stodge

Evening all The GFS 12Z evolution is a classic "winter" scenario as the remnants of Hurricane Teddy create WAA to the west of Greenland allowing a significant build of pressure. In response, the LP drops through the British Isles and a Scandinavian trough develops leaving the British Isles in a cool NE'ly. A lobe of HP breaks off from Greenland and heads SE through the British Isles to set up just to the south and return much more settled conditions. Worth noting we still have a significant Scandinavian trough and heights over Greenland so it ain't going to be warm but the Atlantic is much quieter.

GFS 12Z now has the storm reaching the coast and abruptly turning away south - curious.

Evening all Tentative signals for a warmer spell in the second week of September. I'm not quite sure whether +16 850s would deliver the same values in September as in July but it would still be very pleasant. 12Z GFS OP quickly pushes any heat any south while ECM's evolution ends with the LP very close - too close I think - to the SW so less settled than some might want or hope. 12Z GEM has a transient push of warmer air through the south as early as the end of next week but it's a "blink and you'll miss it" scenario. 12Z GFS Control is pleasant but never that warm - more average temperatures and I suspect a hint of autumnal conditions with fog and chillier mornings. As others have said, tropical energy can render a forecast obsolete quickly at this time of year. Yet there's little sign of anything in the near future - over North America, the pattern is one we see sometimes of a large HP over the Pacific and a shallow heat LP over the interior and a further HP over the Great Lakes. Fantastic weather if you're on the California coast - an off-shore wind so plenty of sun and low humidity - perfect.

Evening all Have stepped away from the models for a few days since the end of the hot spell. I thought we would be seeing signs of a more settled spell by the end of the month and into September. Let's see what the 12Z output offers us for T+168 which is Saturday August 29th: It's not terribly warm, is it? The four models (GFS Op, GFS Control. GEM and ECM) all have a N'ly flow of some sort with LP to the east and HP to the west so western areas doing better in terms of drier and sunnier conditions while eastern areas plagued with rain or showers off the North Sea. Moving on, the GFS brings yet another Atlantic LP in while GEM (and perhaps ECM) initiate a surge of HP from the Azores - you'd expect the latter at the time of year to be more likely to be honest. Frankly, the GFS output is a horror story for those wanting heat - Control goes zonal into FI while OP lowers pressure in the Med while shifting the Azores HP more north than north east. Obviously, we have the Joker(s) in the pack known as ex-hurricanes which can disrupt the energy profile considerably - indeed, the energy they introduce tends to buckle the jet back north and bring in the Azores HP but neither Laura nor Marco look to be influential and we'll have to see what comes out of Africa and how it develops in the weeks ahead.

Indeed - the trajectory of ex-hurricanes causes all kinds of problems as we know. At the moment, while Hurricane Genevieve looks to become a major storm in the Pacific (not a threat to land in itself but likely to bring tropical storm force winds and swells to Baja California), there are a couple of waves in the Atlantic with the one nearer the African coast looking the more likely to develop into a significant feature by the end of the week. IF we get ex-hurricanes moving out into the Atlantic from eastern Canada they usually prop up the Azores HP and keep the jet to the north. What we don't want is a more southerly recurving bringing the storm remnants closer to the UK as they can have large amounts of rain in the circulation.

Evening all As last week's heat recedes into memory and folklore, where are we in the second half of August, a time which can be quite poor weather wise before the settled conditions return just in time for the start of the school year (anecdotal); That's T+192 on the 12Z Output from ECM, GFS OP, GFS Control and GEM and if I'm being all honest all pretty much of a muchness. Control offers a hint of something drier and warmer for the SE but otherwise it's encroaching Atlantic LP bringing cloud and rain. It's a fairly shallow feature unlike this week's depression so no real issues with gales. Looking further ahead to month end, a hint from GFS OP the Azores HP will shift NE and force the jet back north but that's a very long way off (though wouldn't be a great surprise).

