Hello fellow CSE and SW'ers.
Five days can be a long time in Meteorology, so from my post on the 1st February to now, are we any further forward to knowing what's in store for the rest of this month.
On my previous posting it was suggested that FI was around the 7th to 8th February timeframe which gave us at best, approximately 6 to 7 days of predictability in terms of a forecast. What was the reality I wonder? If you recall, here were my key dates in my forecast.
Firstly for Dorset, having edited the summary accodingly.
Key timeframes were suggested as 3rd February for a low impact RAIN event, with the period from the 5th February into 6th February looking a decent shout for a SNOWIER INTERLUDE. Even further out, say the 13th February onwards, it hints at a good deal wetter scenario than the preceding ten days or so.
Basically it was a bust, even under a short-term scenario and furthermore the same was said of the predictions for Berkshire which were as follows.
The trend for Berkshire showed the 4th February as a low impact RAIN event, with the slim probability of backedge snowfall and then the 8th February looking a reasonable shout for a SNOWIER INTERLUDE.
Intriguingly you could possibly rescue the 8th February from the above prediction but we are really clutching at straws I guess. Anyhow, let's move on and have a look at the future. Again, I will attempt a forecast based on some analysis of the GEFS ensembles suite. I will once again be using the 12z suite in isolation.
Here is how the GEFS 12z ensembles saw things developing in terms of precipitation for Berkshire and Dorset some five days ago.
On to today, how does the GEFS 12z ensembles view things in terms of developing precipitation for Berkshire and Dorset. To this I will also add Cornwall.
Please follow the MEAN (red line) in order to see the overall trend expected and in turn to help pick out specific dates over the given timeframe. Where the CONTROL (blue line) consistently differs from the MEAN you can regard such timeframes as currently unreliable, i.e. Fantasy Island.
What can we establish from the above? The trend deciphered from the above would indicate an unsettled period upcoming for all. The wettest part of our region likely to be the furthest SW locations within the UK. As ever, there will be drier interludes, to which I will allude to later.
I will now look into any discernable trends coming from the Upper Air profiles. Once again looking back at Berkshire, Dorset and instead of Cornwall, I am using Berlin as an example.
Firstly the situation expected some five days ago.
Berkshire, Dorset and Berlin T850s
And as of today, to which I can add Cornwall T850s to the mix.
Please follow the MEAN (red line) in order to see the overall trend expected and in turn to help pick out specific dates over the given timeframe. Where the CONTROL (blue line) consistently differs from the MEAN you can regard such timeframes as currently unreliable, i.e. Fantasy Island.
What you can you decipher from this is a hint as to whether the precipitation will be wintry in nature and more especially, SNOW producing. From the above, I would suggest the period from the 8th February to the 14th February as being a watching episode at this range. Cornwall should expect many showery interludes during the earlier part of the above timeframe. The downside for coldies being the ensembles suggest a largely too warm profile (bar significant elevation) for now. As for Berkshire and Dorset, things don't look as wet as first suggested and when the precipitation spikes are shown, the precipition signal in terms of anything wintry will be marginal at first. However, the interest grows as we enter the timeframe 11th February to the 14th February and probably beyond. The reason Berlin T850s were included was to look for any developing Easterly signal. At this range and the timescale concerned is beyond FI, I do believe there are reasonably strong signs of a continental type flow developing from the 14th February onwards and possibly earlier by a day or so. Of course, this will need to push further Westwards in time for this region to benefit from such an event, but there is hope that such a thing could occur IMHO.
Finally we will see if there are any signs of a drying out taking place in the longer-term by looking at the Air Pressure trend shown, firstly from five days ago
Berkshire and Dorset Air Pressure, to which I will add Reyjavic (Iceland) and Oslo (Norway)
And as of today for Berkshire, Dorset, Cornwall and also using further afield locations as Reyjavic (Iceland) and Oslo (Norway).
to 22nd February 2013.png]
Having said what I stated earlier, you can pretty much write off a High Pressure related scenario taking place until at least 14th February. The trend is for Cornwall to be the wettest of the selected counties with 8th, 10th, 11th, 13th and 14th February looking likely to suffer showery/frontal type precipitation events. Of particular interest to us coldies, the period from the 8th to the 10th February suggest high levels of marginality when it comes to predicting SNOW at the surface. However, from the 11th February onwards, more especially the 12th through to the 14th February are dates to keep in mind for a much higher likelihood of SNOW in almost any of the aforementioned counties of England.
The reason for using Reyjavic (Iceland) and Oslo (Norway) ensembles was to identify as possible trend for a Pressure build in that region, North of the British Isles. At the moment, these appear to favour a Scandinavian blocking type scenario come Mid February. If this does come off, AWD will be very pleased - see below for his comment as of the 31st January.
cold mid February from the east/north east/north still looking good, still my long range punt. How cold and if it will be accompanied on snowfall remains to be seen. My guess at the stage is not mega cold but easily cold enough for snow, which we will see at some point being closer to the Euro trough.
My best bet, largely in line with AWD's initial thoughts is for a Scandinavian blocking to take hold from around the 12th February. This subsequently linking up or losing its identity in favour of a more general Greenland type blocking, come the last ten days or so of February. Whilst saying all the above, it has to be stressed that there is very little cross-model suite agreement at less than t+96 right now, which firmly places Fantasy Island at no later than the 10th February.
I hope the above is of use and folks, keep tuned for many more updates from the usual suspects in the coming days.
Still a whole lot to play for with this winter, bar the usual locations which the residents will know about which will most likely experience a unforecasted heatwave.