Archives For spring

How high can we expect temperatures to go and how Spring-like is this weekend set to be in Reigate? Find out below!

This weekend and possibly for much of March, the weather is set to be dominated by HIGH pressure nearby to the south and low pressure to the NW which will bring in mild southerly or SW winds for Reigate.  Cooler and cloudy easterly wind directions are also possible later next week if the high pressure slips NE to Scandinavia which models are suggesting.  Whilst this weekend is expected to be pleasantly mild and spring-like and initially sunny on Saturday, temperatures are not going to break any Spring records because cloud cover is gradually going to spill from the north on a weakening cold front.

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synoptic chart Fri 6 March

The synoptic chart above shows the HIGH over the continent to the south of the UK and a deep low to the NW between Iceland and Greenland.  This is dragging in, with the help of a lively SW jetstream, a SW moist airflow over Scotland.  In fact NW Scotland has an amber warning for huge rainfall totals above 140mm over the next few days assoicated with the stalled cold front that will sit near or over Scotland for much of the time.  Warm air flow ahead of this cold front is advecting large amounts of moisture in a plume over the mountains which is causing the high totals over the NW. The charts below show the unsettled NW compared to the calm, mild and dry SE of the UK under the influence of the HIGH pressure.

The charts below show the story for this weekend.  Initially a dry airmass sits over the SE on Saturday morning but this is gradually replaced as cloudy conditions slip SE.  Temperatures through the weekend are looking mild, with Tmax 15C possible on Saturday, but anything higher is less likely on Sunday as cloud further thickens with the arrival of a weak cold front.  Saturday is probably the most pleasant day with brighter sunnier conditions especially in the morning.  The cold front in Scotland slowly migrates SE during the weekend but weakens as it does so.  By the time it reaches the SE on Sunday evening it is probably only going to bring low cloud and some drizzle.  Throughout the weekend wind in the SE is set to be light, especially on Sunday.  Misty conditions might occur overnight into Sunday and later Sunday evening in light winds.

Next week is looking generally mild and with HIGH pressure not far away to the south mostly dry.  A couple of LOW pressure systems are forecast to pass across the NW of the country and their trailing fronts will be weak in the SE but could bring cloud and some light rain.

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LOW passes to the NW on Monday

Overall the high pressure looks set to dominate Europe during next week bringing dry and warmer than normal conditions.

The GFS and ECM both suggest that the HIGH could slip over Scandinavia by the end of the week, as the chart below suggests.  This would introduce cooler easterly winds to the UK but nothing too icy at this time of year, it would also remain mostly dry. Unfortunately, easterly winds are often cloudy as they pick up moisture from the North Sea that creates days of anticyclonic gloom under an inversion.

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Scandinavian HIGH… would bring dry, cool but gloomy March weather

The charts below summarise the weather outlook: high pressure domintating bringing mostly dry and mild conditions.  Nights next week could turn colder with possible frost returning.  The longer range models suggest March could turn out to be a very dry month especially in the south.

BBC summary

http://www.bbc.co.uk/weather/feeds/31774369?ns_mchannel=social&ns_campaign=bbc_weather&ns_source=twitter&ns_linkname=news_central

 

Update Friday: v unstable atmosphere passing over Reigate Friday after active warm front passes early morning: all ingredients for heavy showers and thunderstorms tomorrow increased risk hail thunder for Reigate, predicted earlier in the week @RGSweather.

Spring warmth is set to arrive big time this weekend, especially from Sunday on wards and particularly in the east of the UK: Reigate could be one of the warmest places so let’s keep our fingers crossed!  The contrast with just a week ago is remarkable with temperatures for Reigate possibly rising to over 20ºC on Sunday and remaining well in the ‘teens during the daytime throughout next week.  There will be a breeze of 15 mph so find a sheltered spot to enjoy the balmy atmosphere or take to the hills with a kite, go sailing, have a BBQ… #getoutside

The initial cause of this long awaited warming is LOW pressure in the Atlantic engaging with a HIGH pressure over Europe which will feed a brisk southerly wind from source regions in North Africa and the Mediterranean.  An upper level ridge building from the south is also critical in feeding warm air aloft (above 5000 m) to the UK.  The jet stream is migrating northwards and helping to feed in this warm upper airmass.  Upper air temperatures at 5000 feet (pic 1 above) are set to rise dramatically from well below freezing last week to +12°C or more through next week: Tropical air has arrived!  The rest of next week looks good with warm and mostly dry weather (but not always) continuing for Reigate and, whilst not always as warm as Sunday, certainly feeling pleasantly springy.  The synoptic configuration is set to remain HIGH pressure in the South and LOW in the North with a warm flow of SW or W winds over Reigate.

However, before all that, Reigate could have some significant rain: while overnight rain should dry up quickly Thursday morning after the front moves North, Friday looks potentially showery and some could be heavy.  April showers are kicked off by heat at the surface causing thermals to rise buoyantly through the atmosphere and condense creating convective clouds called cumulus.  If these grow into shower clouds they are called cumulus congestus or their bigger brother cumulonimbus.  Several of the right conditions for heavy showers are present on Friday such as uplifting air, plenty of humidity and wind shear.  Due to the cold weather thus far, there is currently a lack of heating at the surface to spark off significant thunderstorms but things can change.  Saturday could also have some showers associated with a weak warm front before the much heralded warm and dry weather arrives on Sunday.  Saturday warm front turned out much more perky than first thought… delivered lots of rain all pm! Keep posted on twitter @RGSweather for updates.


Some charts for next week show the Polar LOW which is heading our way for this weekend sitting on top of the UK and a HIGH building to the NORTH. This could drag in cool easterlies for some parts of the country again and keep Spring locked out. Look carefully at the chart which shows upper air pressure and temperatures at 500hpa: around 5000m (half way up through the atmosphere: a good place to predict air flows without the disruption of annoying surface features which complicate things).  It shows Russia warming up and Greenland distinctly spring-like but the UK stuck in a pool of cold air from N Scandinavia.  Details are not certain but don’t break open the beach-wear and bbqs just yet, looks like the Kangaroo Spring is set to continue with a hop back to winter yet again next week.


Has the sun set on the first and last day of Spring?!  Spring will return but certainly not for a while.  The rest of this week will be rather wet but mild. An octopus-like LOW sitting out west in the Atlantic will sweep several tentacle-like fronts across the country (count them = 8) and this will bring frequent, mostly light rain to Reigate, heavier rain does threaten on Thursday: check back for details. The big news is the temperature drop between Saturday (+11C) and Sunday (+2C!): this temperature plunge will feel bracing after our all-too brief flirt with Spring and the mild conditions this week. Over the weekend the LOW looks like it will track south of the UK and drag in amazingly chilly air from a BLOCKING HIGH developing over Scandinavia to the NE.  The HIGH will force the LOW to the south and east of the UK and we will pick up a NE / E air flow.  This air flow could stick around for much of next week.  By Tuesday things could be really cold in the upper atmosphere (1500m= -14C!). Down here in Reigate things will return to a wintry feel with hard frosts, cold temperatures around freezing and possible snow now and again. If the coldest upper air temps reach us then heavier snow from the E and NE is a possibility.  Tricky to tell this far out.  Brace yourselves and keep watching for updates!