Tropical Report

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Sun Sep 3 2017

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

The National Hurricane Center is issuing advisories on Hurricane
Irma, located over the central tropical Atlantic Ocean.

1. A tropical wave located several hundred miles southwest of the Cabo
Verde Islands is producing an area of disorganized showers and
thunderstorms that are currently displaced well to the west of the
wave axis. Environmental conditions are conducive for gradual
development during the next few days, and a tropical depression
could form by the end of the week while the system moves westward
to west-northwestward at about 10 mph over the tropical Atlantic
Ocean.
* Formation chance through 48 hours…low…near 0 percent.
* Formation chance through 5 days…medium…60 percent.

2. A trough of low pressure, located over the southwestern Gulf of
Mexico, is producing disorganized showers and thunderstorms that
extent from the Yucatan Peninsula westward into the Bay of Campeche.
Environmental conditions are forecast to remain unfavorable for
significant development as the system moves slowly northwestward.
* Formation chance through 48 hours…low…10 percent.
* Formation chance through 5 days…low…10 percent.

Forecaster Roberts
CATEGORY THREE HURRICANE IRMA MOVING WEST-SOUTHWESTWARD… …INTERESTS IN THE LEEWARD ISLANDS SHOULD MONITOR THE PROGRESS OF IRMA

Hurricane Irma Discussion Number 17
NWS National Hurricane Center Miami FL AL112017
1100 AM AST Sun Sep 03 2017

The eye of Irma is a little less distinct in geostationary satellite
images this morning, which suggests that the intensity of the
hurricane may be fluctuating yet again. However, the initial
wind speed is maintained at 100 kt for this advisory, which is close
to a consensus of the various objective and subjective satellite
intensity estimates. The first reconnaissance mission, a NOAA P-3
Hurricane Hurricane aircraft, is scheduled to depart Barbados for
tail Doppler radar mission into Irma late this afternoon and should
provide additional information on Irma’s intensity by this evening.

A strong high pressure ridge over the central Atlantic is steering
Irma west-southwestward or 255/12 kt. This general motion with
some reduction in forward speed is expected during the next day or
so. After that time, Irma is forecast to turn westward, then
west-northwestward in about 72 hours as it approaches the western
portion of the ridge. The various consensus aids are generally a
little slower than the previous advisory, but there cross-track
differences are small. As a result, the updated NHC track is very
similar to the previous advisory, and is close to a consensus of the
ECMWF, GFS, UKMET, and HWRF, but is not as far south as the
latest runs of the UKMET or ECMWF.

Irma is forecast to move over slightly warmer SSTs and into a
moistening mid-level environment. These conditions, along with a
favorable upper-level wind pattern, should allow for gradual
strengthening during the next 2 to 3 days. However, eyewall
replacement cycles could result in fluctuations in intensity
during the next several days.

While Irma is currently a small hurricane, the guidance suggests it
should grow in size during the next 72 h. This will affect how soon
watches may be issued for portions of the Leeward and Virgin
Islands, and interests on those islands should continue to monitor
Irma’s progress.

KEY MESSAGES:
1. Irma is expected to be a major hurricane when it moves near or
over the northeastern Leeward Islands by the middle of this week,
and could cause dangerous wind, storm surge, and rainfall impacts,
along with rough surf and rip currents on some islands. Hurricane
and tropical storm watches will likely be issued for some of these
islands later today or tonight. Residents in these areas should
monitor the progress of Irma and listen to advice given by
officials.

2. Direct impacts from Irma are also possible in the Virgin Islands
and Puerto Rico later this week, and tropical storm or hurricane
watches could be issued for these islands by tomorrow. Residents in
these areas should monitor the progress of Irma and listen to advice
given by officials.

3. The possibility of direct impacts from Irma in Hispaniola, the
Turks and Caicos, and the Bahamas later this week is increasing.
Residents in these areas should monitor the progress of Irma and
listen to advice given by officials.

4. It is too early to determine what direct impacts Irma might have
on the continental United States. Regardless, everyone in
hurricane-prone areas should ensure that they have their hurricane
plan in place, as we are now near the peak of the season.

FORECAST POSITIONS AND MAX WINDS

INIT 03/1500Z 17.7N 48.4W 100 KT 115 MPH
12H 04/0000Z 17.1N 50.1W 105 KT 120 MPH
24H 04/1200Z 16.6N 52.2W 110 KT 125 MPH
36H 05/0000Z 16.4N 54.3W 115 KT 130 MPH
48H 05/1200Z 16.7N 56.6W 120 KT 140 MPH
72H 06/1200Z 18.2N 61.8W 120 KT 140 MPH
96H 07/1200Z 20.4N 67.1W 115 KT 130 MPH
120H 08/1200Z 22.5N 72.0W 115 KT 130 MPH

$$
Forecaster Brown

LIDIA DEGENERATES INTO A REMNANT LOW… …THIS IS THE LAST ADVISORY