Model Output discussion 1st September 00z------->

[stodge]

Afternoon all

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao.sprd2.gif

 

Haven't commented much on the teleconnections of late. The NAO has been negative for an extended period and it's not surprising with the Azores HP suppressed and pressure falling to the SW in response to the evolution and development of the HP to the NE.

 

Looking ahead, most members want to take the NAO back into positive territory which suggests a return to a more "traditional" synoptic set up of low heights to the NW and higher heights to the SW. A W'ly or SW'ly airstream or some variation on that theme from post mid-month.

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao.sprd2.gif

 

AO remains broadly neutral for now.

 

On a complete tangent, does anyone know if there is any correlation between the frequency of typhoons and the emergence of the Polar Vortex ? Let me explain - on some models I've seen extratropical systems (ex typhoons) move through the Bering Strait and across the Pole to the west of the meridian taking up residence over northern Greenland - I was simply wondering if these ex-storms could provide a source of energy for the PV and therefore drive a stronger jet over the Atlantic even if they haven't done so over the Pacific ?

[knocker]

The GFS take on four days starting 12z Sunday. No comment necessary.

http://www.tropicaltidbits.com/

 

[049balt]

I

Edited September 10, 2015 by 049balt

[Frosty.]

The Gfs 12z in FI is worth commenting on, it shows a big improvement during low res with high pressure building in over the uk so this upcoming very unsettled spell may not last long.

[Summer Sun]

UKMO and ECM again coming up with different solutions by mid week

 

ECM keeps the low a bit further west allowing some warmer air to move up on a south to south westerly flow

 

 

UKMO though has the low over the UK keeping us cooler

 

Edited September 10, 2015 by Summer Sun

[ANYWEATHER]

As far as the ecm and gfs  go T+120 is far as it goes synoptically , and any detail is well below this time frame in terms of precip and wind etc. The Autumn rollercoaster has come early this year!!!

[Frosty.]

Wow it's quiet in here, anyone would think it's about to turn very unsettled...haha, anyway, yes we are staring down the barrel at a very unsettled autumnal spell with strong winds at times and bands of rain sweeping northeastwards across the uk interspersed with sunshine and heavy thundery showers but if the Ecm 12z verifies we are in for potentially very warm conditions for a time next week with +15 T850's flirting with the east which means some of us could reach the mid to high 20's celsius before temps return to near average and by T+240 hours there are signs we would see high pressure building north across the uk soon after.

Lol now I'll get my coat

Edited September 10, 2015 by Frosty.

[ANYWEATHER]

Wow it's quiet in here, anyone would think it's about to turn very unsettled...haha, anyway, yes we are staring down the barrel at a very unsettled autumnal spell with strong winds at times and bands of rain sweeping northeastwards across the uk interspersed with sunshine and heavy thundery showers but if the Ecm 12z verifies we are in for potentially very warm conditions for a time next week with +15 T850's flirting with the east which means some of us could reach the mid to high 20's celsius before temps return to near average and by T+240 hours there are signs we would see high pressure building north across the uk soon after.

Lol now I will get my hat and coat

Indeed Frosty! Last September saw record low rainfall , looking at the charts tonight ,this September will see record rainfall in some places.....

[Summer Sun]

Rainfall totals taking in the next 7 days show western Ireland taking the brunt of the rain with over 100mm in place whilst in the SE, East Anglia and the far north of Scotland it barely gets to 10mm

 

 

Can't take that as a given though the jet stream will play a big role in how much rain we get next week

Edited September 10, 2015 by Summer Sun

[Singularity]

ECM continues to make a lot of the potential, GFS not much at all, and UKMO is somewhere in between. Typical!

 

Interesting longer-term potential for some exceptional warmth to envelop the UK and NW Europe as the trough retrogresses in the aftermath of the tropical remnants getting involved. After all, the tropical import helps to bring about 850hPa temperatures a whole 12*C above the usual levels across NW Europe on the 7th day of the ECM 12z operational run:

 

 

...so there's plenty of heat potential (relative to the time of year) should we see high pressure develop across Europe and circulate the air around to the UK in some fashion. Way too much uncertainty with regard to the complex low pressure behaviour next week to place much faith in this yet, though.

[knocker]

The anomalies tonight are continuing with the retreat of the upper trough although the ecm is not so bullish. However they both continual the theme in the ext period leading to westerly flow and a mobile latitudinal movement of the cold and warm air giving a not unfamiliar N/S split over the UK.

http://www.tropicaltidbits.com/

 

[knocker]

An overview of the latest EC32 update

 

After the regression of the upper trough around Sunday 20th a westerly regime is established until October the 12th with LP around the Iceland area and HP away to the SW. There will of course be, within this regime, periods when HP will be more influential and others when troughs running probably NE will be the dominant factor. It looks once again like a N/S split favouring the south. Temps around average.

