Cold Snap, T0-180Hours Only

derekon

Folks,

The latest models are showing some serious cold over Europe that looks to be heading towards Britain & Ireland during next week. Really serious cold! :D

Does anyone think that the models in the morning will show a big downgrade or is the signal just too strong now and we are very likely to have a cold easterly hitting Ireland next week?

D

Harps

Dam is the thickness of the atmosphere between two points, typically the 1000hPa (near the surface) and 500hPa levels, 528 dam simply means 5280 metres between the two. The air contracts as it cools so a lower dam basically means a colder layer of air

Anyway, another great GFS run but I'd take it with a pinch of salt again, pointless looking beyond the weekend for anything more than a good laugh :pac: Gonna be a nowcast situation for the next few days by the looks of it

derekon

Harps wrote: »

Dam is the thickness of the atmosphere between two points, typically the 1000hPa (near the surface) and 500hPa levels, 528 dam simply means 5280 metres between the two. The air contracts as it cools so a lower dam basically means a colder layer of air

Anyway, another great GFS run but I'd take it with a pinch of salt again, pointless looking beyond the weekend for anything more than a good laugh :pac:

I think you are right in what you are saying Harps and its good to be cautious. However, have you ever seen such depth of cold heading to central Europe only for it to be washed away by a mild Atlantic front?

D

Redsunset

12z ECM Det is milder than the ENS mean. Cold outlook still on the cards from the ECM.

Matt Hugo

==========================================================
Also a reminder,
Please respect everyone's opinion whether you agree or disagree.

Fully Established

For what its worth it looks like this easterly flow is building and could possibly and probably will continue to track to the east,looking at surface analysis charts the atlantic looks to be relatively quiet out to wednesday.So highly likely the easterly flow wins out but significant snowfall is too early to call until around 72 to 84 hours because if we have such a stable atmosphere where does the precipitation come from?

patneve2

Fully Established wrote: »

For what its worth it looks like this easterly flow is building and could possibly and probably will continue to track to the east,looking at surface analysis charts the atlantic looks to be relatively quiet out to wednesday.So highly likely the easterly flow wins out but significant snowfall is too early to call until around 72 to 84 hours because if we have such a stable atmosphere where does the precipitation come from?

The precipitation should come from the contrast between the cold continental air and the "relatively" warm Irish sea...but still to far out to say much

Min

patneve2 wrote: »

The precipitation should come from the contrast between the cold continental air and the "relatively" warm Irish...but still to far out to say much

Lake effect snow.

DOCARCH

Min wrote: »

patneve2 wrote: »

The precipitation should come from the contrast between the cold continental air and the "relatively"
warm Irish...but still to far out to say much

Lake effect snow.

Will not happen if the pressure is too high.

kittyn

Well from what I can see ( from a very novice standpoint ) is the trend seems to be staying in a cold flow ...... As for snow well I'm hoping to see a few flakes
Here's hoping we can at least maintain the westerly progression of the cold and we get a look in soon

Fully Established

patneve2 wrote: »

The precipitation should come from the contrast between the cold continental air and the "relatively" warm Irish sea...but still to far out to say much

Ia this the DALR versus the SALR for the precipitation?

Deep Easterly

A scan of an old but useful map showing the general temperature anomalies across Europe during typical Scandinavian High set ups during the winter period:



Taken from 'British Weather in Maps' - Taylor, Yates. 1958

The warmer than average temperatures over more Arctic regions are due to the fact that warm Atlantic air masses are diverted more north by the Scandinavian block with the colder anomalies over the European landmass and up through Ireland being the result of the cold continental air which is forced westwards by the high.

pistolpetes11

https://www.youtube.com/watch?v=qNgM5JeSRoI

Ahhhh the times have been cut out again , il get this rite in the morning !!!

BLIZZARD7

Ok-

Everybody- Do not worry about snow and where it will come from, once we have the easterly in place and cold uppers backing west-The snow WILL follow!

Pressure to high? No such thing- December 2010 I was worried about this, pressure at 1040MB, how will we ever get snow?? -10 uppers over an irish sea of +10C creates LOADS of precipitation. Got 10-15cm that day.

The sst's in the Irish sea are currently around 10C, you need a 13C degree difference in sst's and 850 temps to create precipitation. So if the -13C uppers that the GFS 12/18z's came off then we will have a 23C difference!! = Lake effect SNOW in the east.

00Z models are extremely important!





