TS/Hurricane Leslie

M.T. Cranium

Leslie began life as T.D. 12 and became the second-earliest twelfth named storm on 29 August (Luis, 1995, was a day earlier). Since then, Leslie has become a large but relatively disorganized tropical storm moving gradually northwest past the Virgin Islands. Current guidance suggests a period of stronger shear that may make it difficult for Leslie to maintain current 55 knot sustained winds, but then an interval of more favourable conditions as it slowly drifts N (slightly NNW) towards a point that in about seven days may be quite close to Bermuda (the model consensus says 100-200 miles east but this could change). At this point the storm could be a cat-1 to cat-3 hurricane depending on how much it can intensify.

By about 11-12 September Leslie will be accelerating northeast past Newfoundland and this morning's GFS run has the outcome of a very strong extratropical storm making a direct hit on Ireland on Friday, 14 Sep (288h panel). Since exact verification of 12-day GFS forecast maps is unusual, this is only a vague indication of any severe weather to come from Leslie, but something that we will have to monitor if the track does take this evolution.

Changes in the past two or three model runs (only GFS goes beyond 10 days) have brought Leslie across the Atlantic both a little earlier and further south. A few days ago we were being shown 15-16 day maps of extratropical Leslie near Iceland on Sunday 16th. Now it would be closer to the Gulf of Bothnia at that time.

Iancar29

ANd here is its remnants right out in FI effecting the West Coast... shall be interesting to watch it unfold!




Plus... Whats THIS!?


Hurricane for the Med?!

Su Campu

Yes ESTOFEX mentioned about a med hurricane in this morning's forecast

maquiladora

Long way to go with Leslie. I don't have much faith in the models for her at the moment. An awful lot can change with a tropical system, especially one encountering high shear and forecast to slow down to a crawl in an area of weak steering.

maquiladora

Haha, 12Z ECM develops Leslie into a huge extratropical system in FI.

Sponge Bob

V_Moth

maquiladora wrote: »

Haha, 12Z ECM develops Leslie into a huge extratropical system in FI.

Its... hypnotic. ALL GLORY TO THE HYPNOWEATHERCHART!

Iancar29

maquiladora wrote: »

Haha, 12Z ECM develops Leslie into a huge extratropical system in FI.

maquiladora

Iancar29 wrote: »

Well the 12Z GFS had it down to 958 in Donegal Bay. Pure FI of course.



It was just the huge expansion in size on the ECM that I thought was funny.

Iancar29

maquiladora wrote: »

Well the 12Z GFS had it down to 958 in Donegal Bay. Pure FI of course.



It was just the huge expansion in size on the ECM that I thought was funny.

:rolleyes:

Sponge Bob

Sponge Bob

Deep Easterly

Slow weather day. :cool:

maquiladora

Thread derailed.

I hope Ian won't be too disappointed when we just end up with a wet day with a breeze instead of a hurricane in 10 days time. :pac:

Bermuda on the other hand, could be facing a hurricane, if Leslie manages to strengthen like the models show.

catch.23

If the storm were to maintain Hurricane/TS strength winds, would it still be classified as such or as post-tropical/random depression?

M.T. Cranium

Probably, the NHC classifies on the basis of storm organization rather than maximum wind speeds. Once the tight core, eye feature and lack of frontal patterns that are indicative of a tropical cyclone are dispersed, the storm would become extra-tropical no matter how strong, although in marginal cases they would probably hold on for public safety reasons. By modern naming standards, Debbie (Sep 1961) would probably have been extra-tropical after passing 48N and before reaching Ireland.

However, the more important point is how strong the winds might be in whatever type of storm exists at the time where it passes Ireland.

The 18z GFS was also quite intense although somewhat later, passing Donegal around Saturday 15th. This is only an indication of potential until we get to about 144-168 hours and the major models still showing an intense storm near Ireland. Then it would start to become a real forecast issue instead of a "what if" discussion. Nobody should be too surprised if this entirely disappears from model runs later today or tomorrow, then comes back later, etc. It is a bit ominous seeing that much agreement between ECM and GFS on such a development in 10 days.

Worth keeping in mind also that the new moon occurs on the night of 15-16 Sep (03z 16th) and almost perigeean. So any region impacted by strong winds 14th to 16th would have storm surge issues.

maquiladora

Models for Leslie. UKMO taking it pretty far west.

maquiladora

Bermuda directly under the gun with the new official track. Huge cone of error though.

maquiladora

12Z ECM goes crazy with Leslie.

