The 12zs tonight continue in general to paint a dry theme. There are subtle differences in the prognosis of the big three beyond the innitial retrogression of the High pressure west of the UK. GFS gradually brings a slack rather cold Northerly biased airflow over the UK with the chance of a few showers and frost by night. High pressure returns over the UK by the end of the run although it would be a much colder version than that we have currently. The GFS ensembles show a slow cool off towards the long term mean by the end of the run with the Control falling off a cliff right at the end though it has little support.  ECM also brings a Northerly of sorts but at the end of its run it looks almost like a re-run to where we started this current spell off with High pressure ridging NE from the Azores to no doubt show a centre of high pressure over the UK in the days that follow 240hrs. In Summary the weather would become cooler by the end of this week and after a few cooler days with frost at night I wouldn't be surprised to see a steady warming again in 10 days time if ECM is to be believed. With regard to rain it's looking as bleak as ever for the water authorities as High pressure maintains it's shield around the British Isles. 

Updated CFSv2 pressure anomalies for April continue to suggest high pressure to north west.

http://www.cpc.ncep.noaa.gov/products/CFSv2/htmls/glbz700e3Mon.html

http://www.cpc.ncep.noaa.gov/products/CFSv2/htmls/glbz200e3Mon.html

The 00zs from GFS, UKMO and ECM this morning all show high pressure easing its way West to the West of Ireland by Thursday. The very warm temperatures currently will ebb away in the far North from tomorrow and the South by Friday. Thereafter, UKMO sinks the High South towards the Azores but maintaining a ridge NE across the South keeping fine but less warm conditions here but hardly cold. GFS gradually brings a Northerly down South on consecutive attempts and eventually succeeds late in FI with rather cool but dry weather persisting for many though increasingly showery in the East in the far reaches. The Ensembles though show the operational a bit of a cold outlier from April 6th with many members maintaining dry conditions in London until at least the 7th. ECM finally takes High pressure right away West to a ridge in mid Atlantic allowing a gentle chilly Northerly over the weekend. The far NE could see some showers but a lot of dry weather maintained elsewhere. Late in its run a high pressure ridge collapses away East from Southern Britain and the Atlantic takes hold with some rain in the NW. However, as always in this setup the NW would revert to its status quo of capturing the rain while Southern and Eastern areas see very little. Nevertheless, it is a slightly different option than shown of late. More runs needed.

Originally Posted by: snow 2004

Don't forget if we get a cold northerly combining with the strengthening sun there could well be a lot of heavy thundery hail and snow showers in the afternoons. Temperatures wold typically be around 7 degrees in the sun but would dive closer to 0 in the beefy showers.

Now your talking.

What we really need is lots of prolonged heavy rainfall.......!

Originally Posted by: Matty H

Originally Posted by: Charmhills

Originally Posted by: snow 2004

Don't forget if we get a cold northerly combining with the strengthening sun there could well be a lot of heavy thundery hail and snow showers in the afternoons. Temperatures wold typically be around 7 degrees in the sun but would dive closer to 0 in the beefy showers.

Now your talking.

What we really need is lots of prolonged heavy rainfall.......!

We don't really, Duane. What some need is a showery-type spell of weather. A deluge will largely run off.

I wasn't meaning weeks and weeks of the stuff Matty, but it would help alittle and even with the local flower in bloom project going on round here as the soil is so dry.

An impressive GFS 12z FI today. Convective showers widespread and potent in the north(east).

IF we end up with a massive block to our NW, its proximity will be very important for determining the shower extent and intensity.

Often such blocking tends to be followed by high pressure near the UK but tending to back west again (in my experience, anyway) with a reload or two possible in the time between now and mid-May. Potentially we could then break out of the "cool blocked" pattern in time for summer... you never know!

Before dreaming of tremendous April showers lasting into May only to be followed by a splended summer, one should not that ECM has been quite persistent in breaking down a northerly outbreak and setting up a Euro block rather than a Greenland block. That isn't too hard to do with the Atlantic tracking south and it could lead to insane warmth once again - there's a fine line that divides what would evolve into a chilly pattern and what would evolve into a very warm pattern.

Either way we can get some useful rain but in both cases high pressure needs to let troughing get close enough to the UK. ECM's tropical blowtorch idea from the end of the 00z run could deliver a right old deluge if the trough gets far enough east, although as Matty says, we don't want loads of rain in a short period of time, rather a more moderated amount for a few weeks.

Edited by user 27 March 2012 18:59:32(UTC)  | Reason: Not specified