Evening all Having had seven days of 30+ maxima, the last thing I want is more heat but let's see what the models proffer tonight: 12Z at T+144 from ECM, GFS OP, GFS Control, GEM and UKMO Variations on a theme if I'm being honest - I don't see much evidence of the LP slowing or stalling and variations on track and intensity to be expected at this range. It could bring a brief warmer interlude back to SE parts but otherwise it's cool with rain or showers and for those who seem surprised we get a deep LP in mid-August, just look up the Fastnet Race Disaster of 1979 - the LP then was 975 MB over southern Ireland. Looking further ahead: So that's T+240 from GFS OP, GEM, ECM and GFS Control Perhaps a transient ridge but this looks a typical early autumnal profile and let's not be surprised - we can and often do get a poor spell late in August while in September (often in response to the energy redistribution of tropical features over the western hemisphere) HP builds back as the Atlantic flow is disrupted and/or an ex-hurricane pulls the jet back north. In truth, neither TS Josephine nor TS Kyle look to have much of an impact and for now the Atlantic looks quiet but as we know that can and does change quickly. I can only speak for myself but I enjoy HP in September and October more than July and August but that's just me.

A band of heavy rain and showers moving NNW just to the east of us here in East Ham. We may get something from it or we may not. Currently 20c with 94% humidity so rain wouldn't be the biggest surprise.

Well, that was the heat that was (as someone never said). After seven days of daily maxima of above 30c in East London, back to 21c today and a welcome respite though humidity has returned with a vengeance. Looking ahead to the next four days with the 12Z Arpege: As we've seen forecasted for a while, the last of the warmthis driven further north and west tomorrow with a cooler stretch and then the first sign of a return of warmer air back across the SE which we see on Sunday with 25-27c forecast. That all gets swept away with a cool day Monday and a modest recovery on Tuesday. The 500HPA charts tell the story. Tomorrow we see the E'ly pattern move further north so the sheltered west and NW of England is the palce to be but note also the onshore flow in the SE replaced by a weak offshore flow so the recovery in temperatures on Sunday but likely to be accompanied, you'd think, by a return of heavy showers or storms. By Monday an Atlantic sourced flow has re-established bringing in cooler air but note on Tuesday it's a TM air source so the longer passage across the land allows the SE to get the warmest of the conditions. It doesn't likely from the 12Z suite any Atlantic LP will stall in situ to the west of the British isles and allow a return of hot air from Iberia but if, as GFS OP suggests, the LP moves more NE, there would be a brief push of warmer TM air across southern and south eastern parts before the cold front sweeps the PM airmass back.

A much more pleasant day snapping the 7-day 30+ streak here in East London. Around 21c today - rain overnight with a little thunder and a couple of lighter spells of rain today but the main thing is and has been the cloud - there was a brief interlude of sunshine late morning. The other big change is humidity which has shot up to 88% here so it's a different kind of cool.

Evening all Just has a few minutes of rain here in downtown East Ham and with the circulation coming up from the ESE I'm looking at NE France or Belgium for any storms so we'll see. Anyway, that's not what here is about... The next four days on Arpege and the story has changed slightly since last evening. As I mentioned yesterday, the current heat is dispelled north and west tomorrow and into Saturday but then we see a brief return of warmth on Sunday followed by a final clearance on Monday. The 500HPA tells the story - tomorrow a shallow LP off th east coast keeps the NE flow for many areas but right along the coast there's an offshore flow so some residual warmth. Further north, the Peaks and the Pennines offer some shelter to keep NW England warmer than other areas. On Saturday the onshore flow from the North Sea has shifted northward and there's a slack pressure gradient over the south and east so temperatures can start to rise again. By Sunday, that has switched from a NE to an E'ly flow so more of a continental influence so very warm air from Germany and the Low Countries can move back across the south so 27c is perfectly possible but with an enhanced risk of storms.

Finally got s few minutes of rain here in lowland East London but no thunder or lightning. With the circulation revolving round the LP in the Channel I'm looking at disturbances coming out of NE France or Belgium for my neck of the woods. Suspect we may get something more substantial overnight.

