Cold Spell Media Forecasts and Model Output (General Chat)

squigo

Sorry folks but how do you put images onto your post directly?

BEASTERLY

RAIN RAIN RAIN:( Thats all I can see on the 18z for here, FFS, i hope its just a dud run and not the start of a trend.:rolleyes:

irish1967

Pangea wrote: »

Im suprised ,I havent had any grauphel here, just a bit earlier before the real snow came.
A few showers came earlier and had real fluffy snow, like if it was coming out of a blowing machine ,didnt last too long though.

Could one of the experts explain why all the 'snow'' I am also getting is grauple ? Radar showing the precip but it's not snow. Will it change and what present condition needs to change to facilitate this change. Thanks.

Harps

irish1967 wrote: »

Could one of the experts explain why all the 'snow'' I am also getting is grauple ? Radar showing the precip but it's not snow. Will it change and what present condition needs to change to facilitate this change. Thanks.

I've always wondered that as well. Asked during the last cold spell as it seems totally random as to whether it falls as snow or graupel.

Obviously there has to be a reason behind it

ffarrell7

Even on some of my money trips to the French alps there are times when a lot of graupel falls but I do not know why.

ciaranm

ffarrell7 wrote: »

Even on some of my money trips to the French alps there are times when a lot of graupel falls but I do not know why.

Oooooooh la de dah

what the hell is a money trip?

Musicman2000

BEASTERLY wrote: »

RAIN RAIN RAIN:( Thats all I can see on the 18z for here, FFS, i hope its just a dud run and not the start of a trend.:rolleyes:

Thats not a precp type chart posted above, this would be.
There is a serious amount of toys being throwing out of the pram over on netweather, but dont panic the GFS is all over the place, take it with pinch of salt if it did come off, get the snow ploughs out

Hammy_irl

Here is what Irish weather say graupel is:
http://www.irishweatheronline.com/2010/12/grapuel-what-on-earth-is-it.html

lucernarian

The pattern for me was that showers that only started to form when the humid air reaches the coast fell more as graupel, while more mature showers that were already formed by the time they hit the coast fell more as snow. So places further inland or where the showery conditions are more established or indeed organised were possibly more likely to see snow instead of graupel?

cherryghost

I'm not trusting any GFS models beyond 24 hours at this point. Everything that it's rolled out this week has gone awry. The only event set in stone is tomorrow evenings one and even that's been given a slight downgrade

cherryghost

Right, I'm off for the night. Got a headache looking at everything change so drastically in the space of 24 hours:

To summarize:

West/Midlands, expect 10-15cm of snowfall tomorrow afternoon and evening
North, expect about 10cm of snowfall on top of what you already got
South/East, expect about 5-10cm of snowfall

Saturday should be showery again, but the damn models are showing some snowfall on the south/east, and some aren't showing anything, so hard to predict.

Sunday is showing a snowstorm with a possibility of rain along the south/east margins. Really can't see it happening. Very confused :pac:

Night all

Rosswind

https://www.fnmoc.navy.mil/wxmap_cgi/cgi-bin/wxmap_all.cgi?type=prod&area=ngp_europe2&prod=prp&dtg=2010121618&set=Core

Thought I'd add my tuppence and see does anyone agree that Sunday seems to be showing as the day the low really develops and arcs back over Ireland (South and East). If it deepens to the 968 suggested here there could be massive fallout with potential for drifting... Supposed to be driving from Cork to Mayo on Monday....
Edit: I've used this site for years even though Explorer doesn't recommend entering it.

Pangea

Grauphel showers here now. What a waste.

@ Rosswind
It won't go to 968.
That kind of thing only usually happens over open water.Anyway thats the nogaps model,it's not consulted very much I think.

The GFS especially and all models are chopping and changing right left and centre so really all you can do is take and average and hope for the best.
That would broadly put the heaviest precip south of Dublin alright.
It should be snow except for some sleety mixes within a mile of the coast from time to time as the strong winds slosh up the 11c sea adding a bit of warmth above it.
Note though that in the previous spell,there were strong winds at times too with the streamers and here 2 miles inland,it all fell as snow and 3 weeks later it's still on the ground,some of it!

BEASTERLY

Deleted User wrote: »

@ Rosswind
It won't go to 968.
That kind of thing only usually happens over open water.Anyway thats the nogaps model,it's not consulted very much I think.

The GFS especially and all models are chopping and changing right left and centre so really all you can do is take and average and hope for the best.
That would broadly put the heaviest precip south of Dublin alright.
It should be snow except for some sleety mixes within a mile of the coast from time to time as the strong winds slosh up the 11c sea adding a bit of warmth above it.
Note though that in the previous spell,there were strong winds at times too with the streamers and here 2 miles inland,it all fell as snow and 3 weeks later it's still on the ground,some of it!

