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Posts posted by knocker

  1. The NH 500mb profile and the North Atlantic surface analysis for midnight


    Once early morning stratus/mist has cleared the east coast it should be a sunny and warm day in the light airs for N.Ireland, Wales and England with just a slight risk of an isolated shower. A tad cooler along the coasts as sea breezes kick in.  Not so Scotland where currently there is some persistent rain across the north east, courtesy of the occlusion, but this should cease as the front drifts away. But only to be replaced by the development of heavy, and perhaps thundery, showers through the day which will spread down through central and southern areas, They could well coalesce along the trough. The temp variation reflects all of this


    The showers will eventually die out this evening leaving a clear night for all with the odd fog patch by morning. But some rain will sneak into the north of Scotland again by morning as the occlusion moves a tad south.


    Apart from some brief showery rain across N. Ireland and northern England for a time in the morning it will be another warm and sunny day in most places on Wednesday with the usual caveats. But the front will continue to bring persistent rain to northern Scotland throughout the day


    Over Wednesday night and into Thursday the slow change is underway that has been mentioned in previous posts and the troughs to the NE and in the Atlantic are taking closer order. At the moment this just results in an occlusion edging in to Ireland and the south west which  will bring patchy rain to western regions through Thursday, Elsewhere still dry and quite warm



    The waving, and weakening, occlusion tracks slowly across the country on Friday thus a sunshine and showers day. But another frontal system is approaching west of Ireland


    Much of the country will be dry with the odd shower as the occlusion is still hanging about, but during the day more cloud and patchy rain will arrive in the west and south,courtesy of the warm front which is part of the elongated trough across the Atlantic.



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  2. The ext EPS has been reasonable consistent over the last three days with the pattern and has in fact 'sharpened' it up a tad which is not totally surprising. The main players upstream are the trough/ridge in the SW/SE united States and the vortex lobe in the Hudson Bay area. This combination results in a strong westerly upper flow exiting the north east seaboard under the continuing Greenland ridge to the now established trough over the UK. This would portend unsettled weather, perhaps trending towards a N/S split, and temps a tad below average.


    NOAA is in the same ball park


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  3. The ecm has the waving front bringing rain to N. Ireland and western Scotland by midday Saturday This tracks east, mainly north of a line north Wales > Wash, and clears into the north Sea by midday Sunday. The cold front following on will clear the south east by same time leaving a residue of showers. By midday Monday another front is bringing rain to western regions,


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  4. The weather for the holiday weekend has been exercising a few minds of late and I'm not sure we are any nearer pinning down the detail this morning. Essentially it's all about the movement of the Atlantic trough and the associated surface features.


    So according to the gfs Saturday is a day of sunshine and showers with a warm front bringing rain to N. Ireland western Scotland by evening. The front will track east overnight and through Sunday bringing rain and quite strong winds to most areas. This will clear on Monday but there is now a shallow low over the north so a showery and quite windy day. But to reiterate, this is a very long way from being set in stone

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  5. The NH 500mb profile and the North Atlantic surface analysis for midnight


    The mist/Stratus along eastern coastal regions may be slow to clear this morning but elsewhere in England and Wales any patches will clear quite quickly.  Here a sunny day will develop with the odd shower popping up but the showery rain currently effecting N. Ireland and northern Scotland will continue through the morning and during the afternoon heavier outbursts, accompanied by thunder will effect NE Scotland, courtesy of the trough lying down that region. Simultaneously outbreaks may occur along the convergence zone down eastern England.Thus quite a temp spread NW/SE


    The trough hangs around northern Scotland through the evening and overnight and the showers may well coalesce to give longer periods of rain. Further south they will die out to give a clear night with the odd fog patch forming by morning.


    Tomorrow a weak 'tongue' of high pressure resides over the country and once the early fog/mist has cleared a fine sunny day will ensue in many areas and getting quite warm in the south east. But the trough is still around over Scotland and quite frequent and heavy thundery showers will develop here during the day.


    The tongue still happily ensconced on Wednesday and apart from the odd shower still in the north east early on as the trough is reluctant to depart, a generally warm and sunny day


    By Thursday the change that has been covered in previous posts is underway and a waving front encroaching from the west will bring rain to western regions whilst elsewhere will remain sunny and quite pleasant



    By Friday the occlusion has stalled over western regions and there are complications involving the trough to the north east so mixed bag sort of day with with sunny intervals and showers, perhaps heavy with thunder in the mix, and even longer periods of rain.



