Wintry Weekend

[ZONE 51]

(please move/re-name/merge or anything else if needed, couldn't see another thread for the weekend snow )

As many know there is the risk of snowfall on saturday and sunday, its looking interesting this weekend, some likely to see snow, at this stage Scotland has the highest chance of distruptive snowfall as freezing air sweeps all areas throughout the weekend, not everyone seeing snow but Northern areas at risk with the South in with a chance somewhere along the line!

The chart above is the thickness 500-1000hpa, this shows the 528dam line sweeping right down to the south coast by early sunday,

There is also the risk of blizzards in Scotland, and very windy in many areas at some stage, cold front could be squally as it pushes through from the north/nw.

on the next chart you can see the wind direction swiftly change from sw-nw, indicated well on the chart,

This is milder air from the sw swapped for the cold air from the nw,

if we take alook at the surface temperatures below this clearly shows the drop in temps after the front has swept through from the nw, the chart is the same time as the wind chart,

Next the Saturday cold front is shown on the NAE precipitation,

now we take a look at the rain/snow chart from NAE for Saturday afternoon,

the very cold air has now pulled down after the fronts which is indicating snow, the rain is still in the south, but as this pulls away south/se then this would allow the cold air to move in here to.

(data GFS-00z/NAE 00z)

The is a risk of the cold air undercutting the front creating back edge snow! something to keep watch on then! also the swift change in wind direction and other factors we could see some very squally conditions along the cold front, some of the snow showers filtering down into the more prone areas in the North, the South some snow showers could make it south, so we have plenty to keep track on.

Below is a map of where i expect snow to fall, the map was created using the 18z data from NAE/GFS,

Southern areas have a low risk but it is being indicated on GFS weather type charts.

The High/Very High Risk zones is where the most likely areas to see significant snow amounts on the ground, looking at upper temps.dew points... then snow could fall in most places, its how far the ppn can make it in and filter those snow showers down form the north/northwest.

Edited February 17, 2012 by Coast

[ZONE 51]

Not sure if theres anything wrong with what i have input on here but no replies at all, i do try and add info when i can, i make the snow maps using real data, in the model discussion area i made a topic on short range forecasting and no replies.

I think seperate topics on events is the best way as the events can get less attention in a general cold spell thread, unless it is a widespread cold/snowy spell, not sure why but when i create topics there is no replies usually, what am i doing wrong? maybe its the type of topic that has not created interest, i find it difficult to discuss in the threads on many subjects, although when its about the weather i can say loads, i read the threads and i choose what i am interested in, or if i have less time then il view certain ones, i think this applies to most people, but i can't see why no replies on an event that has warning out for lots of snowfall, an active squally cold front, maybe i should have named it something more impacting like some of the papers do, im not in a mood its just a feeling i get, i have this away from the computer to, maybe i should just take a break, to much computer work i think, one thing though if its anything to do with meteorology then living at a computer is just fine.

[Cheshire Freeze]

Thanks for putting that forecast together ESS......keep up the good, informative work

[Backtrack]

Awesome job there ESS. Only just seen this, but thank you!

Did you use paint for the annotated map giving snowfall estimations?

[ZONE 51]

Thanks, i done that friday morning, and BackTrack i use an image editor, using multi layers from ppn data.

The lower yellow risk zone in the south covers backedge snow that is possible especially over higher ground, and the following wintry showers mostly near to western areas, il take alook at the cold front and winds/upper temps and see if the cold catches up with the back edge of the front, proberly not getting under the front until the ppn has finished, that is usually what happens, but the risk is there, the strong Arctic cold fronts from a direct north usually get undercut with the cold very quick and turning rain to snow, this cold might not hit the back end quickly to do that.