Hi BB, the 18Z shows pure rain not even a hint of sleet for the south east(netweather precip-type charts). Do you think this wrong?

M.T. Cranium

I've been basing my forecast on the assumption of greater development around 19th-20th so the 18z GFS isn't going to cause a forecast amendment, as to the actual strength of the storm as shown, would prefer to see this confirmed by model consensus at 00z ... agree that it shows potential for very heavy precip that could be mixed near southeast coast, but would likely be all snow inland. My hunch is that the eventual solution will be similar but a bit further south and angled somewhat less to the northeast, perhaps a track across the south coast of England as far north as London. This would allow some of the toys back into the pram over on the other forum, without robbing Ireland of its snow.

Not wanting to wishcast either but I have to keep the larger picture in mind and with the PV dropping southwest then apparently circling around to ESE, the more likely track evolution would be west to east along the 528 dam thickness. Just looks a bit too easy a rebound on the 18z GFS.

BEASTERLY

M.T. Cranium wrote: »

I've been basing my forecast on the assumption of greater development around 19th-20th so the 18z GFS isn't going to cause a forecast amendment, as to the actual strength of the storm as shown, would prefer to see this confirmed by model consensus at 00z ... agree that it shows potential for very heavy precip that could be mixed near southeast coast, but would likely be all snow inland. My hunch is that the eventual solution will be similar but a bit further south and angled somewhat less to the northeast, perhaps a track across the south coast of England as far north as London. This would allow some of the toys back into the pram over on the other forum, without robbing Ireland of its snow.

Not wanting to wishcast either but I have to keep the larger picture in mind and with the PV dropping southwest then apparently circling around to ESE, the more likely track evolution would be west to east along the 528 dam thickness. Just looks a bit too easy a rebound on the 18z GFS.

Hi M.T,

How from the coast would you consider inland. I presume if the low shifts south there will be less chance of the precipitation to be mixed? Mild air not getting as far north?

Eastcoastryan

Deleted User wrote: »

@ Rosswind
It won't go to 968.
That kind of thing only usually happens over open water.Anyway thats the nogaps model,it's not consulted very much I think.

The GFS especially and all models are chopping and changing right left and centre so really all you can do is take and average and hope for the best.
That would broadly put the heaviest precip south of Dublin alright.
It should be snow except for some sleety mixes within a mile of the coast from time to time as the strong winds slosh up the 11c sea adding a bit of warmth above it.
Note though that in the previous spell,there were strong winds at times too with the streamers and here 2 miles inland,it all fell as snow and 3 weeks later it's still on the ground,some of it!

Hey BB, thanks for the updates today. Just a quick question if you dont mind. I noticed on the weather earlier that Evelyn mentioned a Low Pressure coming down from Scandanavia tomorrow and positioning itself over Ireland for the weekend, would this mean continuous snowfall or would it fizzle out? I have noticed over the past few years that we seem to do much better from streamers from the Irish sea rather that weather fronts, the latter seem to raise temps and generally mean rain for here. I also noticed that even though winds were easterly, that trogdors site was saying NW winds for here, I am assuming that dropped the temp as the air wasn't coming off the warm sea, when it did switch Easterly, the temps went up!!!

Sorry if I am waffling but I am wondering (based on models) which set up is most likely for this weekend?

Eastcoastryan

M.T. Cranium wrote: »

I've been basing my forecast on the assumption of greater development around 19th-20th so the 18z GFS isn't going to cause a forecast amendment, as to the actual strength of the storm as shown, would prefer to see this confirmed by model consensus at 00z ... agree that it shows potential for very heavy precip that could be mixed near southeast coast, but would likely be all snow inland. My hunch is that the eventual solution will be similar but a bit further south and angled somewhat less to the northeast, perhaps a track across the south coast of England as far north as London. This would allow some of the toys back into the pram over on the other forum, without robbing Ireland of its snow.

Not wanting to wishcast either but I have to keep the larger picture in mind and with the PV dropping southwest then apparently circling around to ESE, the more likely track evolution would be west to east along the 528 dam thickness. Just looks a bit too easy a rebound on the 18z GFS.

Hi, I know this thread is for model discussion only but can I just say that it's great to see somebody thats so dedicated to weather and so detailed in their analysis, it helps so many people over here, I dont like bashing Met Eireann as I know sometimes they are in a no-win situation but if they gave an accurate forecast like you do, then I think they would be appreciated much more! I look forward to reading your forecasts and want to wish you a Happy Christmas!

maquiladora

BEASTERLY wrote: »

Hi BB, the 18Z shows pure rain not even a hint of sleet for the south east(netweather precip-type charts). Do you think this wrong?

