MikeCAdministrator
(Admin)
Tue Oct 03 2017 02:46 PM
HURRICANE Nate

This area in the west Caribbean is worth watching this week as several models show it in the Gulf.

The Euro has a cat 1/2 hurricane .landfall from it Sunday night near Destin, FL and the GFS has a Sunday morning cat 1 landfall in Southeast Louisiana.


Invest 90L is now a Tropical Depression and the title has been updated accordingly .. Now a hurricane 07 04z- Ciel


OrlandoDan
(Storm Tracker)
Tue Oct 03 2017 08:48 PM
Re: 90L Lounge (West Caribbean)

I would love to see the wind fields here where I am in St Pete. What is going on?

cieldumort
(Moderator)
Wed Oct 04 2017 02:03 AM
Re: 90L Lounge (West Caribbean)

Some 04 0z model runs on 90L .. As a group they generally favor the NNW path scraping by or over Nicaragua > Honduras > Yucatan, en route to the southern U.S.


0z GFS NNW track interacts with Nicaragua > Honduras > Yucatan and remains weak, with even two competing vorts for a while, until in the Gulf .. Landfall over central Louisiana as a low-end Tropical Storm

0z HWRF Landf interaction, but less impact ... possibly an assist from all the very warm waters in the NW Caribbean this year. Landfall over the weekend in SE Louisiana as a formidable Cat 1/2

0z HMON - Takes a more northerly track with less land interaction en route to U.S. Becomes a formidable Cat 4/5.. on approach to a likely landfall between Destin, Fl and Mexico Beach, Fl.. while still a Major (end of run 910mb Major, just offsore)

0z GEM - Similar to HMON with less land interaction and a landfall a little further east (but not so far east as to make landfall on the Florida panhandle like HMON does) as a 989mb 45 knot tropical cyclone thingy .. a bit of a stretch to envision 45 knots and 989 hPa. Almost want to toss this one out.


MikeCAdministrator
(Admin)
Wed Oct 04 2017 06:05 AM
Re: 90L Lounge (West Caribbean)

0Z Euro, takes the system over the northeast tip of Nicaragua/Honduras then keeps it east of the Yucatan, Then landfalls near alligator point (Just west of Apalachee Bay) in Florida just after noon on Sunday as a sheared category 1 hurricane.

06Z GFS keeps it a messy gyre that passes over the Yucatan and then into Southeast Louisiana noon on Sunday as a sheared Tropical Storm.


Lamar-Plant City
(Storm Tracker)
Wed Oct 04 2017 12:26 PM
Re: 90L Lounge (West Caribbean)

NHC track seems to be east of the consensus....what do they know that those models don't? They did a great job second guessing GFS with Irma. I am just east of current cone. Looks like one of those re-curving storms whose cone moves east steadily....

cieldumort
(Moderator)
Wed Oct 04 2017 01:03 PM
Re: 90L Lounge (West Caribbean)

GFS, its ensembles and like-minded model runs (may) be mishandling the trof southeast of Florida... running it further west, whereas the Euro and like minded runs intensify Cuba/Bahamas trof, and allow it to turn more northerly ... possibly even riding up off the Florida east coast. Without the more northwesterly tug induced by the aforementioned trof as runs like the GFS sees it, 16 (Nate) is more likely to respond to its own more NNW oriented associated trof.

Pay attention to what the feature over central/eastern Cuba does in the next 48 hours for additional clues.

Edited 'appear to be' with 'may be,' which is more accurate.


MikeCAdministrator
(Admin)
Wed Oct 04 2017 02:49 PM
Re: 90L Lounge (West Caribbean)

12z Euro is similar to earlier runs, but a bit slower slightly west, and stronger.

The Euro is now bringing landfall (As cat 2/borderline 3) into just east of Panama City Monday morning. This one clips the eastern tip of Yucatan as a Tropical Storm or cat 1 hurricane Friday evening however.


