitate a more +PNA pattern and subsequent build of pressure to our north and east as we move towards week 3.

 

GFS continues to be more aggressive with the trough..

 

[knocker]

Correct me if I'm wrong sb but a positive PNA surely indicate negative heights to the NE and positive to the W and SW? In any case the ECM is just going positive by day ten.

 

Looking at the ECM anomaly this morning it's still playing ticketeboo with the trough next weekend before settling on the HP influence into the ext period.

 

Edited May 19, 2015 by knocker

[coldcomfort]

Correct me if I'm wrong sb but a positive PNA surely indicate negative heights to the NE and positive to the W and SW? In any case the ECM is just going positive by day ten.

 

Looking at the ECM anomaly this morning it's still playing ticketeboo with the trough next weekend before settling on the HP influence into the ext period.

If that's what it shows then so be it, but I really can't see anything other than HP remaining centred to the west, with a subsequent dominance of flow from between N and W. On a positive note however the HP looks close enough to deliver predominantly dry weather, with a pleasantly warm feel likely in the late spring sunshine, but any genuine warmth, let alone heat still appears set to elude us into June. 

Edited May 19, 2015 by coldcomfort

[knocker]

If that's what it shows then so be it, but I really can't see anything other than HP remaining centred to the west, with a subsequent dominance of flow from between N and W. On a positive note however the HP looks close enough to deliver predominantly dry weather, with a pleasantly warm feel likely in the late spring sunshine, but any genuine warmth, let alone heat still appears set to elude us into June. 

 

All I meant by that was there is a bit of a flip between Sunday and Monday. But yes the HP will remain centred to the west.

Chart weatherbell

Edited May 19, 2015 by knocker

[coldcomfort]

All I meant by that was there is a bit of a flip between Sunday and Monday. But yes the HP will remain centred to the west.

Chart weatherbell

Agh right, apologies for the mis interpretation Knocker. It seems equally prudent for all of us to keep feet on the ground this time of year too, what look like very good ops charts one day can look distinctly ordinary the next

Edited May 19, 2015 by coldcomfort

[knocker]

Agh right, apologies for the mis interpretation Knocker. It seems equally prudent for all of us to keep feet on the ground this time of year too, what look like very good ops charts one day can look distinctly ordinary the next

 

If you survive a winter in this thread you will reflect on that statement cc. Mind during this period counselling is available through the NW counselling service.

Edited May 19, 2015 by knocker

[summer blizzard]

Correct me if I'm wrong sb but a positive PNA surely indicate negative heights to the NE and positive to the W and SW? In any case the ECM is just going positive by day ten.

 

Looking at the ECM anomaly this morning it's still playing ticketeboo with the trough next weekend before settling on the HP influence into the ext period.

 

Yes although the forecast US pattern has this signature over Canada rather than the US (the trough and ridge both too far north) which is a tad weird. 

 

Not the most inspiring outlook as we enter June on the 6z..

 

[Frosty.]

There is plenty of good news on the GEFS 6z mean / Met Office outlook, especially by the time we reach early june, high pressure looks a lot more dominant by then and temperatures into the 70's F. In the meantime, there is also good news in the short term, especially for the southern half of the UK with a ridge of high pressure building in by Thursday with chilly starts and then pleasantly warm in the sunshine, a stronger ridge of HP for the long weekend bringing fine and warmer weather with sunny spells to most of the UK. Next week a ridge of high pressure is maintained, especially across the south and west which is where the best of the weather is likely to be. Longer term, early summer could become very pleasant.

Edited May 19, 2015 by Frosty.

[mushymanrob]

There is plenty of good news on the GEFS 6z mean / Met Office outlook, especially by the time we reach early june, high pressure looks a lot more dominant by then and temperatures into the 70's F. In the meantime, there is also good news in the short term, especially for the southern half of the UK with a ridge of high pressure building in by Thursday with chilly starts and then pleasantly warm in the sunshine, a stronger ridge of HP for the long weekend bringing fine and warmer weather with sunny spells to most of the UK. Next week a ridge of high pressure is maintained, especially across the south and west which is where the best of the weather is likely to be. Longer term, early summer could become very pleasant.

