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Offline nouska  
#61 Posted : 05 September 2013 22:25:16(UTC)
nouska

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Location: SW France and Weybridge, Surrey.

When one looks at the current pouches being tracked, it is hard to believe that something will not develop soon.

http://www.met.nps.edu/~...13/latest/TEtracer-0.png

Having said that, no signs of much activity on the major models and I have to wonder about the naming of three of this years storms - the blink and you miss it lifespans would probably not have been named had they not been so close to populated areas. Six named storms is more than generous for the season.

Offline nouska  
#62 Posted : 06 September 2013 09:35:04(UTC)
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Location: SW France and Weybridge, Surrey.

A graph of the latest date for a hurricane to develop in the Atlantic basin.

I had been wondering what cycles, oscillations and phases might be at play in hurricane development, from this I don't see any discernible pattern that ould be attributed- it all looks pretty random.

Image courtesy of the Washington Post.

http://www.washingtonpost.com/blogs/capital-weather-gang/wp/2013/09/05/tropical-storm-gabrielle-brushes-puerto-rico-still-no-hurricanes/

SHOW EXTERNAL IMAGES

Edited by user 06 September 2013 09:36:24(UTC)  | Reason: Not specified

Offline yorkshirelad89  
#63 Posted : 06 September 2013 15:39:44(UTC)
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http://www.wunderground.com/blog/24hourprof/comment.html?entrynum=66

Interesting post which may offer some clues as to why hurricane activity in the Atlantic has been none existent so far.

Hull
Offline Stormchaser  
#64 Posted : 06 September 2013 20:04:00(UTC)
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Location: West Hants

Should be an interesting read (will look soon), thansk Jonny

http://tinypic.com/?ref=2uhto93

Looks like the UK has also been experiencing unusually low relative humidity during the half-month (not including the past couple of days).

If you have any problems or queries relating to TWO you can Email twomoderationteam@gmail.com :)

Homeland: Rural Mid-West Hants nearly 10 miles S of Salisbury (near Fordingbridge). More insights: https://twitter.com/peacockreports

2018's Homeland Extremes:

T-Max: 30.9*C 8th July | T-Min: -7.7*C 28th Feb | Wettest Day: 19.2mm 14th October | Ice Days: 4 (28 Feb - 2 Mar & 18 Mar)

Keep Calm and Forecast On

Offline doctormog  
#65 Posted : 09 September 2013 21:54:01(UTC)
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So, will Humberto become the first Atlantic hurricane of the season?

It seems probable if it develops as modelled, although it also seems probable that it will remain well out in the Atlantic while it is at hurricane strength.

Offline Stormchaser  
#66 Posted : 09 September 2013 22:33:58(UTC)
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Humberto is well organised and seems to be developing rapidly - so the first hurricane of the season might only be a day away. It may also come soon enough to avoid setting a new record for the latest occurance of the first hurricane... by a single day.

As well as Humberto, it looks like Gabrielle may have regenerated not far from Bermuda. It's not official yet, but convection has increased markedly in the past 6 hours and is also looking more organised again.


In 5-7 days time, there is strong model support for a storm developing in the Bay of Campache (SW corner of Gulf of Mexico) and becoming a notable TS or even a hurricane. Interestingly, a marked spin has developed in the NW Caribbean today and although it's currently lacking convection, once across the Yutacan Peninsula and into the BOC (presuming it does head that way) it could turn out to be the seed for development that the models have spotted.


With favourable setups looking probable for a fair while now, it seems that the hurricane season may well have finally finished the appetizer and got started on the main course. Here's hoping it doesn't play out tragically for too many people... ideally nobody, but that's a very tall order for any season.

