Captain Shortwave

Given the set up, we cannot guarantee that the low will correct southwards, purely because the track is down to the nature of the trough over and east of us. More substantial cold pooling that spreads into the Atlantic, the more likely that the low will be able to maintain a round shape and head more ENE. Tough call at the moment because we still don’t have the details regarding the initial northerly and then the track of that low. As such we have a range of solutions ranging from snow for near enough everyone (stronger northerly and a runner low through the channel), to a bust for near enough everyone (Slack pattern followed by the low pushing on a track through Scotland). Tough call, especially as this could be the last hurrah regarding cold weather until next Autumn.

Yesterdays 12z day 7 Todays day 6 Looks like the more aggressive southwards push of cold air may very well end the spell pretty swiftly unless the low gets squeezed southwards.

850s out for the UKMO, given a northerly flow I suspect areas close to windward coasts would see plenty of showers blowing in on that northerly. Day 6 is probably drier (possible home grown showers), but that Atlantic system is waiting to move across the south.

Quite a difference at day 5, the UKMO has a clean northerly with showers pushing south, the GFS develops a low over the U.K. that raises the risk/reward factor by bring more organised precipitation along with less cold air.

Depends on the mechanics of said breakdown. If it is a direct attack with a trough to the west moving east we often see the trough disrupt and sheer away as it hits cold dense air over Europe. However in set ups with blocking to the north west then we often see the jet returning northwards over Europe as heights continue to back westwards. Anyway, the UKMO day 7 chart does possess an area of interest over future runs. That area of higher heights over Eastern Greenland is the sort of scenario where we could retain heights that could steer Atlantic lows further south later on. Something to keep an eye on. Something like this….

Some subtle differences between the UKMO and GFS regarding that Atlantic low. GFS A secondary feature breaks off from the parent low to move eastwards. UKMO The UKMO keeps the low enclosed and is beginning to build the Azores ridge, direction remains to be seen it i sense the two would diverge further from here.

ECM cold to day 10, with a snow event in the south. The movement of the key players looks quite consistent, as usual though the picture will be a lot less black and white and surface heights may persist to the north, even as the core high moves away.

I suspect that large low off Newfoundland will come into play for day 9/10 as it interacts with the cold air moving west from the Scandi trough. That block over Greenland and Canada is huge, expect another solution bring a low close to the south of the U.K.

I believe it was February 2021 We never got the full blow from that vortex segment and instead saw several days of easterly winds with a weak high to the north. ECM at day 6 I don’t think we will miss out now on being hit by that developing trough over Europe. Impressive consistency comparing to yesterday.

Given we will be in March, then the strength of the sun should be sufficient for convection to develop inland. So a slack low heights overhead shouldn’t be clear and dry like it was during the December spell. Some truly stunning Synoptics with a near perfect cross polar flow. Again I can only stress that momentum will continue to drag the pattern westwards so we need to enjoy what we can get from the 5-10 day range before the high migrates far enough away to pull the jet stream northwards again. This transition could result in significant snow mind you as the Atlantic tries to get back in. The ECM shows this nicely with an active frontal system beginning to move into the south west of the U.K. As someone has mentioned, the GFS quickly creates a surface high after the initial northerly that keeps conditions cold.

Oddly the pattern after day 10 probably has higher confidence than the days preceding this. Purely because the outcome of successful retrogression eventually ends in the same position as the pattern where the Azores high ridges in early on in week 2 The retrogression looks swift as conditions will quickly become more west based -NAO and eventually see low heights return to our north west. A west to south westerly flow will return at some point, it is more a case of seeing whether we can get a northerly flow across the U.K. for a time. I will say that there is a good chance of a quite potent northerly occurring, especially with the polar vortex relocating to our north east.

Not an overly helpful suite in determining where things go, we have hyper-aggressive retrogression still on the table, meanwhile the ECM never really allows retrogression to happen full stop. The ECM keeps the cold pool that moves over the south this weekend entrenched throughout the rest of the run. However that would only really allow for slightly below average temperatures and a few wintry showers in places.

A much better suite so far, still beyond the day 10 mark but you can see the end game by that point on the GEM; GFS still trickling out, but it appears to be pulling the high westwards nicely;

In all honesty the initial northerly/Easterly was going to be pretty weak, so having high pressure closer to the U.K. should mean that sunshine will be more widespread with light winds and overnight frosts. The retrogression signal later on shouldn’t be impacted that much.

