Archives For strong winds

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!

Winds in the North Sea exceeded 60 mph today, creating waves over 30 feet high. On the Beaufort Scale winds topped out at violent storm force 11. The strongest winds preceeded a frontal system attached to the same LOW pressure which brought the heavy rain to the UK yesterday.  Every region of the country has flood alerts and almost every sea area surrounding the UK has been issued with gale warnings. 

With serious flooding elsewhere in the UK it seems that Reigate and the South East fortunately escaped any serious problems from this storm. The River Mole has burst its banks but this seems rather trivial in comparison! The low pressure and unsettled conditions are set to continue.

dec 23 storm force gales in north sea

Wind speeds measured today, Saturday 22 December, at 8am on the Greenwich Lightship (in the middle of the English Channel) topped 40mph (Force8) and are increasing as the low passes over to the north. In contrast, wind speeds in Reigate remain at a 10 minute maximum average of 13mph. Wind speeds are usually higher out at sea because there is less friction at the surface (fewer hills, trees etc) to slow it down. The map shows NOAA data buoys located all over the world and used by meteorologists to forecast weather.  The graph is for the Greenwich Lightship this morning: note the big wind increase since the “calm before the storm” at 20:00 GMT.

Most agree that this cold snap-ette will be beaten back by a return to a more “normal” run of LOW pressure systems from the Atlantic with attendant milder, windier and wetter conditions from the end of the week. Some models show low pressure systems dominating UK weather for weeks to come and maybe all the way up to Christmas. Low pressure usually means mild, wet and windy. The temperature chart (called an 850hPa ensemble showing atmospheric temperatures at 1500m) shows a collection of temperature predictions from the Global Forecast System which spread out towards Christmas showing increasing uncertainty but overall warmer than right now.

Highest wind gust = 41mph at 4am Sunday morning.

An unusual weather pattern exists right now: High pressure in the Atlantic is stopping our normal south/westerly winds and allowing cool north and north westerlies to dominate.  Once the rain on Monday shifts from the South East, Tuesday will be our best day – especially out west where a ridge of high pressure briefly flirts with the UK.  After that an ugly low pressure system swoops down from Iceland and the Low will centre over NW Scotland.  Strong winds and heavy rain will affect much of the country, especially the western half.

However, a tricky beast of a storm (a wave depression) might rapidly develop to the SW of the UK and rip across the south rather quickly sometime around Friday / Saturday.  Look at the jetstream chart below for next Saturday and see how the jetstream really picks up over the South during this time, dragging the storm along on the surface, like an unruly dog on a lead! This “dog” has a pretty big bark and a big bite and could deliver a deluge of rain and strong gales over the south.  Let’s wait and see: some bonfire nights might be wet and windy.