Tropical Report

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 AM EDT Thu Sep 21 2017

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

The National Hurricane Center is issuing advisories on Tropical
Storm Jose, located a couple of hundred miles southeast of
Nantucket, Massachusetts, and on Hurricane Maria, located less than
one hundred miles northeast of Punta Cana, Dominican Republic.

1. Shower and thunderstorm activity associated with the remnants
of Lee remain very limited. Upper-level winds are expected
to remain unfavorable for significant development during the next
several days. The low is forecast to move north-northwestward or
northward over the open waters of the central Atlantic Ocean.
* Formation chance through 48 hours…low…10 percent.
* Formation chance through 5 days…low…10 percent.

Forecaster Pasch

GUSTY AND RAINY CONDITIONS ALONG PARTS OF THE SOUTHEAST NEW ENGLAND COAST WILL CONTINUE TODAY… …HIGH SURF AND RIP CURRENTS LIKELY TO CONTINUE ON US EAST COAST

Tropical Storm Jose Discussion Number 64
NWS National Hurricane Center Miami FL AL122017
500 AM AST Thu Sep 21 2017

Jose’s structure continues to consist of bands of shallow to
moderate convection that are well removed to from the center, mainly
in the northeast and northwest quadrants. Dvorak Final-T numbers
from TAFB and SAB have fallen a little bit, but due to the lack of
deep convection near the center, it isn’t clear how applicable the
Dvorak technique is in this case. The intensity has therefore been
held at 50 kt, in deference to earlier ASCAT and aircraft data.
Another reconnaissance mission is scheduled for later this morning,
and this should provide more information on Jose’s intensity and
wind radii.

The intensity guidance is still in very good agreement that Jose
will continue to gradually weaken. I have no reason to doubt this,
since Jose will remain over cold waters and embedded within a fairly
dry environment. Little change was made to the previous intensity
forecast, except to show Jose becoming post-tropical within 36
hours, based on the latest GFS and ECMWF model runs.

A deep-layer trough to the northeast of Jose has continued to pull
away, and the tropical storm has come to a near stop. The
estimated motion is 90/2 kt, but it may be even slower than that.
The global models continue to agree that Jose will remain within
weak steering flow through the forecast period. The new NHC
forecast remains close to the various consensus aids and keeps Jose
nearly stationary through 96 h.

KEY MESSAGES:

1. While the center of Jose is forecast to remain offshore of the
U.S. east coast, the large cyclone is expected to cause some direct
impacts in portions of extreme southeastern New England during the
next day or two, and a tropical storm warning remains in effect for
Cape Cod, Block Island, Martha’s Vineyard, and Nantucket.

2. Minor coastal flooding is possible along portions of the coast of
southern New England during the next few days. Please see products
issued by local National Weather Service forecast offices.

3. Swells generated by Jose are affecting Bermuda and much of the
U.S. east coast, and will likely cause dangerous surf and rip
current conditions for the next several days in these areas.

FORECAST POSITIONS AND MAX WINDS

INIT 21/0900Z 39.8N 67.8W 50 KT 60 MPH
12H 21/1800Z 39.7N 67.7W 45 KT 50 MPH
24H 22/0600Z 39.8N 68.3W 45 KT 50 MPH
36H 22/1800Z 39.8N 68.8W 40 KT 45 MPH…POST-TROPICAL
48H 23/0600Z 39.6N 69.2W 35 KT 40 MPH…POST-TROPICAL
72H 24/0600Z 39.4N 69.0W 30 KT 35 MPH…POST-TROP/REMNT LOW
96H 25/0600Z 39.5N 68.5W 25 KT 30 MPH…POST-TROP/REMNT LOW
120H 26/0600Z…DISSIPATED

$$
Forecaster Zelinsky
MARIA CONTINUES TO LASH THE NORTHEASTERN DOMINICAN REPUBLIC… …EXPECTED TO PASS NEAR THE TURKS AND CAICOS LATER TODAY

Hurricane Hurricane Maria Discussion Number 21
NWS National Hurricane Center Miami FL AL152017
500 AM AST Thu Sep 21 2017

Although the large, 40 n mi diameter, eye of the hurricane is still
a little ragged-looking, it is gradually becoming better defined,
and a ring of cold cloud tops is intensifying around the eye. The
current intensity estimate is 100 kt based on earlier Air Force
Hurricane Hunter data and recent Dvorak classifications from TAFB
and SAB. Maria is likely to move over warm waters with moderate
southwesterly vertical shear for the next couple of days. Maria’s
well-developed upper-level outflow suggests that shear is probably
not having much influence over the hurricane at this time. Although
the numerical guidance is not very aggressive about intensification,
based on the current trends of the cloud pattern, some strengthening
seems likely over the next day or so. Later in the forecast period,
shear will probably cause gradual weakening. The official intensity
forecast is a little above the latest model consensus.

Maria continues its northwestward motion, at about 315/8 kt. The
hurricane is expected to turn north-northwestward and northward
around a subtropical ridge over the Atlantic for the next 2 to 3
days. Late in the forecast period, a mid-level high over the
northeastern U.S. could slow the forward motion somewhat. This
high is forecast by the global models to subsequently weaken
however, which should allow Maria to turn north-northeastward in
the flow on the northwestern edge of a subtropical ridge over the
west-central Atlantic. The official track forecast lies between
the corrected consensus guidance and the latest ECMWF prediction.
This is quite similar to the previous NHC track.

KEY MESSAGES:

1. Heavy rainfall is expected to continue, and catastrophic flash
flooding is occurring in Puerto Rico, especially in areas of
mountainous terrain. Everyone in Puerto Rico should continue to
follow advice from local officials to avoid these life-threatening
flooding conditions.

2. A Hurricane Warning is in effect for the northern coast of the
Dominican Republic, the Turks and Caicos Islands, and the
southeastern Bahamas, where Maria is expected to bring dangerous
wind, storm surge, and heavy rainfall.

FORECAST POSITIONS AND MAX WINDS

INIT 21/0900Z 19.6N 68.4W 100 KT 115 MPH
12H 21/1800Z 20.5N 69.3W 105 KT 120 MPH
24H 22/0600Z 21.6N 70.4W 110 KT 125 MPH
36H 22/1800Z 22.9N 71.1W 105 KT 120 MPH
48H 23/0600Z 24.3N 71.7W 100 KT 115 MPH
72H 24/0600Z 27.4N 72.3W 100 KT 115 MPH
96H 25/0600Z 30.0N 72.0W 90 KT 105 MPH
120H 26/0600Z 32.5N 70.5W 80 KT 90 MPH

$$
Forecaster Pasch