Saturday - Sunday Low Pressure

[Eskimo]

A deepening area of low pressure is beginning to form over France, this area of low pressure will bring to our shores some unusual weather for April (more akin to October). We could see the potential for up to 60mph winds, locally 70mph gusts in prone parts are likely. Rain totals will widely exceed 30mm but there is potential for 40mm, even 50mm somewhere. Below are the models.

Fax Charts: +48h http://62.89.145.4/fax/PPVI89.jpg

+60h http://62.89.145.4/fax/PPVJ89.jpg

+72h http://62.89.145.4/fax/PPVK89.jpg

NAE Precips: +36h http://www.weatheronline...S=0&WMO=&PERIOD=

+48h http://www.weatheronline...S=0&WMO=&PERIOD=

NAE Accum: +48h http://www.weatheronline...M=0&PERIOD=&WMO=

I don't have access to any other models but It would be welcome for many if you could post other charts based on this system below.

[Eskimo]

Looks like I may have put this in the wrong place. Severe weather discussion thread is more appropriate.

[I remember Atlantic 252]

unnecessary thread, just a normal Sunday, only a bit of rain,

[Bishop Brennan]

unnecessary thread, just a normal Sunday, only a bit of rain,

I disagree. This type of system is quite an unusual occurrence for the time of year. The forecasted rainfall accumulations combined with strong winds certainly make it a noteworthy event IMO.

Please continue Eskimo.

Bish

[Eabie]

Thanks for starting this thread. There's been relatively little discussion about Sunday's system, so it gives us all a go-to place to discuss or read about it in more detail. I'd be overjoyed if rainfall totals exceeded 30 mm over here -- I haven't seen a good hard rain like that in a couple years, to be honest. Not really sure what to expect for my area, but we'll see.

Edited April 27, 2012 by Eabie

[Eskimo]

unnecessary thread, just a normal Sunday, only a bit of rain,

Sorry to disappoint. Only a bit of rain is a huge underestimation, many areas could get totals nearing 50mm which will inevitably cause localised flooding. A "normal sunday, only a bit of rain" is ignorant.

[Gael_Force]

A very unusual system for any time of year, more so on the penultimate day of April. The high res models (NAE, WRF, HIRLAM) make more of it, being deeper and slower to clear to the west. Copious amounts of rainfall and strong winds from a non prevailing direction will make for a thoroughly horrible weekend.

[Bishop Brennan]

Eskimo, am I right in saying that the large area of rain snaking up from France is the beginnings of this system? The Will It Rain Today radar (http://www.raintoday.co.uk) shows this very clearly if you scroll down far enough.

Bish

[Eskimo]

Eskimo, am I right in saying that the large area of rain snaking up from France is the beginnings of this system? The Will It Rain Today radar (http://www.raintoday.co.uk) shows this very clearly if you scroll down far enough.

Bish

I've been tracking that for some time, in fact it looks totally different than on the models. The main bulk of the precipitation in question isn't due to hit until later on Saturday for most parts, according to the radar we might see rain start in the next couple of hours which wasn't forecast I believe.

[Gael_Force]

Eskimo, am I right in saying that the large area of rain snaking up from France is the beginnings of this system? The Will It Rain Today radar (http://www.raintoday.co.uk) shows this very clearly if you scroll down far enough.

Bish

The low is forming in the area of disturbed weather on the Costa Almeria, SE Spain.

http://www.aemet.es/es/eltiempo/observacion/satelite/masas

[Evening thunder]

Some of the more recent charts are unfortunately suggesting we won't get any interesting totals in my location, with heavier stuff going to the west and east.

We actually had a bit of unforecast rain this morning, but most of the heavier stuff went to my SW and got heavier after it has passed over.

[Bishop Brennan]

Some of the more recent charts are unfortunately suggesting we won't get any interesting totals in my location, with heavier stuff going to the west and east.

We actually had a bit of unforecast rain this morning, but most of the heavier stuff went to my SW and got heavier after it has passed over.

Indeed, it seems the far south may escape the worst of the conditions. It'll still be wet & wild for a time though.

Bish

[johnholmes]

the 12z outputs from GFS/Extra/NMM and the Met NAE will be interesting for spot totals for the rainfall. I am still amazed just how divergent they can be at times so close in to an event.

[Aaron]

NAE totals for 6am Monday

A dry slot in NW England but wet elsewhere, especially the east coast from East Yorkshire down to Essex

[Aaron]

unnecessary thread, just a normal Sunday, only a bit of rain,

We understand you dislike rain but can you keep the silly comments to yourself please?

[Bishop Brennan]

A dry slot in NW England but wet elsewhere, especially the east coast from East Yorkshire down to Essex

I'm always intrigued when these sort of "dry slots" appear in forecasts. What do we think this might be down to - I'm guess a slight sheltering effect due to the higher ground in the north?

Bish

[suffolkboy_]

The NAE totals show 37mm of rain for my location by 6am tomorrow. That would be the wettest day for over 5 years! We very rarely get large rainfall totals from frontal rainfall in the East, over an inch of rain in a day is quite rare here, maybe only once a year for my location.

The river through my village (the Deben) has already breached its banks twice this week, from relatively moderate rainfall totals. We now have saturated heavy clay, and the possibility on an inch and a half of rain coming......doesn't take a genius to work out whats going to happen.

[knocker]

Rainfall sequence for tomorrow and 1300 surface chart.

[Aaron]

I'm always intrigued when these sort of "dry slots" appear in forecasts. What do we think this might be down to - I'm guess a slight sheltering effect due to the higher ground in the north?

Bish

I recall NAE predicting something similar in February during the snowfall for Huddersfield - a dry slot. It came to fruition and Huddersfield was frequently in an area of light to no precipitation. Something to do with topography, Huddersfield being in a valley.

[NW Leeds Russ]

Tbh shocking meto forecast last night for today.. was supposed to be dry, odd shower. It hasn't stopped raining here all day bar 10 minutes.

Really surprised nobody has mentioned what tomorrow would have bought in mid January perhaps ????

[Terminal Moraine]

I'm always intrigued when these sort of "dry slots" appear in forecasts. What do we think this might be down to - I'm guess a slight sheltering effect due to the higher ground in the north?

Bish

I would think this is down to the prevailing wind direction during the rain being NE/E, thereby putting NW England in a rain shadow area from the Peak District and southern Pennines. Whether or not the rain shadow effect would be great enough to reduce to total to around 5 mm is open to question.

The Met' Office forecast for the Peak District this morning was suggesting heavy and persistent rain on east facing slopes suggesting a significant orographic effect.

[The underwriter]

I agree Russ. When you think how far below normal the temperature is today -its around 7 degrees at the moment in Essex, and gradually falling, if the same system happened in the winter the temp would probably be no more than -2 during the day with heavy snow. When the wind picks up, as forecast tonight it would be drifting badly.

[jamesay]

Tbh shocking meto forecast last night for today.. was supposed to be dry, odd shower. It hasn't stopped raining here all day bar 10 minutes.

Really surprised nobody has mentioned what tomorrow would have bought in mid January perhaps ????

and here too -it was raining at 9 this morning and hasnt stopped yet, prob won't til tomorrow avo.

[johnholmes]

welcome jamesay but would you do everyone a favour please and drop your nearest town in your avatar please otherwise your weather reports mean little to us?

many thanks

[weatherobsuk]

I would say central/northern England expected to get the worst of the rain tomorrow along the lines of the convergence as milder air coming up from the continent meets the colder air pooling down from Norway. Could be one or two surprises as these two airmasses get together across the Pennines and Yorkshire with orographic lift to boost.