ATL: IRMA - Post-Tropical - Discussion

[Aric Dunn]

The last hour or so it has really started diving wsw to nearly SW. if the current motion continues it will be south of the NHC forecast point but a good bit.

[Aric Dunn]

back to 115 mph and heading wsw..

[Blown Away]

The last hour or so it has really started diving wsw to nearly SW. if the current motion continues it will be south of the NHC forecast point but a good bit.

Lowest Latitude Predicted By Past Few Forecasts:
5am: 16.5 (Sunday) **Keeps Irma at 16.5 from 36-48 hrs, which is a delay from the WNW turn.
11pm: 16.5 (Saturday Night)
5pm: 16.8
11am: 17.1
5am: 17.0
11pm: 16.8 (Friday Night)

*** NHC keeps dropping the lowest latitude point and IMO these short term nudges S are creating the W nudges in the long term... These S nudges have pushed that NHC track S & W over past day and delaying that WNW turn to just miss the NE Caribbean and delaying the N turn to just miss Florida and impacting Carolinas...

*** Also, the 11pm 5 day latitude was 22.5N and remained the same at 5am which is decent shift W late...

[Aric Dunn]

The last hour or so it has really started diving wsw to nearly SW. if the current motion continues it will be south of the NHC forecast point but a good bit.

Lowest Latitude Predicted By Past Few Forecasts:
5am: 16.5 (Sunday) **Keeps Irma at 16.5 from 36-48 hrs, which is a delay from the WNW turn.
11pm: 16.5 (Saturday Night)
5pm: 16.8
11am: 17.1
5am: 17.0
11pm: 16.8 (Friday Night)

*** NHC keeps dropping the lowest latitude point and IMO these short term nudges S are creating the W nudges in the long term... These S nudges have pushed that NHC track S & W over past day and delaying that WNW turn to just miss the NE Caribbean and delaying the N turn to just miss Florida and impacting Carolinas...

That is what I have been saying for 2 days now..

[jlauderdal]

south x south west...nhc has been left leaning since it was named and the system has responded accordingly, latest euro run has responded too..nhc adjusts west and then says we are to the east of reliable guidance, this is the key statement in the disco "It should be noted
that the official forecast still lies to the east of some of the
better-performing models, such as the ECMWF, HWRF, and HCCA, so
additional adjustment are possible in subsequent advisories."

one thing that seems like a sure bet is intensity, no reason to think we have anything but a major on our hands for the next week at least

[bob rulz]

Matthew was devastating for the Bahamas last year, hard to imagine another storm of similar or greater magnitude passing over just a year later.

Lesser Antilles are the more immediate concern, however.

And Joaquin the year before... Bahamas have been hammered as of late.

Right, I knew there had been another major one for them, but couldn't recall in the moment. That is unbelievable.

[USTropics]

NHC is seeing the same thing Aric has been alluding to for the past few days:

Irma's convective pattern has improved slightly overnight. Very
cold cloud tops completely encircle the eye, which has warmed and
become a bit clearer in infrared satellite images. The initial
intensity is raised to 100 kt based on a blend of the latest
subjective and objective Dvorak estimates.

Irma has been losing latitude since yesterday due to strong high
pressure to its north, and the initial motion is now west-
southwestward, or 255/13 kt. The hurricane is likely to continue
moving on this trajectory for the next 36 hours, after which time it
should gradually turn toward the west and then west-northwest on
days 3-5 when it reaches the western extent of the ridge. The new
NHC track forecast is very similar to the previous one during the
first 48 hours, showing Irma bottoming out around 16.5N. However,
the track guidance has shifted westward after 48 hours, delaying a
turn toward the west-northwest, and this required a corresponding
westward shift in the official forecast toward the multi-model
consensus at the end of the forecast period. It should be noted
that the official forecast still lies to the east of some of the
better-performing models, such as the ECMWF, HWRF, and HCCA, so
additional adjustment are possible in subsequent advisories.

The environment ahead of Irma appears conducive for gradual
strengthening for at least the next 2 to 3 days, with increasing sea
surface temperatures and a moistening in the mid-levels of the
atmosphere. We may still observe fluctuations in intensity, but
overall, the model guidance seems to suggest a general upward
trend with a peak in intensity possibly occurring around day 3.
This type of intensification would coincide with the timing of
Irma's west-southwest to westward motion, a pattern which we have
observed in other west-southwestward-moving hurricanes in the past
(i.e., Katrina, Joaquin, Fernanda, etc.). The NHC intensity
forecast is bumped up slightly, showing a peak in intensity on day
3, and is largely a blend of the ICON intensity consensus and HCCA.

