Ireland Regional Discussions 17th January 2013 onwards

[SnowJon]

the rain is turning more sleety here on the Holywood Road in Belfast

[The watcher]

sleet and wet snow in bangor now. its changing fairly quick.

Pomeroy, sorry to hear about that. I send my best wishes.

[skywatcher]

According to xc, temps and dp finally falling at Aldergrove.

[gingercat]

It's all a bit feeble really! We have 1.5 c and just very light sleet! A non event so far!

[skywatcher]

Last night Su Campo posted a very useful chart which I think was called a theta-W. I've scoured meteociel for it but can't find it (not a morning person, lol). Can anyone advise? Also, how the heck do you read these properly? Any info appreciated. pm me if The Watcher thinks it will clutter up the thread but there may be others who'd like to know more about this as well. Su Campo, if you're around, perhaps you could help here????

[markok]

still 2c in Dublin. come on temps, drop!

[patneve]

2.7 in coastal dublin, persistent sleet

[mountain shadow]

How is the Radar looking?

Im at work and can only access The Met Office radar which is stuck at 9.30.

Useless.

[ronan]

Very sorry to hear that Pomeroy! Not good when stuff like that happen. Snowing in Omagh now!

[ronan]

MS this look to be pepping up for the south where the band is looking like its becoming more organised!

[somofagun]

Nothing in Dungannon yet.

Just started to snow

Edited January 18, 2013 by somofagun

[gingercat]

Hard to believe this is going to a significant snow event at this stage!

[ronan]

Why is it hard to believe? It's a rain to snow event and how often do you see snow coming from the south. Give it a chance to set in. Been snowing in Omagh for 40 mins now.

[mountain shadow]

Now snowing in Dromore Down.

[snowmore]

Picture taken 7.30 this morning Longford. On my way to work snow from Longford to Mullingar 1 deg. Then Rain/sleet to Dublin 2 deg.

Edited January 18, 2013 by jamesd

[gingercat]

Why is it hard to believe? It's a rain to snow event and how often do you see snow coming from the south. Give it a chance to set in. Been snowing in Omagh for 40 mins now.

Cos not much is happening here! But as you say, patience grasshopper

[stormforce 10]

after a night of very heavy rain and flooding, the rain turned to sleet and snow, at 10:00 am this morning for half an hour, then stopped. oh wellat least i seen a few flakes. goodluck to the rest of ye in the country.

met eirann forecast not very promising this morning, I couldn't believe it,less cold by wednesday, so I looked at wetterzentrale weather charts, looked at ecm and thought what charts are they looking at?

pomeroy: best wishes mate.

[snowydog]

Trying to snow here in Belfast. Nothing lying though. Hopefully it plays out well later. I'm no expert at all though so just reporting what I'm seeing outside at the minute.

[Neiller22]

Snowing well in saintfield co down

[markok]

still 2c in Dublin with on off heavy rain/sleet. no sign of a temp drop.

[Neiller22]

In fact very heavy snow in saintfield now!

[Su Campu]

Current weather and dewpoints at 12 pm.

Weather

http://www.ogimet.com/cgi-bin/gsynop?lang=en&esc=2&nav=Yes&lat=55N&lon=005W&proy=orto&base=bluem&ano=2013&mes=1&day=18&hora=12&min=0&vsg=Sg

Dewpoints

http://www.ogimet.com/cgi-bin/gsynop?lang=en&esc=2&nav=Yes&lat=55N&lon=005W&proy=orto&base=bluem&ano=2013&mes=1&day=18&hora=12&min=0&vtd=Td

The theta-w 850 chart (850 hPa wet-bulb potential temperature) is a good estimate of snowline. It takes the wet-bulb temperature at 850 hPa (which lies around 1/3 of the way between dewpoint and dry-bulb temperature at that level) and reduces it moist-adiabatically to 1000 hPa. It gives a good idea of what will happen to a snowflake as it falls towards the ground because as it falls it melts, and as this moisture evaporates it cools the flake and prevents it from further melting.

A rough guide for snow to sea-level would be theta-w of 0-1 °C. For every increase in theta-w the snowline increases by around 50-100 m.

This is only one factor that needs to be taken into account, however, so it's not always plain sailing.

Weatheronline have theta-w charts for the GFS and NAE.

http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000&CONT=ukuk&MODELL=nae&MODELLTYP=1&VAR=thew&HH=12&BASE=-&WMO=&ZOOM=0

[The watcher]

heavy snow on and off in Bangor, right down to coast. nothing lying though.

[Cavehill Snow]

Anybody got any snow lying away away from high ground?

[SnowJon]

just light snow in Belfast but definitely snow now and not sleet!