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  6. Satellites yield insight into not so permanent permafrost


    17 May 2019

    Ice is without doubt one of the first casualties of climate change, but the effects of our warming world are not only limited to ice melting on Earth’s surface. Ground that has been frozen for thousands of years is also thawing, adding to the climate crisis and causing immediate problems for local communities.

    In Earth’s cold regions, much of the sub-surface ground is frozen. Permafrost is frozen soil, rock or sediment – sometimes hundreds of metres thick. To be classified as permafrost, the ground has to have been frozen for at least two years, but much of the sub-surface ground in the polar regions has remained frozen since the last ice age.

    Permafrost holds carbon-based remains of vegetation and animals that froze before decomposition could set in. Scientists estimate that the world’s permafrost holds almost double the amount of carbon than is currently in the atmosphere.


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  7. The ecm interpretation for the weekend is not as bad as the gfs and after a sunshine and showers day Saturday with a west/east temp variation, with above average over the latter the frontal rain will track east overnight and through Sunday,


    And the 5-10 anomaly  which pretty much fits with last night's. Not a brilliant outlook


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  8. To continue with the gfs. The front clears by Friday  which will be a day of showers, but by midday Saturday the next front and the developing area of low pressure to the north west  has brought rain to Ireland  The low and associated fronts all track east through the next two days resulting in sunny intervals and showers interspersed with longer periods of rain. The detail for the weekend is a long way from being finalised



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  9. The NH 500mb profile and the North Atlantic surface analysis for midnight


    Today will start off cloudy in many areas particularly N Ireland and western coastal areas of Scotland where the occlusion is still lingering but in most areas the cloud will dissipate and as the sun gets to work, similar to yesterday, showers will pop up and could occur virtually anywhere and could well include some thunder in the mix,. Temps quite respectable but coastal areas cooler particularly in the east where low Stratus/fog could drift in from the North Sea.


    The showers will tend to dissipate in most areas overnight but still a few in the south courtesy of a trough and they will continue over Scotland where shallow lows and another occlusion are still exerting some influence


    Monday will be another day of sunshine and showers but  less so over Wales, south west and west central England during the afternoon. The usual caveat eastern coastal areas and the north of Scotland will be markedly cooler


    By Tuesday the UK is in a very slack gradient as low pressure continues to fill in the north and a weak ridge edge in from the west. So notherr sunny day with a few showers around and temps generally a tad above average. But there are developments upstream with troughs dropping into the western Atlantic which was covered in a little more detail last evening.



    Another quite pleasant day on Wednesday but some patchy rain in the north east courtesy of the occlusion straddled across the North Sea. And surface fronts associated with the developing upper troughs in the western and central Atlantic are taking closer order south west of Ireland



    Overnight Wednesday and through Thursday a wave has formed on the front to the west and is 1006mb off the west coast of Ireland at midday with the front,accompanied by strengthening winds and rain tracking, north east across the south west of the country. And this will continue through the afternoon and evening. Cooler air in the wake of the front whilst remaining quite warm elsewhere



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  10. The blocked Arctic essentially only leaves two directions of travel relevant to the UK with main one being the strong upper flow exiting the north eastern seaboard, courtesy of the complex pattern over North america, Downstream this gets modified/influenced by  the ridging of the mid Atlantic subtropical high and the trough associated with the vortex lobe north of Svalbard. Thus the upper flow veers NW portending cool and unsettled but how these two are aligned is critical


    In the ext period much less amplification (which in itself is no big surprise) and basically a fairly mundane westerly flow which would indicate changeable weather, with nothing particularly nasty lurking in the woodshed, with temps variable but a tad below average


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  11. The ecm has frontal rain into western regions by midday Thursday But by midday Friday the upper trough is pretty much neutrally tilted over the UK as the subtropical high amplifies to the west.The main surface low over France and I would imagine a very showery day for the UK. Showers and sunny intervals remain the order of the day over the weekend, with, hopefully strarting to die out by Sunday, as the ridge/trough nudge slowly east. The detail for the weekend a long way from settled



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  12. It starts to get more unsettled by the middle of next week as another trough is ejected into the western Atlantic courtesy of amplification in the eastern Pacific and the trough in the south west US. This promotes a shallow surface low and associated fronts into western regions of Britain  by midday Thursday. This turns into quite a complex area with two centres but after bringing rain on Friday and showers Saturday it should start clearing the mainland through Sunday. According to the gfs/


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