Tropical Report

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 AM EDT Tue Sep 19 2017

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

The National Hurricane Center is issuing advisories on Hurricane
Jose, located a few hundred miles south of Nantucket, Massachusetts,
North Carolina, and on Hurricane Maria, located over the
northeastern Caribbean Sea.

1. A small low pressure area, the remnants of Lee, is located roughly
midway between the Cabo Verde Islands and the Leeward Islands.
Environmental conditions could become marginally conducive for
redevelopment of a tropical cyclone by late in the week while the
system moves northwestward to northward over the central Atlantic
Ocean.
* Formation chance through 48 hours…low…10 percent.
* Formation chance through 5 days…low…20 percent.

Forecaster Stewart

 

JOSE STILL A CATEGORY 1 HURRICANE… …EXPECTED TO PRODUCE DANGEROUS SURF AND RIP CURRENTS ALONG THE EAST COAST OF THE UNITED STATES FOR SEVERAL MORE DAYS

Hurricane Jose Discussion Number 56
NWS National Hurricane Center Miami FL AL122017
500 AM EDT Tue Sep 19 2017

Satellite images indicate that a small area of deep convection is
persisting near the center of Jose. While it doesn’t look
particularly tropical at the moment, there is no evidence of fronts
connected to the center and the system is definitely warm core.
Thus, Jose will stay a tropical cyclone. The initial wind speed
remains 65 kt based on the previous reconnaissance mission.
Some weakening is likely to begin within 24 hours due to Jose
moving over colder waters. Continued weakening is in the forecast
due to the marginal water temperatures, although the system could
eventually move over the warm Gulf Stream again if it takes a
southward turn in the right spot. Thus, the intensity forecast is
about the same as the previous one through 72 hours, then is
leveled off at 45 kt to account for the warmer water possibility.

Jose continues to move erratically northward, with the center
wobbling due to the convective bursts. The hurricane should turn
toward the northeast and east over the next two days as it moves
around a ridge over the western Atlantic. After that point, the
forecast becomes more uncertain, with some models curving the system
south and west under a building high over the northeastern United
States, and others drifting the cyclone eastward just out of the
reach of the ridge. With the guidance shifting eastward on this
cycle, the official forecast will follow the trend, although not
shift as strongly to the east since it wouldn’t take a very large
track error to either catch or miss that ridge.

KEY MESSAGES:

1. While the center of Jose is currently forecast to remain offshore
of the U.S. coast, the large cyclone is expected to cause some
direct impacts in portions of New England, and a tropical storm
warning is in effect for the coast of Rhode Island and a part of
the Massachusetts coast, including Cape Cod. Any deviation to the
left of the NHC forecast track would increase the likelihood and
magnitude of impacts elsewhere along the U.S. east coast from
Delaware to southern New England.

2. Minor to moderate coastal flooding is possible from Delaware to
southern New England during the next several days. Please see
products issued by local National Weather Service forecast offices.

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

4. Jose will produce heavy rain over a small part of southern New
England and eastern Long Island as it passes offshore of these
locations on Tuesday and Wednesday. Total accumulations of 1 to 3
inches are expected over eastern Long Island, southeast Connecticut,
southern Rhode Island, and southeast Massachusetts. 3 to 5 inches
are expected for Martha’s Vineyard, Nantucket and Cape Cod. This
rainfall could cause isolated flooding. Elsewhere, Jose is expected
to produce light rainfall with little risk of flooding over the
mid-Atlantic coast and the northeast states.

FORECAST POSITIONS AND MAX WINDS

INIT 19/0900Z 36.0N 71.3W 65 KT 75 MPH
12H 19/1800Z 37.1N 71.1W 65 KT 75 MPH
24H 20/0600Z 38.5N 70.1W 60 KT 70 MPH
36H 20/1800Z 39.6N 68.7W 55 KT 65 MPH
48H 21/0600Z 40.0N 67.2W 50 KT 60 MPH
72H 22/0600Z 39.3N 66.4W 45 KT 50 MPH…POST-TROPICAL
96H 23/0600Z 38.7N 66.6W 45 KT 50 MPH…POST-TROPICAL
120H 24/0600Z 38.5N 67.0W 45 KT 50 MPH…POST-TROPICAL

$$
Forecaster Blake

POTENTIALLY CATASTROPHIC HURRICANE MARIA HEADED FOR THE VIRGIN ISLANDS AND PUERTO RICO

Hurricane Maria Discussion Number 13
NWS National Hurricane Center Miami FL AL152017
500 AM AST Tue Sep 19 2017

Interaction of the small core of Maria with the mountainous terrain
of Dominica caused only a slight diminution of the intensity of
the hurricane. Data from the Air Force Hurricane Hunter aircraft
after the center passed the island indicate an intensity of about
135 kt, at the high end of category 4 strength. Another Air Force
aircraft has begun investigating Maria, and preliminary data
from the plane suggest that the hurricane may have regained
category 5 intensity. Maria will be moving through a low-shear
atmospheric environment and mainly over warm waters for the next
couple of days. Some fluctuations in intensity are possible in the
early part of the forecast period due to eyewall replacement events.
Land influences could cause some weakening within the next 36
hours. Later in the forecast period, a modest increase in vertical
shear could cause some weakening. The official intensity forecast
is near or above the latest model consensus.

After smoothing out the trochoidal wobbles of Maria’s eye, the
initial motion estimate remains west-northwestward, or 300/8 kt.
There is little change to the track forecast reasoning from the
previous advisory package. A weak ridge situated over the western
Atlantic is expected to steer Maria west-northwestward through 48
hours, and on this track the center of the hurricane is forecast to
pass near or over the Virgin Islands and Puerto Rico on Wednesday.
After that time, the western portion of the ridge is forecast to
weaken, partially due to the influence of the large circulation of
Hurricane Jose. This should cause Maria to turn northwestward, then
north-northwestward by day 4-5. There is fairly good agreement
amongst the reliable guidance, and the new official track forecast
is very similar to the previous one. This is generally near the
left side of the envelope of model tracks, and favors the ECMWF and
the corrected consensus predictions.

KEY MESSAGES:

1. Maria will affect portions of the northern Leeward Islands as an
extremely dangerous major hurricane during the next day or so.

2. Maria is likely to affect Puerto Rico and the U.S. and British
Virgin Islands as an extremely dangerous major hurricane tonight
and Wednesday. Preparations to protect life and property should be
rushed to completion.

3. A life-threatening storm surge, accompanied by large and
destructive waves, is expected for the Leeward Islands, the U.S. and
British Virgin Islands, and Puerto Rico.

4. Life-threatening flash floods and mudslides from heavy rainfall
are expected across the Leeward Islands, including Puerto Rico and
the U.S. and British Virgin Islands.

FORECAST POSITIONS AND MAX WINDS

INIT 19/0900Z 16.0N 62.3W 135 KT 155 MPH
12H 19/1800Z 16.7N 63.4W 140 KT 160 MPH
24H 20/0600Z 17.6N 64.8W 135 KT 155 MPH
36H 20/1800Z 18.5N 66.3W 125 KT 145 MPH…NEAR PUERTO RICO
48H 21/0600Z 19.3N 67.8W 125 KT 145 MPH
72H 22/0600Z 21.2N 70.4W 120 KT 140 MPH
96H 23/0600Z 23.7N 71.7W 110 KT 125 MPH
120H 24/0600Z 26.5N 72.5W 100 KT 115 MPH

$$
Forecaster Pasch