If you have any problems or queries relating to TWO you can Email twomoderationteam@gmail.com :)

Homeland: Rural Mid-West Hants nearly 10 miles S of Salisbury (near Fordingbridge). More insights: https://twitter.com/peacockreports

2018's Homeland Extremes:

T-Max: 30.9*C 8th July | T-Min: -7.7*C 28th Feb | Wettest Day: 19.2mm 14th October | Ice Days: 4 (28 Feb - 2 Mar & 18 Mar)

Keep Calm and Forecast On

Offline Stormchaser  
#67 Posted : 10 September 2013 10:24:13(UTC)
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http://www.meteo.psu.edu/ewall/SAT_ATL/atlanim8ir.html

News... Gabrielle has regenerated into a 40mph tropical storm some way to the east of Florida and south of Bermuda - where a tropical storm warning has been issued. She's expected to intensity a little, reaching around 50mph max. sustained winds in 24h time. I reckon she could throw a few surprises, as often happens when storms are climbing to higher latitudes while in a variable and complex environment. Interestingly the forecast then keeps her at the same intensity all the way out to day 5, despite going post-tropical on day 4.

Anticipated track:

http://www.nhc.noaa.gov/storm_graphics/AT07/refresh/AL0713W5_NL_sm2+gif/081108W5_NL_sm.gif

She may feed some energy and moisture into the strong storm affecting the UK early next week, but looks to be too slow to be fully absorbed into it, instead being caught by a trough upstream.


Looking far away from Gabrielle, the strong convection in the western Caribbean is an AOI at 10% chance of development - it's the feature that I reckoned could become the seed for development in the BOC if it crosses the Yutacan Peninsula (the huge outcrop of land to the west of the convection).

Some models then develop the storm into a strong hurricane:

http://fim.noaa.gov/FIM/for_web/fim7_jet/2013090912/244/wmag_850_f198.png

That's something to pay close attention to.


Meanwhile...

http://www.nrlmry.navy.mil/tcdat/tc13/ATL/09L.HUMBERTO/ir/geo/1km/20130910.0600.msg3.x.ir1km.09LHUMBERTO.55kts-998mb-142N-263W.100pc.jpg

Humbero's nearly a hurricane. He's got 50kt sustained winds as of the most recent advisory.

Anticipated track:

http://www.nhc.noaa.gov/storm_graphics/AT09/refresh/AL0913W5_NL_sm2+gif/084758W5_NL_sm.gif

No threat to land areas within the next 5 days. A favourable environment during the next couple of days - with the storm expected to reach 100mph max. sustained winds - and then dry air and wind shear look to start weakening it, halving the max. winds by day 5.

If you have any problems or queries relating to TWO you can Email twomoderationteam@gmail.com :)

Homeland: Rural Mid-West Hants nearly 10 miles S of Salisbury (near Fordingbridge). More insights: https://twitter.com/peacockreports

2018's Homeland Extremes:

T-Max: 30.9*C 8th July | T-Min: -7.7*C 28th Feb | Wettest Day: 19.2mm 14th October | Ice Days: 4 (28 Feb - 2 Mar & 18 Mar)

Keep Calm and Forecast On

Offline Stormchaser  
#68 Posted : 11 September 2013 22:29:41(UTC)
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That 10% AOI became invest 93L and has since had it's % upped to high values and for good reason as most models show significant development once into the Bay of Campache.

The 18z GFS run, which keeps a competing monsoonal low in the Pacific weaker (and more realistic) compared with the 12z, turns 93L into a notable hurricane:

http://www.tropicaltidbits.com/analysis/models/gfsfull/2013091118/gfsfull_pres_pcpn_atl_34.png

93L has a large field of convection and will be entering an unusually moist environment coupled with favourable upper-level winds. GFS produces a large 'cane out of that - more so than the synoptic chart suggests:

http://www.tropicaltidbits.com/analysis/models/gfsfull/2013091118/gfsfull_ir_watl_37.png


So that's definately something to watch as the system moves into the BOC tomorrow. Currently it's over the Yutacan and has a good bit of rotation after practically becoming a TD while still in the Caribbean.


Elsewhere, Gabrielle peaked at 60mph for a time but then wind shear displaced the deep convection away from the low level circulation and since then the storm has been gradually waning.


