Atlantic Storm Watch: Turning Unsettled with Gales

waterways

Haven't you read the disclaimer? We never predict weather we only discuss models.

cyclops999

Maq with the isobars so tightly packed on Monday if this was to happen what strenght would overland winds be?

maquiladora

cyclops999 wrote: »

Maq with the isobars so tightly packed on Monday if this was to happen what strenght would overland winds be?

I posted some charts on the previous page with gusts in knots to give a rough idea. I wouldn't focus too much on the details because things will change.

JanuarySnowstor

The models are now firming up on a very stormy period ahead.
We have about 3 storms now in the next week or so, one more powerful than the next
Interesting weather, in ways almost more so than these half hearted cold spells!!

Harps

Yep finally (potentially) an active week of weather after 4 months with absolutely nothing of note

Problem at the moment is that the global models are next to useless with so many different storms showing up at different times and no continuity between runs

Even tomorrow night, UKMO has very strong winds in the NW while ECMWF doesn't seem to develop the system at all

maquiladora

Harps wrote: »

Yep finally (potentially) an active week of weather after 4 months with absolutely nothing of note

Problem at the moment is that the global models are next to useless with so many different storms showing up at different times and no continuity between runs

Yep. Feast or a famine. After no significant windstorm potential for ages we now have a possible system tomorrow for the northwest, followed up by maybe the most intense Atlantic storm in 20 years (out at sea) over the weekend, followed by two more potential storms on Monday and Tuesday which could impact us more...

UK4 shows tomorrows low quite well.

Ahorseofaman

will it rain in my backyard?and how many mm to the nearest decimal point? :pac:

maquiladora

Ahorseofaman wrote: »

will it rain in my backyard?and how many mm to the nearest decimal point/
:pac:

Enough to make a rainman.

Ahorseofaman

maquiladora wrote: »

Enough to make a rainman.

:pac::pac::pac:

dfx-

Is there a chance this could be like the previous really low storm on a model that turned into two weaker storms in reality..

maquiladora

dfx- wrote: »

Is there a chance this could be like the previous really low storm on a model that turned into two weaker storms in reality..

I can't remember which low you mean there, but all 3 main models are in agreement on the deep Atlantic low by 48 hours, only difference between them at that point being exactly how intense it would be.

Plenty of uncertainty with the other potential systems though.

vizualpics

Harps wrote: »

Yep finally (potentially) an active week of weather after 4 months with absolutely nothing of note

Are you forgetting the storms we had before Christmas 21st/22nd Dec and another on the 28th Dec?

maquiladora

vizualpics wrote: »

Are you forgetting the storms we had before Christmas 21st/22nd Dec and another on the 28th Dec?

I remember Dec 28th. There was a recorded gust of 131 km/h. Here is the chart from that day.

Mr Cumulonimbus

18Z GFS appears to be keeping the low a little further west with each new frame.

Mr Cumulonimbus

New frame at +78 keeps the low quite a further bit west now with a new feature developing to its south.

maquiladora

Mr Cumulonimbus wrote: »

New frame at +78 keeps the low quite a further bit west now with a new feature developing to its south.

There will be changes with these lows on every run. Even for tomorrow night the 18Z GFS has that small low to our northwest 10mb deeper than the last run six hours ago.

This is the difference at the 27 hour mark. 18Z on the left, 12Z on the right.

maquiladora

Here is some stuff from around the weather world about the big Atlantic low. I'm surprised there's not more interest about it on here.

From senior meteorologist at The Weather Channel Stu Ostro's Facebook page :

A system which is currently relatively innocuous but with a potent core of jet stream energy aloft (top map) will become very intense by Saturday over the North Atlantic. The bottom image is the ECMWF model's depiction of how the cyclone will appear on satellite imagery. This won't necessarily be exactly how it'll look, but it should have a vivid comma/swirl. Latest runs of both that model and the American GFS forecast a central pressure to reach ~925-927 millibars, which would be exceptionally low.

Models also indicate it'll become a "warm seclusion," which is as that sounds: warm air becoming secluded from colder air around it. I.e. it would be warm-core, which tropical cyclones are, but by a different process and with an overall different structure and winds not as strong as with a hurricane that has a central pressure in the 920s.

Fortunately the storm should weaken before directly affecting land, but it'll generate extremely big waves on the ocean, and another large & strong storm may approach Iceland and northwest Europe early-mid next week.

The Weather Channel also have an article on it today.

Meteorologists use central pressure as a proxy for measuring the strength of both "extratropical cyclones" (those with cold/warm/occluded fronts) and "tropical cyclones" (hurricanes, tropical storms, tropical depressions).

The lowest surface pressure as measured by reconnaissance aircraft in Superstorm Sandy's lifecycle was 940 millibars. The North Atlantic storm we reference below will likely bottom out with a lower central pressure! Fortunately, its worst impacts will stay offshore of Iceland, Ireland and Scotland.

Isobar after isobar encircles the low pressure center in this model forecast (Saturday) of the powerful north Atlantic storm.

