Just what are the perfect conditions to guarantee snow?

[shacks]

Just what are the perfect conditions to guarantee snow?

Can anyone please tell me what weather conditions are perfect to guarantee snow?

What wind directions and temperatures should I be looking out for?

I live in North West Cumbria a town called Whitehaven right on the coast.

I always thought that if the wind were coming from the North East it was the 1^st part of the recipe for snow, but the wind came in from Ireland this time bringing with it the snow. But this never made it to our coast, or it went straight over?

So can anyone please give me the perfect recipe that could guarantee us snow? What wind direction, what tempreture? “ Is the saying true that it as to get warmer than + 1 before it will snow” The only thing I notice more times than not is that the snow comes down from Scotland either side of us, over the Irish sea and down over Penrith. Anyhow any information would be appreciated. Thanks

[Bottesford]

Here's a start: http://www.netweather.tv/forum/index.php?showtopic=20474

For other questions like this make sure you have a look at the net-weather guides which can be found here:

http://www.netweather.tv/forum/index.php?showforum=5

[jam]

Ive got this saved but never had much chance to use it recently!

Snowfall Criteria - What's Needed?

Temperatures:

500mb Temps: -25ºC (below -30ºC preferable)

850mb Temps: -5ºC (below -6ºC/-7ºC preferable)

850mb theta-w (wet bulb potential temp): 2ºC (below 0ºC peferable) 850mb theta-e (equivalent potential temp): 15ºC (below 10ºC peferable)

Surface Temperature: 1.0ºC (below 0.0ºC preferable)

Surface Dew Point: -0.5ºC (below -1.0ºC preferable) *Highly Variable*

Thickness Values:

1000-500mb thickness: 525dam (below 522dam preferable) 1000-850mb thickness: 1290dam (below 1285dam preferable)

850-700mb thickness: 1500dam (below 1490dam preferable)

Other Variables:

Wet Bulb Zero (WB0): Height figures will vary, but gives a general/good idea as to what altitudes (200m, 300m etc) snow will fall down to. Calculated in conjunction with evaporational cooling:

Below a 1000ft (approx 300m) - (below 500ft preferable (approx 150m preferable))

3000ft or over: Always rain, snow highly unlikely.

2000ft-3000ft: Mostly rain, snow unlikely, low risk of sleet.

1000ft-2000ft: Snow more likely than rain/sleet.

below 1000ft: Mostly snow, light precipitation and low lying ground may still see sleet/rain.

Freezing Level (Height of 0ºC isotherm): 300m (below 250m preferable)

**************************************************************

NB: The above information is a general guide as to the risk of precipitation falling as snow. Snow forecasting is highly variable and there are many factors that can mean the difference between snow and rain. The greater the number of the above variables that are evident the greater the overall risk of snow.

M.Hugo. BSc, FRMetS.

[johnholmes]

like Bottesford suggests try our Guides as a first stop, in particular, if you have NW Extra try the thread I did on 'trying to forecast snow' for your location.

Remember that being on the coast at sea level may lead you to have less chance than anyone inland.

For the so called perfect set up for you, bitterly cold nw flow with troughs or even polar lows in it.

that was for the Whitehaven post but the suggestion about the Guide and trying the charts in NW Extra also applies to the Sheffield query.

Here with height and inland you are, in one way, better placed although being in mid England does mean coastal shower activity is rare that far inland. You do need a trough or polar low to give the showery snow.

In a frontal situation then Sheffield is well situatted for pre frontal snow and also post frontal snow.

hope that helps you both.

you are almost certain to get someone saying something along the lines, 'ah but in this or that and in 19?? such and such!

Edited February 5, 2008 by johnholmes

[DAVID SNOW]

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