916 mb west of Bermuda.

cherryghost

Getting close to the 892 hurricane record, and not far off Hurricane Katrina's 902.

maquiladora

cherryghost wrote: »

Getting close to the 892 hurricane record, and not far off Hurricane Katrina's 902.

I think the ECM just went a bit bananas with it to be honest. I'm pretty sure there's never been a Cat 5 hurricane that far north in the Atlantic in recorded history.

It's crazy that it gets Leslie down to 917 at just 120 hours and not way off in FI. But no other model is close to that in intensity, so I'm not buying it. I'm sure there will be a climbdown on the 0Z.

Sponge Bob

Still forecast by the ECM as a large and mean ( but by then fast moving) system with a 955 low in its centre as it barrels between Iceland and Scotland next week. I'd watch out for a visit by the new TS/Hurricane Michael before then once the models start to get a handle on it.

maquiladora

0Z ECM still wants to make Leslie into a very strong hurricane.

928mb center, the type of pressure you'd see typically see in an extremely dangerous Cat 4, less than 200 miles off the coast of Rhode Island.



0Z GFS, a close call for the Canadian Maritimes.

Sponge Bob

The unusual thing about Leslie is that it could hang about largely static for a week off the Virginias and kick up a severe sea state along the US East Coast without ever making land. It has been a large system for some time now and with TS winds out to 200 miles from the centre.

Certain 06z runs place it further west ...making landfall in Nova Scotia or Newfoundland perhaps on Mon or Tue of next week.

maquiladora

Majority of 0Z GFS ensembles go for some kind of Canadian landfall.



5 or 6 days out though, a lot can change.

maquiladora

US East Coast is pretty safe now. Looking like a Canada landfall though.




Edit : We don't have a thread of Hurricane Michael (no threat to land) but he is now a Cat 3, the first major hurricane of the season. And the NHC has this interesting piece of trivia :

WITH MICHAEL BECOMING THE SEVENTH HURRICANE OF THE SEASON EARLIER
TODAY...IT MARKS THE THIRD EARLIEST FORMATION OF THE SEVENTH
HURRICANE IN A YEAR...ONLY BEHIND 1886 AND 1893.

Redsunset

And here is Michael who won't be rowing any boat ashore.

maquiladora

Models are shifting further east with Leslie now. Good news for Bermuda and if trend continues Leslie could end up missing Canada too.

(shorter tracks are the most recent runs)

Iancar29

Interesting 5 day Track of Leslie and Michael ....
makes me wonder what would happen if 2 hurricanes were to collide? ...
" THE PERFECT STORM " haha :rolleyes:

catch.23

Would the wind shear from the other storm not prevent development of each storm instead of enhancing it?

maquiladora

catch.23 wrote: »

Would the wind shear from the other storm not prevent development of each storm instead of enhancing it?

And for Ian's post above.

http://www.chbcnews.ca/explainer/6442709962/story.html

maquiladora

Leslie is a tropical storm now and should miss Bermuda well to the east. She is forecast to regain hurricane strength in a day or two. Still a bit too early to know if she will impact Newfoundland or just miss it.

Meanwhile, Invest 91L will probably end up being our next named storm in a couple of days.

M.T. Cranium

The trend on the models today is for Leslie to cross southeast Newfoundland on Tuesday as a strong extratropical storm, make a long run northeast almost to Iceland then start to dive east-southeast. The closest approach of strong winds to Ireland would be around Thursday and the range of possibilities between maximum gusts of 40 and 65 knots depending on how sharp the turn southeast is. Michael just gets absorbed or forced to trail.

M.T. Cranium

Radar for southeast Newfoundland will show the passage of "Leslie" going extratropical this morning ... local time on radar (NDT) is 3.5 hours behind IST so for example 1100h NDT is 1430h IST. Thus the time stamp is 2.5 hours behind GMT/UTC or z.

http://www.weatheroffice.gc.ca/radar/index_e.html?id=WTP

Will post some wind gust data as they happen. At time of posting, storm was about 3-4 hours from arriving in southwest corner of this radar field.

