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Metcheck Forecast Room - Meteorological Discussions
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Sometimes, the front page articles just aren't big enough to cover all our thoughts and ramblings on the developing weather.
By using graphical analysis from the weather models, as well as full forecasting terminology, you can see how events are being discussed here at Metcheck. The discussions aim to provide unparalleled access to forecasters thoughts and you may even start talking like us too ;-)
Here are the latest discussions from the Metcheck forecasters.
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| Current Discussions (PREMIUM ONLY) |
| 850mb Temperatures - Its Use In Forecasting |
A few days ago we were discussing the use of the 1000-500mb thickness lines and how they are used in meteorology and weather forecasting. This discussion will cover a very important and highly useful variable, the temperature values at the 850mb level...
As we previously discussed the atmosphere is made up of varying pressure levels which are directed related to a specific height up in the atmosphere. The 850mb level is approximately 1,700m above the surface.
The 850mb temperatures are very important because they can give us an indication of what the temperatures at the surface will be like, but more importantly during the winter period can be a good indicator as to whether precipitation will fall as rain or snow.
Below are a couple of examples of the 850mb temperatures.
 
During the summer period, like at present, 850mb temperatures normally range between +5C and +15C across the UK. Values of +15C and above indicate very warm conditions at the surface. Sometimes values may approach +20C, which would mean surface temperatures hit the 'hot' category with surface temperatures likely to exceed +30C.
The first image shows how the hottest weather is reserved for places like North Africa and other parts of the Med. These areas during the summer are obviously very hot. In contrast across Greenland there are areas where values are at and below -5C.
The second image highlights the blue area across Greenland where 850mb temperatures are at and below -5C.
During the winter months, the 850mb temperatures are a good indication to precipitation type. If values are BELOW -5C then there is a chance that snow will fall, values below -10C indicate a high chance of snow and also very cold conditions at the surface. 850mb temperatures at or below -15C indicate bitterly cold conditions at the surface, from a UK's point of view.
So if you see us forecasters mentioning things like; "850mb temperatures will generally be between -5C and -10C through the forecast period", expect some cold weather and also the potential for some wintry precipitation, as long as there is some precipitation present.
850mb temperatures, a simple variable but highly useful when it comes to forecasting.
FORECASTER: HUGO
Discussion Added : 20 August 2007 |
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