Cold Spell Discussion: Heavy Snow this evening especially in eastern/southern areas

HereticPrincess

Waiting on a bus at 6.30am in Meath this morning.
Unreal cold & everything was frosted over.

Couldn't even see the timetable properly under the ice :rolleyes:

ch750536

Tom Cruises Left Nut

pistolpetes11 wrote: »

You can't beat the drunk post alrite !

Hangover here alrite !!! hahaha

Just wobbled out of the bed, have my ticket... when does the ride begin ??? :pac:

Min

Met Eireann weather warning: Issued at 20 February 2010 - 09:40
Weather Warning
Showers of sleet and snow this evening and early tonight, mainly over Munster and Leinster, with accumulations in places .

http://www.met.ie/forecasts/warnings.asp

jambofc

bbc not giving a whole lot for this evening/tonight,fingers crossed

derekon

darkman2 wrote: »

I don't think I am. I think most threads and posts I make are fairly accurate. Sometimes things don't turn out as planned. But that is the nature of a science where the chaos theory takes over after 0hrs. I think the forecasts from everyone here are very good indeed - I don't recall any widely inaccurate forecasts tbh. I mean I started the snow potential thread last Friday IIRC with "after midweek" being of particular interest and that seems to be the case. I think the forum is very good and was extremely useful to boardsies during the floods last summer and the freeze in January...and entertaining aswell. We are not mystic megs...

I wish to make an apology Darkman2 re my post yesterday regarding my view that I thought you were ramping about snow in Ireland on Saturday/Sunday. My apology is based on the following:

1. Met Eireann weather warning just issued for snow tonight in Munster & Leinster

2. Just watched the BBC forecast and Ireland (from the midlands through to Louth/Dublin/Wicklow is covered in white for this evening from around
7pm through to 2am in the morning

3. We are now in the "reliable" timeframe hence the Met Eireann warning

I humbly offer my apology which I hope you will accept in good grace

Derek

derekon

jambofc wrote: »

bbc not giving a whole lot for this evening/tonight,fingers crossed

You must have been watching a different forecast than me!

Just watched the BBC weather before 11am news (with Laura Toibin) and Leinster is covered in the white stuff from this evening from around 7pm/8pm

Derek

Su Campu

Weathercheck wrote: »

As much as i totally respect and hightlight your input i do believe you have an unnecessarily negative attitude towards sneactha.

We all know TAF forecasts are cack, and to be honest i would expect someone as experienced as you to know this.

Lets be honest.. we know if not know more than the guys in the Met, we access virtually the same info barring the HIRLAM predictions, otherwise we virtually own the same data! ooooooooops......springs a business venture......! But really believe in yourself mate.. Obv negativity may override the snow malarky and i may slightly overdo it but i would say that the Met and possibly you???? only every expect snow when its virtually falling.. The Met refuses to forecast snow, even at 72/96hrs again they refuesed to mention any snow in the forecast, like other times during this winter.

To be honest its embarassing. They are a Weather service afraid to predict snow! hahah:D:D

........... The whole prob30 thing is a pisstake, i reckon prob30 = prob 70... they are quite simply an embarassment.

Firstly, remember that TAFs are valid only at the surface and within a 10 nautical mile radius of the airport, to give pilots an indication of the conditions on approach and departure. The Dublin TAF say will not give any indication of what's going to happen in say the Wicklow mountains. I myself am an amateur pilot and use them a lot and have found them on occasion to be way out, mostly on their timings, but other times they're bang on. The PROB30 thing is an international standard, and OK you think maybe they bandy it about too much when they should be more positive, and you're right sometimes. But as they're issued 4 times a day, subsequent forecasts usually do reflect increased or decreased probabilities, which is why the golden rule for pilots is always check the weather again last thing before setting out. I think it's very pompous for any of us (with the exception of MT Cranium) to think we know as much as, or do a better job than, professional forecasters. Yes we have access to a lot of data, but we don't have the experience they have. And this experience has taught them not to bandy about weather warnings until they're pretty sure they're going to happen. Last night nobody was certain what was going to happen tonight.

