Extratropical Storm Ophelia - Technical Analysis Only - MOD NOTE post #1

nagdefy

aidanodr wrote: »

Looks like a massive bullet dodged? Its off out to the Atlantic? Great news if so ..

It's not i'm afraid Aidan. Very much on track as predicted. It's westerly at 23.35 on your map, but programmed, and has started, to move north easterly and will hit the Kerry coast.

uck51js9zml2yt

M.T. Cranium wrote: »

Just ran an IR loop and noted rapid development of central calm spot (hesitate to call it an eye after the discussions earlier) and signature of very strong wrap-around winds as suggested on most guidance. Approx location 48N 12 W.

Pressure fall of about 11 mb at K1 buoy located about 40 miles nw of current estimated low and if it is at 960 mb, quite a pressure gradient, the buoy reads 988. They stopped taking wind obs unfortunately, 2.5 m waves (but on weak side of the storm).

Storm has loaded up on available heat energy, 21 C at Biscay buoy located 4 deg east of centre. SSTs near centre now about 16-17 C.

Can you explain all that in English please?

firemansam4

spookwoman wrote: »

Sorry aidanodr Here's latest track with 1am def swing to the east

Seems to well west?

pauldry

If you look at sat24 and the black and white to the N and NE of white blob you can see the future track the storm will take

drunkmonkey

Will the lightning go inland seems to be at the head...

Gremlin

aidanodr wrote: »

Looks like a massive bullet dodged? Its off out to the Atlantic? Great news if so ..

It's too late now. Even if the center misses the west coast (as the GFS model seems to suggest) its going to make little difference to the over all picture. Looking at the most recent sat pics suggests the centre will brush up along the west coast. Look at the extent of the strong winds. Even a 100 km deviation would still leave a huge portion of the country right in the thick of it.

lucernarian

Kai Rotten Shipwreck wrote: »

Can you explain all that in English please?

This is the technical analysis thread in fairness. Basically what he's saying is that the storm is acting similarly to what the computer-generated forecasts were predicting for now.

aidanodr

Always the optimist guys .. at least I tried

nagdefy

Kai Rotten Shipwreck wrote: »

Can you explain all that in English please?

Your on the technical discussion page it's the experts thread. It's up to the rest of us to catch up with MT and the other posters if we want to run with the big dogs;)

uck51js9zml2yt

nagdefy wrote: »

Your on the technical discussion page it's the experts thread. It's up to the rest of us to catch up with MT and the other posters if we want to run with the big dogs;)

I don't mind technical..just as long as it's in English.
It beats "the hype" threads over in discussions:)

Was just looking again at the 18Z GFS pressure chart for +18 hrs (1pm), and I notice there is a predicted 30mb difference from the centre just off the West Kerry coast (967) to Dublin (998). Thats a hell of a change from west to east.

lucernarian

spookwoman wrote: »

Sorry aidanodr Here's latest track with 1am def swing to the east

I'm not putting so much stock in the static image as I feel like the looping satellite image gives a better idea of where the wind is blowing so to speak. Though the infrared images that have to be used at night are more likely to trick an amateur like me, I still see this landing a bit west of the NHC guidance and for it to hit Co. Galway/Mayo, having just skirted past Kerry. We'll know soon enough either way, that's for certain!

spookwoman

lucernarian wrote: »

I'm not putting so much stock in the static image as I feel like the looping satellite image gives a better idea of where the wind is blowing so to speak. Though the infrared images that have to be used at night are more likely to trick an amateur like me, I still see this landing a bit west of the NHC guidance and for it to hit Co. Galway/Mayo, having just skirted past Kerry. We'll know soon enough either way, that's for certain!

using photoshop and stacking screenshots of the different times on top of each

Hooter23

Anyone know if it is tracking faster toward us than the forecast...if so it could be worse as Hurricane Debbie had alot more strength by the time it arrived here as it traveled alot quicker

IR image at 1am.

Gremlin

Darn 1:15 Eumetsat IR sat pic doing that blackout thingie. No consideration for storm trackers!

MJohnston

Hooter23 wrote: »

Anyone know if it is tracking faster toward us than the forecast...if so it could be worse as Hurricane Debbie had alot more strength by the time it arrived here as it traveled alot quicker

It looks like its movement (not the wind strength) has slowed a little bit, so it could well still take a little bit longer to make landfall.

nagdefy

Maybe i'm wrong but the more westerly theme of the storm centre skimming Kerry and Galway would seem to downgrade that little for Dublin that could make a lot of difference there??

D.Q

Finding all this technical stuff absolutely fascinating.

Hope it isn't too off topic to ask if most of the people commenting are amateur hobbyist types or actual meteorologists, insane amount of knowledge, fair play to all of ye.

Middle Man

nagdefy wrote: »

Maybe i'm wrong but the more westerly theme of the storm centre skimming Kerry and Galway would seem to downgrade that little for Dublin that could make a lot of difference there??