OrlandoDan
(Storm Tracker)
Wed Oct 04 2017 06:44 PM
Re: 90L Lounge (West Caribbean)

What is the potential of 16 heading more east? Like Tampa?

Marknole
(Weather Watcher)
Wed Oct 04 2017 07:19 PM
Re: 90L Lounge (West Caribbean)

Quote:

NHC track seems to be east of the consensus....what do they know that those models don't? They did a great job second guessing GFS with Irma.




Same bias on the later runs. GFS insistent on the surface ridge holding strong, with that central LA landfall. That's a long way from Panama City/Destin/NHC center track. Wonder if the FSU super ensemble is weighing in?


Keith B
(Verified CFHC User)
Wed Oct 04 2017 07:37 PM
Re: 90L Lounge (West Caribbean)

I was watching Tom Terry on CH 9 this evening. He was showing the GFS and EURO models. EURO was right / East towards Appalachia bay area. The GFS was more towards to LA area.

Further more, from NHC 5p discussion:

While there is some agreement on the
synoptic pattern, the model track agreement is rather poor, even in
the short term, with the GFS and ECMWF being 90 miles apart on the
forecast track as soon as 24 hours out. This has profound
differences down the road, with the GFS-based guidance moving
considerably faster and to the left of the ECMWF and UKMET across
the Gulf of Mexico. Overall, the guidance has generally shifted a
bit westward since the last cycle, so the latest points in the long
range have been adjusted in that direction. At this point, I
wouldn't focus too much attention on the details of the long-range
forecast until the guidance comes into better agreement. A G-IV
mission and Florida special soundings have been set up for tomorrow
to better determine the synoptic steering flow around the cyclone.

It looks rather fluid.


Keith B
(Verified CFHC User)
Wed Oct 04 2017 08:28 PM
Re: 90L Lounge (West Caribbean)

I was just watch Levi's update from Tropical Tidbits. Very interesting insight of the computer models and what should be more clear. If the system / energy is off the East coast of FL on Thursday.

Tropical Tidbits


JMII
(Storm Tracker)
Thu Oct 05 2017 10:58 AM
Re: 90L Lounge (West Caribbean)

Quote:

I was just watch Levi's update from Tropical Tidbits.




Levi's information is top notch, he is quickly becoming my "go-to" for long range things to watch for. The pattern over S FL for the last few days as been decidedly wet with strong E to W winds. If the high is building to our E then I sure haven't noticed it using the standard "just look outside" forecasting system. So at this point I would favor the models that see the H weaker thus turning the system more NE.

Nate looked really good this AM but it has two areas of land to clear. However we all know what can happen to tropical systems in the gulf this time of year (Wilma) so definitively keeping tabs on this.


Prospero
(Weather Guru)
Thu Oct 05 2017 07:03 PM
Re: 90L Lounge (West Caribbean)

Skinniest Cone from NOAA I have ever seen! Looks more like a "Coastal Watches/Warnings and Forecast Worm for Storm Center"!

Guess this is due to the accuracy of modern prediction models...



MikeCAdministrator
(Admin)
Thu Oct 05 2017 07:14 PM
Re: 90L Lounge (West Caribbean)

The cone size doesn't change it's always based on the same error range, however this storm will be moving very quickly up there, it's in the 3 day range, so it appears more narrow than a slower moving storm may.

Models have concentrated int he cone area, so I believe the NHC's track is good. There's a disturbingly high chance for rapid intensification, but the storm will be moving into the northern Gulf quickly on Saturday. I hope folks prepare for a cat 3 and hope for less up there.



Prospero
(Weather Guru)
Thu Oct 05 2017 07:47 PM
Re: 90L Lounge (West Caribbean)

Thanks Mike C!

I hadn't thought about the time frame vs width of the cone, I'm used to seeing a wider cone which is obviously a longer time frame. So a fast moving storm will have a narrower cone in the 3 day range.

