Nick F

By the time Ophelia reaches Ireland waters it will be extratropical meaning that it derives most of its energy from horizontal temperature contrasts of Polar and Tropical air masses along baroclinic zones i.e. Cold/warm fronts and occluded fronts. The large scale ascent of air at the surface created by divergence aloft by left exits and right entrances of jet streaks which the depression moves into helping to deepen the low if they phase favourably. Whereas true hurricanes derive energy from warm sea temperatures above 26C, certainly the seas around Ireland won't be the main source of energy Most likely over the western side of County Kerry.

Looking at GFS and EC precip charts, they keep heaviest rain over the Atlantic and western coast of Ireland on northern and western side of Ophelia, so rainfall may not be so much of an issue as the winds and coastal or tidal flooding will be. Of course, this may change if it tracks further east.

I'm not expert on oceanography, but certainly think there will be impacts of such a high swell entering Cork Harbour on a high tide being funnelled into bays and as far as the the city itself and causing tidal flooding low lying areas, particularly given the strong onshore winds and waves likely from the south.

ECM has up to 38ft or 11m just offshore of Southern Ireland on Monday evening, up to 29 ft or 8m Celtic Sea / southern Irish Sea by early Tuesday

00z EC and UKMO still appear to be tracking ex-Ophelia up far western side of Ireland, hard to tell if landfall given 12hr positions, but ECMWF will update on Icelandic weather service in 6hr positions around 8am, so will find out then. Fortunately, the depression looks to fill quickly as it passes over far west of Ireland.

The unusually active hurricane season seems to be not going out with a whimper, as Ophelia now being a cat. 2 storm makes it the strongest an Atlantic hurricane that has been this far east (35.5°W) this late in calendar year on record. 18z still keeping Ophelia well west of Ireland, the 12z European models (UKMET-G, ECMWF and ARPEGE) tracking Ophelia over Ireland, be interesting if the Euros back west in the morning runs! Have updated my blog recently which is tracking Ophelia: https://www.netweather.tv/weather-forecasts/news/8492-tracking-hurricane-ophelia-heading-our-way-as-an-ex-tropical-storm

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Yep, think you're right, it developed over Bay of Biscay rather than an ex-hurricane reintensifying, nonetheless still weird Ophelia makes potential landfall on the exact date of the 30th anniversary

Michael Fish on the BBC news this evening and I still remember well the night of the Great Storm of '87 coming to our village in Kent, even though 30 years have passed, it was kind of burnt in the brain for life, as did the Burns Day Storm of 1990 and January 1987 snowstorm. Wow, wasn't '87 an exciting year for weather? Anyway, kind of eerie that another ex-hurricane like the Great Storm comes a-knocking exactly on the 30th anniversary, though probably not a UK landfall as it stands for now. But, nonetheless, seems surreal too that the NHC have a wind cone aimed at the British Isles

Blog tracking Hurricane Ophelia, which will head towards Ireland as an extratropical storm early next week. View the full blog here

Ophelia now a hurricane, change of title needed ... 000 WTNT42 KNHC 112031 TCDAT2 Hurricane Ophelia Discussion Number 11 NWS National Hurricane Center Miami FL AL172017 500 PM AST Wed Oct 11 2017 Intensity estimates for Ophelia still range wildly. Dvorak estimates, both subjective and objective, continue to support a much higher intensity than other satellite-derived maximum wind estimates. Adding to the uncertainty, subjective Dvorak classifications at 1800 UTC were higher than 6 hours prior, but since that time, the ragged eye has become obscured in IR imagery. However, a recent SSMIS pass at 1813 UTC indicated that the convective structure of the cyclone has improved during the day, so it wouldn't be surprising if the eye became apparent again shortly. In an attempt to blend all available data, the initial intensity has been increased to 65 kt, making Ophelia a hurricane. However, it should be stressed that the uncertainty of the initial intensity is higher than normal. The hurricane is moving slowly toward the east and the initial motion estimate is 090/3 kt. The hurricane is embedded within weak steering flow, and only a slow northeastward drift is expected for the next 24 h. After that time, an approaching deep-layer trough should force Ophelia to accelerate toward the northeast. All of the deterministic models are in fairly good agreement on the speed and track of Ophelia, however the various model ensembles suggest that the uncertainty is much higher, especially regarding the forward speed of Ophelia beyond 48 h. The official track forecast favors the deterministic model solutions, in part to maintain continuity with the previous advisory. The track forecast is therefore close to the multi-model consensus, but much faster than the various ensemble mean aids. Since it isn't clear exactly how strong Ophelia is, the intensity forecast is low confidence. All of the intensity guidance indicates that strengthening is likely for the next 24 to 36 hours, however the near stationary motion of the hurricane could induce some upwelling and limit the extent to which the hurricane may strengthen. Around 72 hours, the shear should begin to increase substantially as Ophelia begins to interact with the approaching trough, and extratropical transition will likely begin, accompanied by a broadening of the wind field and a gradual decrease of the maximum winds. The global models indicate that this process will complete by 96 h. The new NHC intensity forecast is slightly higher than the previous forecast, but lies on the lower end of the intensity guidance for the first 72 h. It is near the consensus aids thereafter.

