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Paul

Model output discussion - hot spell beckons but then what?

Paul

This thread = Models, models and more models
Please remember that this thread is for discussing the model output only. If you want to chat about the summer weather more generally, please use the Summer chat and moans thread.

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Posted (edited)

The North Atlantic 500mb and surface analysis for midnight

gfs-natl_wide-z500_anom-5136000.thumb.png.d8668542180128d4cdb487a7a0a887e6.pngPPVA89.thumb.gif.0b01635bd3cdbae16edfc427e196ec21.gif

The low that has been dominating our weather of late is now just off the east coast of Scotland so for the time being the country remains within it's circulation Ergo still showers, but far less frequent of late, over Wales and most of England, and with plenty of sun it will be quite pleasant. But the area closer to the low, i.e. N. Ireland, northern England and in particular Scotland, will see more frequent thundery downpours which will be slow moving in the lighter winds.

PPVE89.thumb.gif.55ada5b28e77af10e622b0200ea3b9d6.gif1871453614_maxwed.thumb.png.b434cb6724b4f9130e61fbc2747ee181.pngprecip_d02_15.thumb.png.328375e8f1839b6f4ed094a0ae621207.pngprecip_d02_18.thumb.png.64bbcd0126f8d212cab46c4865d89e0a.pngprecip_d02_21.thumb.png.d2a1a9fcf4f28eba64c3cac588a5697b.pngprecip_d02_24.thumb.png.ca3f67517bed692aeb84d80a7c66d691.png

The showers will fade away this evening and overnight, albeit hanging around for a while over Scotland but even here they eventually start to fizzle out. Thus a night a fresher night with plenty of clear periods

PPVG89.thumb.gif.a100b203b7fff9b1b13c62425006cbd6.gif

Thursday will be a much better day for most with sunny intervals and light winds so feeling quite warm, albeit showers will pop up, mainly in northern and central regions. But during the afternoon cloud and patchy rain from the first frontal system associated with the quite intense low approaching from the south west will effect the south west and south

gfs-natl_wide-z250_speed-5265600.thumb.png.f289bedc8040e1c9f739aaa78411dc89.pngPPVI89.thumb.gif.781856deba41c837f2cd094ad088b684.gif223986515_maxth.thumb.png.a00b22a469bb0739bb7495385acaba0a.png

precip_d02_46.thumb.png.ff831bf56bf99d0a9dfee53c9562036c.png

Over Thursday night and through Friday the low continues to curve north east as the jet runs around the upper trough and the the associated fronts will bring heavy rain to most area with thundery outbreaks embedded in the mix accompanied by strengthening winds

gfs-natl_wide-z250_speed-5352000.thumb.png.9c9dee4496967db01ecb992b8c156650.pngPPVJ89.thumb.gif.30984a3258d9182c887a6ffcef7a245e.gifPPVK89.thumb.gif.30f2a5216e1c7b6186690e90232eb698.gif

1597676400_maxfr.thumb.png.c8cb2835161437ec952a008a670d1711.png

By Saturday the low is centred over southern Scotland and has become elongated as the subtropical high zone amplify to the west and east.So another day of heavy rain and frequent thundery showers with some intense localised downpours and some strong winds with gales in the south/

gfs-natl_wide-z500_anom-5438400.thumb.png.eeb039b259369893edda910857539372.pngPPVM89.thumb.gif.4f69e8ee16ac2a0610b2a004d79c3481.gif

By midday Sunday the low is adjacent to Iceland as the subtropical zones continue to amplify so a much better day as the rain and showers become much less significant ant the strong winds abate quite quickly. A chilly day in northern regions

gfs-natl_wide-z500_anom-5524800.thumb.png.701bdde05222206b3da6209f5184ad36.pngPPVO89.thumb.gif.900081876b84e569b340e343ecc8e663.gif162105395_maxsun.thumb.png.835b59d67f7d2b388972046ec39e70f3.png

Edited by knocker

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Posted (edited)

According to the gfs the amplification of the subtropical zones is very transient and by midday Monday a trough has broken away from the lobe over NE Canada and a low is forming in mid Atlantic.

gfs-natl_wide-z500_anom-5611200.thumb.png.6883b850af8937a5b53eca9a02440434.png132.thumb.png.f81b1b11fd215ec13dd059cd345ef2aa.png

It tracks east and merges with our in situ trough and then intensifies as it traverses the UK Tues/Weds courtesy of the jet

gfs-natl_wide-z250_speed-5740800.thumb.png.e7c64793c672f538a2980d47ddb507e6.png156.thumb.png.6f01364aa8e7747801b11f23609b1b0a.png180.thumb.png.49fcf8b08f5e9828b352aca6462b0510.png

The ecm wanted nothing to do with this last evening so it will be interesting to see what it comes up with later

 

Edited by knocker

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No big surprise that the ecm still does not develop the low next week although it does bring a front across the country on Tuesday associated with the disturbance

132.thumb.png.460bbf60de60eb3e20510cafec59c4c2.png156.thumb.png.fc59efd5b6a15d3af9cb754d906e7926.png

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Posted (edited)

As a result of the GFS going mad with another low in a weeks time, the rainfall plot for the next 10 days looks a bit scary:

image.thumb.png.486977b09eb44dc26908ffdf859befcd.png

4-7 inches of rain in the next 10 days across a large area, with only East Anglia and the SE being spared the worst. Places like Whaley Bridge under real threat again. Thankfully none of the other models develop the low in this way yet, so it's not likely at this stage. More worryingly though, it's not an isolated wet outlier, with a number of big spikes on this day:

image.thumb.png.65325ceacf150cb9c4974a35f7cc89cd.png

One to watch. We could get slammed with soaking rain and gale force winds twice in a week.