Huh? Might be sleet right on the coast at times but away from the sea at all and you would have serious snow inland for the southeast of the GFS.

mickger844posts

BEASTERLY wrote: »

Hi BB, the 18Z shows pure rain not even a hint of sleet for the south east(netweather precip-type charts). Do you think this wrong?

Just took a look at GFS and UKMO and your right, -4 850s :eek: We are screwed in the south east if that happens.

M.T. Cranium

I would consider "coastal" when applied to snow discussions to be land within 5 kms of the shore that is also lower in elevation than 50 metres asl. But I should get a handle on what readers think coastal means, because if I use it, I would like the readers to get the right message from the use.

Around here, we also get a lot of mixed winter precip by shoreline exposure and elevation. I live about 120 metres above sea level and probably 10-15 kms from the shore depending on the operating wind direction. In general, this is just about the 50-50 point for rain and snow in marginal situations. There's a hill nearby here (with a university on it) that rises to 300 metres and it quite often has snow when we have rain and 3 degrees or less.

Whether it would work around Dublin and the southeast, I'm not sure, but I've learned to recognize maybe three rain-snow boundaries at approximately 25m, 100m and 200m that seem to occur more frequently than other possible elevation dividers. Perhaps this has something to do with the way arctic air flows out of the interior from perhaps three different routes with varying intensity to almost reach the shore.

In a normal winter, we get a bit more snow even in the lower elevations around here, than most of Ireland, but this winter, we have had only two days with snow lying at my location, and maybe five days on "the mountain" but the local real mountains have remained snow covered throughout the past two months. Our local mean temperature so far this month stands at about 4.5 C. The "IMT" that we use in the forecast contest is below zero C.

isle of man

isle of man wrote: »

they do, but there going that hard that it passers before it gets chance to do anything worth talking about.

its all hail so far

i would like to thank my negative comments that brought the snow, 10mm so far dropped in about an hour between showers,

BEASTERLY

maquiladora wrote: »

Huh? Might be sleet right on the coast at times but away from the sea at all and you would have serious snow inland for the southeast of the GFS.

This shows rain for me anyway(15km inland):


M.T's post has reassured me a bit though:)

BEASTERLY

M.T. Cranium wrote: »

I would consider "coastal" when applied to snow discussions to be land within 5 kms of the shore that is also lower in elevation than 50 metres asl. But I should get a handle on what readers think coastal means, because if I use it, I would like the readers to get the right message from the use.

Around here, we also get a lot of mixed winter precip by shoreline exposure and elevation. I live about 120 metres above sea level and probably 10-15 kms from the shore depending on the operating wind direction. In general, this is just about the 50-50 point for rain and snow in marginal situations. There's a hill nearby here (with a university on it) that rises to 300 metres and it quite often has snow when we have rain and 3 degrees or less.

Whether it would work around Dublin and the southeast, I'm not sure, but I've learned to recognize maybe three rain-snow boundaries at approximately 25m, 100m and 200m that seem to occur more frequently than other possible elevation dividers. Perhaps this has something to do with the way arctic air flows out of the interior from perhaps three different routes with varying intensity to almost reach the shore.

In a normal winter, we get a bit more snow even in the lower elevations around here, than most of Ireland, but this winter, we have had only two days with snow lying at my location, and maybe five days on "the mountain" but the local real mountains have remained snow covered throughout the past two months. Our local mean temperature so far this month stands at about 4.5 C. The "IMT" that we use in the forecast contest is below zero C.

Thanks M.T, im glad to hear im not coastal:D
Cheers

Musicman2000

mickger844posts wrote: »

Just took a look at GFS and UKMO and your right, -4 850s :eek: We are screwed in the south east if that happens.

Dont worry it wont, That low could push further south, and MT also said this

Musicman2000

BEASTERLY wrote: »

This shows rain for me anyway(15km inland):


M.T's post has reassured me a bit though:)

wouldnt worry to much about that chart:)

maquiladora

BEASTERLY wrote: »

This shows rain for me anyway(15km inland):


M.T's post has reassured me a bit though:)

I wouldn't put those kind of charts too much attention. You'll notice that all areas of snow, everywhere are surround by bands of rain/sleet at the edges regardless of what the conditions are.

I can also tell you as a fact that during the last cold spell I had snow falling at close to sea level where that GFS precip type chart was showing rain/sleet.

The situation would be more complex than those type of 'black or white' charts can display.

Anyway, this is far from nailed yet so no point looking at it in much detail yet, things will change before then.

isle of man

If things stay as they are.

then the isle of man is right in the fireing line of all that prep going round in circles,

o the joys:D

Calibos

BEASTERLY wrote: »

Thanks M.T, im glad to hear im not coastal:D
Cheers

150m from my house...



F**K

:rolleyes: