2017 Atlantic Hurricane Season

[Windspeed]

12z ECMWF continues to scream potential for another Lesser Antilles impact in 5 days even if the cyclone that is revolving isn't particularly strong. Feature placement is more important at this point until we have a tracking cyclone. Central Atantic ridging remains strong and heights south of Jose would likley drive whatever is there into the northern Caribbean.

[wxeyeNH]

Couple of general questions about naming tropical cyclones.

First one is about the name list.  I saw a post above about the name "Lee" and why it was not retired.  There are thousands of names.  Why are the same lists used over and over again?  Names like Irma, Gerta, Agnus?  Sounds like a name from 50 years ago.  To stop with confusion just use new names every year.  Up to date modern names too!

Second is about naming invests.  Why use the same names like 92L.  Each invest should have a unique name so that if someone wants to go back in archives and look at invests that never fully formed its easy.  For instance an invest that was named today could be 91417A.   Month, date and year, A for Atlantic, P for Pacific.  Or at least 171A,  172A,173A  year first  then the number for the invest formed that year.  These are just a couple of quick thoughts but I'm sure other people can think of other ideas to make it less confusing...

[Windspeed]

Couple of general questions about naming tropical cyclones.

First one is about the name list.  I saw a post above about the name "Lee" and why it was not retired.  There are thousands of names.  Why are the same lists used over and over again?  Names like Irma, Gerta, Agnus?  Sounds like a name from 50 years ago.  To stop with confusion just use new names every year.  Up to date modern names too!

Second is about naming invests.  Why use the same names like 92L.  Each invest should have a unique name so that if someone wants to go back in archives and look at invests that never fully formed its easy.  For instance an invest that was named today could be 91417.   Month, date and year.  Or at least 171,  172,173  year first  then the number for the invest formed that year.  So many easy ways to make everything less confusing.  

Names are planned out years in advance by the WMO. Retired names are removed and replaced with unused names regardless of basin, they can't be used again. Obviously that means over time we will lose more commonly used names.

I don't disagree about invests. Obviously in current format they have to be repeated frequently as there are hundereds around the globe per year. However, using a 4-digit + multi-character combo would be easier for archive purposes.

Edit: I should reiterate that the WMO is responsible for all basins. If they did not reuse names, we would burn through thousands in a few decades and they do make an attempt to keep Western and Eastern names respective of their geographic locations, but there are exceptions. As a side note, the Phillipines uses their own names for cyclones regardless of WMO.

[SnowGoose69]

24 minutes ago, Windspeed said:

 

 

Names are planned out years in advance by the WMO. Retired names are removed and replaced with unused names regardless of basin, they can't be used again. Obviously that means over time we will lose more commonly used names.

I don't disagree about invests. Obviously in current format they have to be repeated frequently as there are hundereds around the globe per year. However, using a 4-digit + multi-character combo would be easier for archive purposes.

Edit: I should reiterate that the WMO is responsible for all basins. If they did not reuse names, we would burn through thousands in a few decades and they do make an attempt to keep Western and Eastern names respective of their geographic locations, but there are exceptions. As a side note, the Phillipines uses their own names for cyclones regardless of WMO.


 

 

I wasn't aware they had planned names in advance.  That maybe explains how such an oddly old fashioned name like Irma replaced Irene.  In general most of the replacements in the past 15 years have been more modern names.  It's still odd though how some automatic slam dunk names for certain letters have never appeared.   

[Windspeed]

I wasn't aware they had planned names in advance.  That maybe explains how such an oddly old fashioned name like Irma replaced Irene.  In general most of the replacements in the past 15 years have been more modern names.  It's still odd though how some automatic slam dunk names for certain letters have never appeared.   

 

 

Irma may be a more classic Western name, but it is easy to say which helps in communications for charting, forecasting and shipping navigation between stations. Not all names are perfect examples but they do at least make an attempt at names befitting their geography that are easier to use by the peoples/countries they would potentially impact. Also, perhaps someone on the Region IV Hurricane Committee may have just been fond of it?

 

 

"Experience shows that the use of short, distinctive given names in written as well as spoken communications is quicker and less subject to error than the older more cumbersome latitude-longitude identification methods. These advantages are especially important in exchanging detailed storm information between hundreds of widely scattered stations, coastal bases, and ships at sea." -WMO

 

 

 

[MJO812]

GFS has the next wave behind Jose crashing into Florida as a strong hurricane

[Windspeed]

GFS has the next wave behind Jose crashing into Florida as a strong hurricane

It's similar to a Hurricane David track. Deeply intensifies from Lesser Antilles into the Dominican Republic, then reintensifies in the Bahamas. Either way, we don't have a cyclone to track so location and timing will change, but it is interesting that the ECMWF also shows a cyclone entering the eastern Carribean in 4-5 days.

[SteveVa]

Too bad ASCAT missed 97L this afternoon, I'm positive the surface circulation is closed by now. 

