Model Output Discussion

[damianslaw]

eh?

Am I missing something?

The first low-the main one starts life way SW of the UK, the next one starts life w or sw of Iceland, so how can they follow 'a similar track', at least not until they have got east of the UK, assuming they both do that?

Maybe its just me being a bit thick?

Yes granted the two lows will have developed in very different locations, perhaps I should have clarified that the eventual path of both will be similiar i.e. out into the North Sea.

[Thundery wintry showers]

Is it going to get colder? We seem to have gone from 1 page a day to 4 today! Also. now that winter is over & we're well into spring, would you mind not talking about charts that show colder weather as "upgrades", I assure you that for many of us, they are most definitely downgrades!

Aside from the obvious issues, this argument contains a key flaw: the term "upgrade" generally means "increase in intensity/significance", and in the last couple of days successive runs have tended to increase the intensity and significance of the northerlies: therefore, from that perspective, the northerlies have upgraded and the use of the term is completely justified.

Re. Robthefool, one irony with the current setup is that you're actually more likely to get 6C and cold rain if the northerly reduces in intensity in successive runs, because that implies more in the way of Atlantic frontal activity getting into the mix. ECM's setup still could give wintry showers for a couple of days on Wednesday and Thursday, then turning pretty wet and windy (though probably a mixture of weather types rather than continually dull & wet) through the Easter weekend. UKMO keeps things pretty wintry, while the GFS's outlook sees two or three days of northerlies and then a fairly cool showery Easter weekend. Thus how cold, and how wintry, are factors that are still open to question.

[SP1986]

is it just me or are the daytime maximums the GFS programming just way too unrealistic? The GFS is showiing 0C degrees in the daytime, now I remember the 10th March 2006 even when it was snowing it wasnt below 0C. I imagine 0C maximums in April are rare?

dont get me wrong though, snow looks fairly likely but not to the tune of 0C maximums surely?

[A.J]

Well, well, well, I dont post on this particular thread very often, but, who would have 'thunk it'?...GFS showing a definite trend towards mid-week winter madness for a good chunk of the country...Re-occuring charts now for the past 48 hours, all showing the same thing...WB's and DP'S 0C or a tad below for the midlands on the 18z, and if that pans out then there's only one outcome....snow (On a side note, I've lived in the West Midlands for the past 4 years, and the best accumulative snowfall has always happened just before easter )

[BlueHedgehog074]

is it just me or are the daytime maximums the GFS programming just way too unrealistic? The GFS is showiing 0C degrees in the daytime, now I remember the 10th March 2006 even when it was snowing it wasnt below 0C. I imagine 0C maximums in April are rare?

dont get me wrong though, snow looks fairly likely but not to the tune of 0C maximums surely?

Probably a touch extreme considering on Tuesday, in particular, there looks to be some very reasonable 850 hpa high-up temperatures with Dewpoint temperatures generally around 1*C or below (except for some South-Eastern areas, where Dewpoint temperatures look to be higher at first). The Dam's are also looking mostly good with lower Dam's getting pushed down to Southern areas from the North.

With temperatures indeed looking close to freezing, with Southern areas getting a the same treatment throughout Tuesday, those temperatures do look a little worryingly cold when comparing them to some other forcasts. Interestingly, the BBC have my place down for 11*C on Tuesday, which is a fair deal warmer. Come to think of it, that 11*C perhaps is just representative for just the very beggining part of Tuesday and expect the temperatures to quickly drop as it approaches mid-morning, onwards.

I feel that, especially up North, there would be not much of a problem for places receiving snow with temperatures above freezing. There have been a few times this Winter, in fact, where I've had wet/dry snow falling with temperatures a degree or two above freezing. I think the heavier bursts of precipitation had helped, too, and seems like one of the other factors to help for next Tuesday's event. Mind you, heavier bursts of precipitation during colder periods does seem to lower temperatures.

While I would say freezing point temperatures can be rare in April (though definitly not impossible), I think the fact that it can still snow during that month means some possible freezing point temperatures occuring at times. Obviously, though, this would depend on other conditions such as the high-up temperatures and Dam's numbers and whether the winds were coming from a suitable direction to drag in some very chilly air from the North

To conclude, I agree with the above post(s) that there is some good snow potential for the next few days during next week. I remember once reading one of the member's statuses saying how Tuesday's Low needs to have an Easterly postioning to it to allow those cold Notherly winds to penetrate far South (think it was something like that, anway). And that circular Low Pressure, according to the GFS Sea Pressure Map, does seem to be sort of doing that, so should help to open up the door to some cold winds.

@ajpoolshark: Same here. This is my third post I've done in here now, having spent a while looking at the GFS Maps. But yeah, I definitly agree with you about the outcome and the low Dewpoint's; would make for some very exciting days ahead.

Although this is looking great, I would probably say that I'm starting to get a little too excited for an event which is some days away, but I have a feeling that some sort of snowy mix will still arise from this. Sorry for waffling on a bit, too - I think I spent too much time looking at the Maps/Forcasts (lol).

[Eugene]

Daytime temps charts on GFS look very realistic to me, 11C to 13C next three days falling to single figures for all on tuesday, must be noted only daytime 0C's are in northern england and -1C over the highlands, i dont think anybody can dismiss max temps of 0C to -1C in the lake District/Highlands in late March.

There have been a few times this Winter, in fact, where I've had wet/dry snow falling with temperatures a degree or two above freezing

Hey when it snows in the UK to low levels the temperature most of the time is a degree or two above zero in winter.

[mushymanrob]

Is it going to get colder? We seem to have gone from 1 page a day to 4 today! Also. now that winter is over & we're well into spring, would you mind not talking about charts that show colder weather as "upgrades", I assure you that for many of us, they are most definitely downgrades!