While Irma is currently a small hurricane, the size guidance
suggests it should grow in size during the next 72 h. This will
affect how soon watches may be issued for portions of the Leeward
and Virgin Islands, and interests on those islands should continue
to monitor Irma's progress.

[Blown Away]

Morning met for WPB news just said the reliable model keeps Cat 4/5 Irma just E of SFL by a hundred miles or so and with a big smile says "Looks like good news for Florida"

[northjaxpro]

Yes I am extremely worried about the Bahamas. The Bahamas have been hit and impacted significantly by. major hurricanes Joaquin and Matthew just recently. However, Irma potentially could become the worst hurricane to ever hit the Bahamas if the current projections come to fruition. I am very worried about that island chain as we go into next weekend.

[jlauderdal]

Morning met for WPB news just said the reliable model keeps Cat 4/5 Irma just E of SFL by a hundred miles or so and with a big smile says "Looks like good news for Florida"

a sarcastic smile im sure...

the nhc is foreshadowing things to come in the 5 am disco with their talk about westerly movement...remember they go out to 5 days on the official track but they know what is coming beyond that out to at least 7 days with decent confidence...at minimum this thing gets in the the southern and central bahamas as a major hurricane with movement clearly towards florida, sc and nc...will be interesting to see if 57 raises his gulf chances, yesterday it was 2%

for anyone new to the board, the bahamas does absolutely nothing to mitigate intensity..islands are flat, the water is very warm, hurricanes roll through there like its the open atlantic, they are as prepared for big wind as anyone in the world but like most tropical systems its the water, rain and surge...the structures there are very well built like bermuda but you cant stop water, take a look at houston

[bob rulz]

First visibles of the day show some really mean-looking hot towers firing in the eyewall.

[KWT]

If the models are right it really isn't going to need a huge amount of adjustment to become a huge risk to PR and also Hispaniola, and at the strength it is even a glancing blow is going to cause havoc.

Also the eye is starting to really pop out again and now its diving towards warmer waters and getting past 50W soon it should start to tap into warmer waters and thus will probably go to the next level soon enough (Ie, cat-4) as it feeds into the more supportive SSTs for such powerful systems.

[KWT]

They are obviously taking it very seriously if they are flying out to 49W to catch this system, thats pretty far east for recon to go.

[WeatherGuesser]

Five day cone of 'maybe somewhere in this area' not looking good for the Islands.

[Nimbus]

Five day cone of 'maybe somewhere in this area' not looking good for the Islands.

5 days? I will be happy if it makes the current 18z forecast point.
Even if they have to shift the official track right over the islands sometime in the next 24 hours that still leaves 48 hours to shift it back north before the Lesser Antilles.

[NDG]

I hope the residents of the northern Leeward Islands are making preparations for possible impact by Irma, the models keep inching closer and closer on each run.
The next 48 hrs will be very critical of how close it gets to the Islands, the further south it tracks the greater the chance it is for a direct impact. IMO.

Regarding a possible impact to the US I say that by at least Tuesday we should have a better idea.
Like I said yesterday I would had felt better if the trough was to push offshore the Carolinas then a recurve out to sea would be happening without a question.

[NDG]

Down to 17.9N this morning. To think that a couple of nights ago some people were doubting the models in their short range forecast of a WSW track instead they were going with climatology of a continuing WNW track.

[cycloneye]

I am not liking at all the southern trend of the guidance and the system.Puerto Rico surely will get impacts from Irma in the form of Tropical Storm force winds along with copius rains that can cause massive flooding.That is assuming the 5 AM forecast track verifies.Any adjustment more south will mean much more impacts with Hurricane force winds reaching the island.People here since Saturday have been jamming the supermarkets,Depot stores etc getting all they need if the worst case scenario comes.But I can tell you that the power grids here are not very good so we can expect blackouts that may last days depending how severe it turns out.Let's see how all unfolds in the next couple of days to really know what Puerto Rico will face.

I hope all the friends in the Leewards,BVI and U.S Virgin Islands are preparing and hoping for the best.

[tropicwatch]

Glad to hear they are taking it seriously in PR.

[WeatherGuesser]

Unless it manages to go south and west enough to snake around the islands and into the G .... Naw, we don't want to think about that.