Archives For easterlies


Sunday final analysis update: crossing the Channel Monday?…be warned of v cold blizzard conditions!  LOW centre set to track thru N France most likely bringing only light snow to Reigate Monday morning but increasing risk of significant accumulation later in the day and overnight into Tuesday.  Any shift further north in the fronts could bring heavy snow to S counties pm.  Latest hi-resolution NMM model (below) shows light snow showers all day but risk increasing to heavy snow pm extending into southern counties of England, reaching Reigate late pm or evening….; UKMet Office predicts the least snow of all the models.V V tricky forecast.

So: Reigate forecast for Monday-Tuesday: emphasis on bitterly COLD, snowy day with extreme wind chill for (any) time of year with a low risk of heavier snow later and overnight to Tuesday, especially for places further South. so…accumulations 0 – 10cm by Tuesday am.

sunday 06Z NMM model

Cold weather alert! Reigate should prepare for an impressive weather change this weekend into next week.  The temperature will drop like a stone over Sunday night: shown by these Reigate maximum temperatures at midday on Saturday max +11ºC, Sunday max +5ºC, Monday max -1ºC with wind chill even as low as -18ºC (yes) possible in forecast 40 mph gusts in exposed places.  Winds will average 20 mph but even this will cause wind chill of -8ºC.  It will feel cold on Monday!  Light snowfall could start Sunday pm and continue overnight through to Monday. It may seem odd, but this snow will be caused by warm air from the South over-riding the frigid COLD Polar air blasting in from the NE: meeting at a front.  Check the temperature height diagrams to see how this works: warm, moist air circulating around the LOW in the Channel will be undercut by the dense freezing cold polar air from NE. The warm air forced to rise causes cooling, condensation, cloud formation and, as upper air temperatures are so cold… SNOW is likely to fall. Possible accumulations Sunday – Monday around Reigate could be 0-3cm (higher figures on hills) and more possible to the south of the region where precipitation could be more intense nearer the fronts.  So…positioning of the LOW is critical.  The snow maps give an idea of potential snow areas in the south on Monday.  There could be light snow showers on and off in Reigate and another moderate fall is possible Monday pm as the LOW tracks nearer to the south east of our region.  It will feel cold in strong gusts from the East: wind chills down to an outrageous -18ºC are theoretically possible if you are caught in strong easterly gusts with air temps below 0ºC all day. Temperatures will actually fall through the day on Monday as the Polar air takes a grip.  Lowest temperatures all winter are possible overnight Monday-Tuesday. Hopefully, this weather change will not take anyone by surprise: it has been on the cards for over a week and flagged up here on 2 March. The rest of the week will remain cold, but feel less cold in light winds, and drier with pressure building from the north, but more snow might precede rain later in the week as things warm a little next weekend.  More updates later as details emerge for Monday which is still v changeable!


This week for Reigate: dry and increasingly cold!  Watch the video which shows cold air (at 1500 metres) flooding in from the east.

Wind direction is so important in controlling our winter and early spring weather: many of the “source regions” (where our winds originate from) are at their most extreme at this time of year: the continental interiors, for example, are at their coldest and driest in late winter, so any air mass coming from the continent will be very cold indeed, despite Spring being just round the corner.  These cold and dry easterly winds contrast with our usual warm and wet SW Tropical winds that arrive from the Atlantic.  This week it is the turn of Easterly winds and HIGH pressure to dominate our weather: this means cold and dry.
UK unusual dry patchThe HIGH to the north east and the LOW to the south is a perfect set-up for dry and icy Easterly winds to flood across the South East, arriving from a very cold Russia on Tuesday and strengthening through to the weekend.  It should stay dry with a low risk of snow flurries reaching Reigate.   Actual max temperatures will be +1 or 2°C during the day but the 15 mph wind will make it feel very chilly at -3°C in the daytime and, during the night, as low as -8°C wind chill.  Cloud cover will control how low air temperatures actually fall at night: clear skies could see temperatures drop to -4°C with frosty mornings.  Want to warm up?  Get to Reykjavik in Iceland which will be the warmest city in Northern Europe this week with unseasonably high temperatures of +8°C with a “warm” and wet southerly Tropical wind.  Next week looks warmer and staying dry for Reigate with temperatures up to 10°C. An early taste of Spring perhaps?

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The “Russian ice bear” is escaping again and will arrive in Reigate from Tuesday!  A HIGH pressure developing over Scandinavia and a LOW over Europe will open the cage and let the Russian ice bear gallop across Northern Europe and arrive freezing and growling in the UK from mid-week.  Expect cold easterly winds on the back of the bear.  The frigid continental interior, where the bear lives, has had the whole winter to cool down: the source region is now -10ºC and frequently lower. (View the Urals meteorite shower youtube clips again to get an idea of how cold the source region of this air mass is!) There is the potential for some of the coldest temperatures of this winter yet to be recorded in the SE as the bear bites back.  The week looks mostly dry but snow showers are also possible, especially further east.  The easterly winds warm up on their journey west and also pick up some moisture from the Baltic and comparatively warm North Sea; any warming causes instability (a tendency for air to rise and form cloud and rain/snow) and snow showers are therefore possible on the east coast, some of these could reach further inland on the strong easterly winds forecast.  Whilst the duration of this cold snap is not certain, the end of this sort of episode often sees westerly winds return with substantial snow on the leading edge of fronts.  How and when the bear returns to it’s cage remains uncertain,  but it will be prowling around Reigate from Wednesday on wards this week.

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Thursday update: situation on Sunday – Tuesday is mostly GRIM, wet, miserable and cold but details are still uncertain regarding snowy-ness here in Reigate: could be lots or just sleet and rain mix.  Snow up north definitely but SMALL changes in location and speed of LOW centre and wind direction will make a BIG difference to what weather we get in Reigate. Stay tuned for latest! (nb re-reading my post here: “mild” means “relatively mild” at Tmax 4°C Sunday, Monday “cooler” means Tmax 2°C: so cold, wet and miserable right through from Sunday am!)

The Arctic wind built threatening, angry stratocumulus clouds over Reigate early today (pictured) and some built into perky sleet showers by the end of the day.  The rest of this week should be brighter, clearer, frosty and less windy but sadly no sign of Spring yet – models show cool conditions continuing next week. Light snow is possible in Reigate on a decaying occluded front over Thursday night.  The Arctic wind will shut down in the next few days as a HIGH pressure builds from the SW.  Significant snow is a possibility in the first part of next week anytime from Sunday night through to Tuesday for Reigate and SE England as winds swing Easterly associated with a trough slipping SE. It’s tricky to forecast whether it will be snow, sleet or rain and where exactly it will fall at this stage but ,despite this vague detail, models do agree that a SLIDER LOW will move down from the NW and bring, initially warmer southerlies and rain on Sunday, but then drag in some cool Easterlies which could cause a spell of snow, possibly for the rush hour on Monday.  Early next week will be cold and snow / sleet showers threaten anytime. It’s a tricky forecast because the temperature of these Easterly winds is now creeping up as Spring approaches and surface temperatures will hover at the upper threshold of snowfall (2° or 3°C) so that it could easily fall as sleet or rain. Places further east and higher up on the Downs are more likely to get snow rather than sleet: it is that close. Follow 1-10 on the slides to check the causes of this potential snowy event: it is quite different from our Skyfall last month.