Tormenta Isaac

[edgardo]

BULLETIN
Tropical Storm Isaac Advisory Number 9
NWS National Hurricane Center Miami FL AL092018
500 PM AST Sun Sep 09 2018

...ISAAC ALMOST A HURRICANE...
...MOVING FASTER TOWARD THE WEST OVER THE TROPICAL ATLANTIC...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...14.5N 40.3W
ABOUT 1390 MI...2240 KM E OF THE WINDWARD ISLANDS
MAXIMUM SUSTAINED WINDS...70 MPH...110 KM/H
PRESENT MOVEMENT...W OR 275 DEGREES AT 12 MPH...19 KM/H
MINIMUM CENTRAL PRESSURE...997 MB...29.44 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.

Interests in the Lesser Antilles should monitor the progress of
Isaac.


DISCUSSION AND OUTLOOK
----------------------
At 500 PM AST (2100 UTC), the center of Tropical Storm Isaac was
located near latitude 14.5 North, longitude 40.3 West. Isaac is
moving toward the west near 12 mph (19 km/h) and is expected to
accelerate during the next 36 hours. A westward motion is forecast
to continue through the end of the week, with Isaac expected to
move across the Lesser Antilles and into the eastern Caribbean Sea
Wednesday night or Thursday.

Maximum sustained winds have increased to near 70 mph (110 km/h)
with higher gusts. Additional strengthening is forecast, and Isaac
is expected to become a hurricane tonight. Weakening is anticipated
to begin by the middle of the week while Isaac approaches the
Lesser Antilles.

Tropical-storm-force winds extend outward up to 45 miles (75 km)
from the center.

The estimated minimum central pressure is 997 mb (29.44 inches).


HAZARDS AFFECTING LAND
----------------------
None.


NEXT ADVISORY
-------------
Next complete advisory at 1100 PM AST.

$$
Forecaster Berg

[Villafañe]

355
WTNT44 KNHC 092032
TCDAT4

Tropical Storm Isaac Discussion Number 9
NWS National Hurricane Center Miami FL AL092018
500 PM AST Sun Sep 09 2018

Isaac is a tiny tropical cyclone, but even still, recent SSMIS
data showed that it has developed a mid-level microwave eye
feature. At the time of the pass (1800 UTC), the convection was a
little thin on the southern side, but geostationary satellite images
suggest that it has filled in since that time. Dvorak intensity
estimates are T4.0 from TAFB and T3.5 from SAB, so the maximum
winds are estimated to be 60 kt.

The intensity forecast philosophy has not changed since this
morning. Isaac is strengthening in an environment of low shear and
over warm sea surface temperatures, and for the next 36-48 hours,
the NHC intensity forecast is above the bulk of the intensity
models. The main reason for this is that Isaac's tiny size could
allow the intensity to increase quickly within the favorable
environment. However, the cyclone's tiny size will likely also be
to its detriment after 48 hours when northwesterly vertical shear is
expected to develop and increase to 20-30 kt. The shear will
probably easily decouple the small system, causing the intensity to
decrease much faster than suggested by most of the intensity models.
For that reason, the official NHC intensity forecast is below the
intensity consensus on days 3 through 5. It should be noted that
both the GFS and ECMWF models show a weakening cyclone moving into
the eastern Caribbean Sea by days 4 and 5, with the GFS even making
the system an open wave by the end of the forecast period. These
global model solutions lend credence to the belief that it may be
difficult for Isaac to maintain hurricane status while it approaches
the Lesser Antilles.

Isaac is accelerating toward the west with an initial motion of
275/10 kt. Ridging to the north is expected to keep the cyclone on
a westward trajectory for the entire forecast period, with
acceleration continuing for the next 36 hours. The UKMET remains
the biggest outlier, showing Isaac turning northwestward and
northward into the central Atlantic after 48 hours. That still
appears to be unlikely at this time, and the NHC track forecast is
still close to the center of the guidance envelope. Only a slight
northward shift was made to the new forecast based on the latest
model solutions.


Key Messages:

1. Isaac is expected to become a hurricane tonight or on Monday
while it moves westward across the tropical Atlantic Ocean.

2. While Isaac is forecast to begin weakening by Tuesday while it
approaches the Lesser Antilles, it is still expected to be at or
near hurricane intensity when it reaches the islands, and the
uncertainty in the intensity forecast is higher than usual.
Interests in the Lesser Antilles should continue to monitor Isaac
during the next few days.


FORECAST POSITIONS AND MAX WINDS

INIT 09/2100Z 14.5N 40.3W 60 KT 70 MPH
12H 10/0600Z 14.6N 42.2W 70 KT 80 MPH
24H 10/1800Z 14.8N 45.0W 80 KT 90 MPH
36H 11/0600Z 14.9N 48.0W 85 KT 100 MPH
48H 11/1800Z 14.9N 50.9W 85 KT 100 MPH
72H 12/1800Z 15.0N 56.5W 70 KT 80 MPH
96H 13/1800Z 15.5N 63.0W 60 KT 70 MPH
120H 14/1800Z 15.5N 69.5W 50 KT 60 MPH

$$
Forecaster Berg

[megadicto]

Aun esta 'too close to call'...no bajar la guardia y prepararse para lo q sea

[boleco]

[Silvio29]

palabra clave en el NHC alta incertidumbre de intensidad[/b]

[StormWatch]

[Silvio29]

A eso me refería en un post pasado

[Silvio29]

Si Florence hace lo mismo que Jose y no entra a territorio de USA. podría haber problemas.

recuerden que Jose recurvo hacia arriba.

[Silvio29]

wao, wao, wao, cuanta semejansa con ese trio.

[StormWatch]

Aunque lo mencione anteriormente! Debe ser huracán a las 11pm!

Tuit de CycloForumsPR:
Una imagen reciente de microonda de la tormenta Isaac mostró la formación de la estructura de un ojo a niveles medios, señal de intensificación. Si Isaac sube a 74 mph o más será clasificado como huracán.