Humberto is a decent hurricane now, making a run at category 2. The expected track keeps it far from any land in the next week, as the current NNW motion followed by a turn west steers it some way south of the Azores. From some time tomorrow to when it's south of the Azores, weakening to a low-end tropical storm is expected, but then there are some models showing re-strengthening before eventually being scooped up by the Atlantic westerlies... and potentially being thrown somewhere in the vicinity of the UK - watch this space in about a week's time, when we might have a reasonable idea as to where Humberto's ex-tropical form will be heading.

If you have any problems or queries relating to TWO you can Email twomoderationteam@gmail.com :)

Homeland: Rural Mid-West Hants nearly 10 miles S of Salisbury (near Fordingbridge). More insights: https://twitter.com/peacockreports

2018's Homeland Extremes:

T-Max: 30.9*C 8th July | T-Min: -7.7*C 28th Feb | Wettest Day: 19.2mm 14th October | Ice Days: 4 (28 Feb - 2 Mar & 18 Mar)

Keep Calm and Forecast On

Offline Stormchaser  
#69 Posted : 12 September 2013 16:29:45(UTC)
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Location: West Hants

http://www.ssd.noaa.gov/PS/TROP/floaters/09L/imagery/vis0.jpg

Humberto may have peaked in strength at 85mph but the storm still looks decent, and that's despite the SSTs underneath dropping to below 26°C. Wind shear will be rising over the coming days and the storm should weaken, perhaps even become ex-tropical for a time. Then there's still that chance of re-development which could see a return to hurricane status in about a week's time.

http://www.nrlmry.navy.mil/tcdat/tc13/ATL/93L.INVEST/vis/geo/1km_zoom/20130912.1545.goes13.x.vis1km_high.93LINVEST.30kts-1005mb-195N-927W.100pc.jpg

Here is invest 93L - the biggest threat for the near future. It's got a decent circulation at the mid and low levels, with convection steadily building.

Dr. Jeff Masters sums up the situation very nicely in his wunderblog post:

"

If you have any problems or queries relating to TWO you can Email twomoderationteam@gmail.com :)

Homeland: Rural Mid-West Hants nearly 10 miles S of Salisbury (near Fordingbridge). More insights: https://twitter.com/peacockreports

2018's Homeland Extremes:

T-Max: 30.9*C 8th July | T-Min: -7.7*C 28th Feb | Wettest Day: 19.2mm 14th October | Ice Days: 4 (28 Feb - 2 Mar & 18 Mar)

Keep Calm and Forecast On

Offline DEW  
#70 Posted : 13 September 2013 20:02:58(UTC)
DEW

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GFS 12Z currently has the remains of a hurricane (presumably Humberto) sitting right on top  of the UK at T+192. Should be interesting, even if the threat is rainfall, not wind - though admittedly GEFS has it futher north and ECM nowhere near.

It was most foule weather ... and so we went into an alehouse - Samuel Pepys
Offline Stormchaser  
#71 Posted : 13 September 2013 22:24:56(UTC)
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Humberto is currently having a hard time of it due to sub-26°C SSTs (below the threshold for maintaining a tropical cyclone) and a lot of wind shear from the SW. The convection was displaced earlier today and has since melted away to leave only shallower clouds - a 'naked low level circulation' by tropical standards.

The storm now needs to hang on as a swirling mass of low-level clouds until reaching warmer waters again in 2-3 days time. Then it may re-aquire some deep convection and re-strengthen as a result. ECM takes Humberto back to hurricane status from the looks of the charts.

How soon the Atlantic westerlies pick up the storm is highly uncertain, with GFS doing so far sooner than ECM. The latter seems to have Humberto drifting to the SW of the UK on day 10, with the possibility of heading on towards Europe while gently fading away.


