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

zacharius

Kermit.de.frog wrote: »

Tell me about it

Still time to avoid!

Sigh. I'm a broken man. Again. In Dub 16

lucernarian

John.Icy wrote: »

I'd just relax with worrying about the winds and where the snow will end up for now.

Models were saying mostly E/ENE this morning. Latest guidance has some ESE in there too (but not for the whole Sun-Wed period) due to the low sliding Tuesday coming closer than previous runs. Probably will get a mix of directions in the end. Would equal lower accumulations but better overall spread.

Clearly a fluid situation and we are probably another day or so away from getting a more solid picture on where we are looking for shower activity.

Lucernarian is also right above. The IOM shadow etc. are annoying but I can't remember between 2010 or 2018 where someone ended up under it 100% of the time. It varies. Even without any shadows, you end up with thin strips of precip. coming ashore at the best of times that leave you high and dry while down the road is getting pasted. Such is the nature of these things. If this was a solid one day event fair enough, being left dry will be no craic. But we got Sunday night till maybe Wednesday at this.

May not even have to worry about any of this with how limited some believe snow potential to be

Thank you! Lately when I post in here I'm afraid someone's just gonna flame me for things I didn't even say, or else it gets ignored. And not just during peak hype periods like this week

zacharius

dak wrote: »

I have been a member of boards since 2006 and an occasional poster to the weather forum... I check Mt's daily forecast daily for years.

What I notice over the last year and not just on boards but on other social media is that there is an increasing amount of antagonism and arguements rather than mutual respect and debate about other people's opinion.

I think lock downs and covid have given us all short fuses when confronted with an alternative view to our own. I have even seen it in this thread after reading every post since it started.

Think we should all chill out, pause before we post and remember this weather forum is a place to express our excitement over weather especially snow but not one to kill each other over it.

There are more serious issues in life to deal with!

But let's keep wishing for but waiting for all our snow dreams to come true next week! Where ever you are! ❄️❄️❄️❄️❄️❄️

Hear hear. Some serious moaners on here. I had an outstanding 2mm of snow / ice this year in D16 when we were predicting possibly 5 cm. It blew past us, but I loved the ramp up here when it could have been snowfall. I visit boards weather on the first hint of snow and love riding the wave, but this time it's been crap. Way too much negativity.

On the flip side there are many from the west, south and north wishing their eastern bros and sis's best of luck - that's the spirit.

Mods: remove negativity posts (except mine)??

Oneiric 3

zacharius wrote: »

On the flip side there are many from the west, south and north wishing their eastern bros and sis's best of luck - that's the spirit.

We don't consider you our eastern bros, but as our sworn enemy.

zacharius

Oneiric 3 wrote: »

We don't consider you our eastern bros, but as our sworn enemy.

That made me laugh my arse off. I pray for eternal snow in your region wherever that may be. xx

lucernarian

zacharius wrote: »

Hear hear. Some serious moaners on here. I had an outstanding 2mm of snow / ice this year in D16 when we were predicting possibly 5 cm. It blew past us, but I loved the ramp up here when it could have been snowfall. I visit boards weather on the first hint of snow and love riding the wave, but this time it's been crap. Way too much negativity.

On the flip side there are many from the west, south and north wishing their eastern bros and sis's best of luck - that's the spirit.

Mods: remove negativity posts (except mine)??

There's a lot of reaction to a bit of negativity, might be best to just ignore contrary or grumpy ones if no one's breaking any rules or picking a fight this event is more rollercoastery than usual, haven't seen such knife edge stuff since early 2010 for a possibly big event.

Many people posting here are never around for all the forecasts that do go tits up 5-6 days before the prediction

smellyoldboot

So I'm in Waterford and met eireann has the forecast for the foreseeable as "coldish" about 3 degrees and the odd bit of rain, which seems such a horrible damp squib. What gives? Is everyone else wrong and they know something or are they pure dopes?

lucernarian

smellyoldboot wrote: »

So I'm in Waterford and met eireann has the forecast for the foreseeable as "coldish" about 3 degrees and the odd bit of rain, which seems such a horrible damp squib. What gives? Is everyone else wrong and they know something or are they pure dopes?

Even for Tuesday? That's a bit mad tbh, be hard pushed to see it going above 2 degrees.

Wine Goddess

498 people on the weather forum!!!!

Must be something interesting on the way.....

Here's hoping for a wonderful distraction from the other crap that's going on.

I'm checking the site every 20 minutes at the moment....

Anyone else just as excited about the potential for snow?

smellyoldboot

lucernarian wrote: »

Even for Tuesday? That's a bit mad tbh, be hard pushed to see it going above 2 degrees.

