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

[DTHFCJ]

The latest EC32 update.

 

There is no strong signal for any major change out to the 12th June.

 

Next Sunday and Monday is of some interest as although we are still stuck with the low N. Canada, Iceland and trough Scandinavia it does briefly move the HP closer to the UK and perhaps some pleasant weather, certainly to England, with some warmer temps. Cornwall may even bask.

 

It is but a brief sojourn as by the 23rd the HP has slipped SW again with the LP to the NW although the trough has all but gone and the cool westerly regime is in situ.

 

Not much more to say about the rest of the run apart from the HP remains to the SW around mid Atlantic with LP Greenland so the airflow over the UK remains in the NW/SW quadrant but temps at least average or slightly above.

 

Looking at next Sunday the GFS shows a very brief flirtation with the HP

Chart weatherbell

Not having a dig at you Knocker but the last update from the EC32 that you posted was a fair site better than this one?obviously they have more data but like i said that's a change from the last update....thanks for sharing though

[summer blizzard]

An interesting snippet about the unusual going's on in the Pacific in today's NOAA forecast discussion.

 

IT IS REASONABLE TO ASK WHETHER SUCH A PATTERN, GIVEN ITS APPARENTLY

LOW-FREQUENCY NATURE, MIGHT BE RELATED TO THE ONGOING ENSO STATE IN THE

PACIFIC. THIS WARM ENSO EVENT IS AMONG THE STRONGEST FOR THIS TIME OF YEAR, AND

SO ANY MIDLATITUDE TELECONNECTIONS WOULD BE EXPECTED TO MANIFEST THEMSELVES

DURING SUCH AN EVENT. FOR A BACK OF THE ENVELOPE ATTRIBUTION, WE WILL CONSIDER

THE COMPOSITE 500-HPA HEIGHT ANALOG FOR THE PAST WEEK'S OBSERVATIONS AS WELL AS

FOR THE WEEK-2 OFFICIAL HEIGHT BLEND. BY LOOKING AT THE SST FOOTPRINTS OF THE

TEN-YEAR COMPOSITES FOR EACH MAP, WE SEE THAT THEY ARE QUITE DIFFERENT, WITH

THE OBSERVED PERIOD MORE CONSISTENT WITH EL NINO, BUT THE FORECAST PATTERN

STRONGLY TILTED TOWARD LA NINA. THIS IS NOT ENTIRELY SURPRISING CONSIDERING

THAT THE EL NINO CIRCULATION FOOTPRINT IS WEAKER DURING BOREAL SUMMER OVER THE

PACIFIC-NORTH AMERICA REGION, AND SO VERY LITTLE WEEK-TO-WEEK VARIANCE IS

LIKELY ATTRIBUTABLE TO THE ONGOING EVENT.

 

Full discussion here:  http://www.cpc.ncep.noaa.gov/products/predictions/610day/fxus06.html

 

This is pretty much what i meant when i said that the changed pattern over the US needs to change before any prolonged heat.

[mountain shadow]

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

 

 

Drying trend continues.

Doesn't look like a drying trend to me? Precipitation largely around average?

[049balt]

Doesn't look like a drying trend to me? Precipitation largely around average?

Around average is better that four times average! blue shading is below average.

[AWD]

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

 

 

Drying trend continues.

Looks relatively average to me. Perhaps drier than average towards the south and west.

Spain and Portugal look the places to be, on both those PPN and temperature projections.

[Summer Sun]

ECM has had an update today

 

http://www.ecmwf.int/en/forecasts/documentation-and-support/changes-ecmwf-model/cycle-41r1

[damianslaw]

A fairly static picture, azores high set to lock itself into an unfavourable position for anything particularly warm for the time of year anytime soon. Indeed a flow from between west and north looks like predominating with only subtle day to day changes. Temps average at best cooler than average in the north, but perhaps trending a bit above in the far SW for a time.

 

Low pressure forecast to drop anchor from the NW again next week pulling in cool showery northwest airstream as we head towards bank holiday weekend.

 

A changeable outlook then, nothing particularly wet on the horizon with the exception of Thursday which is forecast to be very wet in the south and notably cool. Set against April, this May is feeling very disappointing. Too much too soon...

[Polar Maritime]

The GFS shows a cool/unsettled Pm flow for next week turning Northerly by weeks end. 'Extensive' Heights pushing up over Greenland towards the Arctic by the end of the run, Prolonging the cool/unsettled theme as Low Pressure anchors itself over the UK.

 

[bluearmy]

Through week 2, looks like a w Russian ridge establishing in conjunction with the mid Atlantic fella. That's going to leave a trough I between. More than possible we will be stick under that. Spring likely to remain on hold for most of the UK though perhaps not overly unsettled.

[knocker]

Well the GEFs anomalies don't fill one with cheer this evening.

 

At T168 we have Alaskan ridge, N.Canadian low, Greenland ridge and low northern North Sea,  So a northerly blast with temps as much as 5C below average in Central England,

 

By T240 the North Sea low has been replaced with a trough and the Greenland ridge has moved east but it is further north than previous runs so still a NW/N component to the wind and temps a fair bit below average. See what the ECM has to say about this.

