No, it’s not my attempt to recreate the intro to “Dad’s Army”, it’s the approximate movement northwestward of a sheet of stratus across southern areas of the country this morning (fig 1). Yesterday’s clear skies are fast disappearing as the bank of cloud moves relentlessly northward, and a return to a dull and dreary January day that we know so well.
It’s a great shame that the anticyclone of yesterday didn’t stick around longer. I’ve got a feeling that we’ll be as sick and tired of January by the end of this month as Pilot where back in 1975.
There is a sharp inversion and associated sub-zero layer on this mornings 11 UTC ascent from the Herstmonceux ascent in Sussex (fig 2), at around 3,000 feet. In fact the ‘proper’ freezing level above is at almost 8,000 feet (fig 2). Low level winds are north of east, so maybe the stratus is forming as the result of moister air feeding in from the E’NE, rather than following the flow that I’ve indicated on the satellite image (fig 1).
Any morning cloud that’s been affecting some southern areas has now dissolved away, and it’s a wonderful afternoon across the bulk of the country. It’s still possible to see the extent of the snow over the mountains of Scotland through the thickening frontal cloud (fig 1).
The easterly wind is blowing fresh or strong across southern areas though (fig 2).
This has meant that wind chill has been sub-zero in the more exposed places (fig 3), but not excessively low because of the clear skies and widespread sunshine (fig 4).
There have been three (soon to be four) bands of quite intense showers associated with short troughs and large CB’s moving E’SE in the strong W’NW gradient across our part of mid-Devon today. The sky has gone intensely black with each of them with a short intense burst of rain, the last one being the sharpest. From my Vantage Pro, I can see that the first one occurred at 0810 UTC, another at 1020 UTC, and the last around 1300 UTC. The fourth band is almost on us judging by the latest frame of the weather radar (fig 1). There have been no SFERICs associated with them. You can see a number of them waiting in line across the Celtic Sea in an earlier visible satellite image (fig 2).
An embryonic low that’s set to develop into storm Eleanor later today sat poised at around 18° west in the Atlantic at 1045 UTC this morning (fig 1). The Met Office have issued a yellow alert for the whole of England and parts of southern Scotland and Northern Ireland, using the gusts 60-70 occasionally 80 mph ploy (fig 2). I was always under the impression from watching the previous named storms closely that they only named a storm if the associated impact was amber and not yellow? So judging by these predicted gusts, Eleanor will likely be no more memorable than storm Dylan which also was a underachiever.
There is a difference in how the UKMO and the GFS handle Eleanor, at 00 UTC the GFS model has her central pressure ~975 hPa (fig 3), whilst the Met Office (fig 4) develop Eleanor more intensely with a minimum central pressure of 966 hPa. The midnight run of the GFS is slightly quicker taking Eleanor across Northern Ireland and southern Scotland late tonight and early on Wednesday.
It maybe that Storm Dylan has developed a bit of a sting jet in the last few hours. I’m no expert, but this was anticipated by some but came as a surprise to me, if that indeed is what the latest frames of the IR satellite image (fig 1) and the weather radar (fig 2) are showing across western Scotland at 07 UTC.
Of course this all may be the work of an overactive imagination and just a curl of frontal cloud and precipitation from the bent back occlusion getting sucked into the vortex of Dylan.
All I can imagine is that it’s a very quiet news day across the UK and the world, because the number one news story all day on the BBC news has been a ridiculously hyped-up story regarding the ‘severe weather’ that’s apparently gripping the country at the present time. According to Rita Chakrabarti tonight is forecast to be the coldest of the year, and yellow ice warnings from the Met Office are in force across the entire country, lets hope whoever forecast that will be more accurate than the Met Office were with last night’s forecast!
If you look at today’s satellite image (fig 1) you can see clearly where the snow of yesterday fell in a band from Bristol northeast across the Cotswolds and into the Midlands, with a dusting left on Exmoor and the Chilterns, at a guess it’s covering less than 10% of England. Admittedly there’s a little more over the high ground of Wales and Scotland from previous days, but there’s no way that this can be regarded as widely affecting the whole country.
Here are today’s maximum temperatures to underline the point that today’s weather has been far from severe (fig 2), in fact for many parts of the country it was a cold but a sunny day as the Worldview satellite image reveals.
All that I can say is that if, and when, we do get a severe snowy spell then God help us!
The 165 cm of snow (65.1″) that’s fallen on Erie Pennsylvania during the last few days does put into perspective the recent snowfall we’ve seen in the UK so far in December 2017. Here’s the BBC news report on the snow emergency that’s going on there right now in Erie.
The city of Erie does have a few advantages that we don’t often see in the UK during winter, and that’s copious amounts of very cold arctic air flowing directly from Arctic Canada, and being situated on the southern shores of Lake Erie in a howling northwesterly. These two things combine to produce a lake effect event and masses of snow in this part of the world, which according to the NWS has broken all previous records in Erie (fig 1).
Here’s the chart for 18 UTC on Christmas Day, I’ve inset the six hourly observations from Erie (fig 2). You’ll notice that the SYNOP from Erie International (WMO #72526) does not include snow depths as some other stations report. This is probably to do the severe drifting that must be going on with powdery snow in temperatures that have fallen from 0°C on the 23rd to -10°C today (28th December).
I would just love to know how they can manage to measure over 65″ of snow with any degree of accuracy when coupled with drifting. Perhaps they measure snow depth at regular intervals at a given spot, then clear it way or drop a board on top of the previous accumulation, before measuring it keeping an aggregate depth. That would be difficult to do because even with just a mean speed of 10 knots powdery snow like that would just blow right back in, and what about compaction over time?
The visible satellite image for December 27th shows how the very cold and dry air picks up moisture and instability in the west northwesterly flow of most of the Great Lakes (fig 3). Most lakes look clear of ice, and the comparatively warm lake surface temperatures must just generate continuous bands of snow showers. The lake effect has to affect other lakes other than Erie, I would have thought the eastern shores of lake Michigan would suffer just as badly as the southern shores of lake Erie, but that never seems to make the news, perhaps it’s because the population is sparser and there are no large cities directly on the eastern shore line of Michigan, or maybe the water temperature is much lower and convection less explosive than over lake Erie.
Just doing a reality check here on that bit of rambling about the SST of Lakes Michigan and Erie (figs 4 & 5), and it turns out that Lake Michigan is considerably warmer than Lake Erie at the moment, so bang goes the increased convection due to higher SST’s in Erie theory!
So if the difference isn’t so much to do with the surface temperature of the two lakes, it must be that the air has picked up more extra moisture, and is generally just much more unstable over lake Erie that it is over lake Michigan further west. Here’s the 850 hPa upper air chart for yesterday (27 December 12 UTC) and the tephigram from the nearest location to Erie that I can find, which is Buffalo (figs 6 & 7). It’s good to see that you can still get a good coverage of sonde stations in some parts of the world. End of rambling.