It’s been a while since the Atlantic has been as active as this.

Tropical Depression 8

TROPICAL DEPRESSION EIGHT DISCUSSION NUMBER   2
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL082016
500 PM EDT SUN AUG 28 2016

The low-level center of the depression is now exposed, with the deep
convection diminishing and displaced to the northwest of the center
due to about 15 to 20 kt of southeasterly shear.  Data from an Air
Force Reserve Hurricane Hunter aircraft suggest that the intensity
remains 30 kt based on the highest believable SFMR winds and peak
flight-level winds of 32 kt.

Given the current satellite presentation and an environment that is
only expected to be marginally conducive for intensification, only
modest strengthening is shown in the official forecast, with the
depression expected to become a tropical storm in the next day or
two.  After that time the shear should increase as the system
accelerates northeastward, and the global models show the cyclone
being absorbed by a front in about 4 days.  The NHC intensity
forecast is close to the intensity consensus through 48 hours and a
little below it at 72 hours.

The initial motion estimate is 280/08.  While the synoptic reasoning
has not changed, the sheared state of the cyclone could lead to some
erratic motion if it remains a shallow system. Assuming deep
convection returns, the cyclone is expected to gradually recurve
during the next 48 to 72 hours, with a slow northwestward motion
expected in 24 to 48 hours, bringing the center just offshore of the
Outer Banks of North Carolina.  Given the uncertainty in the
intensity forecast and the timing of the approach to the coast, a
tropical storm watch is not being issued at this time, but one may
be required later tonight.

FORECAST POSITIONS AND MAX WINDS

INIT  28/2100Z 31.8N  70.9W   30 KT  35 MPH
12H  29/0600Z 32.2N  72.5W   30 KT  35 MPH
24H  29/1800Z 33.0N  73.9W   35 KT  40 MPH
36H  30/0600Z 33.7N  74.9W   35 KT  40 MPH
48H  30/1800Z 34.3N  75.4W   35 KT  40 MPH
72H  31/1800Z 36.8N  72.4W   40 KT  45 MPH
96H  01/1800Z…DISSIPATED

$$
Forecaster Brennan

[s2If current_user_can(access_s2member_level1)]

Tropical Depression 9

TROPICAL DEPRESSION NINE DISCUSSION NUMBER   1
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL092016
500 PM EDT SUN AUG 28 2016

Data from a NOAA Hurricane Hunter aircraft indicate that the area of
low pressure located in the Florida Straits now has a well-defined
center.  Satellite imagery shows a significant increase in the
convective organization today, and as a result the system is now
classified as a tropical cyclone.  The initial intensity is set to
30 kt based on the highest believable wind data from the aircraft,
which reported a central pressure of 1009 mb.

The depression will be moving through a marginal environment for
intensification during the next day or so, with vertical shear of
15 to 20 kt.  As a result only slow strengthening is expected in
the short term.  Later on, the environment may improve a little as
the shear is forecast to decrease somewhat and become
southwesterly, which should allow for a little more strengthening.
However, there are mixed signals in the model guidance, with the
ECMWF now showing the cyclone dissipating in the Gulf, while the
GFS delays development until 4-5 days.  Much of the tropical
cyclone guidance is more aggressive.  Given this uncertainty, the
NHC intensity forecast is quite conservative and shows the system
peaking at 45 kt, below all the explicit intensity guidance in
consideration of the negative signal from the ECMWF.  Needless to
say, the confidence in the intensity forecast is even lower than
usual for this system.

The initial motion estimate is an uncertain 270/09 given the recent
formation of the center.  The cyclone will be steered in the short
range by a mid-level ridge centered over the southeastern United
States.  This ridge will weaken in 2-3 days, which will cause the
cyclone to slow down and turn northward during this time.  Late in
the period a northeastward acceleration is expected ahead of an
approaching mid-latitude trough.  There is reasonable agreement in
the track of the cyclone in the global model guidance, although
there is a fair bit of along-track spread late in the period.  The
NHC forecast is close to a consensus of the GFS and ECMWF through
day 4 and is a little faster than the GFS and GEFS ensemble mean at
day 5.

FORECAST POSITIONS AND MAX WINDS

INIT  28/2100Z 23.7N  81.7W   30 KT  35 MPH
12H  29/0600Z 23.9N  83.6W   30 KT  35 MPH
24H  29/1800Z 24.3N  85.4W   35 KT  40 MPH
36H  30/0600Z 24.6N  86.8W   35 KT  40 MPH
48H  30/1800Z 25.1N  87.6W   40 KT  45 MPH
72H  31/1800Z 26.8N  87.4W   45 KT  50 MPH
96H  01/1800Z 29.0N  84.5W   45 KT  50 MPH
120H  02/1800Z 31.0N  80.0W   45 KT  50 MPH

$$
Forecaster Brennan

Hurricane Gaston

HURRICANE GASTON DISCUSSION NUMBER  25
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL072016
500 PM AST SUN AUG 28 2016

The 15 n mi diameter eye has become more distinct on visible
satellite images today, and enhanced IR images show a cooling of the
cloud tops surrounding the eye.  These features indicate
strengthening, and the current intensity is increased to 100 kt in
agreement with the subjective Dvorak estimates from TAFB and SAB, as
well as objective ADT numbers from UW-CIMSS.  Upper-level outflow is
well-established both to the west and the east of the hurricane.
Based on a consensus of the intensity models, not much additional
strengthening is anticipated.  When Gaston moves to a little higher
latitude, westerly shear on the system should increase, and steady
weakening is expected to commence in about 48 hours.

Gaston continues to crawl northwestward while being partially
blocked by a narrow mid-level subtropical ridge.  The hurricane is
forecast to work its way through the ridge over the next day or so.
By Tuesday, an east-northeastward motion with gradual acceleration
is likely as the system begins to feel the effect of the
mid-latitude westerlies.  The official forecast track is shifted a
little southward late in the forecast period, in line with the
latest global model guidance.

FORECAST POSITIONS AND MAX WINDS

INIT  28/2100Z 30.8N  55.1W  100 KT 115 MPH
12H  29/0600Z 31.0N  55.5W  100 KT 115 MPH
24H  29/1800Z 31.4N  55.5W  100 KT 115 MPH
36H  30/0600Z 32.0N  54.4W   95 KT 110 MPH
48H  30/1800Z 32.8N  52.6W   95 KT 110 MPH
72H  31/1800Z 34.9N  47.7W   85 KT 100 MPH
96H  01/1800Z 37.5N  40.5W   75 KT  85 MPH
120H  02/1800Z 37.5N  33.5W   60 KT  70 MPH

$$
Forecaster Pasch

Latest on the tropics from Levi Cowan.

See today’s video.

[/s2If][s2If current_user_cannot(access_s2member_level1)][magicactionbox id=”18716″][/s2If]