This Week's Storms - FORECAST, MODEL DISCUSSION ONLY

M.T. Cranium · 14-12-2011 8:23pm

There are well-positioned ship reports at 18z giving us a very clear picture of how the low is developing near 42W. No surprises but nothing that could absolutely rule out the sort of last-minute northward-pushing track that might scramble the forecasts and alerts tonight. In other words, 90% confidence in model solutions and 10% chance of a surprise ending.

I ran the satellite loops and could see no odd looking details if the model consensus is to be accepted at face value. The low is not very energetic for time or place. Some part of the energy has clearly surged forward as a leading wave. The only chance now for more significant development would show up by 00-03z in terms of the main body of the low energizing. Absent that I truly think it would be "game over" for a track closer to Ireland and through the central UK.

Will of course be watching this on a regular basis to the bitter end.

ninebeanrows · 14-12-2011 8:29pm

M.T. Cranium wrote: »

There are well-positioned ship reports at 18z giving us a very clear picture of how the low is developing near 42W. No surprises but nothing that could absolutely rule out the sort of last-minute northward-pushing track that might scramble the forecasts and alerts tonight. In other words, 90% confidence in model solutions and 10% chance of a surprise ending.

I ran the satellite loops and could see no odd looking details if the model consensus is to be accepted at face value. The low is not very energetic for time or place. Some part of the energy has clearly surged forward as a leading wave. The only chance now for more significant development would show up by 00-03z in terms of the main body of the low energizing. Absent that I truly think it would be "game over" for a track closer to Ireland and through the central UK.

Will of course be watching this on a regular basis to the bitter end.

Just a question for you.
Thanks for your insight as usual.

What drives Ensembles Perturbation 19 to develop the low, it has almost identical lead as any other run.

And it goes from this

gens-19-1-12.png?12

to this in 24 hours

gens-19-1-36.png?12

maquiladora · 14-12-2011 8:50pm

Can I guess before MT answers? :P

Stronger jet?

gfs-5-18.png?12

M.T. Cranium · 14-12-2011 8:57pm

Sorry I can't say what assumptions go into the perturbations, but from the looks of the 12h time step, it maxes out the possible rebound strength of the flow from 10 to 30W in the next few hours following the short wave's progress east of Ireland tonight. That gives the Azores region low a surface with which to climb north of due east, and with the temp-dp observed in the warm sector at present, a good deal of latent energy which is most likely going to be received in France rather than the UK late Thursday.

24-48h model errors are nowadays pretty subdued so that perturbation would represent a sort of once-a-season if not once-a-year scale of model error.

Signs that perturbation might be verifying would be a northeast swerve on the current low in Ireland, strong SW gales overnight in Cornwall and south Wales, wind staying in SW at places like Johnstown and maybe our amateur weather stations in Waterford. Then a 00z upper air analysis confirming jet stream had begun to rebound. That would really throw the current model consensus for a loop.

Deep Easterly · 14-12-2011 10:03pm

8pm Reports - some strong winds in SW now as low zips through.

Sherkin Island: Mean windspeed: 40kt (Gale 8) Gust 68kt (Hurricane force 12!)
Valentia: Mean: 22kt (BF 6) Gust 48 (BF Storm 10)

http://www.met.ie/latest/reports.asp

In contrast, a mean speed of just 2 knots at Belmullet!

9pm Report:
Sherkin Island gusting 57kt, mean speed 32kt
Valentia gusting 41kt, mean 28.
Roches point: No gust speed reported, mean speed 24kt.
Cork Apt: Gust 37kt, mean 24kt.

http://www.met.ie/latest/reports.asp

Wild Bill · 14-12-2011 10:46pm

Amazing contrast in wind across the island....much of the North and West and here (Dublin) currently calm or nearly so; yet 100mph gusts on the south coast!

Su Campu · 14-12-2011 10:56pm

Wild Bill wrote: »

Amazing contrast in wind across the island....much of the North and West and here (Dublin) currently calm or nearly so; yet 100mph gusts on the south coast!

South coast of where exactly??!!

Wild Bill · 14-12-2011 11:11pm

Deep Easterly wrote: »

Sherkin Island: Mean windspeed: 40kt (Gale 8) Gust 68kt (Hurricane force 12!)

Su Campu · 14-12-2011 11:13pm

Wild Bill wrote: »

68 knots = 79 mph.

NIALL D · 14-12-2011 11:17pm

Su Campu wrote: »

South coast of where exactly??!!

must be in patagonia !!!!

Iancar29 · 14-12-2011 11:23pm

Su Campu wrote: »

South coast of where exactly??!!

Yep...on the motorway going 60 mph SW into the wind :rolleyes:

Wild Bill · 14-12-2011 11:50pm

Su Campu wrote: »

68 knots = 79 mph.

Hey! Deep Easterly said they were hurricane force 12 :rolleyes:

His word is enough for me.

Su Campu · 14-12-2011 11:52pm

Wild Bill wrote: »

Hey! Deep Easterly said they were hurricane force 12 :rolleyes:

His word is enough for me.