For orientation, the complex of bays and peninsulas in the southeast is known as the Avalon Peninsula and the stubby point towards the western edge is the Burin Peninsula. At the end of that you would find French islands St Pierre et Miquelon.

Sponge Bob

Newfoundland schools are closed ( by order) today with 140kph gusts forecast 'in exposed areas'. The storm system, while large (It is 500 miles across), appears very fast moving on that radar.

By the way Maquialdoras pyschedelic animation above is very accurate over the past 2 days for an FI ( bar the core pressure forecast)

M.T. Cranium

Central pressure has dropped to 970 mbs from ocean buoy reading, winds gusted to about 60 knots there from both east then west as the eye moved across. As of 0830z centre is approaching Burin peninsula where latest reports were heavy rain and east winds in the 35-55 knot range. Will return with some 09z (10:00 am IST) wind gusts which could be into the 60-65 knot range. Just early morning there now, that will be 0630h local time.

Severe flooding yesterday in parts of Nova Scotia (100 mms rain in Truro) from the front that has now wrapped around Leslie. Some of that was moisture from Isaac although that storm broke into several pieces a few days ago. Some of the energy from Isaac is probably involved in today's weather system over Ireland too.

At 09z the strongest wind gust reported was 102 km/hr at Argentia (from SE). The winds have eased slightly on the Burin with a pressure of 975 mbs reported. The centre is about an hour or two away from making landfall somewhere near Argentia. I will report more details later (probably much later, getting sleepy here) ... zzz.

Sponge Bob

Pic of Leslie and Michael at c.18z Monday. TS Nadine may even be named by the time MT gets out of bed.

Michael is smaller and slower moving than Leslie. Neither really had an eye at that stage. Mind you Michael is an average to slightly below average sized Hurricane which shows how big Leslie is.



Leslie is very far north to be generating NHC advisories ...which will continue until tonight I should think.

SUMMARY OF 500 AM AST...0900 UTC...INFORMATION

---

LOCATION...45.7N 56.4W
ABOUT 170 MI...275 KM WSW OF CAPE RACE NEWFOUNDLAND
MAXIMUM SUSTAINED WINDS...70 MPH...110 KM/H
PRESENT MOVEMENT...NNE OR 20 DEGREES AT 40 MPH...65 KM/H
MINIMUM CENTRAL PRESSURE...968 MB...28.59 INCHES


WATCHES AND WARNINGS

---

CHANGES WITH THIS ADVISORY...

NONE.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

A HURRICANE WATCH IS IN EFFECT FOR...
* NEWFOUNDLAND FROM STONES COVE TO CHARLOTTETOWN

A TROPICAL STORM WARNING IS IN EFFECT FOR...
* NEWFOUNDLAND FROM INDIAN HARBOUR... TO TRITON

FOR STORM INFORMATION SPECIFIC TO YOUR AREA...PLEASE MONITOR
PRODUCTS ISSUED BY YOUR NATIONAL METEOROLOGICAL SERVICE.

Su Campu

Interesting to note the difference in windspeeds reported by the Hibernia (VEP717) and Sea Rose (VOXS) Platforms off the New Foundland coast. Hibernia's reporting 57 knots at its 139 m high anemometer, while nearby the Sea Rose has just 35 knots at its 42 m high anemometer.

http://www.ogimet.com/cgi-bin/gsynop?lang=en&esc=2&nav=Yes&lat=45N&lon=045W&proy=orto&base=bluem&ano=2012&mes=9&day=11&hora=09&min=0&vwi=Wi

dirtyghettokid

news story on leslie from the weather network in canada

http://www.theweathernetwork.com/news/storm_watch_stories3&stormfile=Hurricane_Kirk_strengthens__tropical_depression_12_forms_30_08_2012

Sponge Bob

500 miles across and moving at 40mph now means it takes 12 hours to go past. It will, if anything, be faster moving when it crosses the Atlantic.

12z Forecast Tracks

Michael. ( hasn't gone away you know )



Leslie.



OH!

and Nadine

M.T. Cranium

Peak gusts of 130-140 km/hr reported from the Avalon peninsula around 11z-13z, and a distinct eye maintained at landfall on the Burin peninsula where Winterland had only 24 km/hr SSW with a pressure of 971 mbs. That eye feature became less well-defined as the storm raced north but was still evident on the northeast coast around 15z as the storm headed out to sea.