Dan

TheMilkyPirate

Would usually stay up for the 00zs, But there is good racing tomorrow so it's off to bed early and up early. Let's hope we get a nice surprise in the morning.

Redsunset

I think expect downgrades cause 18z gfs run was out on its own in the ensembles. Tomorrow will tell alot I feel.

Hope I'm wrong

pistolpetes11

redsunset wrote: »

I think expect downgrades cause 18z gfs run was out on its own in the ensembles. Tomorrow will tell alot I feel.

Hope I'm wrong

Can the runs really get much better from where they are at the moment :pac: , I agree though that the run does seem to be a cold outlier .

nacho libre

derekon wrote: »

However, have you ever seen such depth of cold heading to central Europe only for it to be washed away by a mild Atlantic front?

D

I think 1987 was an example of this. Also last winter the deep cold block, despite initial doubts about the Atlantic being able to sweep it away from Ireland and England, was swept away in the space of a day or two, and banished well into the continent. This time around with the atlantic traditionally weakening at this time of year, the cold could well hang on over the continent throughout February, but as per su campu's point, a weakened Atlantic can still easily banish cold from us.

darkman2

Folks,

We are in a period where either something very serious or benign is coming. I stress the sentence because it is either/or - no in between. 00z's are coming out soon so let's see then if there is further agreement toward either. UKMO going to be crucial this morning I think.

I could not stress enough this country could not handle the possibility of severe cold some runs are progging.

pistolpetes11

darkman2 wrote: »

Folks,

We are in a period where either something very serious or benign is coming. I stress the sentence because it is either/or - no in between. 00z's are coming out soon so let's see then if there is further agreement toward either. UKMO going to be crucial this morning I think.

What time are the due DM2 , I am now in between , go grab a tin or hit the nest !

darkman2

pistolpetes11 wrote: »

What time are the due DM2 , I am now in between , go grab a tin or hit the nest !

Grab a tin for 2 reasons

1. At least you will know

2. If it does not work out drink your sorrows


I will be here for the 00z's

3am onward the models come out


If anyone has any questions concerning this potential weather inconvenience I am free for the next few hours to answer as best I can.

nacho libre

redsunset wrote: »

I think expect downgrades cause 18z gfs run was out on its own in the ensembles. Tomorrow will tell alot I feel.

Hope I'm wrong

there will be ugly scenes over on netweather, if there are dramatic downgrades from the gfs- the model has form in this regard.
a lot of nails being bitten between now and the next outputs!

Calibos

As my dear mother used to say. F**k that for a game of soldiers. Only got 4 hours last night and have to be up at 7.30 in the morrow...

I'll take it as a good sign if I log in when I wake up and this thread has gone from 14 to 25 pages

Redsunset

I agree darkman, tis a savage feed of cold air and would cause problems and maybe it will come, however GFS has a habit of over exaggerating intense cold over us in FI.

So 3 things can happen, it'll either

• Come and freeze us half to death
• Be diluted
• Beaten back at last min by atlantic

sdanseo

Calibos wrote: »

As my dear mother used to say. F**k that for a game of soldiers. Only got 4 hours last night and have to be up at 7.30 in the morrow...

I'll take it as a good sign if I log in when I wake up and this thread has gone from 14 to 25 pages

40 posts per page really should be forum default :P

Redsunset

nacho libre wrote: »

there will be ugly scenes over on netweather, if there are dramatic downgrades from the gfs- the model has form in this regard.
a lot of nails being bitten between now and the next outputs!

I have not looked over at NW, I already know from past set ups the state their in.

mothel

Can someone post the netweather link you're all mentioning please?

mothel

And a good link to the models?

Redsunset

mothel wrote: »

And a good link to the models?

For all your weathering needs.
http://www.boards.ie/vbulletin/showthread.php?t=2056531638

pistolpetes11

mothel wrote: »

Can someone post the netweather link you're all mentioning please?

All seems quite there at the moment

http://forum.netweather.tv/topic/72352-model-output-discussion-06z-27th-january/page__st__500

But they have model chat and banter section in there somewhere although Ive never been in it

mickger844posts

pistolpetes11 wrote: »

All seems quite there at the moment

http://forum.netweather.tv/topic/72352-model-output-discussion-06z-27th-january/page__st__500

But they have model chat and banter section in there somewhere although Ive never been in it

I was never a huge fan of The Netweather forums but had a quick read through their model discussions page and found it very interesting and informative. There is a lot of knowledge over there.
Not long now to the 0Z runs. Should be interesting to say the least