[Gibby]

HERE IS MY LATEST ANALYSIS USING DATA SUPPLIED BY THE NWP OUTPUT COVERING 5 OF THE WORLDS MOST POWERFUL WEATHER COMPUTERS ISSUED AT 09:00 ON FRIDAY SEP 11TH 2015

 

THE CURRENT GENERAL SITUATION High pressure will move away East over Scandinavia today followed by a trough of Low pressure and attendant Low pressure moving NE across the UK tonight and tomorrow.

 

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

 

MODELS-2 WEEK HEADLINE Becoming unsettled and often windy with rain or showers at times.

 

THE GFS JET STREAM FORECAST The GFS Jet Stream Forecast shows the flow repositioning to the South of the UK over the coming days and remaining there for some time before moving back to the NW of the UK later next week. It then becomes more variable in strength and generally shifts back South across the UK late in the period.

 

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

 

GFS OPERATIONAL The GFS Operational Run today shows a very unsettled period developing from today across the UK with Low pressure becoming complex and often quite deep over and around the UK bringing spells of rain and showers to all in blustery winds. The pattern eases late next week especially across Engand and Wales where High pressure to the SE brings a warm and humid few days with little if any rain before the pattern resets to a more unsettled nationwide spell again towards the end of the run.

 

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

 

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

 

THE GFS CONTROL  The theme of the GFS Control Run this morning is better than the operational as the unsettled spell of the coming week is superseded by better weather moving up from the SW across England and Wales later next week and persisting in one shape or form for much of the second week 2 with only weak troughs across the South delivering patchy rain at times while the North and NW maintain rather more directly unsettled conditions from off the Atlantic.

 

THE GFS CLUSTERS(14 Days) The GFS Clusters this morning show 75% of members with Low pressure to the North in 14 days time with rain at times especially in the North and West. The remaining 25% of members show a variety of options with High pressure under control positioned over the UK.

 

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 today shows a cocktail of Low pressure areas revolving around the UK through next week in very unstable, unsettled and often windy weather with temperatures near average.

 

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

 

THE FAX CHARTS The Fax Charts this morning show Low pressure taking control of the weather across the UK from the start of the weekend with troughs crossing all areas from the SW and being reinforced by more early next week when windy weather is shown to become a feature at times too.

 

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

 

GEM GEM today looks generally unsettled throughout with Low pressure only slowly giving way to rather less windy and wet weather towards the end of the run as pressure slowly builds from the SW with a tenuous and slow link to improving conditions across the UK next weekend.

 

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

 

NAVGEM NAVGEM shows no improvement later next week as it maintains Low pressure over the UK through to the end of the period with showers and longer spells of rain at times for all in blustery winds from the West or SW.

 

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

 

ECM ECM this morning has also watered down any sign of major improvements later next week as the weeks unsettled and Low pressure based theme for all areas remains well locked into position into next weekend and to the end of the run.

 

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

 

ECM 10 DAY MEAN The ECM 10 Day Mean Chart  from last night shows Low pressure up to the NW and a geerally Westerly flow across the UK with no doubt rain at times for all, heaviest towards the North and West with some drier spells in the South and East.

 

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

 

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The models maintain their theme of High pressure migrating East away from the UK later next week with a return to more unsettled Atlantic winds thereafter. The theme of recent days to an interlude of less unsettled weather in the South and East late next week has weakened somewhat this morning.

 

31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKMO & ECM The Verification Statistics of GFS, UKMO and ECM show at 24 hours ECM leads UKMO at 99.3 pts to UKMO's 99.2 pts with GFS coming in third at 99.1 pts.  At 3 days ECM leads at 96.0 pts with UKMO at 95.9 pts while GFS lags behind at 95.0 pts. At 5 days UKMO is king at 85.2 pts followed by ECM at 84.7 and GFS at 82.3 pts. Then at 8 Days ECM still leads at 58.6 pts over GFS's 49.9 pts. Finally at Day 10 ECM leads GFS at 37.5 pts to 33.7 pts from GFS

 

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day1_PMSL_MSL_G2NHX.png 

 

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 Things still look very unsettled within this morning's set of output. After today's final gasp of Summer it looks like a week at least of wet and and at times windy weather will affect the UK. Of course it won't be raining all the time and some drier and pleasant sunnier breaks will exist too but when the rain comes it is likely to be heavy with strong winds in places and it will no doubt give a very strong indication that we are now into Autumn. The worst of the weatehr still appears to be towards the middle of next week when strong winds and rain combine to give an unpleasant spell or two for may in between showery weather. There is still some scope for improvements towards the South and East of Britain later next week and GFS lead this camp this morning with High pressure ridging up from the SW and restricting more unsettled weather towards the NW. However, all the rest seem to have limited such improvements to more modest levels if at all with Low pressure looking to remain the dominat feature with rain or showers at times. The emphasis of this may well shift the heaviest rainfall from the SW to the NW with time though. Temperatures look like returning to near to average after today though it will still feel pleasant in any sunshine but cool in rainfall. Looking across the board the charts have a very Autumnal look about them today and with tropical storm features in the mix too over the Atlantic some quite volatile weather could occur at anytime over the coming two weeks with the grain of comfort this morning focusing on that possible if temporary improvement across Southern and Eastern Britain late next week.

