Model Output Discussion 12z 03/04/13

[Gibby]

Hi everyone. Here is a look at the 12z output from GFS, UKMO, GEM, NAVGEM and ECM for today Sunday April 14th 2013.

 

All models show a mild and slightly unsettled SW flow with sunshine and scattered showers for tomorrow. Through the week a couple of active weather systems will cross NE over all areas as the parent depression moves swiftly NE past NW Scotland. With wind and rain sweeping NE on Tuesday and Wednesday winds will freshen to strong again in most places. Sunshine and showers will chase the rain away on Thursday with a mix of sunshine and showers then with a dry day on Friday as the first signs of a pressure build from the SW takes hold.

 

GFS then shows High pressure build across the UK early next weekend with the axis of it sinking South towards the English Channel and Northern France at the start of the new week. Fine weather will predominate for most over the weekend before cloud and rain from the Atlantic encroaches slowly South across the UK early in the week. However a ridge does hold over Southern Britain for much of the week with dry and fair weather largely persisting here while the unsettled conditions persist further North and finally extend further South to all areas over the weekend. the weather would turn rather colder and more showery over the weekend while at the end of the run a rather cool and blustery west to Northwest airflow develops over the UK.

 

The GFS Ensembles shows a period of sustained normality with regard to temperatures over the coming few weeks. rainfall, innitially fairly small in amount in the South does increase a bit in week 2 but there certainly shouldn't be any troubling amounts of rain through the period.

 

The Jet Stream continues to flow East or NE across the UK over the coming week before showing signs of ridging even further North over the Atlantic thereafter as pressure builds to the SW of the UK.

 

UKMO for the start of next weekend shows High pressure building across the UK from the SW with fine and dry weather with sunny periods and relatively warm feeling conditions for all.

 

GEM tonight shows High pressure well in control of the UK weather next weekend with it's centre settled across the UK with fine and warm weather likely for all with patchy mist overnight.

 

NAVGEM follows it's partners too in building High pressure across the UK next weekend with fine and settled weather, sinking it slowly away SE early the following week.

 

ECM too finishes in unison with the rest in building High pressure across the UK too next weekend with the same attendant dry and settled weather with some warm sunshine. late in it's extended run it loses it's grip on the weather in the north as the Atlantic nudges back in from the NW.

 

In Summary tonight a breezy week with occasional rainfall looks likely but some drier and brighter spells too and it should stay reasonably mild feeling. Through the weekend a spell of light winds and sunnier conditions look likely before things begin to turn just a little more unsettled again from the NW later next week. 

[Kentspur]

Manston in Kent hit 22c which makes it the warmest day of 2013 so far

I did wonder why my car thermometer was at 21c most the afternoon I was only 15-20miles away from Manston today was lovely

We north Kent folk may have missed all the main snow events but we always do the best for summer heat:-))

[Purga]

The cpc 500 mb forecast charts indicate a strong zonal westerly or WNW flow setting up in the medium to longer term

 

 

 

Pretty much supported by the GFS / ECM 500mb mean comparison charts, driest in the south

 

Looks consistent across the board so far.

Edited April 14, 2013 by Purga

[KTtom]

A nice end to the UKMO overnight with the high really exerting its influence over the weekend with the lobe of PV stuck to southern Greenland. Sunny and warming up

[shaky]

A nice end to the UKMO overnight with the high really exerting its influence over the weekend with the lobe of PV stuck to southern Greenland. Sunny and warming up

Rukm1441.gif

Thats more like it!!hopefully ecm shows the same!!

[johnholmes]

The cpc 500 mb forecast charts indicate a strong zonal westerly or WNW flow setting up in the medium to longer term

  

Looks consistent across the board so far.

No real argument with that. These were my comments today after seeing each output.

Sun 14 april

Ec-gfs

Gfs changes to ec idea with ridge/+ve area beneath main trough and strong flow turning it n of west into uk, some changes and they seem to be going down road of turning weather more unsettled than the 3 suggested a few days ago-if noaa is similar tonight then it will confirm this if not?