Having just starting to get back to normal in our area after Irma, I'm happy seeing a narrow cone we do not come too close too. I'm not so happy for the people and cities in the cone, though.


cieldumort
(Moderator)
Thu Oct 05 2017 09:59 PM
Re: Nate Lounge

Kudos, GFS. One of a few times this season that the new and improved version has edged out the Euro, with the latter now playing catch up and taking Nate, or "Nate," depending on organization, more up towards Louisiana instead of Florida - the result of the High to his northeast being stronger, with the non-tropical trof and closed surface low now in the northeastern Gulf tracking further west, and not developing or redeveloping east of Florida.

Track-wise, Nate, or "Nate," is now more certain, but intensity remains unusually uncertain, with the following factors, and others, making this part of the forecast decidedly unreliable.

* Tropical Cyclone Nate is embedded within a large Central American Gyre, or CAG (See main page), and this serves both to provide Nate with a moist cocoon, but also hold back the TC a bit, like a parent clutching its offspring too close, keeping it at home with younger siblings, not allowing it to fully stand on its own. This is readily apparent today with the explosion of deep convection to his southwest that is blowing off thunderstorm tops to the northeast and imparting modest southwesterly shear over the cyclone, which was not well handled by models (and other small scale features that are of too small a resolution for globals to generally nail down with much accuracy, if at all).

* Nate is a smaller TC, and these tend to be susceptible to outside forces in an outsized way, with much higher potential to rapidly strengthen, weaken, or even fall part, than average to large size TCs.

* Provided Nate does not fall apart over land (low, but non-zero chance), the cyclone is about to cross over some outrageously warm waters in places - potential fuel for any fire.

* However, Nate's steering currents are about to increase rapidly out of the south-southeast to southeast, limiting his time over these pockets of exceptionally warm waters - and, additionally, potentially even making it a challenge for the cyclone to remain closed off. It is thus possible that Nate makes landfall as a very, very strong wave (low, but non-zero chance), or have something of a lopsided nature.


cieldumort
(Moderator)
Fri Oct 06 2017 02:06 AM
Re: Nate Lounge

Nate likely tracking though an especially favored zone for significant/major hurricanes to develop, historically

cieldumort
(Moderator)
Fri Oct 06 2017 02:35 AM
Re: Nate Lounge

Satellite and new recon data suggests that Nate has a fairly solid inner core, and was barely disrupted, if at all, by his track just inland over Honduras. Markedly lessening shear and high humidity, coupled with roasting hot SSTs (Compare 2017 to 2005 below!) Rapid Intensification possible today.

Yucatan should now be on full notice. As should the central to northeast Gulf. Another Major is very possible.



cieldumort
(Moderator)
Fri Oct 06 2017 03:14 AM
Re: Nate Lounge

As can be seen in the IR image below, Nate is still embedded, in fact even interlocked, within the broader CAG with all of its other 'children' around. Plus, a closed surface low associated with the upper-level trof to Nate's NNW (and sliding southwest), is also still vying for some real estate.

With this overall complex complex, it remains to be seen how well Nate is able to avail himself of the otherwise very favorable environment for Rapid Intensification.



Bloodstar
(Moderator)
Fri Oct 06 2017 10:37 AM
Re: Nate Lounge

Does anyone else see a competing surface low becoming dominant to the east of the current surface low? Recon data seems to be hinting at that possibility.

Or I could be wrong.


JMII
(Storm Tracker)
Fri Oct 06 2017 10:45 AM
Re: 90L Lounge (West Caribbean)

Quote:

Skinniest Cone from NOAA I have ever seen!




I thought the same thing! The low over S FL really moved west out of the way quickly. I sure didn't believe that was going to happen yesterday as this low has been sitting off the coast for what seemed like a week. Now things seem to be happening fast with Nate. Models are very much in agreement on a LA/MS border landfall. They do show a small hook to the NE at the end which could mean a MS, AL, or FL landfall. As all these states touch the northern GOM so it could effect any of them. At this point Nate is large and kind of broken up, so I assume its going to struggle a bit till it hits those warm GOM waters given its surrounded by land.


