July 30 Sunday 2017

Tropical Report

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 AM EDT Sun Jul 30 2017

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

1. A tropical wave located several hundred miles west-southwest of the
Cabo Verde Islands is producing disorganized cloudiness and a few
showers. Any development of this system for the next several days
is expected to be slow to occur due to dry air while the wave moves
westward at 10 to 15 mph.
* Formation chance through 48 hours…low…near 0 percent.
* Formation chance through 5 days…low…20 percent.

Forecaster Brown

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 PM PDT Sat Jul 29 2017

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

The National Hurricane Center is issuing advisories on Tropical
Storm Hilary, located several hundred miles west of the southern tip
of the Baja California peninsula, and on Tropical Storm Irwin,
located more than a thousand miles west-southwest of the southern
tip of the Baja California peninsula.

1. An area of low pressure is likely to form by the middle of next
week several hundred miles south of the southern coast of Mexico.
Conditions appear favorable for some development of this system
while it moves west-northwestward at 10 to 15 mph.
* Formation chance through 48 hours…low…near 0 percent.
* Formation chance through 5 days…low…30 percent.

Forecaster Brown

Tropical Tropical Storm Irwin Discussion Number 32
NWS National Hurricane Center Miami FL EP102017
200 AM PDT Sun Jul 30 2017

Infrared and earlier microwave satellite pictures show that
Irwin remains fairly well organized. An 0308 UTC AMSU microwave
overpass revealed a curved band over the southeastern portion of
the circulation and a mid-level eye-like feature. Recent ASCAT data
suggest that Irwin is slightly stronger than earlier estimates, so
the initial wind speed has been set at 50 kt for this advisory.
Irwin is forecast to move north of the 26 deg C isotherm later this
morning, and over even colder waters within the next 36 to 48 hours.
As a result, Irwin is expected to gradually weaken over the next few
days, and the cyclone is forecast to become a remnant low late
Monday. The new NHC wind speed forecast is identical to the
previous advisory and close to the various consensus aids.

Irwin has begun its much anticipated northward acceleration, with
recent satellite fixes indicating a motion of 350/8 kt. The tropical
storm is forecast to turn north-northwestward today and continue to
accelerate in south-southeasterly low- to mid-level flow in the wake
of Hilary. In 36 to 48 hours, Irwin is forecast to turn
northwestward and slow down when it approaches Hilary’s remnant
low. The dynamical model guidance is tightly clustered through 48
h, with some spread later in the period. The NHC track is similar
to the previous advisory and is near the middle of the guidance
envelope.

FORECAST POSITIONS AND MAX WINDS

INIT 30/0900Z 17.1N 125.0W 50 KT 60 MPH
12H 30/1800Z 18.7N 125.5W 45 KT 50 MPH
24H 31/0600Z 20.9N 126.7W 40 KT 45 MPH
36H 31/1800Z 23.2N 128.1W 35 KT 40 MPH
48H 01/0600Z 25.2N 129.8W 25 KT 30 MPH…POST-TROP/REMNT LOW
72H 02/0600Z 27.5N 132.3W 20 KT 25 MPH…POST-TROP/REMNT LOW
96H 03/0600Z 28.5N 133.5W 15 KT 15 MPH…POST-TROP/REMNT LOW
120H 04/0600Z…DISSIPATED

$$
Forecaster Brown

Tropical Storm Hilary Discussion Number 36
NWS National Hurricane Center Miami FL EP092017
200 AM PDT Sun Jul 30 2017

Deep convection associated with Hilary has continued to decrease in
coverage overnight, with only a small area of cold cloud tops
remaining to the southeast of the center. An average of the Dvorak
T- and CI-numbers from TAFB, SAB, and UW-CIMMS yields an initial
intensity estimate of 40 kt. Hilary will be moving into a more
stable airmass over SSTs below 22C very soon, which should result
in steady weakening over the next 24 to 48 hours. Deep convection
is also expected to dissipate later today, and Hilary is forecast to
degenerate to a remnant low within 24 hours.

Recent satellite fixes show that Hilary has turned west-
northwestward or 300/12 kt. A west-northwestward motion between
a low- to mid-level ridge to the north and Tropical Storm Irwin to
the south should continue over the next couple of days. The latest
global models suggest that cyclone is likely to dissipate before
any merger with Irwin or its remnants takes place. The NHC track
forecast is along the southern portion of the tightly clustered
guidance and is very similar to the previous forecast.

FORECAST POSITIONS AND MAX WINDS

INIT 30/0900Z 23.5N 124.7W 40 KT 45 MPH
12H 30/1800Z 24.4N 126.7W 35 KT 40 MPH
24H 31/0600Z 25.4N 129.1W 25 KT 30 MPH…POST-TROP/REMNT LOW
36H 31/1800Z 26.0N 131.0W 25 KT 30 MPH…POST-TROP/REMNT LOW
48H 01/0600Z 26.3N 132.5W 20 KT 25 MPH…POST-TROP/REMNT LOW
72H 02/0600Z…DISSIPATED

$$
Forecaster Brown