Yeah, and that's from 64 knots (74 mph). Where did the 100 mph come from?

Wild Bill · 15-12-2011 12:02am

Su Campu wrote: »

Yeah, and that's from 64 knots (74 mph). Where did the 100 mph come from?

Well...I thought the lowest "hurricane force" was 100mph. I thought I heard that on the Discovery Channel's Ice Road Truckers.

tbh Su, you don't make much allowance for us enthusiastic amateurs.

Sponge Bob · 15-12-2011 12:10am

Tying yourself up in knots again are we bill?

Wild Bill · 15-12-2011 12:14am

Sponge Bob wrote: »

Tying yourself up in knots again are we bill?

Sponge..extending the hand of friendship to a drowning man?

gbee · 15-12-2011 9:44am

Wild Bill wrote: »

Well...I thought the lowest "hurricane force" was 100mph. I thought I heard that on the Discovery Channel's Ice Road Truckers.(

Anything above 65mph is entering Hurricane strength with 74 mph the official Cat1 tipping point for sustained wind speeds.

Su Campu · 15-12-2011 9:58am

gbee wrote: »

Anything above 65mph is entering Hurricane strength with 74 mph the official Cat1 tipping point for sustained wind speeds.

65 mph is only Violent Storm Force 11 (64-72 mph). Cat 1 hurricane force starts at 73 mph, no lower.

http://en.wikipedia.org/wiki/Beaufort_scale

Su Campu · 15-12-2011 10:00am

The Germans have named tonight's storm Joachim (pron. Yo-AH-kheem).

Tom Cruises Left Nut · 15-12-2011 10:14am

Su Campu wrote: »

The Germans have named tonight's storm Joachim (pron. Yo-AH-kheem).

Apt, wasn't the German team Manager Joachim "Low"

munsterlegend · 15-12-2011 10:23am

Munster
15 December 2011- updated at 06:00
Today

Wintry showers at first, but brightening up. Rain and sleet in the south later. Max temps 5 to 7 C.

Tonight

Rain and sleet in the south, clearing later. Windy showers following from west. Min temps -2 to 0 C.

Tomorrow

Bright or sunny spells and wintry showers, heaviest in the west. Max temps 4 to 6 C.

those windy showers should be interesting tonight! hopefully have a bit of sneachtna in them at the lower levels.

Su Campu · 15-12-2011 10:43am

t|nt|n wrote: »

Apt, wasn't the German team Manager Joachim "Low"

Joachim Löwe, but near enough yeah!

Tom Cruises Left Nut · 15-12-2011 11:07am

Su Campu wrote: »

Joachim Löwe, but near enough yeah!

Check out the big brain on Brad !! :rolleyes:

:pac:

Sponge Bob · 15-12-2011 12:35pm

UKMO Downgrade

Issued at - 15 Dec 2011, 11:26
Valid from - 15 Dec 2011, 20:00
Valid to - 16 Dec 2011, 09:00

An area of heavy rain is expected to move quickly eastwards across southern counties of England during Thursday evening and during the first part of Friday. The rain will be accompanied by fresh to strong winds with a low risk of gales or severe gales near coasts in the far southeast early on Friday.

The public is advised to be aware of the risk of localised flooding due to rain falling onto already saturated ground.

Spindle · 15-12-2011 1:16pm

Sponge Bob wrote: »

UKMO Downgrade

Issued at - 15 Dec 2011, 11:26
Valid from - 15 Dec 2011, 20:00
Valid to - 16 Dec 2011, 09:00

An area of heavy rain is expected to move quickly eastwards across southern counties of England during Thursday evening and during the first part of Friday. The rain will be accompanied by fresh to strong winds with a low risk of gales or severe gales near coasts in the far southeast early on Friday.

The public is advised to be aware of the risk of localised flooding due to rain falling onto already saturated ground.

UKMO 0 : Computer Models 1

Su Campu · 15-12-2011 2:02pm

The main low is located at around 32W at 1200, and the ASCAT pass at 10:53 shows the other ill-defined low ahead of it, near 18W. I don't believe the 55 knot wind speed reported by ship SKWI just south of the main centre as it only reported 4 m wave heights, and 3 other nearby ships along a similar gradient are reporting 30-35 knots.

2011121512_atln.gif?1323953114

Iancar29 · 15-12-2011 3:08pm

Saw this over on Net Weather ... Couldnt help but laugh!

Depicts the last few days perfectly! haha

Sponge Bob · 15-12-2011 3:18pm

Shall we try visual

http://www.sat24.com/en/gb?ir=false

Sponge Bob · 15-12-2011 4:06pm

The business end of the Thu/Fri storm is well south. Look at the map of warnings in France for example

http://france.meteofrance.com/vigilance/Accueil

Forte tempête hivernale, nécessitant une vigilance particulière en raison des vents forts attendus associés à des pluies soutenues et de puissantes vagues en bordure littorale atlantique.

"Strong winter tempest"

Iancar29 · 15-12-2011 4:13pm

Rain Temperature profile right there...

, if only the red line was 10 o C to the left

This Week's Storms - FORECAST, MODEL DISCUSSION ONLY

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