Interesting how ex-Ophelia low keeps a warm core just like a tropical storm/hurricane as it approaches to the SW of Ireland on Monday, unlike the more usual cold cored North Atlantic depressions we see. Certainly likely to be a lot of energy wrapped up in this deep low, wherever it may go.

So the models generally agreeing, for now, on taking ex-Ophelia north close to the west side of Ireland early next week, a close call for Ireland though, with a track further east threatening potential widespread severe gales. 00z UKMO takes this deep low NE toward western Scotland, rather than north toward Iceland like the other models, so western Scotland could come into the frame for strong winds too if this NE track were to transpire. The long track north of ex-Ophelia from south of the Azores will draw a deep warm southerly flow from southern Spain / western Med for the weekend into early next week, some high temps indicated for Monday from the 00z Netwx-MR showing 25-26C for eastern England, would surely threaten some date records. Strong jet stream next week looping N to NE across the UK could pull a few shortwaves NE that could spawn some deepening secondary lows moving NE from the Bay of Biscay. Long-way off for any certainty, but 00z ECMWF and the EC control indicates potential for such a low to move NE from Biscay across NW France and perhaps on to SE UK. All coming around the 30 year anniversary of the Great Storm of 1987 as well! Worth keeping an eye on. 00z ECMWF for mid-next week 00z ECMWF control All-in-all an interesting period of weather coming up, certainly not run-of-the-mill autumn weather, with ex-hurricane arriving from so far south and bringing unusual warmth with it too.

Actually, I think you're right, it probably was 4 mild winters on the run, was thinking 2013 had some cold, but that was early on in the year thinking more about it, Jan-April that year were below par.

Personally I have higher hopes for the coming winter snow and cold wise for lowland Britain than the last three winters. The QBO has been negative for the last 4 months and continues to drop each month deeper into -ve territory. A negative or easterly QBO is linked to a weaker PV on average during winter and thus a weaker Atlantic jet which favours more blocking and greater chances of SSWs too. We have had an unprecedented long stretch of +ve/westerly QBO over the last few years, plus strong El Nino in the middle, which has resulted in a run of mild winters for the UK. How much influence the forecast weak/mod La Nina will have on upper patterns in conjunction with -QBO - we'll have to wait to see, and be interesting if, in the Dec-Feb 500mb means, it plays similar to a composite of years with weak/moderate La Nina and moderate/strong -QBO, like the one below; We also have weakening solar activity heading towards a solar minimum in next few years, how this solar cycle interacts with the QBO is a bit beyond me as the interaction seem rather complex, from what I've read, SSW during a wQBO are less likely than in a eQBO, but when they occur, statistically more often when there's a max solar cycle. However, a solar cycle min may not have such a big influence on SSW while in a eQBO phase. Though reading further it appears a solar min/ eQBO can increase the amplitude of the MJO. All-in-all, a few cold winters more likely in next few years, whether 2017/18 will be one I can't guarantee, but certainly cautiously more optimistic it will be colder than the last 3 winters given the above

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Maybe Storm Brian, though calling an Atlantic depression Hurricane Maria, though obviously incorrect and liable to confuse joe public if the storm is named by the Met Office, will be greater 'click-fodder' for the media.

Morning all, don't think I've posted in here for a while, but will do when things look interesting weather-wise. Following on from Knocker's post above, running MSLP loops of the N Atlantic for the 00z GFS and ECM from later this week until early next week you can see Hurricane Maria (west) and Hurricane Lee (east) joining forces over mid-N Atlantic, by which time ex-tropical over much cooler waters to the north, before running NE as a deep depression towards the British Isles and arriving early next week. 00z GFS 00z ECMWF Ensemble mean MSLP seems to be pointing to disturbed Atlantic affecting the UK from later this week.

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UK Severe Convective & Storm Forecast - Issued 2017-09-18 09:08:33 Valid: Mon 18th Sept 6am to Tues 19th Sept Day 1 Convective / Storm Forecast Click here for the full forecastCheck the full storm forecast here

UK Severe Convective & Storm Forecast - Issued 2017-09-17 09:22:46 Valid: Sun 17th Sept 6am to Mon 18th Sept 6am Day 1 Convective / Storm Forecast Click here for the full forecastCheck the full storm forecast here

UK Severe Convective & Storm Forecast - Issued 2017-09-15 21:42:22 Valid: Sat 16th Sept 6am to Sun 17th Sept 6am Day 1 Convective / Storm Forecast Click here for the full forecastCheck the full storm forecast here

Another good day for convective cloudscape and rainbows in the clean polar flow, my convective / storm forecast: http://www.netweather.tv/index.cgi?action=convective;sess=