Archives For Reigate weather

 

FRIDAY SNOW LATEST as of 12:40pm Thursday: SNOW STARTING EARLIER BUT STAYING LIGHT!

Light snow starting in Reigate around 9 or 10am.  Mostly light snow for the rest of the day (Friday <5cm lying snow), but possibly heavier later afternoon & evening.  Snow showers on Saturday & Sunday and snow possible Monday & Tuesday with a new LOW developing out west.  Temperatures staying low all weekend: at or significantly below freezing throughout: windchill -8°C Friday lunchtime for Reigate.

Predicting the onset of snowfall (or rain) several days ahead is often the least accurate part of weather forecasting. Predicting temperature, wind speed and direction are usually considerably more accurate. The UKMO (UK Met Office) achieve around 70% accuracy for their 3 hourly precipitation forecasts for the current day and over 90% accuracy for temperature forecasts. Pin-pointing exactly WHAT TIME it is going to rain or snow in a particular location several days ahead stretches even the most powerful supercomputers and taxes forecasters. For example… here is a medley of current predictions for snow in Reigate: (no longer a valid forecast but interesting nevertheless!)…

Friday snow starts in Reigate:

Meteogroup = 9am; BBC=11am; UKMO = 12:00pm; GFS = 12:00pm.

Saturday snowfall rate in Reigate:

UKMO = Light snow all day; BBC & GFS = Light snow all day; Meteogroup = none after 6am!

Variations in temperature predictions are less marked but on Sunday there are significant disagreements: the lowest minimum is down to -9°C on Sunday night whilst other models place minimums at -3°C.  Thursday evening will bring the most accurate prediction for snow and models should agree more by then. Our own forecast might go something like: Light snow starting after lunch on Friday and going overnight through to Saturday when there will be continued snow showers for most of the day. Snow accumulation: 3-8cm.

SEE UPDATE! Ready for winter? This weekend sees cold air pushing in from the North East but not much snow for Reigate: icy, sleety rain Saturday with maybe some snow over the hills later and possibly a dusting to lower levels over night to Sunday; but mostly the rain clears off south on Saturday before the very coldest air arrives behind it. However, the chart shows fronts tracking south across the UK from the NW on Monday afternoon through to Tuesday which could bring heavier snow to Reigate and the SE. Watch this carefully! Further ahead, several long range forecasts agree that the cold weather could stay with us for 2 or 3 weeks caused by LOW pressure holding over Central Europe and a HIGH pressure sticking to the North over Iceland blocking our usual warm westerlies and feeding COLD polar winds from the North and North East across the UK for the whole of January.

A cold snap in Reigate looks to be likely for the weekend: temperatures are due to drop from Wednesday onwards as pressure patterns shift shutting off the balmy warm Atlantic SW airflow we have had since the New Year. A HIGH pressure building to the North combined with a LOW to the South will set up north and easterly winds from the cold continent. In January this could mean snow for SE England and that includes Reigate! The jetstream is shifting to the south of the UK so we will be influenced by Polar air masses for a while. Temperatures will be around 3°C daytime and dropping to around -5°C at night, or even lower in clear skies. Any precipitation could well be sleet or snow and freezing fog is possible in light winds as well (though it actually looks quite breezy so be ready for significant wind chill too!). Not a cataclysmic (Daily Mail style) Arctic blast but a “normal” winter cold snap! There is, however, uncertainty in the models at the moment so keep watching for updates!

The colourful pressure chart above shows pressure patterns for Saturday.  The lines show mean sea level pressure (millibars) while the colours indicate pressure in the upper atmosphere at approximately 5000m (note: the colour equates to temperature but do not assume red = warm and blue = cold at the surface, this would not be correct! The blues and greens really show lower pressure at high altitude (500mb = approximately half way up through the atmosphere), while yellows and reds show higher pressure. Forecasting weather using upper atmospheric charts like this one is often used by meteorologists because they show general patterns more accurately than surface pressure charts). The map of the UK shows snow risk for Sunday 13 January.

Happy New year! 2013 dawned bright and beautiful over Reigate for January 1st 2013 as the low pressure of recent weeks gradually gives way to an anticyclone (High pressure) building from the south west which will bring calmer and drier weather for us in Reigate for a week or so, after a final shower or two tomorrow.  It may not be that sunny though: anticyclonic gloom is common in winter.  Also, check the chart below as temperatures are due to take a slide (predictably for January!) from the weekend.

London weather January 2013

satellite photo UK new years day January 2013