Evening all Another day (the sixth in succession) above 30c in downtown East Ham - we reached 33c early afternoon but a more pronounced E'ly wind sprung up and it's starting to feel fractionally more comfortable. Thought I'd see where Arpege is taking us and it's very interesting: A last day of heat (30c?) tomorrow before a much cooler regime takes over for the south and east and the heat switches to the west and north on Friday and the north on Saturday. The 500hpa synoptics are revealing: This isn't your normal end to a short-lived hot spell with a front coming in from the Atlantic and sweeping in fresher air from west to east. In fact, this is the reverse - a complex trough to the south and east is introducing fresher air from the north east so the residual warmth gets pushed back west and north west while the cooler air takes over the east and south. Very unusual synoptics for the end of a prolonged hot spell. Next week is all about what the Atlantic LP will do - fans of heat will be looking for it to stall out west - 12Z GFS OP didn't suggest that, perhaps the 12Z ECM will.

Reached 33c once again in lowland East London so that is our sixth consecutive day above 30c - not record breaking in terms of intensity but noteworthy in terms of longevity. Last night was very uncomfortable for sleeping and I fear it will need 3-4 days for the brickwork to fully release the heat. NO afternoon storms for us - all the action to the west and NW but the huge area of heavy rain coming out of Normandy may well have our name on it.

Evening all Time to consult (or insult) the models. 33c here in downtown East London so that's five successive days over 30c - remarkable or the "new normal" ? Perhaps a discussion for another forum in case the Moderators think I'm going to throw petrol on a well-lit barbecue. So, when and more importantly how will the heat ease? After initially looking as though it would break tomorrow, it now seems we will have a final scorching day (33-35c) before the weather starts to change on Thursday and Friday and by Saturday we'll be shivering in temperatures in the low 20s claiming the next Ice Age is close at hand and asking whatever happened to summer. Looking at my newer friend, the Humidex: The breakdown of the heat is shown more starkly with values over 40 widely across southern England tomorrow which suggests to me a big chance of storms and quite heavy downpours. By Thursday the threat is receding as the humidity starts to ease back and the heat dissipates. After tomorrow a more noticeable NE'ly picks up for southern counties ending the heat draw from the south or south-east and bringing down a much cooler flow from the North Sea.

Reached 33c here in East London this afternoon - very hot of course. Now 29c but with humidity at 49% so still unpleasantly warm. Any earlier cloud has dispersed and we have another fine evening. That's five days of over 30c since last Friday and my guess is another one or perhaps two - off to Arpege for a look.

Day 4 of the Great Heat of 2020 (as I'm calling it) and in lowland East London we reached 31-32c (not sure as I have to work for a living). Wednesday looked very unpleasant in terms of heat and humidity but that seems to have been toned down a bit tonight. The heat hangs on in East Anglia into Thursday and next week may be quite the shock to the system. I'm less convinced about thunderstorms in my part of the world though I do think west and south-west England may continue to be prone to pulses of heavy rain coming north for a few days yet.

Evening all Day four of the great heat of 2020 (apparently) - 32c in lowland East London (I think) but more humidity and really not pleasant. So for how much longer will the oven be switched on? MY acquaintance (I wouldn't call it a friend) Arpege has been of value through this unpleasantness: As has been the case in the past couple of days, Arpege suggests tomorrow's heat will be more over central southern England while for Wednesday it's back to the far SE and East Anglia. It now looks as though there will be a final day of heat on Thursday for parts of East Anglia before by Friday we break out the thermals as the temperature crashes to a chilly 27c. Now, my other new friend, the Humidex, is painting a slightly different story to the weekend. High values over central southern England (40) but surprisingly the humidity isn't as severe on Wednesday as some earlier forecasts suggested so I'm just wondering if the storm risk has been overplayed a little. Obviously, we could import something from France but I'm pleasantly surprised some of the frankly obscenely oppressive numbers have disappeared. The rainfall accumulation also suggest the main rain will be to the west rather than the east so we'll see.