Over in the Gulf of Mexico - more precisely the Bay of Campache in the SW corner - Ingrid is strengthening steadily going by recent recon observations... perhaps even rapidly, as pressure appears to have fallen from around 999mb as of about 10:30pm to 990-992mb as of 11:15pm - that's a big drop in the space of around 45 minutes. The winds haven't risen all that far (to around 50mph as of 11:15), but they do tend to lag behind sharp pressure drops in tropical systems.

Tomorrow morning could prove interesting in terms of what lies in the BOC, By then the storm should be tracking N or close to it.

If you have any problems or queries relating to TWO you can Email twomoderationteam@gmail.com :)

Homeland: Rural Mid-West Hants nearly 10 miles S of Salisbury (near Fordingbridge). More insights: https://twitter.com/peacockreports

2018's Homeland Extremes:

T-Max: 30.9*C 8th July | T-Min: -7.7*C 28th Feb | Wettest Day: 19.2mm 14th October | Ice Days: 4 (28 Feb - 2 Mar & 18 Mar)

Keep Calm and Forecast On

ElusivePolarLow  
#72 Posted : 14 September 2013 11:57:42(UTC)
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Humberto devoid of convection for a long time

Seems like it's going post-tropical

But if the low keeps spinning, i see they are forecasting Humberto could make a

comeback in a few days

Glad i'm not in the position to try to make that forecast

Offline Stormchaser  
#73 Posted : 15 September 2013 18:31:05(UTC)
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ex-Humberto started firing deep convection again for a while earlier today, but that has now dissipated. In a day or so the storm will reach warmer waters and should start to refire persistent deep convection. Then the environment looks to become favourable for some notable re-intensification, potentially back to hurricane status.


The big story of the moment is Hurricane Ingrid, which has had a bit of a rough day thanks to Tropical Storm Manuel, a Pacific cyclone with a broad circulation and pronounced upper-level anticyclone stacked on top. It's the latter that's proved important, as it's been driving moderate to strong westerlies across Ingrid's upper levels, creating wind shear which has caused Ingrid to become ragged with convection almost displacing clear of the low level circulation. Even so, winds have held up in the 60's mph, perhaps a bit higher based on recon data. Despite the data, NHC has kept Ingrid as a minimal hurricane for some reason... possibly in anticipation of a sharp recovery in strength in the near future.

Why a sharp recovery? Manuel made landfall within the past hour or two, and as a result that storm is weakening. The associated upper-level anticyclone - created by upwelling air in the cyclone below - will diminish rapidly once the flow of air is cut off. This will cause wind shear to relax considerably across Ingrid, allowing for reorganisation and a new round of strengthening. The offical forecast only has an 80mph peak at the moment, but the previous one went for 100mph and I reckon the potential remains for Ingrid to peak close to that level.


Beyond the above two storms (three if you include the Pacific entity), it looks as if instability in the far-western Caribbean, associated with a developing low, could be the seed for another tropical system - very similar to how Ingrid began. Remnants from Ingrid following the storm's landfall in Mexico tomorrow or Tuesday could become part of the equation too. Models show the potential for a system to develop and head NE through Florida and then out into the Atlantic where GFS uses it to develop a broad trough near or to the NW the Azores - which is why recent runs have in FI tended to push warm tropical-maritime air towards the UK.

If you have any problems or queries relating to TWO you can Email twomoderationteam@gmail.com :)

Homeland: Rural Mid-West Hants nearly 10 miles S of Salisbury (near Fordingbridge). More insights: https://twitter.com/peacockreports

2018's Homeland Extremes:

T-Max: 30.9*C 8th July | T-Min: -7.7*C 28th Feb | Wettest Day: 19.2mm 14th October | Ice Days: 4 (28 Feb - 2 Mar & 18 Mar)

Keep Calm and Forecast On

Offline Stormchaser  
#74 Posted : 16 September 2013 22:27:10(UTC)
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Manuel made landfall late on yesterday and Ingrid made landfall early on today, at max. sustained winds of 70 and 65mph respectively. The double-whammy on Mexico has produced copious rains across wide swathes of the country.

