Major Hurricane Irma

[OUGrad05]

Just now, vinylfreak89 said:

that station stopped reporting a while ago. Looks to have gone offline.

Oh, great timing!

[PortsmouthWeather]

Based off its current motion, the line shows where the center of the eye would pass.

[NavarreDon]

11:00 pm 185 mph 916 mb WNW 15 mph


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[Smitty97]

2 minutes ago, mempho said:

3 mb is very close to 10 meters (isn't maximum sustained winds supposed to be a 10m, 10 second sustained wind measurement?

Question is, you drop two sondes, wouldn't you take the higher one because you're trying to sample the maximum 10 second sustained wind?

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how high are the ocean waves at that point?  probably more than 10 meters.  maybe it splashed the top of one.

[Coach McGuirk]

3 minutes ago, BuffaloWeather said:

That graph is in knots, so 160 knots is 185 MPH.

I know.  They never said it was going to get this strong during the discussions I read.  There's little reason to believe it will lose much intensity until if/when it turns north.  There's too much energy and not much shear. 

[nwohweather]

Boy the US only chance is if this thing dives into Cuba. Other than that I don't see anyway this doesn't make landfall as a Cat 5 unless it gains latitude and hits GA/SC

[JasonOH]

4 minutes ago, mempho said:

3 mb is very close to 10 meters (isn't maximum sustained winds supposed to be a 10m, 10 second sustained wind measurement?

1mb is approximately 8m, so that is about 24m above the surface. Loosing 6 knots in the 14m down to 10m (friction) wouldn't be too surprising. 

[mempho]

how high are the ocean waves at that point?  probably more than 10 meters.  maybe it splashed the top of one.

Yep, a wave would likely be 50 feet. Just think- a single wave could have cost Irma a tie for the Atlantic record.

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[MazooWeather]

NHC says "Euro all the way"

Latest center fixes from satellite imagery and the aircraft
indicate that Irma is now moving west-northwestward, or 285/13 kt.
A strong ridge extending southwestward from the central Atlantic is
expected to steer Irma west-northwestward during the next couple of
days.  A large mid-latitude trough over the eastern United States is
forecast to lift northeastward, allowing the ridge to build westward
and keep Irma on a westward to west-northwestward heading through
Friday.  In 4 to 5 days, a small trough diving southward over
the east-central U.S. is expected to weaken the western portion of
the ridge, causing Irma to turn poleward.  Some of the dynamical
models have shifted northward a bit from the previous cycle, with
the normally reliable GFS looking like a northeast outlier.  The
official track forecast leans toward the ECMWF solution.  Users are
reminded to not focus on the exact forecast track, especially at the
longer ranges, since the average NHC track errors are about 175 and
225 statute miles at days 4 and 5, respectively

[Jaguars]

NHC not buying GFS at all

[mempho]

1mb is approximately 8m, so that is about 24m above the surface. Loosing 6 knots in the 14m down to 10m (friction) wouldn't be too surprising. 

 

Could be- or a wave 16m high swamped the sonde before it could measure the surface. Guess we'll never know.

 

I'm actually sort of surprised this hasn't been discussed before. Also, wouldn't a sonde that did make it to 10m potentially be in a relative shelter by being between in the trough between waves?

 

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[NavarreDon]

Dr Knabb is saying G4 data will be included in the 5:00 am advisory and we may see some track differences then.


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[Ginx snewx]

2 minutes ago, Jaguars said:

NHC not buying GFS at all

Normally reliable GFS, say wut? 

[HKY_WX]

00z NAM is really carving out a nice (albeit weak) upper low over the southern Miss Valley at hour 84. Checkout the 500mb vorticity to really see it clearly. If that trend continues, this definitely has room to trend north. The 500mb low over the New England is unseasonable for its location, and in the winter time would act to carve out a trough behind it and favor a cutoff low over the southeast. If you apply some winter time logic to this tropical pattern, you get a SECS.

[BuffaloWeather]

 

[winterymix]

2 minutes ago, HKY_WX said:

00z NAM is really carving out a nice upper low over the southern Miss Valley at hour 84. Checkout the 500mb vorticity to really see it clearly. If that trend continues, this definitely has room to trend north. The 500mb low over the New England is unseasonable for it's location, and in the winter time would act to carve out a trough behind it and favor a cutoff low over the southeast. If you apply some winter time logic to this tropical pattern, you get a SECS.

NAM seems to have the storm scrape the east FL coast although I wonder if that is an inverted trough at 1 o'clock to the NNE of

the storm.  If so, wouldn't it track NNE?

 

[RUNNAWAYICEBERG]

euro has been all over the place but we're talking d7+ so what guidance wont be. I'm just not sure dismissing one gfs op run though, which is well within both ens envelopes, is the way to go at this lead time. 