Spring weather will always swithch around from mild to cold. Snow is not uncommon in April, but please don't keep seizing on every model chart that shows a few flakes of snow as if it's January!

Rant over.

well said dave, especially the emboldend

a rather unpleasant few days is pretty much certain before 'normal' is resumed albeit cool. im more concerned about pressure highs in the mid atlantic tbh, mid atlantic ridges will keep us mainly in a cooler regime and delay anything pleasantly warm. as long as we dont have a repete of spring 1975 though im not fussed!

[phil nw.]

Monday into Tuesday is when the Cold air moves across the whole country.

Interesting to note the large temperature differences across Central areas here,

http://www.wetterzentrale.de/pics/Rtavn7217.png

A lot of percipitation about so Snow likely across many areas as the cold air comes through.

It does look less Cold after a couple of days though as the cold Northerly turns more Westerly with more lows coming in from the Atlantic.

[johnholmes]

The 18z using Extra showed 64mm precipitation for my location between 06z Mon-03X Wed. The 00z has 55mm over about the same period.

[Ben_Cambs]

Nothing major has changed from yesterday regarding Tuesday into Wednesday. GFS shows it starting off as rain in all areas, with it starting as sleet over the Pennines (300m+) and then the colder Arctic air begins to bring down temperatures and turns the PPN to snow on its North and North Western Flank, then the colder air filters south bringing snow to many low lying areas by Tuesday night, though I suspect on the south coast it will be of rain and sleet. The snow will clear on Wednesday morning from the East coast. Snow showers will continue affect Northern Scotland, Northern Ireland, Shetland, Orkney and The Hebrides. The LP will affect most of England, Wales and possibly up to the Scottish Borders area

Edited March 27, 2010 by Snowman0697

[frostyjoe]

this is very worrying gfs has 4c maxes right through week but met office say 8c by wednesday that isnt cold we had that yesterday..

[snowmadchrisuk]

this is very worrying gfs has 4c maxes right through week but met office say 8c by wednesday that isnt cold we had that yesterday..

Some changes going on in the 6z .. Nothing to bad just yet but the low is in a different position , The Heavy precipitation on Tuesday is further North and Exits quicker. I hope were not going to see last minute downgrades.

[frostyjoe]

Some changes going on in the 6z .. Nothing to bad just yet but the low is in a different position , The Heavy precipitation on Tuesday is further North and Exits quicker. I hope were not going to see last minute downgrades.

its already downgraded.

[snowmadchrisuk]

its already downgraded.

I haven't had time to see the ooz but the 18z last night was a Snow fest.

[ian34]

Some changes going on in the 6z .. Nothing to bad just yet but the low is in a different position , The Heavy precipitation on Tuesday is further North and Exits quicker. I hope were not going to see last minute downgrades.

forgive me for saying so but it would be my hope that it does downgrade!!!

[snowmadchrisuk]

forgive me for saying so but it would be my hope that it does downgrade!!!

Forgiven But like I say it is not that bad , Still showing heavy Snow Showers Tuesday Night in the Midlands, Just on the 6z it is Showers where before it was Frontal. (For Tuesday anyway)

[ian34]

Forgiven But like I say it is not that bad , Still showing heavy Snow Showers Tuesday Night in the Midlands, Just on the 6z it is Showers where before it was Frontal. (For Tuesday anyway)

i am going on the norfolk broads for a week on tues what will it be like there??

[Wilks]

forgive me for saying so but it would be my hope that it does downgrade!!!

Same here and I'm absolutely sure it will -hopefully no snow around these parts last thing needed, roll on summer.

[Frosty.]

The gfs 00z op run has a wintry look from start to finish with polar maritime air dominant but the ecm loses interest fairly early and reverts to milder but still unsettled conditions with a hint of something more settled in around 10 days time but a lot of weather before then which looks rather colder than recently and a fair chance of heavy rain turning to wet snow from the midlands northwards during tues/wed (mostly on hills) with colder air feeding down from the north bringing scattered wintry showers to most of scotland at times.

[Milhouse]

Same here and I'm absolutely sure it will -hopefully no snow around these parts last thing needed, roll on summer.

Signs are that the northerly will be short lived and wont stick around through Easter. Pressure building from the south looks to be a feature from next weekend onwards with the ecm ending up very nice at 240h. Support from the metO long range forecast too.

[ian34]

i am going on the norfolk broads for a week on tues what will it be like there??

please

[johnholmes]

wet to start at any rate and cold

re the 06z run its now dropped the precip total to 45mm and it mostly finishes by 09z Tuesday, some further mainly light precip to 21z Tuesday giving a total of 48mm.

So its dropped the total from 64mm on the 18z to 55mm on the 00z and now 48mm on the 06z.

Like I posted last evening this is fairly typical of GFS/Extra at this time range.

It could just as easily pick it up again and extend the period on subsequent runs over the next 24 hours or so.

[snowmadchrisuk]

i am going on the norfolk broads for a week on tues what will it be like there??

Wet , Windy and Cold . Feeling bitter under the rain and a chance of Sleet . very limited chance of any bright spells with Low pressure in the North Sea. I left my holiday a little later this year and heading for Felixstowe on the 26th April. (They say on there website the Sunniest place in the UK , but what will the GFS say)

[Pixel]

i am going on the norfolk broads for a week on tues what will it be like there??

please

Maybe time to open up the 'regional threads' one last time so we can read the Model analysis discussion here

[snowmadchrisuk]

Maybe time to open up the 'regional threads' one last time so we can read the Model analysis discussion here

Agreed ... Come on Paul plzzzz it will save a lot of off topic posts

Edited March 27, 2010 by snowmadchrisuk