Cold Spell - Feb 7th to 13th 2021 - Chat

Kermit.de.frog

I'm seeing a trend here where this cold spell doesn't actually end at the end of next week. Maybe moderates for a time next weekend.

Exciting times ahead :cool:

JanuarySnowstor

Gaoth Laidir wrote: »

350 km of fetch along the south is an awful lot for low levels to be expected to support snow. The coldest uppers and hence heaviest showers will be in the northern half of the country. Down south you have not only warmer uppers but also warmer seas and closer proximity to residual slop from the current low that's moving away from us.

-10 uppers across the south, warmer seas only means beefier showers. Thanks now I'm even more convinced lol

YanSno

I disagree with with some here and I'm entitled to my own opinion. North County Dublin to Dundalk could get up to 15cm and some sweet spots it might even reach up to 30cm. Time will tell

derekon

Kermit.de.frog wrote: »

I'm seeing a trend here where this cold spell doesn't actually end. Maybe moderates for a time next weekend.

Exciting times ahead :cool:

Hi Kermit, isn’t it time to set up a new thread with the word “potential” omitted? Also, the days in question could be clearly noted? The cold is NAILED on now. 😊

D

munsterlegend

[quote="Kermit.de.frog;116183679

I'm seeing a trend here where this cold spell doesn't actually end at the end of next week. Maybe moderates for a time next weekend.

Exciting times ahead :cool:[/quote]

Has been big changes in the last 36 hours alright with regards that second low scheduled to arrive on Wednesday/Thursday. Very interesting to watch.

KingJeremy

Very exciting roller coaster going on here! I know nothing about reading weather charts etc...and I know you guys and gals were saying that the weather apps aren't reliable but my heart did a little skip when I checked the met app this morning and it says heavy snow for Thursday in my part of the country

You have mentioned Lake Affect (or is it Effect ) snow which I understand you are referring to for the east coast and the a/effect the Irish Sea will have on precipitation over the coming days...please excuse me if this is a stupid question, but can it be generated from actual Lakes? My location is east county Galway so in the middle-ish of the country...but we are on Lough Derg.

Kermit.de.frog

derekon wrote: »

Hi Kermit, isn’t it time to set up a new thread with the word “potential” omitted? Also, the days in question could be clearly noted? The cold is NAILED on now. ��

D

Good point. This should suffice as the thread, just change title. I can do up a forecast to Wednesday. Any moderators want to do that?

munsterlegend

JanuarySnowstor wrote: »

-10 uppers across the south, warmer seas only means beefier showers. Thanks now I'm even more convinced lol

Probably rain/sleet on the coast but a nice bit of snow say 20/30 miles inland ahem.

Speak Now

SeaBreezes wrote: »

Smart moneys on MT. Models dont show streamers on coast. They didnt for Emma. But MT had us warned on south coast. Snowed in for 2 weeks. Couldnt dig the road out filled to the ditch. All lake effect snow.

Im certainly prepping anyway.

The streamers and Emma and were different things.
You are right though that the streamers were underplayed in 08. We already had 6 inches on Waterford coast before the well forecast Emma gave us the mother of all dumpings (well since 82, surpassing 87).

Longing

Well more downgrades this morning. Mild air pushed back again this trend is getting a bit old now. Also lets not talk about the huge block to the east it getting more dominant in each passing run mild air making a dogs dinner to get in. That's it can't take any more of this taking a few days break from chart watching.

Zogabomb

Does anyone know where I can find Archive Charts for the February 1991 Easterly? We did very well along the East Coast but was it widespread snow from a front or streamers?

Davaeo09

KingJeremy wrote: »

Very exciting roller coaster going on here! I know nothing about reading weather charts etc...and I know you guys and gals were saying that the weather apps aren't reliable but my heart did a little skip when I checked the met app this morning and it says heavy snow for Thursday in my part of the country

You have mentioned Lake Affect (or is it Effect ) snow which I understand you are referring to for the east coast and the a/effect the Irish Sea will have on precipitation over the coming days...please excuse me if this is a stupid question, but can it be generated from actual Lakes? My location is east county Galway so in the middle-ish of the country...but we are on Lough Derg.

