Good morning. Here is the report on the 12 midnight outputs from GFS, UKMO, GEM, NAVGEM and ECM for today Saturday October 26th 2013.
All models show an unsettled and breezy weekend with a steady deterioration in conditions as the weekend evolves. A Brisk showery SW flow over Western and Northern Britain will weaken overnight as winds decrease. A window of drier weather tomorrow will be superseded by a trough of low pressure crossing ESE across the UK with a band of heavy rain and squally winds crossing the UK tomorrow afternoon and night. Following that a very strong WSW showery flow will affect the UK through Sunday with gales in the North and West and showers heavy with hail and thunder in places.
THE STORM SYSTEM GFS takes the storm across Wales and the Midlands at a pressure of 975mbs falling to 970mbs as it exits Eastern England. All of Southern Britain would be affected by winds with gusts to 70mph + in exposed locations and near Bristol Channel and English Channel Coasts.
UKMO has the low a little more south tonight tracking into the Bristol channel at 980mbs in the early hours of Monday morning and exiting the east Coast at 970mbs with the strongest 70mph+ winds affecting SW and all of Southern England with the strongest gusts near the South and Bristol Channel coasts worst of all.
GEM has the Low entering SW England at 975mbs in the early hours of Monday and exiting the East Norfolk coast at 960mbs with the strongest winds here over all of Southern England and South Wales with gusts to 80mph with exposure. Some structural damage would be likely.
NAVGEM shows the Low more vigorous with it's centre sub 980mbs in the Bristol Channel on Monday morning and down to below 970mbs as it leaves the East Anglian coast. Southernmost Britain bordering the English Channel coasts would experience the strongest winds with storm force gusts to 70-80mph for a time through Monday.
ECM shows the Low crossing Wales at 975mbs on Monday morning and on ENE into the North Sea on Monday afternoon at sub 970mbs with severe gales or storm force winds buffeting the South of England and South Wales for a time through the day.
Following the storm GFS settles things down quite quickly as pressure rises rapidly from the West and a ridge crosses the UK midweek. This holds for a day or two across Southern Britain while the North and West quickly become influenced by a strong SW flow with rain at times. Things would turn milder again for many. Thereafter strong winds and rain are a regular feature shown as deep Low pressures continue to cross just to the North of the UK with bands of rain alternating with squally showers in temperatures turning rather chillier with time. Late in the run High pressure replaces Low pressure from off the Atlantic with frost and persistent fog becoming the problem by the end of the run.
UKMO shows pressure relatively High over the South from midweek but with a mild, moist and quite strong Westerly flow thick cloud and rain and drizzle is likely with the North seeing some heavier rain at times.
GEM has a quieter spell midweek with some dry weather in the South. However as the run progresses it quickly become very unsettled again with deep low pressure areas crossing East over or to the North of the UK with strong Westerly winds bringing bands of rain alternating with squally showers across all areas. As winds turn more to the NW late in the run it would turn rather colder later.
NAVGEM shows pressure building to the South of the UK warding off the worst of Low pressure further North to principally continue to affect the North of the UK. This would have the affect of restricting the amounts of rain reaching the South for a time midweek before all areas return to windy and unsettled weather late in the run as Low pressure digs down deeper into Britain next weekend.
ECM this morning shows a continued changeable and sometimes windy theme as winds remain Westerly. Pressure does build midweek across the South with a calmer spell here before all areas become prone to an active Atlantic Low pressure area up to the North of the UK with troughs bringing bands of rain and showers for all in a strong to gale force Westerly flow. The end of the run shows changeable weather continuing with Low pressure remaining close by and it may become somewhat colder by Day 10.
The GFS Ensembles do maintain an unsettled and changeable picture with rain at times and winds blowing strongly at times too. Temperatures are likely to remain quite close to average overall but there is a lot of spread between the members later, both warm and cold of the average as successive periods of alternating warm maritime and colder air masses cross the UK.
The Jet Stream continues to look like blowing strongly across the Atlantic and across the UK for the reliable future. It will fluctuate North and South of this general position at times in response to deep Low pressure areas approaching and moving away, most of which cross East over or to the North of the UK.
In Summary the storm system on Monday is the main talking point and there is some firming up on the path of the storm. It looks like it will cross from Pembrokeshire across Wales and the Midlands then out into the North sea near the Humber. It depth looks like being between 965mbs to 980mbs making it a powerful storm on Southern britain standards so some structural damage is likely along with traffic chaos on Monday morning. Once passed the weather quickly calms to a more standard Autumn pattern of Low pressure to the North and higher pressure to the South giving these areas at least a window of drier weather in the middle of next week. In the longer term conditions look like remaining or becoming changeable for all with rain and wind at times and temperatures never far from average but the North may see some colder incursions later and these may extend a little further South at times.
Edited by user
26 October 2013 09:49:31
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Reason: Not specified
Martin G
Kilmersdon Radstock Bath Somerset