According to the French sats, it now looks as if the centre of the storm will pass just off the west coast...

http://www.boards.ie/vbulletin/showpost.php?p=104982170&postcount=2120

gugsy

M.T. Cranium wrote:

This would evidently track through Ireland and Scotland on a generally NNE to NE path, which would bring damaging wind gusts into most of Ireland.

M.T. Cranium wrote:

Around 2 p.m. with the low somewhere near or over Clare, heavy rain and strong northeast winds will be widespread in Connacht with the southerlies intruding into east Galway and Roscommon. By about 5 p.m. the centre will be tracking closer to Knock and west Sligo and winds over western Connacht will swing around to northwest at 70 to 120 km/hr. About this phase of the storm, inland southerlies will begin to show a gradual decrease also in the 70 to 120 km/hr range, and the southwest will be seeing southwest winds at 70 to 110 km/hr. Rain will wrap around the centre. Anyone in the track of this low centre (and it could include Galway city and Sligo town) will notice an interval of 30 minutes to one hour of relative calm but it would be a shorter interval if you don't get into the exact centre.

M.T. Cranium wrote:

On the east coast, winds will steadily increase all morning to reach about 70 to 110 km/hr by mid-day and then will increase more gradually in the afternoon to peak around 90 to 130 km/hr by late afternoon, the direction likely is SSE but SSW to the west of the Wicklow and Dublin hills.

M.T. Cranium wrote:

Between 0800h and 1100h, winds will increase in the south and veer to southerly 100 to 150 km/hr. Depending on where the centre tracks into Kerry (most likely somewhere near the mid-point of the various peninsulas) winds along the west coast will increase to 90 to 130 km/hr from the north-northeast with heavy rain. The strong southerlies will quickly push inland with the frontal system forming and possibly setting off squally showers and thunderstorms. Winds of 90 to 130 km/hr are likely to get into the midlands by noon with the risk of tornadic wind streaks developing near thunderstorm cells.

M.T. Cranium wrote:

I understand that the whole country is now under a level 3 or red warning. I think this was probably done more for public safety and planning reasons than strictly based on model guidance, and it makes sense to me for a number of reasons which I posted elsewhere on the storm thread.

M.T. Cranium wrote:

But here's what to expect in some detail, subject to revision at the morning forecast.

M.T. Cranium wrote:

Overnight, winds will steadily increase from the southeast (more like east to northeast in northern counties and along the west coast). By daybreak, the wind speeds near the south coast will be 60 to 100 km/hr, about 50 to 80 km/hr on the west coast and across some exposed parts of the midlands and about 40 to 60 km/hr further north. Heavy and at times thundery rain is likely especially near the west coast and some distance inland towards the midlands.

M.T. Cranium wrote:

Between 0800h and 1100h, winds will increase in the south and veer to southerly 100 to 150 km/hr. Depending on where the centre tracks into Kerry (most likely somewhere near the mid-point of the various peninsulas) winds along the west coast will increase to 90 to 130 km/hr from the north-northeast with heavy rain. The strong southerlies will quickly push inland with the frontal system forming and possibly setting off squally showers and thunderstorms. Winds of 90 to 130 km/hr are likely to get into the midlands by noon with the risk of tornadic wind streaks developing near thunderstorm cells.

M.T. Cranium wrote:

Overall, my thinking about the storm tomorrow has not changed. Some recent guidance has been perhaps 1-2 hours faster with the arrival time but I was working off that assumption since the one thing I trust the most about the GEM model is its upper level depictions and that was screaming fast phase. In layman's terms, what fast phase means is that this storm will rapidly transform from a truly tropical system (which is barely the case now as the low moves north from about 43N 14W), into a powerful frontal cyclone. This will rotate the entire system faster and bring the strong winds currently running along to the east of the low into the whole country and at a faster pace than the low centre, forcing an occluded front to form in an arc running a little ahead of the low itself. That will become the focus of the strongest winds inland, but south and southwest coastal locations will continue to have very strong winds for several hours after the low and associated fronts pass.

M.T. Cranium wrote:

I understand that the whole country is now under a level 3 or red warning. I think this was probably done more for public safety and planning reasons than strictly based on model guidance, and it makes sense to me for a number of reasons which I posted elsewhere on the storm thread.

M.T. Cranium wrote:

But here's what to expect in some detail, subject to revision at the morning forecast.

M.T. Cranium wrote:

Overnight, winds will steadily increase from the southeast (more like east to northeast in northern counties and along the west coast). By daybreak, the wind speeds near the south coast will be 60 to 100 km/hr, about 50 to 80 km/hr on the west coast and across some exposed parts of the midlands and about 40 to 60 km/hr further north. Heavy and at times thundery rain is likely especially near the west coast and some distance inland towards the midlands.

M.T. Cranium wrote:

Between 0800h and 1100h, winds will increase in the south and veer to southerly 100 to 150 km/hr. Depending on where the centre tracks into Kerry (most likely somewhere near the mid-point of the various peninsulas) winds along the west coast will increase to 90 to 130 km/hr from the north-northeast with heavy rain. The strong southerlies will quickly push inland with the frontal system forming and possibly setting off squally showers and thunderstorms. Winds of 90 to 130 km/hr are likely to get into the midlands by noon with the risk of tornadic wind streaks developing near thunderstorm cells.