Humberto continues to spin away in the middle of the Atlantic. The winds are back to tropical storm strength and there's some deep convection warranting TS status... or at least there was. It's been sheared off again and for some reason the LLC has been diving SSW during the past hour or so - an unexpected turn of events that could have big ramifactions regarding how much energy the Atlantic has next week, should Humberto not make the trek NW, N then NE to be picked up by an Atlantic trough.

If you have any problems or queries relating to TWO you can Email twomoderationteam@gmail.com :)

Homeland: Rural Mid-West Hants nearly 10 miles S of Salisbury (near Fordingbridge). More insights: https://twitter.com/peacockreports

2018's Homeland Extremes:

T-Max: 30.9*C 8th July | T-Min: -7.7*C 28th Feb | Wettest Day: 19.2mm 14th October | Ice Days: 4 (28 Feb - 2 Mar & 18 Mar)

Keep Calm and Forecast On

Offline nsrobins  
#75 Posted : 23 September 2013 08:00:19(UTC)
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Now the 23rd Sep and we are edging towards calling a bust for the forecast 'active' season. A remarkable lack of classic track storms this year, with Mexico picking up the majority of activity.
Still several weeks left but with little of no tropical activity this morning it would have to go some to reach even normal levels.

Neil

Portsmouth, Hampshire 1m ASL (coast)

Stormchaser, Member TORRO

Offline doctormog  
#76 Posted : 23 September 2013 08:08:05(UTC)
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Remarkably there are no tropical storms or hurricanes currently in either the N Atlantic or E Pacific at what is normally one of the most active times of the season. The outlook seems rather quiet at the moment too. As Neil says it looks like, barring a sudden increase in the coming weeks that, contrary to the forecasts, this (Atlantic) hurricane season will be a rather less active one.

http://www.nhc.noaa.gov

Offline nsrobins  
#77 Posted : 26 September 2013 07:45:38(UTC)
nsrobins

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Location: South Hampshire

'No tropical systems at this time'.

The remarkably quiet season continues, increasingly contrary to predictions.

Neil

Portsmouth, Hampshire 1m ASL (coast)

Stormchaser, Member TORRO

Offline nsrobins  
#78 Posted : 30 September 2013 09:18:37(UTC)
nsrobins

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Location: South Hampshire

TD11 meandering around without troubling anyone and unlikely to either.
Some activity in the far south of the Carribean set once again to affect Mexico later perhaps, otherwise still no sign of a major storm let alone one making US landfall.

Neil

Portsmouth, Hampshire 1m ASL (coast)

Stormchaser, Member TORRO

Offline nsrobins  
#79 Posted : 30 September 2013 09:30:53(UTC)
nsrobins

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Latest 2 week tropical forecast from Colorado State:

http://hurricane.atmos.colostate.edu/Includes/Documents/Two_Week_Forecasts/september_27_2013.pdf

These boys have put their hands up and called a bust to the earlier predictions of an above average season, but do explain circumstances in detail.

It does of course beg the question: If parameter-specific seasonal forecasts can go so badly wrong, what confidence is there in modeling other areas (namely, 500mb height anomolies for winter in NW Europe?)

Neil

Portsmouth, Hampshire 1m ASL (coast)

Stormchaser, Member TORRO

Offline Sevendust  
#80 Posted : 30 September 2013 09:45:32(UTC)
Sevendust

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Location: Alton, Hampshire

Originally Posted by: nsrobins Go to Quoted Post

Latest 2 week tropical forecast from Colorado State:

http://hurricane.atmos.colostate.edu/Includes/Documents/Two_Week_Forecasts/september_27_2013.pdf

These boys have put their hands up and called a bust to the earlier predictions of an above average season, but do explain circumstances in detail.

It does of course beg the question: If parameter-specific seasonal forecasts can go so badly wrong, what confidence is there in modeling other areas (namely, 500mb height anomolies for winter in NW Europe?)

I think you answered that question already Neil

Dave

Alton - deep in the Hampshire Alps

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