Looking at some TAFs issued by the UKMO for western Wales and England for the same period shows a similar use of the PROB30 for tonight and tomorrow morning. And the USAF had no mention of snow for today either, nor has the 00Z UKMO....





Regarding my opinions, I have slightly different methods than most others here in that I find the 850hPa ThetaE and ThetaW values, instead of purely the temperatures, to be the best indicators of snow probabilities, as they take into account the effect of evaporation and latent heat into account. Taking into account the values we had in January when we DID get snow at all levels and those values predicted today, plus the stronger insolation, I don't see us getting the same extent of snow as we did 6 weeks ago, ie, we're not going to get widespread snow at sea level tonight. If I'm wrong I'm wrong, no argument, but with the south of the country in the warmest air, snow should be above around 100m, and around 50m on the northern and eastern extent of the precipitation band. That excludes a lot of people, but that's the way I see it. If everyone's covered this time tomorrow then I'll gladly admit I was wrong, and will go and have a snowball fight with the kids!

snow ghost

Had a relatively heavy snow shower here for 15 mins about 20 mins ago.

jambofc

derekon wrote: »

You must have been watching a different forecast than me!

Just watched the BBC weather before 11am news (with Laura Toibin) and Leinster is covered in the white stuff from this evening from around 7pm/8pm

Derek

looked at the on line forecast,as i said doesn't look like a whole lot,there video hasn't been updated since this morning,so they must be upgrading

http://news.bbc.co.uk/weather/forecast/10209

Min

It will be Munster, the midlands and south Leinster that will get the snow showers later, with risk of accumulations according to the weather after the news on radio1 at 11am.

munsterlegend

Min wrote: »

It will be Munster, the midlands and south Leinster that will get the snow showers later, with risk of accumulations according to the weather after the news on radio1 at 11am.

just looking at the latest weather report at 11am even valentia had recent snow which is a good sign for snow falling surely and not rain/sleet when teh precipitation arrives.

derekon

jambofc wrote: »

looked at the on line forecast,as i said doesn't look like a whole lot,there video hasn't been updated since this morning,so they must be upgrading

http://news.bbc.co.uk/weather/forecast/10209

Thats fair enough Jambo, you can only go on the information you have to hand.

The BBC must have upgraded snow for Ireland - if you have BBC News 24, tune in there at 11.55am and you will see the snow for Ireland tonight (mainly Leinster and Munster)

Derek

Min

Min wrote: »

It will be Munster, the midlands and south Leinster that will get the snow showers later, with risk of accumulations according to the weather after the news on radio1 at 11am.

anecdotally-without looking at any chart [even though obviously i have] it has been getting progressively colder at this location..
Today for instance dewpoints are remaining around -1c
Air is in the mid fours.

Tonight ,it *should* be lots of snow depending on how much precipitation comes and where.
A wind off the sea in coastal locations will make for sleety rain there from any showers.

ninebeanrows

Latest high res UKM is lovely jubly :D

Has 11mm of precip for Dublin region by midday tomorrow

Fingers crossed all goes well.

The east is expected to be in a nice wrap around of the low towards dawn tomorrow.

cherryghost

Weathercheck wrote: »

Latest high res UKM is lovely jubly :D

Has 11mm of precip for Dublin region by midday tomorrow

Fingers crossed all goes well.

The east is expected to be in a nice wrap around of the low towards dawn tomorrow.

LINK

derekon

Weathercheck wrote: »

Latest high res UKM is lovely jubly :D

Has 11mm of precip for Dublin region by midday tomorrow

Fingers crossed all goes well.

The east is expected to be in a nice wrap around of the low towards dawn tomorrow.

