Low pressure dominates the UK pattern tonight through Sunday with a weakening phase through the second half. This low will bring not only the first gales in weeks to southern Ireland and the UK but since we’re now into late April, warm air pushing north with pulses of precipitation will trigger embedded thunderstorms.

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GFS has pressure tomorrow morning down to 986mb. Haven’t seen a centre this low, this close to Ireland in a good 4-5 weeks.

A decent amount of rain to come over the next 72 hrs across not just the UK but Europe as a whole. Note the rains again down towards the Med Sea. You can see why the CFSv2 has a cool summer here given all the rain of late. When going by the wet ground equals, cooler temps theory.

Models indicate a southward weakening process of the low into early next week, followed by a late season shot of cold.

Modelling has unsurprisingly backed off in the snow department but given the chill particularly in the mid and upper levels, hefty showers triggered by higher lapse rates (temperature difference with height), we may see ‘surprise sleet and snow’ mixing with rain late next week as this set often transfers cold aloft down towards the surface. In any sunshine and out of the wind, it feels pleasant but any northerly breeze and it will feel March-like.

Here’s a glance at the latest surface charts as shown in today’s video.

GFS surface 24 hrs

48 hrs

72 hrs

Little change Tuesday-Wednesday but by Thursday, cold air begins to advance south over the UK. Note the wet conditions widely across the continent as the trough drills south and east.

168 hrs

5,000ft level temps at 168 are pretty cold.

We’re likely to get clear skies with this northerly flow and so expect night frosts.

GFS snow chart is unimpressive. Though not unheard of, snow gets tougher and tougher to come by once your into May. Very strong sunshine makes it tough for the atmosphere to stay cold enough, long enough to support snow, even at 1,000ft. Takes a rather cold air mass to do this but we did see this just last year.

NAO looks set to go back towards positive in the 7-14 day period and GFS does have a ridge building back into the UK and western Europe once the trough slides east.

Note that by 204 hrs or next Saturday the model has the trough sliding east with ridging and warmer air building in from the Azores.

Rather wet looking over Scotland.

The GFS ensemble 7-day mean 500mb height anomaly shows the return of positive heights beyond the front running 7 days.

0-7

7-14

9-16

Be sure to watch today’s video.

No post tomorrow but will have a full update again Sunday!

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