Learning To Forecast For London

[goose55]

Hey Guys, I found this board a little while ago and have been reading for a few days. I'm a meteorologist based in the United States, specifically the northeast part of the nation. I'm a total weather nut and love cold and snow especially.

I'm very intrigued by the weather in the U.K. and would like to learn more about it. This site appears to be an excellent resource for doing this. I do not want to clutter your board with useless requests so feel free to move or delete this post if it is seen as such to the moderators.

What I'm curious about is the following:

1. What kind of unique microscale phenomenon should I be aware of when forecasting for London. For example here in the U.S. a Southeast wind in New York City this time of year will mean normally mean a surge of mild marine air. Another example, along the East Coast a northeast wind ahead of a storm will cause something called cold air dammning. This often leads to computer model busts on temperatures and storm placement. Any kind of "lessons learned" from forecasting in the U.K. would be helpful.

2. Here in the U.S. we have something called MOS that is generated from the weather models. Do you have a MOS to look at for temperature guidence. I personally hate the MOS here but would be curious to see it for London since I'm fairly new to forecasting there.

3. Any links to Radar, satellite, weather models etc. I found a few links in the learning section of this board but I know the real weather weenies know where the good links are located.

Thanks for your help and again feel free to move or delete if I'm out of line with this request.

[Nick L]

I am just an amateur (if that!), all I can say is that the UK weather is very unpredictable!

The main radar is on the Met Office website (our national weather service): http://www.metoffice.gov.uk/weather/uk/radar/index.html

And I am sure you will be able to navigate yourself around that site to get the satellite images etc.

[Shirelord]

Just on your first question, London is a sprawling city, only beaten in area by New York City. However, its climate is, as you will no doubt know, maritime dominated. London is on a wide estuary in the east, not far from the continent, but suffers greatly from the urban heat island effect, raising temperatures by some degrees compared to the surrounding countryside. Essentially, sea + concrete = warm. I would say for a city of similar size to NYC the climate differences are sharp.

[SMU]

Hey Guys, I found this board a little while ago and have been reading for a few days. I'm a meteorologist based in the United States, specifically the northeast part of the nation. I'm a total weather nut and love cold and snow especially.

I'm very intrigued by the weather in the U.K. and would like to learn more about it. This site appears to be an excellent resource for doing this. I do not want to clutter your board with useless requests so feel free to move or delete this post if it is seen as such to the moderators.

What I'm curious about is the following:

1. What kind of unique microscale phenomenon should I be aware of when forecasting for London. For example here in the U.S. a Southeast wind in New York City this time of year will mean normally mean a surge of mild marine air. Another example, along the East Coast a northeast wind ahead of a storm will cause something called cold air dammning. This often leads to computer model busts on temperatures and storm placement. Any kind of "lessons learned" from forecasting in the U.K. would be helpful.

2. Here in the U.S. we have something called MOS that is generated from the weather models. Do you have a MOS to look at for temperature guidence. I personally hate the MOS here but would be curious to see it for London since I'm fairly new to forecasting there.

3. Any links to Radar, satellite, weather models etc. I found a few links in the learning section of this board but I know the real weather weenies know where the good links are located.

Thanks for your help and again feel free to move or delete if I'm out of line with this request.

Goose- do you post on Eastern?

Steve ( BritweatherUK)

[Roger J Smith]

You could join Net-weather and subscribe to the Extra service for the best radar. There are three other links I could give you that would provide a large regional overview of all weather parameters:

weatheroffice.gov.uk (navigate to "latest" which at present requires clicking on Heathrow)

met.ie (Irish weather service, very easy to navigate)

meteociel.fr (radar, satellite, pressure and temperature options will cover a large area around London)

I am also based in North America and can tell you these insights gained over four years of watching UK weather closely.

London does not have huge meso-scale or micro-climate issues other than the fact that it is a very large city with the usual temperature modification. The topography to the south is rolling and that leads to local snowfall production in marginal situations. Otherwise, the London area is sometimes near the boundary of some meso-scale sea-effect precip events that are often more rain or sleet than snow because of the relatively high water temps in the North Sea, but the urban heat island of London can add even more probability of rain in these marginal situations.

I find London forecast issues fairly similar to PHL as opposed to JFK or BOS. There is a perception that British weather is "unpredictable" but what people really mean by that is that they have a lot of medium-energy frontal passages and troughs that may or may not produce at any given location along their path, hence, the forecast "partly cloudy with widespread showers" can often verify even without a look at the actual weather pattern. The weather in the UK in general is not as dynamic as in most of North America, frontal passages are often quite diffuse and followed by multiple reinforcing troughs, in this way, if you're familiar with Portland, Oregon you would have some feel for the sort of dynamics to expect, but at the same time, southern England and the nearby continent can ramp up to higher energy levels on occasion and severe weather almost to central US (more like Great Lakes) levels can be witnessed. And you need to expect one or two violent windstorms per autumn-winter half-year.

One other hint, you'll need to adjust your rain-snow thickness divider down from North American experience, the 528 dam thickness is often not enough, sometimes even the 522 dam is marginal, because air masses arrive substantially modified in the lower 300 metres, unlike in North America where cold air comes straight from the icebox with the surface layers modified much less by ground contact. You need thicknesses as low as 516 dam to be fairly sure of snow in some set-ups and it rarely goes much lower than that so, whenever you think you might be forecasting snow for southeast England, be really cautious because in all likelihood that snow will be either changing phase or only up on higher slopes where few people live.

PM me if you have any more specific questions.

[Roger J Smith]

Sorry I can't edit the above but I should have typed

metoffice.gov.uk

I was thinking of weatheroffice.ec.ca which is the Canadian site.

It's been a few years since I bookmarked them all so I don't type them out every day.

[goose55]

Sorry I can't edit the above but I should have typed

metoffice.gov.uk

I was thinking of weatheroffice.ec.ca which is the Canadian site.

It's been a few years since I bookmarked them all so I don't type them out every day.

Thanks guys for the links and the helpful words, chat more in the future.

[cheeky_monkey]

I am just an amateur (if that!), all I can say is that the UK weather is very unpredictable!

i would say that the uk weather in comparison to most of the world is very predictable..changeable is the word i would use...relatively wet through all seasons..relatively cool in the summer and mild in the winter..rarely is it very cold in winter and very hot in summer..rarely are there prolonged spells of dry weather.

london is somewhat drier and warmer than the rest of the country all year round..mainly due to its position in the south east corner..all the hills and mountains are to the north and west..which protects from the atlantic storms..also being close to europe it is more prone to continental incursions than most other areas..so it is well placed to benefit from summer heat in europe..and winter cold..if the continent is cold.

[londonsnow]

you ask a very tricky, but interesting question goose. as people have pointed out london is a sprawling area and especially in marginal conditions its very hard to predict what the weather will be like for "london". you have to split it up into news (ie north east west south london). to generalise we get snow from an eneasterly in late jan and feb (best chance of snow) and we get very warm and irate on the tube in an august spanish plume. again as someone mentioned we are the first, aside from kent and essex, to feel the influence of a true continental easterly. mostly though we are, like everyone else in the uk, at the mercy of that big ocean to our west. all the best LS