Noaa

6-10 a bit ‘odd’ re its intensity of +ve areasx2 across chart?

8-14 similar in pattern but more reasonable looking chart

Reasonable follow on from last 2-3 issues as flow veers slightly as trough flattens out more and ends up over/east of uk giving 500 flow about due west.

Does suggest warmish interval of issues several days ago is not now likely?

[mushymanrob]

im happy... yesterday, today, tomorrow, look great for most even if its abit breezy, temps in the mid teens, plenty of sunshine for most, before something unsettled midweek heralds something cooler, but still normal.

 

odd that this mornings ukmo suggests high building to our northeast, its alone as the ecm and gfs simply dont agree, keeping us in a westerly regime after a breif ridge next weekend.

[Summer Sun]

So this morning we have GFS and ECM going one way and UKMO builds pressure to the east

 

 

Then UKMO do this

 

 

ECM keeps those in the south relatively settled and mild / warm upto the 25th this morning whilst the north especially Scotland is often unsettled with lows crossing north of Scotland

 

http://www.null/ds/ecm.htm

 

EDIT

 

Matt Hugo has tweeted the following this morning

 

IMO little chance of 2nd half of April producing any sustained warm/dry/high pressure dominated weather unfortunately.

 

If thats the case ECM's idea of building pressure over the south is wrong and GFS is on the money

Edited April 15, 2013 by Gavin.

[Frosty.]

NAVGEM, GEM and UKMO 00z look really good with high pressure dominating across the southern half of the uk well into next week, the ukmo looks best for a nationwide anticyclonic spell, some nice charts here to start the day.

 

Whilst the ECM 00z is not quite as good as the above, it's much better than the GFS 00z and the ecm keeps high pressure close to the south so it would only really be northern britain that has the windy and changeable conditions, it's the gfs which looks the odd one out with the more changeable/unsettled and cooler outlook.

[Gibby]

Hi everyone. Here is the report on the 00z output from GFS, UKMO, GEM, NAVGEM and ECM for the start of the new working week Monday April 15th 2013.

 

All models snapshot the coming week in a similar way with just slight differences in timing of events as we move through the week. A bright and slightly showery Westerly flow today will be replaced by a vigorous Low running NE close to NW Scotland later tonight and tomorrow with rain and severe gales affecting the NW with a strong blow and rain and drizzle for other areas too as it goes. A cold front clears the rain away as it crosses SE tomorrow leaving Southern coastal counties with a hangback of cloud and drizzle in places. On Wednesday a repeat performance looks likely with heavy rain sweeping NE on a warm front attached to a further low pressure system moving NE to the NW of Britain. The cold front though will be held back for some time so as yesterday some parts of SE Britain could become warm and humid for a time before the cold front staggers across on Thursday bringing rain and fresher air across from the West with occasional showers later. By Friday pressure will be rising strongly across the UK with lighter winds and dry conditions to end the week and lead us into a pretty decent weekend for many.

 

GFS then shows the fine weather of the weekend being eroded from the NW early next week with rain and showers returning SE to all areas by midweek. by the end of the week winds will be strong from the West across a large swathe of the UK with troughs running East in the flow bringing rain for all at times in average temperatures. In FI this morning changeable conditions look like persisting with some dry and bright spells mixed with cloud and rain or showers too. With winds tilting slightly North of West for much of the time the weather will turn somewhat chillier too.

 

The GFS Ensembles show that the operational was pretty indicative of the majority of the pack with the somewhat unsettled conditions with rain at times looking like persisting over the period with rather more rainfall than recently occurring in the South, especially during week 2.

 

The Jet Stream shows the general trend for the UK be the homing ground for the flow for the next week to 10 days in association with Low pressure north of the UK. It does ridge North high in the Atlantic in about a weeks time as pressure builds north from the Azores which could indicate a more NW flow to the winds over the UK next week and somewhat less mild conditions.

 

UKMO for next Sunday as high pressure over Scandinavia with a strong ridge towards SE England. All areas would stay largely dry and pleasant enough in any sunshine. Winds would increase from the South in the far West and NW later in the day.