The main interest now will be the track closer to Scotland and Ireland, with a slim chance remaining of a more direct impact for Donegal, although the consensus remains northern Scotland where winds could peak at similar levels (130 km/hr or about 70 kts) on Thursday night. You can see from those model tracks posted above that the chances are about 10-20 per cent for those winds to hit Donegal instead, would say 95-100 km/hr or 55 kts peak gusts for exposed sites and just 70-80 km/hr further south most likely.

As for Michael, the tracks may look ominous but the consensus is for progressive weakening and as with Kirk, total absorption into the front before the remnants get close to Ireland, so whatever track verifies the effects are not likely to be noticeable embedded in the wind field around Leslie. We'll watch it carefully but at this point I don't foresee anything more than a slight wave in that front as it slides southeast across Ireland on Friday.

TD 14 now born will eventually become Nadine but seems headed for the western Atlantic on a NNW track towards Greenland.

Pangea

So if we are going to have a fairly stormy night on thursday, how come met eireann haven't mentioned it in their forecasts?
They mentioned severe gusts on the forecast yesterday for thursday but nothing on it today. I thought they would of at least mentioned it in their forecast this evening.

Sponge Bob

even UKMO have not issued a warning for Scotland as of right now. Met E have less reason again.

Elmer Blooker

ME gale warning issued at 1600 but only from Loop Head to Rossan Point so nothing serious.

M.T. Cranium

Seems that Nadine could end up closer to Ireland in the long run, depends on how long it can maintain itself through extratropical transition west to north of the Azores.

Just wanted to clarify that there is no suggestion of a forecast disagreement on wind speeds expected Thursday evening to Friday morning, our current forecast reads maximum gusts in Donegal of 50 knots and this is not considered by us (or by you, I would imagine) as a wind storm as such. I do expect stronger gusts up to 70 knots in parts of Scotland during Thursday night.

Have seen some news reports of blizzard conditions in northern Iceland associated with extratropical Leslie passing by to south, rescues of sheep and other livestock from deep snow being undertaken and said to be worst early autumn storm in 17 years in that region.

Will be keeping a close watch on developments overnight as the current models have an area of 60 knot wind potential not that far to the north of Malin Head around 00z Friday and recalling last January's last-minute shift of wind fields. But at the moment it is a watch situation and not an alert or warning.

Sponge Bob

Oh God the dreaded S word...and it is only early September.

Off hand MT can you remember such a large and a bare 1 day into post tropical blob of moisture running into a Polar system so soon ...anywhere????

M.T. Cranium

Not over Iceland or that sector, there was a 19th century hurricane late in the season that turned into a snowstorm in parts of the inland northeast, and Hazel (1954) turned up in Baffin Island in its extratropical stages, which led to heavy snowfalls in the central arctic islands.

Leslie had quite an unusual evolution with so many days of nearly stationary or slow northwest drift followed by a rush to the north and northeast. It was also a very large storm that never totally developed its potential until perhaps the extratropical stage.

I won't totally trust Leslie until she is off the charts completely.

But also don't be too surprised if the temperature soars beyond 20 C later "today" as the storm has dragged a lot of subtropical air along for the ride, after it blew through St John's the temperature peaked at about 22 C and that was a lot closer to the storm's inner core than you'll be at 3 pm. Notice the thickness ridge coming along with the system peaks at about 567 dm by then. If the low cloud breaks up it could easily reach 23 C.

Sponge Bob

M.T. Cranium wrote: »

If the low cloud breaks up it could easily reach 23 C.

23c and snow or just 23c?

tylercollins

MALIN HEAD(A) SW 32 Gust 48 CLOUDY 15 84 0.0 1006

Pretty windy here where I am, no ideas on speed as weather station is packed away for house move!

Harps

Likewise very windy here on the Donegal coast, more so than I expected. A gust of 40kts just recorded at my nearest station. Only a breeze by winter standards but its probably the windiest day in 5 or 6 months so definitely noticeable

M.T. Cranium

Malin Head reported gust to 50 knots at 1800h and the 2200h report from Lerwick (Shetlands) is WSW 47 mph gusting 69 mph. Not sure if that will be the peak, will edit in anything I see that is higher. Moderately windy by any standard. The storm was a lot stronger in Newfoundland, St John's reported something like 55 mph gusting to 80 mph at peak.