M.T. Cranium wrote:

On the east coast, winds will steadily increase all morning to reach about 70 to 110 km/hr by mid-day and then will increase more gradually in the afternoon to peak around 90 to 130 km/hr by late afternoon, the direction likely is SSE but SSW to the west of the Wicklow and Dublin hills.

M.T. Cranium wrote:

Around 2 p.m. with the low somewhere near or over Clare, heavy rain and strong northeast winds will be widespread in Connacht with the southerlies intruding into east Galway and Roscommon. By about 5 p.m. the centre will be tracking closer to Knock and west Sligo and winds over western Connacht will swing around to northwest at 70 to 120 km/hr. About this phase of the storm, inland southerlies will begin to show a gradual decrease also in the 70 to 120 km/hr range, and the southwest will be seeing southwest winds at 70 to 110 km/hr. Rain will wrap around the centre. Anyone in the track of this low centre (and it could include Galway city and Sligo town) will notice an interval of 30 minutes to one hour of relative calm but it would be a shorter interval if you don't get into the exact centre.

M.T. Cranium wrote:

IMPACTS -- I am expecting widespread moderate damage and isolated severe damage reports. The widespread moderate damage will be mostly tree limbs down, entire trees down but not onto buildings, and roof tiles or other building material blown into streets or pavements. Severe damage would be coastal flooding from storm surges of 2-3 metres, stream flooding in parts of Connacht mostly, and trees falling onto cars or buildings. The south coast will see the worst of the wind gusts and storm surge, locally there could be gusts to 170 km/hr. I don't think too many reading this will experience higher than 130 km/hr but most will be in the 110-130 range at some point. Stay safe and avoid unnecessary travel or walking during the height of this storm.

Here is what mt said earlier

Middle Man

Here's the latest wind map...

https://earth.nullschool.net/#current/wind/surface/level/orthographic=-12.33,50.66,3000/loc=-14.786,46.367

Max average of around 120kph on the southwest quadrant...

MJohnston

Middle Man wrote: »

According to the French sats, it now looks as if the centre of the storm will pass just off the west coast...

http://www.boards.ie/vbulletin/showpost.php?p=104982170&postcount=2120

Again, I'll point to the NHC track ensembles which largely predicted this 'kink' in the track, and then an easterly turn closer in, which is already highlighted in the manual track images that spookwoman is posting.

Lumi

Mod Note

This thread is for technical analysis ONLY please

Off topic posts will be moved to the Ophelia General discussion thread
Post your current weather conditions reports here

Thanks

BoatMad

Middle Man wrote: »

According to the French sats, it now looks as if the centre of the storm will pass just off the west coast...

http://www.boards.ie/vbulletin/showpost.php?p=104982170&postcount=2120

Which is exactly where the models placed it early today, the centre of course on s not where the damage will be

BoatMad

Middle Man wrote: »

Here's the latest wind map...

https://earth.nullschool.net/#current/wind/surface/level/orthographic=-12.33,50.66,3000/loc=-14.786,46.367

Max average of around 120kph on the southwest quadrant...

Jesus that's high for a max average

spookwoman

Looking at https://en.sat24.com/en looks like the top arm or whatever you call it will hit cork coast soon enough

highdef

Kai Rotten Shipwreck wrote: »

Can you explain all that in English please?

If you can't understand it, go to the non-technical thread. This thread is for those who understand basic meteorological terminology.

flaneur

spookwoman wrote: »

Looking at https://en.sat24.com/en looks like the top arm or whatever you call it will hit cork coast soon enough

That’s much earlier than I was expecting.

M.T. Cranium

I think what gave it an appearance of making a NNW jog was probably the old hurricane circulation being captured by rapidly developing upper low to its NW but that process seemed to be complete by about 2330h so now the reformed system will continue to head NNE in the jet stream.

As to anything earlier being a bit on the technical side, I was just saying that on infra-red satellite you could see a tight centre of rotation developing towards the end of the sequence and temps in the warm sector of the developing new frontal system are warm for this time of year.

The 1987 storm had some temps near 18 or 19 ahead of the occlusion, so this one is at least equally loaded with heat energy. The occluded front already becoming visible on satellite is lifting that warm air rapidly, which should lead to widespread thunderstorm activity late tonight (from southwest Ireland to south Wales and Cornwall possibly). These will be elevated storms at first so they won't be producing surface gusts but if the front tightens up and comes into contact with the wrap-around rush of southwest winds, then it could be the estofex forecast tornadic activity (will be watching radar ready to comment on any such developments if I see them tomorrow morning to mid-day time frame).

As you know I am eight hours behind your time zone so would be watching this anyway but expect to find quite a few active participants all night. Amazing how well the ECM did at 120 hours with this, almost a perfect low placement (which is why this thread got started).