 

BEST CHART OF THE DAY 00z RUN

 

http://www.wetterzentrale.de/pics/Rtavn2161.gif

 

In selecting the best Chart of the Day I have gone for the 216hr chart from GFS which illustrates our hopes of an improvement in a week or so as High pressure to the SE funnels warm and humid air up across the UK with the South and East dry and warm with the Atlantic influence at that stage away to the NW.

 

WORSE CHART OF THE DAY  00z RUN

 

http://www.wetterzentrale.de/pics/Rgem1201.gif

 

For the worst chart of the day I have gone for the GEM 120hr chart but there are other canditates too which were possible to achieve this accolade. Here we have a very deep Low to the SW with warm and moist Southerly winds ahead of it delivering copious rainfall to the South and West with possible flooding issues for a time should it verify as shown. 

 

Next update from 09:00 Sunday Sep 13th 2015

Edited September 11, 2015 by Gibby

[knocker]

Gibby your links aren't working again.

[knocker]

Henri 06z

http://derecho.math.uwm.edu/models/al082015.png

 

[Summer Sun]

Henri 06z

http://derecho.math.uwm.edu/models/al082015.png

 

The track of Henri is gonna be crucial for next week if the jet stream picks it up some places could get some very heavy rain given the tropical air associated with it

[Gibby]

Gibby your links aren't working again.

Sorry folks. Will try and correct the problem for Sunday's report. No report tomorrow too busy.

[Frosty.]

The Gfs 6z is a generally unsettled run with strong winds at times and bands of rain moving northeastwards across the uk interspersed by brighter, showery spells and feeling cool, particularly in the wind and rain but there are some drier and relatively warmer brighter periods, especially for the south and east. Later in the run high pressure makes a comeback with fine and pleasantly warm conditions to the south of the uk but the next 7-10 days shows low pressure becoming complex and often quite deep over and around the UK.

[Midlands Ice Age]

The Gfs 6z is a generally unsettled run with strong winds at times and bands of rain moving northeastwards across the uk interspersed by brighter, showery spells and feeling cool, particularly in the wind and rain but there are some drier and relatively warmer brighter periods, especially for the south and east. Later in the run high pressure makes a comeback with fine and pleasantly warm conditions to the south of the uk but the next 7-10 days shows low pressure becoming complex and often quite deep over and around the UK.

 

Frosty..

 

I found your charts above interesting for a couple of reasons.

1) Displaying one after the other, video style, show the rapid temperature reductions at this time of year (sun below horizon at the end.) in the far north.

2) The last 3 charts start to bring in a tropical depression across from the west, which appears to be deepening quite rapidly at this stage, even looking as if an eye is forming and riding along on the jet.

 

At the moment the GFS is going for a 'pumping up' of the high to our west as a result.

 

 

It is probably the best outcome for the British Isles. The other option is for the 2 features to crash together, not sure of the consequences, but it probably wouldn't be nice for us!

 

MIA

[Frosty.]

Frosty..

 

I found your charts above interesting for a couple of reasons.

1) Displaying one after the other, video style, show the rapid temperature reductions at this time of year (sun below horizon at the end.) in the far north.

Yes I like to show various snapshots of a run to give a general overview. What struck me about the 6z is how the next week or so looks very unsettled with complex low pressure over the uk and then a gradual improvement after mid month.

[knocker]

Omega unblock?

 

Chart weatherbell

Edited September 11, 2015 by knocker

[Frosty.]

The Gfs 12z shows a very unsettled week ahead with complex areas of low pressure over the UK but then there is a gradual change to more settled weather by week 2 with the southern half of the UK under the influence of a building ridge of high pressure with the jet stream shunted further north. So before this unsettled spell begins there is already signs of high pressure making a comeback, at least for southern UK.

Edited September 11, 2015 by Frosty.

[knocker]

The recent theme of retrogressing the upper trough continues apace with this evening's GEFS anomalies. With no positive height build up over Europe it sets the  tone for a westerly flow (also indicated by the EC32) with alternating influence over the UK of the colder/warmer air leading to the usual N/S split. Average temps.

http://www.tropicaltidbits.com/

 

[Frosty.]

The Ecm 12z shows an increasingly unsettled spell with low pressure dominating next week before a ridge of high pressure gradually builds in towards the end of the run. The good news is there are signs of improvement from the end of next week onwards on both the gfs and ecm.

[Summer Sun]

The low ECM has for Wednesday looks a nasty so and so potential for very strong winds in parts of the south and south west coupled with some heavy rain

 

 

By Thursday its center is over Wales