Hints of an easterly by start of next week

Figure 1

I realise International Science Fiction Day is still a few months away, but the latest few runs of the GFS model have built a large anticyclone over Scandinavia by early next week, at the start of what could be a run of easterlies across the UK. It also keeps the deep low formed from the remains of Hurricane Jose in mid-Atlantic, and it could be the strong southerlies ahead of this intense low of Friday that helps in the formation of a blocking pattern.

Next week’s developments in the Atlantic

Another interesting week in the Atlantic coming up.  The GEFS model takes the long-lasting hurricane Jose (1)  finally northward, and just skirting the east of the American eastern seaboard (fig 1). Of the two new tropical storms that have recently formed, Lee and Maria (3), it looks like Lee will perish but Maria is forecast to flourish into a category four hurricane by Wednesday. Maria looks likely to follow a similar track to that of Jose, but maybe come a little further west and cause more problems to the Lesser Antilles, before turning northward as Jose did (fig 1). Further north in the Atlantic, the warm air associated with the remnants of Jose looks like it may trigger the formation of a major extratropical cyclone in the central Atlantic by next weekend (3). This is probably science fiction, but the T+156 from the latest GFS run has an intense low of 959 hPa at 60° north and 21° west by Saturday (fig 2). This

Figure 2 – Courtesy of OGIMET

If this does come about, the southwesterlies ahead of this intense low, could pump up some warm air across the British Isles for the first time this month.

Figure 3 – Courtesy of wxcharts.eu

Look back at Aileen – the forecast

Figure 1

I can’t see much wrong with the forecast charts from either the UKMO or the GFS (figs 2 & 3) when compared with the 00 UTC plotted chart for 13th. It may have been that there was not just enough oomph in Aileen to produce more of an impact, or maybe the explosive development started just a little bit too late and further east. Having said that pressure did fall by around 20 hPa across northern England in 10 hours during Tuesday afternoon and Evening.

Figure 2

Figure 3

Sebastian a little further south

Figure 1

The GFS model was correct when it had the tightest gradient from storm Sebastian at midnight tonight further south, across most of England and Wales south of 54° north. It’s a subtle change between todays T+24 (fig 1) and yesterdays T+48 from the Met Office (fig 2).

Figure 2

Here’s the latest GFS solution, with the tightest gradient at midnight south of 53° north.

Figure 3

The low being a little further south of course changes the position of the occlusion, and the area that will see the heaviest of the rain. That yellow warning for heavy rain has now been moved south and extended (fig 4).

Figure 4 – Courtesy of the Met Office

The only thing left that they have to do now is to extend the area of strongest winds further south, Oh I nearly forgot, and decide if they should call it Aileen or leave it at Sebastian. In light of recent tropical cyclone activities, and not wanting to cause any mass panic amongst the populace, naming it Aileen seems unlikely now, but what if Sebastian has more fire in its belly than they think?

Come on Aileen!

Figure 1

I see that the Met Office have just issued a yellow warnings for strong winds for Monday across the southwest of England, but the gradient on Tuesday evening when the next low breezes in looks even tighter in the latest GFS model run, maybe this is storm Aileen, and the first storm of the 2017-18 season?

Figure 2

If anything the Met Office model seems to have the low (981 hPa) a little more intense and deeper than the ~984 hPa of the GFS.

Apologies for the title of this one, but I thought that I would get in before the Daily Express did!

The Met Office online 10 day trend video forecast

The Met Office online video forecasts are a great idea, but the ’10 Day Trend’ they publish on YouTube hardly lives up to its name as the latest forecast chart they show in it is for next Tuesday, and that’s only 5 days from now (fig 1). They do of course have NWP forecast charts that go beyond T+120, but thankfully, the Americans do generously publish the output from their GFS model, and here’s a look at the output from it for next week (fig 2).

Figure 2

I am still mystified at the disparity between the forecast charts from the GFS (fig 2) and the headline in the Met Office video (fig 1). The chart for next Thursday from the GFS looks quite ominous with a very tight gradient across the whole country, with gales over coasts and hills, and I hardly think that ‘windy at times’ really does it justice.

Because of the Met Office’s refusal to publish forecast charts beyond T+120, the only thing that you do is imagine that their model don’t generate as intense a depression as the GFS model does for next week. I watch with interest to see if there are in fact gales next Wednesday and Thursday, or if the ‘perhaps drier later’ promise in the video, turns out to be correct.

Jose poised to follow Irma

Tropical storm Jose, currently at 12.5° north and 42.8° west, is poised to become the fifth Atlantic hurricane of 2017 according to the NHC, and follow in the tracks of Irma, at least for a while before curving to the right, that’s according to the latest GEFS forecast. If that happens then we will have two hurricanes in the Atlantic basin, and it’s perfectly possible that Katia in the Gulf of Mexico will make it three, even if it might be for just a short while. Meanwhile the latest track for Irma has it turning north earlier and skirting the east coast of Florida before making landfall in South Carolina (fig 1).

Figure 1 – Courtesy of wxcharts.eu

Irma Florida bound

Figure 1 – Courtesy of NHC

It looks very likely that as well as crossing the Leeward Islands  in the Caribbean, that Hurricane Irma which has now strengthened to category four, will then make for Florida and make landfall there late on Friday (fig 1), in fact according to the latest rum of the GEFS model, Irma will turn northbound and track through the heart of the state (fig 2).

 

Week number 36 – another interesting week of weather ahead

Figure 1

Before I go any further, equinoctial gales, there I’ve said it and got it out of my system. It looks like another interesting week of weather ahead, judging by the latest run of the GFS model. It certainly won’t be on the cold side, because it seems to take all week to push the 552 dm thickness line to clear the whole country. Once we’ve got through Monday and Tuesday and the cold front has finally cleared, Wednesday and Thursday look lovely days, particularly in the south. Next weekend is when the action really starts though, because that’s when the wave that you can see poised on Saturday’s chart, will develop into quite a fierce-looking depression, as it zips across the country overnight and into Sunday. I’ll add the obvious rider to last four forecast charts, and that is charts beyond T+84 are usually more science fiction than they are science fact. If it does come about, it may well get tagged the remnants of Hurricane Harvey by some sections of the media by Monday morning. It will be interesting to see if this scenario does play out as forecast, but the odds are that it more than likely won’t.

A finger of rain that may bring a shock to the system

Figure 1

Early tomorrow morning a finger of rain will push up across the southwest of England extending northeast towards Lincolnshire, that’s according to the latest GFS forecast run (fig 1). What exactly this feature is that will introduce this area of rain across the south isn’t that easy to fathom, but according to the T+36 forecast chart from the Met Office it’s an upper cold front (fig 2).

Figure 2

What it does mean that tomorrow looks like being a wet day for a good part of the south and southeast of England, and it won’t be overly warm either, because the dashed line in the chart across west Wales, is the 546 dm thickness line, as a cold trough pushes into western areas. This will come as quite a shock to people in London and the southeast, where temperatures today have been around 26° C, tomorrow in stark contrast they may be more than 12°C lower in places once the rain has set in.