[yoda]

Sounds like 97L will be a TD shortly per the 8pm NHC TWO

[BuffaloWeather]

Have got to feel for the islands. Have friends that live on St. Martin and St. Thomas. The friends in St. Martin say the damage is incredible. The ones on St. Thomas say it's nothing compared to the damage on some of the other islands. Looks like another possible hit in the next week?

[donsutherland1]

TD 14 has formed at 10.7°N, 25.4°W. Although most tropical cyclones that form in that vicinity don't make U.S. landfall, those that do have often been major hurricanes. Since 1851, 12% of tropical cyclones that formed within 100 nautical miles of TD 14's 11 pm position made U.S. landfall. The synoptic pattern argues that TD 14's actual landfall prospects are higher than what is implied by historic climatology.

In terms of the tropical cyclones from the above sample that made U.S. landfall, 75% did so as major hurricanes. Those hurricanes were:

Hurricane #9 (1893): Landfall in South Carolina as a Category 3 hurricane
Donna (1960): Landfall in Florida as a Category 4 hurricane
Frederic (1979): Landfall in Alabama as a Category 3 hurricane

Considering that TD 14 developed near mid-September, landfall odds would likely favor the U.S. East Coast more than they would the U.S. Gulf Coast. 

Overall, TD 14 is very likely to develop into Lee based on the guidance.
 

[peribonca]

0z gfs had three tropical system landfalls (Jose x2, Lee x1) within a week of each other in NYC-Bos corridor. That would be something.

[Windspeed]

The disturbance around 43W in the MDR that is still imbedded in the ITCZ is beginning to show signs of broad rotation in the mid-levels and curved banding features. The surface trough and wave axis is contained within a robust moisture envelope and convection is perhaps beginning to organize. This is the feature out of which both the GFS and ECMWF want to develop strong vorticity and tuck under the WAR. The mid-to-upper trough that is modeled to dig into the Central Atlantic will miss a potential future Maria, allow it to continue west and pose a significant threat to the Antilles. Further east, TD 14 will probably be named Lee today. However, it looks like Lee will interact with the central Atlantic trough and eventually take a more northern track into a sheared upper environment.

 

[MJO812]

Euro also has either Maria or Lee at 240 offshore

 

https://www.tropicaltidbits.com/analysis/models/?model=ecmwf&region=us&pkg=mslp_pcpn_frzn&runtime=2017091500&fh=12&xpos=0&ypos=0

[NJwx85]

The invest in the Central Atlantic is up to 90% odds of development in the next five days. The track over the next several days should take it close to the Leeward Islands in about four days. Those poor people cannot catch a break this year. Looks slated for Puerto Rico thereafter. 

[Heisy]

Check out the 12z GFS between the hours of 210-252 hours. I'm not sure which named storm that is if it is Lee or Marie, but a pretty dangerous pattern for the SE Coast/Florida with the major block it shows during these hours. 

[jojo762]

5 minutes ago, Wentzadelphia said:

Check out the 12z GFS between the hours of 210-252 hours. I'm not sure which named storm that is if it is Lee or Marie, but a pretty dangerous pattern for the SE Coast/Florida with the major block it shows during these hours. 

Also, as has been seen in previous runs as well, GFS shows a storm in the gulf toward the end of September. (LaLa land of course, but nonetheless a very active period coming up as should be expected this time of year)

[hawkeye_wx]

What happens with Jose will play a big part in what happens to 96L down the road.  Models are suggesting that if Jose is able to lift up and out of the picture, then the ridge can build in and turn 96L(likely a hurricane) back to the west toward the southeast US coast.  However, if Jose misses the trough and meanders around the northeast US or just offshore, 96L cannot turn west, but instead follows Jose north and then northeast out to sea.  The last two GFS runs show the former, while the last two Euro runs show the latter.

[Windspeed]

TD-14's LLC is exposed. Convection and the weak MLC has rotated south of the center. This may be temporary but it will likely delay any upgrade to a named TS today.

 

96L continues to organize and may be classified by tomorrow. With the current trend, it could even be named before TD-14.

 

[NortheastPAWx]

14 doesn't seem like it will do too much looking at the NHC forecast and discussion.

[yoda]

47 minutes ago, NortheastPAWx said:

14 doesn't seem like it will do too much looking at the NHC forecast and discussion.

Tropical Depression Fourteen Discussion Number   4
NWS National Hurricane Center Miami FL       AL142017
500 PM AST Fri Sep 15 2017

The depression has become less organized since earlier today with
the center now exposed to the north and northwest of the deep
convection due to northwesterly shear.  Dvorak data T-numbers have
decreased, but an average of the current intensity numbers of
1.5 and 2.5 support maintaining an initial wind speed of 30 kt.
Although the depression is forecast to move over warm water,
moderate northwesterly shear and dry mid-level air to the north
of the cyclone is likely to prevent significant intensification.
However, most of the intensity guidance shows some strengthening and
the depression is forecast to become a tropical storm within the
next day or two.  After that time, increasing westerly shear
produced by a mid- to upper-level trough over the central Atlantic
is expected to weaken the system, and the tropical cyclone is now
forecast to degenerate to a remnant low by day 5.  The new NHC
intensity forecast has been adjusted downward to be in better
agreement with the various intensity consensus aids.