[Hoosier]

16 minutes ago, HillsdaleMIWeather said:

NHC says "Euro all the way"

Latest center fixes from satellite imagery and the aircraft
indicate that Irma is now moving west-northwestward, or 285/13 kt.
A strong ridge extending southwestward from the central Atlantic is
expected to steer Irma west-northwestward during the next couple of
days.  A large mid-latitude trough over the eastern United States is
forecast to lift northeastward, allowing the ridge to build westward
and keep Irma on a westward to west-northwestward heading through
Friday.  In 4 to 5 days, a small trough diving southward over
the east-central U.S. is expected to weaken the western portion of
the ridge, causing Irma to turn poleward.  Some of the dynamical
models have shifted northward a bit from the previous cycle, with
the normally reliable GFS looking like a northeast outlier.  The
official track forecast leans toward the ECMWF solution.  Users are
reminded to not focus on the exact forecast track, especially at the
longer ranges, since the average NHC track errors are about 175 and
225 statute miles at days 4 and 5, respectively

I don't take it that way.  They are skeptical of the 18z GFS but lean toward the ECMWF does not necessarily mean go 100% all the way.

[LovintheWhiteFluff]

1 minute ago, Hoosier said:

I don't take it that way.  They are skeptical of the 18z GFS but lean toward the ECMWF does not necessarily mean go 100% all the way.

That's how I took it. I took it as if they are blending the Euro with the other guidance, otherwise they would have the track over Cuba. 

[jburns]

1 minute ago, Hoosier said:

I don't take it that way.  They are skeptical of the 18z GFS but lean toward the ECMWF does not necessarily mean go 100% all the way.

Exactly. They end with a reminder of the average track errors.  They really don't have much more of an idea than we do.

[Jaguars]

I will be mildly surprised if GFS doesn't come back west tonight 

[bdgwx]

The NHC works with D5 forecasts and you can't really blame them for leaning towards the Euro. Afterall, in terms of Irma track forecast skill it has been annihilating everything...all other models, consensus of models, humans, etc. You name it and it's probably beating it...easily.

[Random Chaos]

Cross-section of last pass through hurricane:

 

[Hoosier]

Here is the state of the cone

[weatherdude888]

So this is the forecast position from NHC's 11PM discussion:

INIT  06/0300Z 17.4N  61.1W  160 KT 185 MPH
12H  06/1200Z 18.1N  63.1W  155 KT 180 MPH
24H  07/0000Z 19.1N  65.9W  150 KT 175 MPH
36H  07/1200Z 20.1N  68.5W  145 KT 165 MPH
48H  08/0000Z 21.0N  71.2W  140 KT 160 MPH
72H  09/0000Z 22.0N  76.2W  135 KT 155 MPH
96H  10/0000Z 23.2N  79.5W  125 KT 145 MPH
120H  11/0000Z 25.0N  81.5W  120 KT 140 MPH

Looking at this, it's only showing a gain of .7N over 12 hours, but it's current heading is 285.....shouldn't the N gain be somewhat larger than .7N, assuming a fairly constant heading?

Also the first line is 06/300z and the second is 06/1200z which is 9 hours and not 12....

 

 

[Radtechwxman]

NHC is def not biting on the eastward trend yet. I don't blame them. Models still wavering quite a bit. Several days out. But personally I'm not thinking it will be as close to Cuba as they are showing

[RUNNAWAYICEBERG]

3 minutes ago, Jaguars said:

I will be mildly surprised if GFS doesn't come back west tonight 

Doesnt really matter what it shows though. We should heavy ens this until Sat, or there abouts. 

[Hoosier]

1 minute ago, weatherdude888 said:

So this is the forecast position from NHC's 11PM discussion:

INIT  06/0300Z 17.4N  61.1W  160 KT 185 MPH
12H  06/1200Z 18.1N  63.1W  155 KT 180 MPH
24H  07/0000Z 19.1N  65.9W  150 KT 175 MPH
36H  07/1200Z 20.1N  68.5W  145 KT 165 MPH
48H  08/0000Z 21.0N  71.2W  140 KT 160 MPH
72H  09/0000Z 22.0N  76.2W  135 KT 155 MPH
96H  10/0000Z 23.2N  79.5W  125 KT 145 MPH
120H  11/0000Z 25.0N  81.5W  120 KT 140 MPH

Looking at this, it's only showing a gain of .7N over 12 hours, but it's current heading is 285.....shouldn't the N gain be somewhat larger than .7N, assuming a fairly constant heading?

That's 9 hours, given the initial of 03z.

[PressureDrop2017]

ABS TV (Antigua and Barbuda) are live-streaming the approach of Hurricane Irma. This is exceptional coverage from the primary source, check it out for as long as they are able to maintain their broadcasts

 

https://www.facebook.com/abstvradio/

www.abstvradio.com

[weatherdude888]

2 minutes ago, Hoosier said:

That's 9 hours, given the initial of 03z.

Somewhat confused then (my apologies if I am misunderstanding), but that line shows 12H....why then is the time difference only 9 hours then?