No there's generally a requirement of at least 100km of warmer water to generate enough convection.

Its why you see the people from Wicklow worry so much about wind direction

munsterlegend

Longing wrote: »

Well more downgrades this morning. Mild air pushed back again this trend is getting a bit old now. Also lets not talk about the huge block to the east it getting more dominant in each passing run mild air making a dogs dinner to get in. That's it can't take any more of this taking a few days break from chart watching.

Reverse psychology superb.

derekon

Kermit.de.frog wrote: »

Good point. This should suffice as the thread, just change title. I can do up a forecast to Wednesday. Any moderators want to do that?

Thanks and YES on the forecast Kermit!

D

TTLF

In a ENE, is it Wicklow or south Dublin that suffers from the Anglesey Shadow? I think it's Wicklow correct?

Cluedo Monopoly

KingJeremy wrote: »

Very exciting roller coaster going on here! I know nothing about reading weather charts etc...and I know you guys and gals were saying that the weather apps aren't reliable but my heart did a little skip when I checked the met app this morning and it says heavy snow for Thursday in my part of the country

You have mentioned Lake Affect (or is it Effect ) snow which I understand you are referring to for the east coast and the a/effect the Irish Sea will have on precipitation over the coming days...please excuse me if this is a stupid question, but can it be generated from actual Lakes? My location is east county Galway so in the middle-ish of the country...but we are on Lough Derg.

Great question. I am convinced Lough Corrib has robbed me of snow in the past. West Galway.

esposito

KingJeremy wrote: »

Very exciting roller coaster going on here! I know nothing about reading weather charts etc...and I know you guys and gals were saying that the weather apps aren't reliable but my heart did a little skip when I checked the met app this morning and it says heavy snow for Thursday in my part of the country

You have mentioned Lake Affect (or is it Effect ) snow which I understand you are referring to for the east coast and the a/effect the Irish Sea will have on precipitation over the coming days...please excuse me if this is a stupid question, but can it be generated from actual Lakes? My location is east county Galway so in the middle-ish of the country...but we are on Lough Derg.

Yes it can be generated by lakes if they are big enough. Chicago for example gets lake effect snow from Lake Michigan.

JCX BXC

This is weather forecasting. It's not a discussion of undisputable facts here, various users here have vastly different experience which they draw on to give their opinion on what weather will come.

Have we all forgotten how to agree to disagree? There's no 1 outcome/opinion here.

15-30cm snowfalls? Over the entire event in localised areas, yes that is possible, however don't expect this all to accumulate at once.

Many of us have been here years and know how to take posters information, I know which posters are generally conservative and generally ramp a little bit. What you want to do is take everything into consideration and make up your own mind. Don't jump to one opinion you like and berate every other forecast.

Honestly lads, ye have really taken the joy out of reading the thread. Some of the pettiness about fine details that posters get hung up on here is downright childish. Pages and pages of terribly low quality posting this morning.

If you are unable to handle the emotions in this thread and insist on lashing out like an angry child, I recommend you stick to reading text only forecasts such as Met Éireann or MT, there's no point. We generally here try to enjoy the rollercoaster, not kill eachother like a family on a roadtrip.

JCX BXC

Looking at the charts myself this morning I have a feeling we may be surpised by the longevity. Perhaps an outdated view, but for snow events I always put my faith into the ECM and the constant pushing out of the mild conditions is a trend I like very much.

Chalkitdown147

JCX BXC wrote: »

Looking at the charts myself this morning I have a feeling we may be surpised by the longevity. Perhaps an outdated view, but for snow events I always put my faith into the ECM and the constant pushing out of the mild conditions is a trend I like very much.

Looking like a quick reload too with that possible Scandi high

lulublue22

Tzardine wrote: »

People in Cork right now

People in Cork right now - oh my god it’s going to SNOW

lucernarian

Gaoth Laidir wrote: »

Personally I can't see that happening. 5-8 cm yes, but much higher than that, maybe high ground near the east coast (like Mount Oriel in Collon) but not to low levels.