For what it is worth the ECM control goes down a similar path with a cold northerly during the first week of March. GEM control Different orientation to the trough, but ultimately the outcome is cold with more of an easterly element rather than northerly in the onset. The fact is we have a lot of runs all pointing the same way, the only question is will the signal hold up for this long wave pattern and can the cold push fully across the U.K. in reality.

Very encouraging signals as we move into March regarding the chance of cold weather. First off; Solid support for high pressure to build towards the north of the U.K. during next weekend. ECM ens there doesn’t appear to be anything substantial at this stage regarding the Arctic maritime flow that backs easterly during this period. There is uncertainty regarding the depth of cold that could back eastwards, but at the moment it is probably the difference between near normal temperatures like where the cold air gets blocked off and low single figures with scattered wintry flurries that have appeared on a few runs now. The ECM operational looks reasonable for this cold flow. The 850s are chilly and the north of east flow should allow for a few showers. Beyond this lies the main interest, the models are toying towards retrograding this high with low heights developing to our east. The result a northerly blast that could offer more potential for those wanting snow. Some pretty extreme solutions have been produced towards the back end of week 2. One to watch. The GFS 00z is very much a dream scenario, low pressure moving south fully embedded in cold air. I guess as usual we would want a colder flow initially from next weekend, as this will keep the high further north and more prone to retrograding when the chance arises. In this case we would rather want to avoid the high sagging with a subtropical ridge over Eastern Europe getting involved.

The ECM this morning will raise some eyebrows. Unfortunately that low never passes the meridian, which basically reduces the wintry potential to zero as opposed to the other models that bring a northerly as the low clears east. Hard to tell where the modelling will go, apart from high pressure being likely to be close by for the rest of the month.

Not a lot on offer this morning, well with the exception of the pattern looking more amplified at the end of week 1 with high pressure hanging on. Yesterdays 00z GEM/UKMO for day 7 Two thoughts, the first is if the ridge retains its core from the subtropics then obviously there is a chance of some very mild or even warm weather developing. The second and polar opposite thought (pun intended) is that the more sheered solutions are not actually far away from developing something far more interesting into week 2. Even if the effects of the SSW will not be visible for some time, we do have a scenario where the zonal winds will be railing off and with the general long wave pattern, there is still a chance of a block to the north east developing and sustaining itself with a colder continental feed. The ECM is still the flattest, but is very different to yesterday when the pattern was a flat westerly.

Another spell of sunny days and frosty nights, this will probably mean that there is a good chance of another positive anomaly for sunshine amounts to add to December and January. In the end this will probably be the most notable element of this winter.

A continental feed for week 2 seems to be increasing in probability. That said there is little sign so far of a clean flow of polar continental air, so at the moment the trend is for conditions to turn colder, but little sign yet of something more significant.

Not overly sold on a stormy period coming up. I get the feeling that the low heights will be a little more compact to the north west. As such conditions will probably resemble a NW/SE split rather than a full on unsettled period. That said it doesn’t change the situation that we will see, with low heights to the north west and higher heights to the south east, which is never good for the U.K. I guess there is hope that any ridging over Europe could become more dominant over time, so I wouldn’t rule out cold during the first half of February just yet. Though we probably need a bit of luck for this to be a snowy set up (Dry/continental would be a favoured version of a cold pattern).

Another minimum of -5c or lower last night. Sunny skies to start here.

It is unusual to have a spell of such slack conditions and not have the high slowly fill with fog and low cloud. As such we have managed to develop some impressively cold minima. It has been interesting to see the bbc forecast that correct the minima for here downwards by a significant amount (Tonight is now forecast to drop to -5c, it wasn’t even expected to drop below freezing just a couple of days ago). Whilst we will probably end up with a mild January overall, it does look like it will be a much more moderate anomaly compared to what was expected just a week or so ago.

A high of 5c again today, it felt surprisingly pleasant given the clear skies and calm conditions. Another very cold night tonight, probably the last one as fronts will start to move south eastwards through the middle of the week.

Third morning in a row where temperatures dropped below -5c. Like yesterday there is some high cloud around but it is looking like another decent day with long spells of sunshine.