 

GEM shows a largely settled weekend giving way slowly from the North to more unsettled conditions, at least in the North with a little rain reaching the South at times too in a general mild and rather cloudy Westerly flow.

 

NAVGEM is very similar with the North becoming unsettled and windy again early next week while the South hangs on to the drier, brighter and warmer conditions rather longer into next week.

 

ECM finally follows the same drift with the North seeing unsettled and windy weather early next week while the South sees a lot of cloud at times but very little rain with the chance of some dry and bright weather too at times in temperatures well up to average for late April.

 

In Summary a changeable week is to come this week with occasional rain and strong winds at times. A more settled period looks likely for all at the weekend with some warm sunshine for many over Saturday and Sunday. Next week then looks like a slow deterioration in weather could take shape from the north though the South looks never far from high pressure to the south maintaining some fine and bright conditions between any bands of very light rain. There are no potential weather hazards for farmers and growers to be wary of apart from strong winds and heavy rain in the NW over the next few days so overall this should enable them to catch up somewhat on time lost through the extended Spring cold spell.

[snowking]

 

 

Matt Hugo has tweeted the following this morning

 

IMO little chance of 2nd half of April producing any sustained warm/dry/high pressure dominated weather unfortunately

 

 

If thats the case ECM's idea of building pressure over the south is wrong and GFS is on the money

 

I have highlighted the key part of Matt's wording there

 

If we take a look at the GFS 11-15 day outlooks over the past few runs:

 

 

With high pressure just to the SW and NE of the UK, always the chance of something drier from time to time with temporary ridges building (as per this coming weekend), however I suggested back at the start of this month that unfortunately, given the signal for a rather cyclogenesis dominated start to May from my preliminary summer forecast work, and the fact that synoptic setups at present seem to be becoming rather locked in for long periods (likely to bear fruit at present, especially given the lack of MJO forcing at present), the second half of April in general was likely to be rather unsettled. Interestingly, though, whilst the idea is of a low pressure dominated pattern, the rainfall levels overall didn't look anything particularly concerning (especially against the backdrop of Summer 2012), and to a certain extent, the last couple of EC32 runs tend to suggest this:

 

 

With just a gradual increase in rainfall as we head towards May.

 

For interest purposes, my early research suggests the best chance of any extended settled weather is during the latter part of May and into the first half of June

 

SK

[Frosty.]

There is growing model support for next weekend to be fine and pleasant with plenty of sunshine but with chilly nights, beyond next weekend the Ecm 00z ensemble mean trends more unsettled from the northwest but only briefly because then the low near iceland begins to fill and drift away slowly north and at the same time, pressure rises from the south with more settled weather edging north during next week. The Gefs 00z mean takes a different view, by early next week it shows a much more unsettled pattern with low pressure becoming dominant, the trough slowly fills but remains over the uk and then it drifts down to the south of the uk, now this might sound like a poor outlook for the uk but in my opinion it could turn out to be the most interesting outcome because with a slack cyclonic pattern covering the uk we could look forward to a mixture of sunshine and heavy, thundery slow moving showers, perfect for storm enthusiasts with sunny mornings followed by afternoon and evening big showers and thunderstorms but also increases the risk of localised flooding.

[snowmadchrisuk]

Got to laugh at the Heavy Snow in GFS 6z FI , and the -5 mins in the South ... ECM on the other hand is great in FI extending +10 uppers over Southern UK.  The weekend is now looking Sunny on all models, But we will only reach low teens as upper's are still quite cool in the South . 

[Frosty.]

Well, winter bites back for maybe one last time on the Gfs 06z operational run, it's a potent arctic incursion so close to may with a few damaging frosts and snow showers to the north and hills further south, it may seem unlikely but with a nw/se aligned jet in FI, these type of charts are possible if the pattern becomes amplified enough, it's been the kind of spring so far where you just think there could be one more surprise before may.