Charts weatherbell

 

Edited May 12, 2015 by knocker

[Yarmy]

Around average is better that four times average! blue shading is below average.

 

The blue shading on the anomaly chart at the bottom is above average ppn. Light blue is 150-300% of average on the legend. The other 2 charts show absolute values:

 

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

 

Norn Iron is below average which just goes to show how much ppn they normally get.

 

Still 3 weeks till Summer even begins so nothing to be concerned about longer term.

[049balt]

The blue shading on the anomaly chart at the bottom is above average ppn. Light blue is 150-300% of average on the legend. The other 2 charts show absolute values:

 

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

 

Norn Iron is below average which just goes to show how much ppn they normally get.

 

Still 3 weeks till Summer even begins so nothing to be concerned about longer term.

I beg to differ, blue shading is about 75% of normal which is explained by bottom chart and graph.

[Gael_Force]

I beg to differ, blue shading is about 75% of normal which is explained by bottom chart and graph.

To settle arguments, here's the anomaly chart in question. Only blue shading I see starts at 150%

 

[knocker]

The ECM anomalies are very similar to the GEFS so certainly looks like the weather will be quite candy ball for a period but of course it's still subject to change.

 

Just a reminder the ECM upgrade is operational from 12z.

Edited May 12, 2015 by knocker

[Yarmy]

I beg to differ, blue shading is about 75% of normal which is explained by bottom chart and graph.

 

75% and below is red, 75%-150% is white, 150% and over is blue.  

 

Edit: I see Gael Force beat me to it.

Edited May 12, 2015 by Yarmy

[049balt]

To settle arguments, here's the anomaly chart in question. Only blue shading I see starts at 150%

 

Both wrong, example, Northern Ireland is shaded red, which is 75% of normal rain fall for the period 12 to 20 May, then look at the top chart and you will see blue shading for that period, "precipitation as % of normal during the first period"

[Yarmy]

Both wrong, example, Northern Ireland is shaded red, which is 75% of normal rain fall for the period 12 to 20 May, then look at the top chart and you will see blue shading for that period, "precipitation as % of normal during the first period"

 

The legend in the top chart is showing total rainfall for for the period in mm (Precipitation (mm) during the period). The blue shading in the top chart indicates 2.5 to 20mm of total ppn. The green shading indicates ppn above 20mm.

 

The blue shading in the anomaly chart at the bottom indicates 150% and above average rainfall:

 

[049balt]

The legend in the top chart is showing total rainfall for for the period in mm (Precipitation (mm) during the period). The blue shading in the top chart indicates 2.5 to 20mm of total ppn. The green shading indicates ppn above 20mm.

 

The blue shading in the anomaly chart at the bottom indicates 150% and above average rainfall:

 

Agreed, and the precipitation for Northern Ireland as a % of normal is shaded in red, 75% of normal. It might be changed by the time you read thin.

[mushymanrob]

looking like a chilly but fresh second half of May

still, in the sun itll feel very pleasant, when theres no cloud the sky should be very blue (as opposed to milky) with good air quality. good for viewing noctilucent clouds?
 

 

Edited May 13, 2015 by mushymanrob

[coldcomfort]

looking like a chilly but fresh second half of May

still, in the sun itll feel very pleasant, when theres no cloud the sky should be very blue (as opposed to milky) with good air quality. good for viewing noctilucent clouds?

 

610day.03.gif814day.03.gif

Think it will be OK along the south coast for much of the time given the relatively good protection, but if the current GFS verifies it will be a cold 2nd half of May (relative to normal) in my opinion, with night frosts and high level snow impossible to dismiss even during the last week of the month. To my mind the charts offer up the possibility, even likelihood of just about everything, barring any warmth and/or heat of course...ergo standard UK stuff   

[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 WEDNESDAY MAY 13TH 2015.

 

THE CURRENT GENERAL SITUATION A ridge of High pressure will move East across the UK today followed by a small depression moving across Southern Britain tonight and clearing away to the SE later tomorrow. 

 

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

 

MODELS-2 WEEK HEADLINE Changeable with some showers at times especially over the North and East but spells of dry and fine weather too for all. Generally rather cool, especially by night.

 

THE GFS JET STREAM ENSEMBLE FORECAST The Jet Stream axis will move gently North after the next few days across the UK to lie West to East across Scotland at the weekend. Through next week it then eases back South as a UK trough develops gradually becoming broken up and ill defined in both strength and positioning late in the period under a maintained UK trough.

 

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

 

GFS OPERATIONAL The GFS Operational this morning continues to show changeable and often rather chilly conditions across the UK in the next two weeks. The flow will be from the West innitially with rain at times chiefly across the North with average temperatures for many. Then from next week Low pressure to the NE and building High pressure through the Atlantic makes for a cold Northerly flow over the UK with days of heavy and thundery showers and some jolly chilly nights given the time of year still with the risk of local ground frosts as winds fall light.