Yep, temp looks to be flat lining at around 2/3 for days and general outlook is : cloudy. Like every single day from now until next Thursday looks like a copy and paste forecast. lol

Nqp15hhu

Yes temps will max out at about 2c each day for an hour or two but the wet bulb and dew point temps will be well below freezing so that will not be an issue.

It is a very shallow layer of above freezing temperatures.

The chan chan man

So now its predicting 0.2cm of snow in Dublin on Sunday..

Daz_

smellyoldboot wrote: »

So I'm in Waterford and met eireann has the forecast for the foreseeable as "coldish" about 3 degrees and the odd bit of rain, which seems such a horrible damp squib. What gives? Is everyone else wrong and they know something or are they pure dopes?

The difference is Met E don’t pray for snow . They just call it how they see it actually happening . A lot of snow dance folk don’t like that...

M.T. Cranium

SleetAndSnow wrote: »

Is ESE winds not good for us down here in cork too? I remember reading that earlier, or would it have to be purely SE winds really?

During 2018 I remember they came from just below dublin and all the way down, but I doubt that will happen again!

I think you're right, ESE is fine, anything south of about 070 deg would work for Cork but the inland penetration would be better with SE than ESE, some of the discussion (without having read every post yet because I'm quoting you on the move through the thread) seems to overlook the possibility of regionally variable wind direction so just because Dublin ENE not a sure thing Cork also ENE, could be some convergence in the flow, or moving trough features.

I said earlier that I expected a moderate event rather than a heavyweight to contend with 2010 or 2018, of course that's a fairly high bar and moderate has a fairly big range, even one or two of the March 2013 days got into what you might call low-moderate range. There was also that event around 1 Feb 2009 about which I remember almost nothing (because not forecasting here until after that date). Seems like that might have been high-moderate range.

Anyway, the relief for me is that the models started to converge, until the last few runs the GFS was disturbingly marginal to be making very definite calls (unless you wanted to ignore it which I realize many do). I thought it would come along because of problems I could see with its N American analysis compared to ECM or GEM (the latter is starting to pull its own weight after some upgrades, I've even seen times where it proved to be the most reliable, which you would not say very often before 2019).

Every model I consulted at 0600h seemed to be on roughly the same track although there's always going to be small variations.

Saying moderate outcome I can only be one category wrong if it snows. :pac:
So I hope to be wrong on the low side, can see how that could come about (talking only about the streamers here, I am nowhere near convinced that there would be much breakdown snow, the climatology on that is not too great with this shape of cold block).

The CET record allows comparison with a lot of similar outbreaks in the period 1772 to present, and assuming a five-day average of -1.5 C there (Sun to Thurs the most likely) I found 27 cases that spanned any five days from 5th-9th to 9th-13th, and achieved at least -1.5 (the coldest was 1895 which got as low as -7 C for an average). Oddly enough 1947 was not particularly extreme although it had been cold for two weeks before this time frame and remained cold for another month. The lowest average in recent times was -3.1 in 1991, when there was a notable snowstorm in south-central England. Only 2012 (a spell that largely missed Ireland) made the list after that one, although 26 Feb to 2 Mar averaged -2.2 (spells outside the range 5-14 Feb were not analyzed, but noted). If you wanted to see the whole list, it's in the contest thread in the same subforum as the model threads on Netweather.

The list is fairly skewed towards the first half of the interval (1855 and 1917 were quite cold also). About half to two-thirds of these spells break down fast and flip to quite mild or very mild. The rest seem to persist to about the 23rd although a couple went into March. I didn't list the parameters for starting but almost all of them seemed to get into deep cold for 5-7 days (only), and the same was true of some spells that I added in the notes for 1-5 Feb.

So what I'm saying is that from a purely statistical point of view, the chances are fairly good that this cold spell will break down rather quickly, and the faster they break down, the lower are the chances of a wintry spell of precip lasting very long.

Danno

READ THIS POST:

Cool the jets folks. The models showing precip at this early stage should be totally disregarded.

A few pointers:

* Ignore all precip charts until they are within a 24hr range, even at that a 12hr or a 6hr chart should only be trusted with some limited respect.

* All models under-model lake/sea-effect snow. When these babys kick off they take on a life of their own.

* Don't fret about the breakdown yet. It's almost a week away. If you cast your mind back to earlier this week, this upcoming cold spell was still with a health warning too.

* Please show more courtesy to others on here. Play the ball, not the man.

Thank You all.

Gaoth Laidir

Mount Vesuvius wrote: »

As Paddy says , Best to look at the 700hpa , charts for wind direction for clouds as this is the middle layer just over 3000 metres high.

With shallow convection like next week the 700-hPa level will be a bit too high and at the top of the clouds. A blend of 850 and 700 would be better, leaning more towards the 850.