Evening all As I was trying to work, I'm not sure what temperature was reached here in lowland East London. Certainly 31c, maybe a notch higher. Currently 29c with humidity at 48% but a refreshing breeze from the river helping a bit.

I think we're seeing increasing humidity as well - my guess wild be central southern England on Tuesday and widely across the SE on Wednesday.

Unpleasantly hot in lowland East London - 31c but with higher humidity than the past couple of days barely mitigated by an E'ly off the Thames Estuary. Not nice. Looking ahead to the next couple of days, where will the heat be concentrated? That's the Arpege 12Z for Monday and Tuesday afternoons and the 00Z for Wednesday. Tomorrow looks as though it will be hottest to the west of Londn while Tuesday keeps the core to the heat more to the south. Wednesday looks horrendous with some very high temperatures to the east of London and along the east coast and if memory serves this is what we saw in 2003. The Sunday was the last day of the heat but it was strongest where it had lasted longest (the reverse happens with cold spells oddly enough). Looking at the Arpege Humidex charts: That suggests central southern England for the storms on Tuesday and more widely across the SE on Wednesday which is going to be a really unpleasant day in the SE of England.

Topped off at 31c here in lowland East London. Fine currently but less pleasant than yesterday with higher humidity - up to 43% according to NW and despite a noticeable E'ly breeze picking up from the river.

Afternoon all 31c in East London today making the roast lunch - indoors but well ventilated - perfectly pleasant apart from the insects. Looking at the Arpege charts for the next few days: Plenty of heat still to come for southern and south eastern areas through to midweek but the nature of the heat profile contains some subtle changes on a day-to-day basis. The highest temperatures tomorrow and Monday look to be along the south coast (presumably with a NE wind those areas would see the longest track of hot air over land which is counter-intuitive to the traditional S'ly plume for which the coast often has slightly cooler temperatures owing to the brief passage of the very hot air over the cooler English Channel). There are some extraordinary values forecast for NE France and Belgium as well. By Tuesday the hottest air is starting to draw away east and by Wednesday the hottest areas are right along the east and south east coast as the heat heads toward the Low Countries and Germany and France cools down a notch. Another way to look at it is to use the Humidex measure of heat plus humidity: Some really uncomfortable numbers coming up for southern and south eastern areas with the Humidex hitting 40 on Wednesday. That suggests both Tuesday and Wednesday look more likely to have thunderstorms than tomorrow or Monday but those storms could be real brutes.

Topped off at 31c in East London this afternoon so down a little from yesterday. Once again, that pleasant little NE breeze has helped along with the cloud - the roast lunch was fine.

Evening all We're in two forms of model discussion currently it seems - the "nowcasting" of the hot spell which has rather overshadowed the usual discussion of the medium and longer term prospects. Starting with the former and looking at the WRF-NMM charts for a change: The heat profile changing with each day - Saturday sees the hottest air confined to the south coast, Sunday sees a wider distribution of heat but not quite as strong as today and Monday suggests the heat easing away to the east with only the far SE still under hot conditions. Let's move on and there seems a general concensus by midweek the hot conditions will ease back to something which although still warm will be much more tolerable (at least for me Looking to the charts for next Thursday: That's ECM, GFS OP, GEM and UKMO at T+144 for comparison. I'm struck by how far to the north the Azores HP is ridging in mid-Atlantic and while GEM looks the outlier, the others all keep the trough near or over southern Britain. There's a huge amount of uncertainty (as you would expect) after these charts but there seems (as we see many summers) a struggle between the ridging Azores HP and a growing trend for LP to develop to the NW and seek to join with the trough across the British Isles. There doesn't seem to be any sign currently of a renewed substantial push of heat after the current spell though that doesn't mean there won't be warm or possible very warm conditions as Exeter suggests - it's a classic NW/SE split but that's far from resolved and the other option of a negatively aligned trough through the British Isles cannot be discounted.