MikeCAdministrator
(Admin)
Fri Oct 06 2017 10:50 AM
Re: Nate Lounge

Recon is showing the system on the eastern edge of the models (Euro Ensembles) and east of the forecast cone by a fair margin, I'd expect the track to shift east somewhat at 11AM.

cieldumort
(Moderator)
Fri Oct 06 2017 11:37 AM
Re: Nate Lounge

Quote:


Does anyone else see a competing surface low becoming dominant to the east of the current surface low? Recon data seems to be hinting at that possibility.




This mission has been flying up around 5000' and suggests that the mid-level center is possibly misaligned from the surface low pressure minimum, perhaps some overall vortex tilting with height (leftovers from yesterdays southwesterly shear? maybe with the overall influence from the parent gyre?) Either way, Nate is lopsided, with the stronger winds by far in the northeastern quadrant, well away from the surface pressure minimum, and mostly much weaker winds in the western semicircle ... potential implications for Florida, even if landfall point is much further west.

With deep convection globules located well southwest, over, and well northeast of the surface center, within the large region of parent vorticity, model runs that suggested satellite vorts of one kind or another seem realistic enough. Interesting to watch play out - tricky forecast, tho


cieldumort
(Moderator)
Sat Oct 07 2017 01:01 AM
Re: Nate Lounge

Compare tonight's 0345z image to last night's 0615z. Nate has devoured everything else in sight. Even hard to tell there is a parent Gyre left.

Combined with low shear and very high oceanic heat content, the stage has been set for RI. Watch out for more upside surprises to the official forecast today. Odds of Nate reaching Major before or into landfall are ominously real. Even a vicious Cat 1 "it was only a Cat 1!" can do tremendous damage, and take countless lives, let's not forget.




Genesis
(Weather Guru)
Sat Oct 07 2017 12:09 PM
Re: Nate Lounge

The biggest surprise will come from the fact that the forward speed of the storm is additive to the windfield on the east side (and obviously subtractive on the west); it'll seem like not much at all west-of-center, but on the east that extra 20mph is a lot!

richg
(Verified CFHC User)
Sat Oct 07 2017 04:35 PM
Re: Nate Lounge

My understanding, after years of reading this forum, is the forward motion of the storm is included in the NHC forecasts.

Good luck to Biloxi and everyone else in the path.


cieldumort
(Moderator)
Sat Oct 07 2017 06:17 PM
Re: Nate Lounge

Quote:

My understanding, after years of reading this forum, is the forward motion of the storm is included in the NHC forecasts.




This is correct. The maximum winds as posted by NHC already include any and all additions, such as forward speed.


cieldumort
(Moderator)
Sat Oct 07 2017 06:34 PM
Re: Nate Lounge

Nate's lopsided and slightly still-incoherent structure has been making it challenging for the cyclone to continue to strengthen in the presence of increasing shear, dry air, and slowly cooling SSTs, and it is now looking less possible that Nate comes ashore as a Major. However, this is not the time to conclude all is well. Nate is a ferocious Category One Hurricane, with a very strong and long fetch of southerly winds blowing in, with attendant significant storm surge, and damaging gusts. Also, the usual risk for tornadoes exists, and SPC has 5% TORN probabilities up.


Note: This is NOT an official page. It is run by weather hobbyists and should not be used as a replacement for official sources. 
CFHC's main servers are currently located at Hostdime.com in Orlando, FL.
Image Server Network thanks to Mike Potts and Amazon Web Services. If you have static file hosting space that allows dns aliasing contact us to help out! Some Maps Provided by:
Great thanks to all who donated and everyone who uses the site as well. Site designed for 800x600+ resolution
When in doubt, take the word of the National Hurricane Center