Historical Perspective

Most Powerful Atlantic Extratropical Cyclones on Record (Source: Weather Underground)

913 mb (26.96") on Jan. 10-11, 1993 near Scotland’s Shetland Islands (lowest sea-level adjusted barometric pressure ever observed on the earth’s surface besides tropical cyclones and tornadoes)

920.2 mb (27.17”) by the ship Uyir while she sailed southeast of Greenland on December 15, 1986. The British Met. Office calculated that the central pressure of the storm, which was centered some distance southeast of the ship, was 916 mb (27.05”).

921.1 mb (27.20") on Feb. 5, 1870 measured by the ship Neier at 49°N 26°W (another ship in the area measured 925.5 mb)

924 mb (27.28") on Feb. 4, 1824 at Reykjavik, Iceland (the lowest on land measured pressure in the North Atlantic)

925.5 mb (27.33") on Dec. 4, 1929 by the SS Westpool somewhere in the Atlantic (exact location unknown)

925.6 mb (27.33") on Jan. 26, 1884 at Ochtertyre, Perthshire, U.K. (the lowest pressure recorded on land in the U.K.)

From a marine meteorologist's blog :

North Atlantic Storm update


A 1003mb low off the Middle Atlantic Coast this afternoon will move and deepen very rapidly as it tracks northeastward with winds forecast up to 50 knots this evening, reaching upwards of 60 knots by 12Z Friday and as high as 80-85 knots possible Friday night. Significant wave heights associated with this low will buildup to 17 meters (56 feet) by early Saturday. This system will likely deepen to near historical levels with models suggesting a minimum pressure of about 923mb early Saturday.

Spindle

Maquiladora, thanks for all the updates on this, a lot of discussion around the place is still about snow potential, completely ignoring the beast of a storm out in the Atlantic.

Looks bit like a big swiss roll on the chart above

ninebeanrows

Interesting, some ENS are starting to indicate the super low will spawn off a secondary depression quite early in the output, the 18z GFS does build this but doesn't go to the extreme as some ENS members.

Below is an example of an output at T60hrs and isnt a complete outlier.

Harps

Satellite loops of the US coast and the North Atlantic here, in darkness for the next while obviously but the general features should be visible on infrared. It should come into view on our own sat24 tomorrow

http://www.weatherplaza.com/en-US/sat/?region=northeast.vis

http://www.sat24.com/imageloop.aspx

Already forming a baroclinic leaf south of Newfoundland at the moment



Edit: Another one here shows the whole North Atlantic and has a zoom feature

http://www.ssd.noaa.gov/goes/east/natl/flash-vis.html

DaithiMa

I've been looking and lurking in the weather forum for ages (jesus that sounds dodgy!) and I have learned loads about weather/charts from those in the know on here. Thanks. This development in the Atlantic looks by far the most interesting/epic thing on here in the last year or so since i've been on, and from what I can see on the charts it looks like some serious s#@t. I, for one, cannot wait to see how it unfolds.

teddybones

DaithiMa wrote: »

I've been looking and lurking in the weather forum for ages (jesus that sounds dodgy!) and I have learned loads about weather/charts from those in the know on here. Thanks. This development in the Atlantic looks by far the most interesting/epic thing on here in the last year or so since i've been on, and from what I can see on the charts it looks like some serious s#@t. I, for one, cannot wait to see how it unfolds.

You echo my thoughts exactly Daithi. Thanks to everyone for your wonderful analysis and thoughts on this thread and especially Maq! I have been quietly glued to this thread! Fascinating stuff people.

shmaupel

teddybones wrote: »

You echo my thoughts exactly Daithi. Thanks to everyone for your wonderful analysis and thoughts on this thread and especially Maq! I have been quietly glued to this thread! Fascinating stuff people.

Just to add my own thanks here too, its great to get your thoughts on the models Maq, I appreciate all the time and effort :-)

Elmer Blooker

I found this on NW are few mins ago, look at the Atlantic laughing at us - the Atlantic always has the last laugh!

red_bairn

Elmer Blooker wrote: »

I found this on NW are few mins ago, look at the Atlantic laughing at us - the Atlantic always has the last laugh!

That's well creepy...

Weathering

Have we reached the stage to warrant a level1 thread for any of these possible storms or is there still too much uncertainty?

Elmer Blooker

red_bairn wrote: »

That's well creepy...

creepy alright

http://upload.wikimedia.org/wikipedia/en/f/f4/The_Scream.jpg

maquiladora

Weathering wrote: »

Have we reached the stage to warrant a level1 thread for any of these possible storms or is there still too much uncertainty?

Too much uncertainty still from Sunday onwards.

Mr Cumulonimbus

Thermal IR image at 9am.

maquiladora

It's just starting to slip out of range of the Northwest Atlantic view here -
http://www.ssd.noaa.gov/goes/east/nwatl/flash-bd.html

Wider North Atlantic view -
http://www.ssd.noaa.gov/goes/east/natl/flash-bd.html

Main GOES East page - http://www.ssd.noaa.gov/goes/east/

It was 984mb at 9am.