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98L in the Central Atlantic has now been declared Tropical Depression 13. 

Tropical Depression Thirteen Discussion Number 2 NWS National Hurricane Center Miami FL 

There has been little change in the organization of Tropical Depression Thirteen during the past several hours. An area of ragged but persistent convection continues near the estimated center position, and there is some outer banding in the southern semicircle. Dvorak-based satellite intensity estimates have changed little since the last advisory, so the initial intensity remains 30 kt. The initial motion is a somewhat uncertain 295/18. The subtropical ridge to the north of the cyclone is expected to build westward to the north of the Greater Antilles during the next several days, and this should steer the cyclone generally west-northwestward through the forecast period. The track guidance remains in fairly good agreement with this scenario, but there remains a spread between the GFS/UKMET on the south side of the guidance and the Canadian/HMON on the north side. Overall, the envelope has shifted a little to the south since the previous advisory and the new forecast track, which lies just to the north of the consensus models, is also nudged southward. The new track calls for the cyclone to pass near the Leeward Islands in 36-48 h, near or north of Puerto Rico and the Virgin Islands in 48-60 h, and then near or over Hispaniola and the southeastern Bahamas by 72 h.

Overall, the environment looks generally favorable for strengthening, with the cyclone expected to encounter light- to moderate shear during forecast period. However, the guidance responds to this environment with a wide range of solutions. The HWRF/HMON forecast the cyclone to intensify into a major hurricane by 120 h. On the other hand, the GFS and ECMWF show the system degenerating into an open wave by 120 h. The UKMET and Canadian models are between these extremes. The weak GFS solution appears to be due to forecast dry air entrainment, which is a possibility as satellite imagery suggests Saharan dust not far from the cyclone. Between these factors and the possibility of land interaction, the low-confidence intensity forecast is changed little from the previous advisory. Key Messages: 1. Tropical storm conditions are possible across portions of the northern Leeward Islands by Friday night, and Tropical Storm Watches have been issued for some of these islands. Heavy rainfall is likely across this area beginning late Friday. 2. There is a risk of tropical storm conditions in the Virgin Islands and Puerto Rico Friday night and Saturday and Tropical Storm Watches could be required for these islands later today. Interests there should closely monitor the progress of this system. 3. The details of the long-range track and intensity forecasts are more uncertain than usual since the system could move over portions of the Greater Antilles this weekend. However, this system could bring some rainfall and wind impacts to portions of Hispaniola, Cuba, the Bahamas, and Florida this weekend and early next week. Interests there should monitor this system's progress and updates to the forecast over the next few days.

FORECAST POSITIONS AND MAX WINDS

INIT 20/0900Z 15.2N 49.8W 30 KT 35 MPH

12H 20/1800Z 16.4N 52.7W 30 KT 35 MPH

24H 21/0600Z 17.5N 56.4W 35 KT 40 MPH

36H 21/1800Z 18.4N 60.2W 40 KT 45 MPH

48H 22/0600Z 19.1N 63.9W 45 KT 50 MPH

60H 22/1800Z 19.8N 67.1W 50 KT 60 MPH

72H 23/0600Z 20.8N 71.0W 55 KT 65 MPH

96H 24/0600Z 23.0N 78.0W 60 KT 70 MPH

120H 25/0600Z 26.0N 83.0W 60 KT 70 MPH

$$ Forecaster Beven

 

Track carries a risk from interaction with the Greater Antilles however Florida and the Gulf Coast are at risk. 

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As alluded to in the NHC discussion shear is light although convergent (westerly) until day 6.

Moisture and speed profiles are also good.

Edited by Jo Farrow
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Just been on Sky News at 2pm talking to Colin Brazier about the Hurricane decent little interview didnt big it up too much as it was thankfully not as bad as expected with the storm surge etc

If Josh Morgerman is telling people to get out, you know this thing is bad - he doesn't quit on any hurricane.  

The power of Nature...

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Posted (edited)

Now forecast to be a Hurricane on approach to Florida.

INIT 20/1500Z 16.0N 52.0W 30 KT 35 MPH

12H 21/0000Z 17.0N 54.7W 35 KT 40 MPH

24H 21/1200Z 18.0N 58.3W 40 KT 45 MPH

36H 22/0000Z 18.9N 61.6W 45 KT 50 MPH

48H 22/1200Z 19.6N 64.7W 50 KT 60 MPH

60H 23/0000Z 20.4N 68.1W 55 KT 65 MPH

72H 23/1200Z 21.5N 71.8W 60 KT 70 MPH

96H 24/1200Z 24.0N 78.6W 65 KT 75 MPH

120H 25/1200Z 27.0N 83.4W 65 KT 75 MPH

Fodder models actually drop into the 940mb's.

Edited by summer blizzard
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The afternoon models have shifted Laura's track a bit further south which means that she will have to cross Puerto Rico, Hispaniola and Cuba. Unless this track changes then this will inhibit any strengthening.

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So we are going to see record flooding after last years record flooding, following the year before record....

 

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Amusingly some Euro ensembles have the ridge to the north so strong that Laura actually ends up south of Cuba and headed for Texas. 

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I think the GFS is to far East -

The initialisation location V the new circulation centre is a fair bit north..

Edited by Steve Murr
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Yes, the low level center is actually a tad north of that image (storm is tilted with height) but south of forecast and now looks like it may stay over water south of Cuba. Interestingly the UKMO as with Irma has called that correctly while the Euro for once has been wrong. 

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NHC now expect 100mph at landfall (though its worth saying they assume steady state until its second Cuban landfall in the west - Gonzalo 08 highlights the potential to be wrong there) however hurricane models went as low as 939mb on the 0z runs.

 

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Laura looks decoupled at the moment with the low level circulation off to the North & the mid level circulation still churning away to the south...

Edited by Steve Murr
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Posted (edited)
2 hours ago, Steve Murr said:

Laura looks decoupled at the moment with the low level circulation off to the North & the mid level circulation still churning away to the south...

There is still some tilt however the low level center is to the south near the mid level center. The vorcity max however is what is to the north, if the southern one gets ripped apart over southern Cuba only then would it probably try develop there. 

The Euro however shows exactly that, the maximum vorcity area becomes dominant, rides land and so Laura struggles.

Edited by summer blizzard
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19 hours ago, summer blizzard said:

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Superb appearance.

and now (not an official term)

 

Edited by Jo Farrow
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