ATL: JOAQUIN - Post-Tropical - Discussion

[cycloneye]

TROPICAL STORM JOAQUIN DISCUSSION NUMBER 5
NWS NATIONAL HURRICANE CENTER MIAMI FL AL112015
1100 PM EDT MON SEP 28 2015

Satellite images indicate that the shower and thunderstorm activity
associated with the depression has increased and become better
organized during the past several hours. In addition, the low-level
center now appears to have moved closer to the convection than it
was earlier. The latest Dvorak classifications from TAFB and SAB
were 2.5/35 kt, and the initial intensity is set at that value,
making the cyclone Tropical Storm Joaquin. This intensity analysis
also agrees with the reconnaissance aircraft data from earlier today
that showed winds just under tropical-storm force.

The center of Joaquin has been moving southwestward during the last
several hours, but it is expected to begin moving slowly westward
overnight. This westward track is forecast to continue for a couple
of days while a mid-level ridge remains to the north of the storm.
After that time, a trough is anticipated to amplify over the eastern
United States, which should cause Joaquin to turn northward and
accelerate. There is considerable spread in the models, mainly due
to the timing of when and how fast the storm makes the northward
turn, due to differences in the evolution of the trough. In
general, the guidance envelope has shifted southward for the first
couple of days and then westward after that time. The official
track forecast has been adjusted accordingly, but additional
southward and westward adjustment may be needed in subsequent
advisories.

Northwesterly shear of about 20 kt is currently affecting Joaquin,
causing most of the thunderstorm activity to be located to the
southeast of the center. The shear is expected to lessen some
during the next couple of days, which in combination with warm water
and high relative humidity values should allow Joaquin to
strengthen. The official intensity forecast is raised from the
previous one, but is lower than the intensity model consensus at
days 3-5.

FORECAST POSITIONS AND MAX WINDS

INIT 29/0300Z 26.7N 70.4W 35 KT 40 MPH
12H 29/1200Z 26.9N 71.0W 40 KT 45 MPH
24H 30/0000Z 27.1N 72.0W 40 KT 45 MPH
36H 30/1200Z 27.2N 72.8W 45 KT 50 MPH
48H 01/0000Z 27.4N 73.4W 50 KT 60 MPH
72H 02/0000Z 28.6N 74.0W 55 KT 65 MPH
96H 03/0000Z 32.4N 74.0W 55 KT 65 MPH
120H 04/0000Z 38.0N 74.0W 55 KT 65 MPH

$$
Forecaster Cangialosi

[CaliforniaResident]

Could this become......Sandy....the SEQUEL?

[ozonepete]

Moving SW!! That will be ending quite soon since part of that motion is just center consolidation. It has no atmospheric steering support to continue that direction. But the net result is it basically ducked the shear that would have killed it. We discussed this last night.

[Hammy]

Looks like I was wrong on the short term intensity but still have a hard time believing this will strengthen much given that massive trough just to the west. As far as the immediate future, there should be another ASCAT pass any time so that should be interesting to see what it shows.

[Andrew92]

I know someone earlier was calling Henri from 1985 a decent analog, but with intensity forecasts generally trending up, I have a question. I'm not getting my hopes up too high that anyone will know, and I'm not saying these are great analogs....but does anyone know what the intensity forecasts for Belle in 1976 and Bob in 1991 were at about this stage of development? Certainly would be eye-opening if either weren't initially forecast to intensify much anyway, and given the models, the track looks quite similar so far anyway.

-Andrew92

[cycloneye]

[gatorcane]

The NHC stated the intensity forecast is lower than the IVCN and right now they are showing a strong TS. We could see them going up on intensity in future runs with this thing aiming at the Eastern United States. Long days and nights ahead all...

[ozonepete]

Looks like I was wrong on the short term intensity but still have a hard time believing this will strengthen much given that massive trough just to the west. As far as the immediate future, there should be another ASCAT pass any time so that should be interesting to see what it shows.

Doesn't matter how massive the trough is if it isn't moving. The WPC has been discussing the blocking pattern that is setting up for days now. i.e. a big blocking high east and north of this which will not allow the trough to carry it out to sea nor cause a lot of shear over it. While a lot remains to be seen, expect the forecast strength from the models that didn't develop it to go up now.

[CrazyC83]

A long week ahead, that is for sure!

[TheStormExpert]

Also Levi Cowan from Tropical Tidbits mentioned in his latest video discussion that the trough could either work in Joaquin's favor or against it in terms of strengthening.

[Hammy]

I know someone earlier was calling Henri from 1985 a decent analog, but with intensity forecasts generally trending up, I have a question. I'm not getting my hopes up too high that anyone will know, and I'm not saying these are great analogs....but does anyone know what the intensity forecasts for Belle in 1976 and Bob in 1991 were at about this stage of development? Certainly would be eye-opening if either weren't initially forecast to intensify much anyway, and given the models, the track looks quite similar so far anyway.

-Andrew92

For Belle, I have no idea about the intensity forecasts, but the satellite appearance was vaguely similar about this location.


For Bob, while the forecasts only went out 72 hours it showed it moving more towards Georgia as a 70kt hurricane at the end of the period on the first TS forecast advisory.

[wxman57]

NHC track looks too slow. I'll bet they don't want to commit to a landfall within 5 days yet. Interesting week ahead. Time for bed, early day tomorrow (and the next 5 days).

[northjaxpro]

Just upgraded to Joaquin at 11 p.m. by NHC. One of the most unique developments this season from the Large Upper Low from last week north of Leewards, Puerto Rico and Hispaniola, which made that rare transition to tropical cyclone. I take pride somewhat in calling this feature first to make that rare transition!

[Andrew92]

Wow, thanks Hammy! I especially wanted to bring those two up because they, like Joaquin, also occurred in El Nino years (though 1991 was a Modoki admittedly).

II just remembered there might be a database on NHC's FTP server with older advisories, though I'm not sure how far back itngoes. I hope it includes 1991 so I can read about Bob as it was developing, but little hopes about Belle. I will check and reply shortly!

-Andrew92

[Bocadude85]

Have we ever had a hurricane landfall in the Northeast during a strong to super El Niño?

[storm4u]

Should be a fun one to track either way tons of rain coming

[northjaxpro]

Joaquin could cause some mischief across New England late this week into the weekend.

[Andrew92]

Found advisories on Bob! Take a look at this first discussion and compare it to Joaquin's:

http://www.nhc.noaa.gov/archive/storm_w ... al0391.001

Only one I've looked at so far....but needless to say, I have answered my own question about Bob's early forecasts versus Joaquin's anyway!

-Andrew92

[Hurricaneman]

Found advisories on Bob! Take a look at this first discussion and compare it to Joaquin's:

http://www.nhc.noaa.gov/archive/storm_w ... al0391.001

Only one I've looked at so far....but needless to say, I have answered my own question about Bob's early forecasts versus Joaquin's anyway!

-Andrew92

They're very much similar and thats why you can't rule out a hurricane a this point and while I dont expect a major right now it also cant be ruled out so it will be days of watching in the NEUS

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products

[Andrew92]

Two advisories later though they already started forecasting a hurricane. They aren't yet with Joaquin, though models are definitely trending in that direction.

-Andrew92