11 millimetres of snow is very heavy. Will this look like a heavy frost? :cool:

Derek

Trogdor

derekon wrote: »

11 millimetres of snow is very heavy. Will this look like a heavy frost? :cool:

Derek

Hehe;) 1mm of precip usually translates to about 1cm of snow, so that's about 11cm:) (if it all or any sticks that is..:pac:)

irishdub14

Weathercheck wrote: »

Latest high res UKM is lovely jubly :D

Has 11mm of precip for Dublin region by midday tomorrow

Fingers crossed all goes well.

The east is expected to be in a nice wrap around of the low towards dawn tomorrow.

Watching this thread closely...!

derekon

trogdor wrote: »

Hehe;) 1mm of precip usually translates to about 1cm of snow, so that's about 11cm:) (if it all or any sticks that is..:pac:)

Thanks Trogdor, did not know that equation....11cm of snow for Dublin would easily close the airport!

Derek

Su Campu

The latest satellite loops showers some signs of organisation of the cluster of showers west of Kerry, Clare and Galway in the last hour or so, in response to the upper vorticity max shown below (red colurs). This is related to a developing jet streak to our south and will sustain convection as it crosses the country later.





Upper theta values still not conducive for sea level snow

ninebeanrows

derekon wrote: »

Thanks Trogdor, did not know that equation....11cm of snow for Dublin would easily close the airport!

Derek

The feature is almost nothing at the moment, see the band of convection just approaching the southwest? That is expected to develop rapidly in the next 6 hours and by 6am tomorrow be a circulation in the north Irish sea.

- I have a funny feeling a place called Meath might to well out of this tonight.

ninebeanrows

Su Campu wrote: »

The latest satellite loops showers some signs of organisation of the cluster of showers west of Kerry, Clare and Galway in the last hour or so, in response to the upper vorticity max shown below (red colurs). This is related to a developing jet streak to our south and will sustain convection as it crosses the country later.

11am readings.

VALENTIA E 03 RECENT SNOW 3 81

Thats gotta be a rarity.

I expect maringality to surface in the far southern areas as the feature develops but i expect widespread snow to low levels from Wicklow northwards in Leinster and the mids.

munsterlegend

Weathercheck wrote: »

11am readings.

VALENTIA E 03 RECENT SNOW 3 81

Thats gotta be a rarity.

I expect maringality to surface in the far southern areas as the feature develops but i expect widespread snow to low levels from Wicklow northwards in Leinster and the mids.

hmm so not looking good for down here then! met eireann are wrong in saying munster?

snow ghost

Su Campu wrote: »

Upper theta values still not conducive for sea level snow

Su Campu,

I'm exactly at sea level - well maybe 10 cm above - and I've had a couple of relatively heavy snow showers already this morning... and it was proper snow not sleety stuff, etc.

JanuarySnowstor

I wonder is the cluster of cloud West of Donegal where we should be looking for tonights action??
I think the cluster to the West of Kerry is just the regular convection.
If anything the main trough looks like being late, which will help snowfall, crossing the Southern third of the country from 9pm tonight.

Speak Now

Looking forward to some sleety rain in Waterford this evening

cherryghost

JanuarySnowstor wrote: »

I wonder is the cluster of cloud West of Donegal where we should be looking for tonights action??
I think the cluster to the West of Kerry is just the regular convection.
If anything the main trough looks like being late, which will help snowfall, crossing the Southern third of the country from 9pm tonight.

yeah it seems to tipp off donegal and down towards mayo and galway before making a retreat. interesting prospects all around, except the northeast, so it seems

snow ghost

Su Campu,

Just as I posted that last post to you, it started raining! :pac:

I take it something must have changed since my last snow shower... well spotted.

Su Campu

snow ghost wrote: »

Su Campu,

I'm exactly at sea level - well maybe 10 cm above - and I've had a couple of relatively heavy snow showers already this morning... and it was proper snow not sleety stuff, etc.

Fair enough, maybe I am way off then. I wouldn't expect them to be snow in the afternoon though with solar heating, but it'll be interesting to watch what happens tonight.

Weathercheck, I agree with you regarding spatial coverage, the difference is we disagree on whether or not we'll see snow at sea level. If we do then I deserve a slagging!