Edited by mb018538

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The EPS 5-10 mean anomaly pretty much as expected although with some adjustments to the troughs in the east with one now positively tilted through Iceland so although still still a suggestion of two flows a more consolidate upper westerly flow  Ergo unsettled with temps below average

5-10.thumb.png.db318370acbfe8fbfb8843ce88df9681.pngindex.thumb.png.8c32380514fd888d35477644e06aecb9.png

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Well, certainly not the most encouraging of 00Z ensembles I've ever seen...But, it is only one run from one model...

t850London.png   prmslLondon.png

t2mLondon.png   prcpLondon.png

At least the constant humidity'll be on its way out?:oldgrin:

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If the 06Z ensembles are anything to go by, FI starts at Day 6! Very mixed signals methinks?:unknw:

t850London.png   prmslLondon.png

t2mLondon.png   prcpLondon.png

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Gale force winds over the Channel and Southern coastal areas Friday.

212376989_viewimage(19).thumb.png.db01c14a53fe22ab469a651993e2688f.png

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Posted (edited)
On 05/08/2019 at 20:49, Gael_Force said:

Remember it well: was sent to report on the rescues. If I'm allowed to stray for a moment, a bit of archive coverage.

https://www.yachtingworld.com/features/fastnet-race-1979-storm-122408

archivesuk-1979-8-14-0-0.png

 

The French model has central pressure of 979mb...usually considered good for those type of lows arriving from SW. At least, this time plenty of advance warning to wisely cancel events.

arpegeuk-2-54-0_rbj9.png

Edited by Gael_Force

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I'm watching it with interest, Friday its Padstow to Tewkesbury & Saturday we are heading back to Hadfield. I'm pulling a medium size trailer but would imagine pulling a caravan would be an experience to forget.

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GFS is pretty poor next week, while Tuesdays low is weaker and crosses further south the next weekend features a double low with fronts passing Friday and Sunday.

The Euro this morning is not quite as bad with signs that the Azores is throwing a transient ridge instead at the end but cool and showery beforegand.

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Posted (edited)

The gfs has toned down next week's low a tad but still running with the breakaway trough, merging with the one in situ, and an active surface low

gfs-natl_wide-z500_anom-5611200.thumb.png.3267562cc6d9c67c4d3bfd8803d165b9.pnggfs-natl_wide-z500_anom-5665200.thumb.png.584d0f76d18a0d2fdc4b481a1bb3bbfd.pnggfs-natl_wide-z500_anom-5730000.thumb.png.ea3eff1cc8a4ec356d38dba32522a4de.png120.thumb.png.d471326e5056ffc6a31f42eec1f9e36e.png156.thumb.png.ecdfe9e14d1d097803f98dc9e5916678.png

Edited by knocker

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Usually find the aperge over does windspeeds  and I expect it may be doing the same on this run  gusts mid 50mph  approaching 60 over central and eastern parts Saturday    hopefully way out 

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Little change with the gfs 5-10 mean anomaly with the trough conduit running south of the Labrador Strait high cell across the Atlantic

gfs-nhemi-z500_anom_5day-6043200.thumb.png.e7739b65debeaf89a303fbc4c976993c.pnggfs-nhemi-z250_speed-5870400.thumb.png.9d0b682db920fa80c4b3e9aa3f663e4b.png

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Posted (edited)

A little later but the Low is still showing on the 12z, Not as deep but with heavy rain over Central UK and gale force winds as it exits the N/E on Thursday.

viewimage (20).png

viewimage (21).png

Edited by Polar Maritime

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Another eminently forgettable set of 12z runs - Greenland high remaining, and as @knocker has highlighted from the 500mb plots above, simply serves to condense the jet stream and storm track off the eastern seaboard in a nice straight line into the UK. Low after low. Let’s hope the multiple tropical disturbances on the Pacific side of the N Hem will buckle the jet and send a ripple downstream to change our pattern in a couple of weeks.

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8 hours ago, Ed Stone said:

Well, certainly not the most encouraging of 00Z ensembles I've ever seen...But, it is only one run from one model...

t850London.png   prmslLondon.png

t2mLondon.png   prcpLondon.png

At least the constant humidity'll be on its way out?:oldgrin:

That would be a blessing, its been quite unusual this summer has it not to have had such a high number of humid days. Current models show a much more autumnal feel even if temps are a bit higher, not often do we have a succession of lows modeled to hit us. 

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12 minutes ago, pinball wizard said:

That would be a blessing, its been quite unusual this summer has it not to have had such a high number of humid days. Current models show a much more autumnal feel even if temps are a bit higher, not often do we have a succession of lows modeled to hit us. 

It’s not that unusual - the meto did a good live stream earlier where they showed that average slp in August between 2003 (last dry and warm August) and now has had persistent Greenland blocking and -ve NAO dominating. Only 2 of the last 16 have been drier than average, so the suggestion that August has turned into a bad summer month rings true in recent times at least.

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I think tonight's GEFS 12Z ensembles give the term 'deterministic chaos' a whole new meaning?:oldgrin:

t850London.png   prmslLondon.png

t2mLondon.png   prcpLondon.png

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The ecm tracks another system across the south midday Tuesday before the main low later on Wednesday. Obviously there is a fair bit of mileage to negotiate before the detail next week is sorted

ecmwf-natl_wide-vort500_z500-5697600.thumb.png.83e7cf95c61d541bfa2aaed1336f6e00.pngecmwf-natl_wide-vort500_z500-5805600.thumb.png.7b93184a14e47dadea6f3fafe44907b1.png

 

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Good Evening! Perhaps a dusting  of snow for the likes of Ben Nevin etc  

ecmt850.120.png

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