Once and for all to settle this isobars v surface wind confusion, below are the surface pressure and 10-m wind streamline charts for 3 am Tuesday. Note how much to the left of the isobars the wind direction is pointed. In this case it's also fairly much aligned with the 850 hPa wind too, with the 700 hPa a little more of a northerly component. Above that level the wind actually does a complete 180, with stiff northwesterlies at 500 hPa and above.

In any case, there is no point worrying over exact directions at this point. The movement of the current low towards the continent could introduce minor variations that would have major effects on spatial sleet/snowfall distribution.

TeaCup2

Wine Goddess wrote: »

498 people on the weather forum!!!!

Must be something interesting on the way.....

Here's hoping for a wonderful distraction from the other crap that's going on.

I'm checking the site every 20 minutes at the moment....

Anyone else just as excited about the potential for snow?

Wine Goddess I'm extremely excited! Unbelievably we've had 2 days of heavy(ish) snow in South Kilkenny this year, it's gotten my hopes up for a snowmaggedan. That snow didn't last too long but it was great to see! Can't wait for the next round, loving the roller coaster 😂

torres9kop

Just looked at weather for uk. They are getting 20 inches in the southeast on Sunday. Jammy feckers

Dazler97

nacho libre wrote: »

So am I, but i doubt very much that chart will verify as is. I expect it to remain dry here.

I'm expecting zilch until Thursday here Carrick on Shannon and even then I wouldn't be holding my breath

Tyrone212

torres9kop wrote: »

Just looked at weather for uk. They are getting 20 inches in the southeast on Sunday. Jammy feckers

20cm but yeah jammy indeed.

lucernarian

Gaoth Laidir wrote: »

With shallow convection like next week the 700-hPa level will be a bit too high and at the top of the clouds. A blend of 850 and 700 would be better, leaning more towards the 850.

Once and for all to settle this isobars v surface wind confusion, below are the surface pressure and 10-m wind streamline charts for 3 am Tuesday. Note how much to the left of the isobars the wind direction is pointed. In this case it's also fairly much aligned with the 850 hPa wind too, with the 700 hPa a little more of a northerly component. Above that level the wind actually does a complete 180, with stiff northwesterlies at 500 hPa and above.

In any case, there is no point worrying over exact directions at this point. The movement of the current low towards the continent could introduce minor variations that would have major effects on spatial sleet/snowfall distribution.

Those charts actually show a lot of vertical shear... If I understand correctly, that would not be ideal for convection?

Nqp15hhu

torres9kop wrote: »

Just looked at weather for uk. They are getting 20 inches in the southeast on Sunday. Jammy feckers

Seriously doubt that!

Jizique

Nqp15hhu wrote: »

Seriously doubt that!

10cm according to bbc news at ten, their week ahead forecast

2nd Row Donkey

Jizique wrote:

10cm according to bbc news at ten, their week ahead forecast

All the more for us

Nqp15hhu

lucernarian wrote: »

Those charts actually show a lot of horizontal shear... If I understand correctly, that would not be ideal for convection?

It’s vertical shear and there’s not much going on.

For ex, in this Hodograph you can see the wind is mostly Easterly from the surface to 3000 metres.

igCorcaigh

torres9kop wrote: »

Just looked at weather for uk. They are getting 20 inches in the southeast on Sunday. Jammy feckers

Southeast England is looking at very bad disruption. Hope they are prepared.

Danno

torres9kop wrote: »

Just looked at weather for uk. They are getting 20 inches in the southeast on Sunday. Jammy feckers

That may not be widespread, watched that forecast and Alex Deakin was keen to point out that it will be sleet for some. Alex and Adrian I would think are cold rampers but still with their professional hat on will bring in the caveats.

The South Downs will do well along with the High Weald and if there is much of an overspill across the A3 route that will be snow - but will the retreating occluded front deliver for them?

Gaoth Laidir

Nqp15hhu wrote: »

It’s vertical shear and there’s not much going on.

For ex, in this Hodograph you can see the wind is mostly Easterly from the surface to 3000 metres.

That sounding is for 9 hours later.

There is a bit of speed shear alright but probably nothing too severe. Directional shear is still within the ~30-degree limit.

Jizique

Danno wrote: »

That may not be widespread, watched that forecast and Alex Deakin was keen to point out that it will be sleet for some. Alex and Adrian I would think are cold rampers but still with their professional hat on will bring in the caveats.

The South Downs will do well along with the High Weald and if there is much of an overspill across the A3 route that will be snow - but will the retreating occluded front deliver for them?

10-20cm, not inches

Danno

Jizique wrote: »

10-20cm, not inches

I know!

Was responding to someone up the discussion.

The SE England scenario is of interest to us, if that low hangs around there a bit longer and the cloud shield is not extensive, it could pep up Irish sea convection earlier than forecast...