 

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

 

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

 

THE GFS CONTROL The GFS Control run this morning follows a very similar path though the weather does warm up a little late in the period as the cold Northerly drift is cut off by falling pressure over the Atlantic and the return of milder SW winds.

 

THE GFS CLUSTERS The GFS Clusters show a general theme biased towards High pressure lying just to the West of the UK in a light northerly drift in two weeks time. The minority members are split between High pressure just to the NE or South of the UK with a milder SW flow setting up across the UK, similar in type to that shown by the Control Run.

 

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 High pressure likely to lie to the South of the UK at the weekend with Westerly winds and occasional rain to the North. This then spreads South as Low pressure eases down towards the Uk from the North with rain at times for all by midweek next week.

 

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

 

THE FAX CHARTS The Fax Charts follow the theme of the raw data charts well today showing tomorrows wet weather from a complex Low and frontal systems clearing away SE later tomorrow before a new set of troughs cross east Friday night. The pattern simplifies then as High pressure to the South sets up a Westerly flow with occasional rain in the North later in the weekend.

 

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

 

GEM GEM this morning shows a similar trend to GFS next week but the build of High pressure over the Atlantic late in the period is shown closer in towards Western Britain meaning the extent and widespread nature of the showery regime from GFS is more restricted later on this run towards the East of the UK with a lot of dry if rather chilly weather more likely by then especially towards the SW.

 

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

 

NAVGEM NAVGEM shows a chilly NW flow developing next week as Low pressure slips SE just to the NE of Scotland with a mix of chilly conditions and sunshine with showers in NW winds affecting all areas 1 week from now.

 

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

 

ECM ECM joins the theme shown by the rest of the models with Low pressure easing down over the UK next week with cool and showery weather shown as a result for all moving forward to include a re-run of the pattern late in the period as a new Low slips down from the NW maintaining the showery and cool theme.

 

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

 

ECM 10 DAY MEAN The ECM 10 Day Mean Chart  from last night shows High pressure to the SW of the UK still badly positioned for the UK while Low pressure remains locked to the North and NE of Britain with cool air enveloping the UK in NW or West winds and showers.

 

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

 

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The trends all agree on cool NW winds and occasional showers across the UK for the extended outlook period this morning.

 

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 96.8 pts followed by UKM at 96.2 pts and GFS at 95.3. At 5 days ECM  leads UKMO with 86.7 over UKMO's 84.6 pts with GFS at 83.2. At 8 days ECM remains the leader with 54.1 pts over GFS's 53.3 pts. Then at Day 10 ECM maintains superiority at 37.7 pts over GFS at 36.7. 

 

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 The weather patterns remain poor for enhanced warmth over the next few weeks as the pressure forces, both high and low remain poorly aligned for warm weather across the UK. Having said that the weather will never be a washout with plenty of dry and bright weather for all. However with a source of wind from between West and North from early next week we cannot expect temperatures to be any better than average and they will often be rather below. The nights become a worry too for gardeners and growers as the NW or North flow of air is sufficiently weak at times for winds to fall light at night and under clear skies ground frost is a real risk even though we are approaching late May. With regard to rainfall there looks likely to be rather a lot of dry weather for all but showery days are expected for all too and at times these could be heavy and thundery locally. Longer term there is still a weak signal for High pressure to build in somewhat from the West late in the two week period which could hopefully kill off the North flow and showers to something rather warmer and settled but that seems a long way off at the moment. So it looks like we will have a reasonable amount of dry and bright weather over the next two weeks with showers in places and temperatures near to or somewhat below normal at times and some very unseasonably chilly nights. 

 

Next update from 08:00 Thursday May 14th 2015

[johnholmes]

The 3 main anomaly charts appear to be moving towards a fairly extended 'cool' spell. If they are correct then ground frosts and occasional air frosts in prone locations would be likely at times under clear skies right out to the end of May, links below

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

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

It is rare for them to be far out, and that applies especially to the NOAA versions.

Cold lovers from the winter brigade would love these charts in mid December onwards!

Edited May 13, 2015 by johnholmes

[Summer Sun]

Just a side note for anyone viewing ECM Op on wetterzentral it hasn't updated since Tuesday 00z, the ens is updating as normal

[Eugene]

looking like a chilly but fresh second half of May

still, in the sun itll feel very pleasant, when theres no cloud the sky should be very blue (as opposed to milky) with good air quality. good for viewing noctilucent clouds?

 

610day.03.gif814day.03.gif

 

 

Yes mushy it looks lovely and as you say the sun is very strong so will override any cool airmass, not sure where the cold and grey came from.

[mushymanrob]

Yes mushy it looks lovely and as you say the sun is very strong so will override any cool airmass, not sure where the cold and grey came from.

 

well its hard to predict cloud amounts that far ahead, a shallow trough or slightly east of north draft could easily see us under cloudy grey skies and with those low 'uppers' itll not be warm.

but hopefully, the strong sun will at least make it feel warm enough if theres no cloud and breeze.