[Cheshire Freeze]

Well, winter bites back for maybe one last time on the Gfs 06z operational run, it's a potent arctic incursion so close to may with a few damaging frosts and snow showers to the north and hills further south, it may seem unlikely but with a nw/se aligned jet in FI, these type of charts are possible if the pattern becomes amplified enough, it's been the kind of spring so far where you just think there could be one more surprise before may.

Boom, heavy sleet,snow and hail showers from that.

Edited April 15, 2013 by CreweCold

[Milhouse]

Interesting UKMO 0z. If this was to ocur it would certainly block or divert the low pressure away from the UK. In recent runs high pressure has been all to weak to stand up to the advancing low but this is the first indication we may see a more favourable positon of the high to deliver a continuation of the dry and reasonably mild conditions. Not exceptionally so however with a easterly likely to result from the UKMO from 144h onwards. ECM once again the pick of the models for warmth.

Edited April 15, 2013 by Milhouse

[Summer Sun]

Interesting UKMO 0z. If this was to ocur it would certainly block or diverly the low pressure away from the UK. In recent runs high pressure has been all to weak to stand up to the advancing low but this is the first indication we may see a more favourable positon of the high to deliver a continuation of the dry and reasonably mild conditions. Not exceptionally so however with a easterly likely to result from the UKMO from 144h onwards. ECM once again the pick of the models for warmth.

 

 

Yes another good outlook however even I would like to see some April showers now getting in desperate need for some rainfall now it feels like we are going through a mini drought with just 3mm of rain in the last 23 days a bit of rain and some warmth will kick start the growing season fully now

[Milhouse]

A warm and humid day to come on Wednesday with rain for northern parts.

 

[Frosty.]

Today's met office update (6-15 day) in my opinion sounds similar to the latest Ecm 00z ensemble mean beyond T+168 hours with an unsettled spell developing across all areas next week but especially for the north and west, but with some ebb and flow across more southern areas with the brightest, driest and warmest spells for southern and eastern england. The weekend ahead looks fine and sunny with slight overnight frosts as high pressure will be in control apart from nw britain which looks like turning unsettled after a brief improvement, then pressure falling by early next week from the northwest.

Edited April 15, 2013 by Frosty039

[Summer Sun]

UKMO is holding steady out to t120 another spell of high pressure looks likely now later this week

 

 

EDIT

 

Holds firmly to t144 (21st)

 

 

Edited April 15, 2013 by Gavin.

[Frosty.]

The Gfs 12z op run is looking  progressive with unsettled weather spreading from the northwest as early as sunday, and the unsettled trend continues next week with some additional trough activity ahead of the main low, the jet aligning nw/se which is what the gefs 00z mean and ecm 00z ens mean are showing.

[Frosty.]

Well the ukmo 12z is sticking to it's guns from the 00z earlier, blocking high to the east which holds the atlantic at bay, it's the type of pattern which would probably persist well beyond the weekend but it's at complete odds with what the met office update mentioned today.

 

UKMO 00Z and 12z says NO to UNSETTLED

[Methuselah]

Well the ukmo 12z is sticking to it's guns from the 00z earlier, blocking high to the east which holds the atlantic at bay, it's the type of pattern which would probably persist well beyond the weekend but it's at complete odds with what the met office update mentioned today.

 

UKMO 00Z and 12z says NO to UNSETTLED

That's cos the Met take account of what all of the models are saying; they don't rewrite their monthly outlooks each and every time their model output changes...that's what the Daily Mail is for!

[Summer Sun]

As you were from ECM again to t96 looking like a nice dry settled and mostly sunny start to the weekend is coming up

 

 

More unsettled for the north on Sunday dry and settled for the south

 

Edited April 15, 2013 by Gavin.

[Milhouse]

Models firming up on a fairly settled weekend but Sunday will see more unsettled conditions spreading down from the northwest during the day. Uppers do look a bit below average so where it stays cloudy it will be rather cool. In any sunshine and light winds it should feel pleasant although becoming increasingly breezy on Sunday. This is going by the ECM and GFS.