The depression has jogged a little northward this afternoon, but the
long-term motion is west-northwestward at about 10 kt.  The
depression is expected to move westward to west-northwestward to
the south of a narrow ridge over the eastern Atlantic over the
weekend.  By early next week, the ridge is forecast to weaken as a
deep-layer trough becomes established over the east-central
Atlantic.  This should cause the cyclone to gain some latitude
later in the forecast period.  The more northward initial position
has required a northward adjustment of the track forecast, but the
NHC track remains along the southern side of the guidance envelope,
in agreement with the typically reliable HFIP corrected consensus
model.


FORECAST POSITIONS AND MAX WINDS

INIT  15/2100Z 12.6N  29.7W   30 KT  35 MPH
 12H  16/0600Z 12.8N  30.8W   30 KT  35 MPH
 24H  16/1800Z 12.9N  32.2W   35 KT  40 MPH
 36H  17/0600Z 13.0N  33.4W   40 KT  45 MPH
 48H  17/1800Z 13.2N  34.7W   40 KT  45 MPH
 72H  18/1800Z 14.6N  38.4W   35 KT  40 MPH
 96H  19/1800Z 16.5N  42.5W   30 KT  35 MPH
120H  20/1800Z 18.5N  46.5W   25 KT  30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Brown

[yoda]

From the 8pm TWO (96L, right?)

1. Showers and thunderstorms associated with a tropical wave located
a little more than 1000 miles east of the Windward Islands are
showing signs of organization.  Environmental conditions are
conducive for additional development, and a tropical cyclone is
likely to form during the next day or so while the system moves
westward or west-northwestward around 20 mph.  Interests in the
Lesser Antilles and northeastern Caribbean should closely monitor
the progress of this system.  Tropical storm or hurricane watches
could be issued for portions of the Lesser Antilles on Saturday.
* Formation chance through 48 hours...high...80 percent.
* Formation chance through 5 days...high...90 percent.

Forecaster Brown

[Windspeed]

There is clearly mid-level vorticity in 96L. But ACSAT keeps missing the area of suspicious rotation so we are lacking good evidence of a closed LLC. However, this disturbance has about as healthy an appearance pre-classification as they come. It looks one deep convective blowup away from taking off and I would expect the NHC to begin PTC Advisories for the Lesser Antilles by 5PM EST Saturday if for whatever reason it hasn't been classified by then. The system is moving at a pretty good clip and will be impacting them by Monday.

 

[Windspeed]

0916 00z GFS rapidly intensifies would be hurricane out of invest 96L as it is passes near Dominica and has a major hurricane just south of Puerto Rico on a west-wnw heading. It has repeatedly developed a hurricane on previous consecutive runs for days now, but this is by far quicker intensification and is deeper by the time is reaches the Lesser Antilles.

 

[Paragon]

3 minutes ago, Windspeed said:

0916 00z GFS rapidly intensifies would be hurricane out of invest 96L as it is passes near Dominica and has a major hurricane just south of Puerto Rico on a west-wnw heading. It has repeatedly developed a hurricane on previous consecutive runs for days now, but this is by far quicker intensification and is deeper by the time is reaches the Lesser Antilles.

 

That kind of track would have some major interactions with mountainous islands though before any future CONUS impact.

[Windspeed]

That kind of track would have some major interactions with mountainous islands though before any future CONUS impact.

Just focusing on the Antilles right now. Obviously a track over the central range of Hispaniola would wreck the circulation. But it would also be a devestating hit like David to the Dominican Republic and possibly a bad hit on one of the central Lesser Antilles depending on how fast this rapidly intensifies Sunday night into Monday.

[yoda]

 

[Paragon]

5 minutes ago, Windspeed said:

16 minutes ago, Paragon said:

That kind of track would have some major interactions with mountainous islands though before any future CONUS impact.
 

Just focusing on the Antilles right now. Obviously a track over the central range of Hispaniola would wreck the circulation. But it would also be a devestating hit like David to the Dominican Republic and possibly a bad hit on one of the central Lesser Antilles depending on how fast this rapidly intensifies Sunday night into Monday.

What did David (1979 right?) do post Hispaniola?  Did it enter the Gulf and hit Texas as a Cat 3?  For some reason I think it did, or I might be thinking of a different storm.

[MJO812]

GFS has the next system into Georgia/ South Carolina border as a major hurricane.

[Paragon]

1 minute ago, Snow88 said:

GFS has the next system into Georgia/ South Carolina border as a major hurricane.

On a Hugo NW trajectory or a northward climb up the coast?