Tropical Report

UPDATE: Now TS Cindy

Potential Tropical Cyclone Three Discussion Number 3

NWS National Hurricane Center Miami FL AL032017

400 AM CDT Tue Jun 20 2017

Nighttime infrared satellite imagery suggests that the circulation

associated with the low pressure area in the Gulf of Mexico is

gradually becoming better defined. However, the system is

struggling to maintain organized convection near the center, and

the radius of maximum winds remains large. Based on this, the

system is still maintained as a potential tropical cyclone.

The low is moving erratically northwestward around the southwestern

portion of a deep-layer ridge located over the western Atlantic and

Florida. The large-scale models suggest this ridge will strengthen

some during the next 36 hours or so and cause the low to turn a

little more westward. This would be followed by a northward turn

around the western end of the ridge and eventual recurvature into

the westerlies. Overall, there has been a left shift of the track

guidance models since the previous advisory. The new forecast

track is also shifted left, but it is to the right of the model

consensus, especially at 36-48 h. Given the nature of the

circulation, though, and the fact that the wind and rain hazards

extend well north and east of the center, users are encouraged to

not focus on the details of the track forecast.

The initial intensity remains 35 kt based on partial scatterometer

overpasses and continuity from the previous advisory. Significant

strengthening is unlikely due to strong vertical shear caused by an

upper-level trough over the northwestern Gulf of Mexico and

entrainment of dry air into the system. However, the large-scale

models suggest slight strengthening before landfall, and thus the

intensity forecast is unchanged from the previous advisory. One

change from the previous advisory is that it now appears more

likely that the system would become a subtropical cyclone than a

tropical cyclone due to the current structure of the low and

interaction with the aforementioned trough. That being said,

development into a tropical cyclone remains possible.

The primary hazard from this disturbance is expected to be heavy

rainfall over portions of the central and eastern Gulf Coast.

FORECAST POSITIONS AND MAX WINDS

INIT 20/0900Z 24.8N 90.1W 35 KT 40 MPH…POTENTIAL TROP CYCLONE

12H 20/1800Z 25.7N 91.0W 35 KT 40 MPH…SUBTROPICAL CYCLONE

24H 21/0600Z 26.6N 92.1W 40 KT 45 MPH

36H 21/1800Z 27.5N 93.0W 40 KT 45 MPH

48H 22/0600Z 28.9N 93.5W 40 KT 45 MPH

72H 23/0600Z 32.5N 93.5W 25 KT 30 MPH…INLAND

96H 24/0600Z 36.5N 88.0W 20 KT 25 MPH…POST-TROP/INLAND

120H 25/0600Z…DISSIPATED

$$

Forecaster Beven

 

Tropical Storm Bret Discussion Number 7

NWS National Hurricane Center Miami FL AL022017

500 AM AST Tue Jun 20 2017

Bret continues to have a fairly well-organized appearance on

satellite imagery, but the presentation on radar from Trinidad and

Venezuela is not so impressive, with a lack of well-defined banding

features. The structure of the cyclone continues to be

characterized by a northward tilt of the vortex with height, so

the center is estimated to be located near the southern side of the

CDO. The initial intensity is held at 35 kt for this advisory,

which is the mean of Dvorak T-numbers from SAB and TAFB. The

intensity forecast reasoning remains about the same as before. No

significant short-term strengthening seems likely while the

circulation interacts with Venezuela today. In 24 hours or so, a

weakening trend should commence due to strong south-southwesterly

shear associated with an upper-level trough over the Caribbean Sea.

The global models continue to be in good agreement that the system

will dissipate over the west-central Caribbean in 2-3 days. The

official intensity forecast is near or slightly above the intensity

model consensus, IVCN.

The forward motion has slowed just a bit from yesterday and is now

around 290/18 kt. There continues to be little change to the track

forecast philosophy. The flow on the southern side of a

well-defined mid-level subtropical ridge should steer the cyclone on

a west-northwestward to westward track for the next couple of days.

The official track forecast lies between the latest ECMWF and GFS

solutions and is close to the model consensus.

FORECAST POSITIONS AND MAX WINDS

INIT 20/0900Z 10.6N 62.9W 35 KT 40 MPH

12H 20/1800Z 11.5N 65.3W 35 KT 40 MPH

24H 21/0600Z 12.4N 68.7W 35 KT 40 MPH

36H 21/1800Z 13.3N 72.7W 30 KT 35 MPH

48H 22/0600Z 13.6N 76.7W 30 KT 35 MPH…POST-TROP/REMNT LOW

72H 23/0600Z…DISSIPATED

$$

Forecaster Pasch

Tropical Weather Outlook

NWS National Hurricane Center Miami FL

500 AM PDT Tue Jun 20 2017

For the eastern North Pacific…east of 140 degrees west longitude:

Tropical cyclone formation is not expected during the next 5 days.

$$

Forecaster Avila

Weather In Cayman

Synopsis

Not available. See Weather Forecast Top Right of Website.