There's feck all people living on Mount Oriel (probably for the best with the amount of snow I expect there). From seeing the charts for the past week, I've been thinking that south Louth is the "sweet spot" for accumulations as it's less susceptible to small changes in wind direction and a lack of shadow from the Mourne mountains. I've already warned friends and family about potentially disruptive snow.

I'm thinking 5cm is a much more realistic target for the the likes of Dublin though. One thing I didn't account for was the forecast 850 hPa wind speed chart, and 50 kts is definitely on the high side for allowing convective potential. Any thoughts on that? On one hand, slower upper air allows more time for saturation and cloud formation, on the other the faster speeds might allow precipitation to simply cross Britain outright and regain momentum over the Irish Sea (this happened in 2010 with showers reforming only 50-60 km off the English coast).

Zogabomb

Looks like the 6z GFS brings much more of the country in for a snowy event on Thursday, could Ireland be the sweet spot where the two airmasses meet I wonder?

munsterlegend

Zogabomb wrote: »

Looks like the 6z GFS brings much more of the country in for a snowy event on Thursday, could Ireland be the sweet spot where the two airmasses meet I wonder?

That it does. Seems to be correcting further south though with every run.

Rebelbrowser

Gaoth Laidir wrote: »

350 km of fetch along the south is an awful lot for low levels to be expected to support snow. The coldest uppers and hence heaviest showers will be in the northern half of the country. Down south you have not only warmer uppers but also warmer seas and closer proximity to residual slop from the current low that's moving away from us.

Thanks GL, every day is a school day and all of that. So not alone are there minima for fetch for Lake effect snow, but there are maxima too?

Lantern Jaw

Thanks for all the post folks, I follow with interest but I'm lost at this stage 😀...Is snow likely for Dubli this week before I either built it up to the kids, or let them down gently 😆

Calibos

Its constantly said that the models under estimate streamers.

I assume this means that they are not programmed to take into account every single little variable that can affect their formation and then their intensity.

However, one has to assume that no matter how many variables and conditions are met, THE most important one with the strongest effect is Sea Fetch. So it doesn't matter if every other condition is met, if you don't have the Sea Fetch, none of it really matters.

This is why knowing what direction the wind is blowing at the required level (700-850mb) is so important in order to work out if you have any chance at all of anything decent.

Now even if the precipitation models are not programmed to take into account all the variables (Which is why we can't 100% trust them) surely the one variable guaranteed to be programmed into them right is the Wind direction at the relevant height.

ERGO, if the precipitation models are showing high intensity into Meath and Louth from due East, surely we can at least trust that it got the wind direction at 700-850mb right. What we can't trust is the intensity. Might be overblown, might be under-cooked, the most intense region of precipitation might be a bit further south etc, but broadly speaking the model will have got the general area right.

If the only thing you can trust about the precipitation model is the track/direction of the Streamers than surely experience tells us that most of Dublin and Wicklow will be in the Angelsey/Wales shadow and end up getting SFA.

The overall point I am making is that when some of us see the latest output and have a little moan that it doesn't look like we'll get much if anything, we are told to relax and that the Precipitation models can't be trusted anyway. My point is that surely at the very least the orientation/direction of the Streamers on the Precipitation models can be trusted, in which case we can make educated guesses based on experience which of the various Irish Sea Precipitation Shadows are going to affect us.

sjb25

The chan chan man wrote: »

Pardon my ignorance but who is MT and where can i find these forecasts?

.....

Nqp15hhu

Just had a look at my forecasts and indeed this cold spell has been extended. Latest GFS model has me at 1c high for next Saturday!

Supercell

AuntySnow wrote: »

We might just miss it if it does
Due east is the llewlyn peninsula at the north of cardigan
Shortest hop to Wales there is

This is my most absolute weather nightmare and most likely scenario given current charts speaking from long experience, heres hoping they change.