Archives For wind

A very deep depression (936mb) to the south of Iceland is whipping up 60 mph+ westerly winds in the Mid-Atlantic. Fronts with rain attached to this LOW pressure will rapidly cross the country overnight tonight and should clear Reigate tomorrow morning leaving a bright showery day. The winds in Reigate will be blustery with maximum gusts reaching over 40 mph tonight and calming down to ~20 mph Sunday, but do spare a thought for ships in the Atlantic where waves could exceed 40 feet (13 metres on map) in height in sustained violent storm force winds (Force 11).

An unusual winter pressure pattern is building in the early part of next week: a HIGH over Spain and NW Africa and deep LOWS over the Atlantic to the NW of the UK will combine to create what some meteorologists call the “blowtorch”. The relative position of HIGH and LOW pressure will funnel Tropical air from the Azores direct to Reigate possibly raising temperatures to 12°C on Tuesday (the big map shows temps for today, Saturday). This effect is sometimes called the “BLOWTORCH” (or hairdryer) because it can bring unseasonably high temperatures and melt snow rapidly across NW Europe (this blowtorch could reach as far as Russia where snowfall has been extreme). Reigate snow will be long gone by Tuesday but the warming effect could still be marked and a big contrast to a week ago when Tuesday temperatures fell to -6°C. Don’t break out the flip-flops just yet! Unfortunately, the blowtorch is unlikely to last more than a day or two at most and, in any case, it will be accompanied by rain and wind which might make it feel fairly unremarkable! Watch the video clip below which shows temperatures rising across the continent and the cold being beaten back as BLOWTORCH blasts through Europe!

A snap-shot of weather today reveals how diverse and extreme and fascinating our European weather actually is! The east – west split is obvious: freezing temperatures on the continent with everywhere east of Germany below freezing. To the west we are bathed in warm balmy Atlantic air which is over 10°C. Northern Italy is enjoying almost spring-like weather in the Po Basin, possibly due to air sinking and warming from the Alps.

Meanwhile, Iceland is due to be hammered by hurricane force winds over 76mph (>34m/s)with an intensifying LOW pressure bringing extremely high winds to the NW of the country on Saturday. This LOW pressure will have a central pressure of 942mb: which is extraordinarily low.  Winds blow from HIGH to LOW pressure (albeit deflected to the right by the coriolis force – more later on this).  The bigger the difference between HIGH and LOW pressure, the higher the winds.  See the weather map below and spot the isobars placed close together over NW Iceland: this indicates ferocious Force 12 winds.  The UK will be breezy, located on the edge of this LOW, but no where near as windy as Iceland, fortunately. Heads-up for a “heat-wave” in the UK next week :-)!!

intensifying LOW near Iceland

A text book depression / low pressure system approaching the UK from the west might signal the beginning of the end for this long run of bad weather. It’s a big low pressure system tracking NW rather slowly and will take all weekend to clear off but most of the rain will fall in the west and not much will reach Reigate. The warm front is due to pass over Reigate around midday on Friday bringing some brisk SW winds and cloud and some light rain. The “warm sector” following the warm front comprises an air mass called “Tropical Maritime”, bringing balmy +10°C temperatures to Reigate over night Friday through to Saturday morning. The cold front is due to pass over Reigate after lunch on Saturday when temperatures will drop by several degrees to 3°C overnight . Despite the slow movement of the depression as a whole, winds will be pretty strong especially as the cold front passes. The cold front will bring gusty winds, possibly up to 50mph on Saturday morning, and heavier showers on a cooler NW wind. The air mass following a cold front is called “polar martime” and will feel significantly cooler in the wind, even in sheltered Reigate.
There are signs that a HIGH pressure will build up over the south of the UK by the new year week bringing drier weather, at last! The ensemble forecast below shows a drier spell to start off 2013. An ensemble forecast is one which combines several computer weather forecasting model “runs” and sees how well they match.  The closer the match, the more confident the forecast and more probability that it will be correct.  Each “model run” is “perturbed” which means tiny differences in starting data are used to simulate the error and vagaries of real chaotic weather systems.

27-12-2012 22-58-26 dry spell in january

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.

The predicted change in weather has arrived. This was predicted 10 days ago by the models and is arriving exactly on time!
Torrential rain and strong winds are predicted to pass through during Friday. Winds gusting 40mph+ and very heavy rainfall, especially around mid-morning / lunchtime are likely for Reigate. Rainfall accumulations could top 30mm in 24 hours with half of that falling between 10am and 1pm Friday.
The milder air from the South West has arrived already in our area but is still hovering aloft over the very cold surface air. Temperatures have already moved above freezing and will continue to climb throughout tonight and right the way through tomorrow reaching a balmy 11C by Friday afternoon! Rain should clear by the early evening.  As the song goes (not)… “What a difference an air mass makes, 24 little hours!!” Apologies to Dinah Washington.

http://www.youtube.com/watch?v=OmBxVfQTuvI

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

A deep depression centered over Iceland is crossing to the North of the UK bringing windy conditions to south east through Thursday / Friday:

Wind gusts could reach a whopping 50mph overnight thursday 22 November to friday here in the South East.  Average wind speeds will be more like 20mph+.  The cold front moves through overnight and this will herald a taste of that cold wind brought down from the North – more of this next week!