 

wish that was a mirror image... id be much happier if the mean high was to our east!

[picog]

wish that was a mirror image... id be much happier if the mean high was to our east!

I'm just thankful for HP indicating drier and quieter weather.

[Eugene]

After a brief ridge it looks like back to NW'ly regime, more fresh lively weather to look forward to.

[049balt]

After a brief ridge it looks like back to NW'ly regime, more fresh lively weather to look forward to.

West is best.

[Milhouse]

Given how bad the models handled the weekends low pressure to the NE of the UK i wouldnt want to predict the track of any low pressure next week. In the meantime it looks like some more seasonal weather is on offer with average temperatures and more in the way of dry and bright weather. Its been in short supply so far this month.

 

[mushymanrob]

I'm just thankful for HP indicating drier and quieter weather.

But its only just got wet.... Twas dryza bone here anyway.

Interestingly, the anomaly charts dont look like being spot on, neither do the ops, as theres unlikely to be a northen low as per the anoms, nor a high centred over us as per the most progressive ops.

[summer blizzard]

Well, at least we don't have the humid rubbish from last year.

 

[johnholmes]

The NOAA anomaly outputs are really playing with any of us who try to use them to give an idea of the weather type. Having gone for a less meridional and more W'ly flow yesterday tonight they are back where they were 2-3 days ago. So all bets are off and jh sits on the fence for at least 24 hours!

link below

http://www.cpc.noaa.gov/products/predictions/610day/500mb.php

[ANYWEATHER]

Some real warmth on the way for the final week.

 

http://wxmaps.org/pix/prec4.html

High pressure staying well to the west of the uk from gfs and ecm...guess what happens,,,

[knocker]

The NOAA anomaly outputs are really playing with any of us who try to use them to give an idea of the weather type. Having gone for a less meridional and more W'ly flow yesterday tonight they are back where they were 2-3 days ago. So all bets are off and jh sits on the fence for at least 24 hours!

link below

http://www.cpc.noaa.gov/products/predictions/610day/500mb.php

 

Funny you should say that John but I was just looking at this evenings GEFS and ECM and getting that deja vu feeling again. Good old Groucho. Fence sitting is I agree the only sensible option but it didn't stop me dreaming and looking at the GEFS T384 anomaly which has a wedge of very warm air  just to the east of Scandinavia with a nice HP cell. Now if that was to nudge west............................

Charts weatherbell

Edited May 20, 2015 by knocker

[Summer Sun]

Latest ECM rainfall anomaly charts between June 1st and 7th show below average rainfall over the UK

 

June 8th to 14th shows most of the UK remaining with below normal rainfall though some western parts are closer to the average with the south west and western Ireland slightly above normal

 

Temperatures are mixed with CFS warmer for the UK from June 8th with ECM closer to the average maybe even a touch below in some northern and eastern parts during early June

[049balt]

Latest ECM rainfall anomaly charts between June 1st and 7th show below average rainfall over the UK

 

June 8th to 14th shows most of the UK remaining with below normal rainfall though some western parts are closer to the average with the south west and western Ireland slightly above normal

 

Temperatures are mixed with CFS warmer for the UK from June 8th with ECM closer to the average maybe even a touch below in some northern and eastern parts during early June

It's not going to too bad, a lot of dry weather with around normal temps.  warm in any sunshine, not the fire works some here want.

[knocker]

Back to this weekend. This morning the GFS is still running with the HP to the SW and bringing the cold front down from the NW and running SE over the country on Sunday so periods of rain for all except possible the SW. Similar to the last fax I've seen. Given the vacillations vis the upper trough I'm wary of travelling further afield without consulting various oracles.

 

EDIT

The ecm has the front running east and just affecting Scotland.

Edited May 20, 2015 by knocker