Tropical Weather Discussion
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AXNT20 KNHC 201106

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
706 AM EDT Wed Sep 20 2017

Tropical Weather Discussion for North America, Central America
Gulf of Mexico, Caribbean Sea, northern sections of South
America, and Atlantic Ocean to the African coast from the
Equator to 32N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 0600 UTC surface analysis and satellite imagery through
1130 UTC.


At 20/1035 UTC, major Hurricane Maria was located near 18.0N
65.8W or about 15 nm west-southwest of Vieques, and 30 nm
southeast of San Juan, Puerto Rico. The present movement of Maria
is northwest at 9 kt. The estimated minimum central pressure is
917 mb. Maximum sustained winds are 135 kt with gusts to 165 kt, a
Category 4. Numerous strong convection is within 120 nm of the
center. Scattered moderate convection is elsewhere within 175 nm
of the center. Maria is moving across Puerto Rico today, and will
pass just north of the northeast coast of the Dominican Republic
tonight and Thursday. Please see the latest NHC Forecast/Advisory
under AWIPS/WMO headers MIATCMAT5/WTNT35 KNHC for more details.

At 20/0900 UTC, Tropical Storm Jose was located about 165 nm
south of Nantucket Massachusetts near 38.4N 70.3W, moving
northeast at 7 kt. The estimated minimum central pressure is 975
mb. Maximum sustained winds are 55 kt with gusts to 70 kt.
Scattered moderate convection lays on the NW quadrant of the storm
from 38N to 41N between 70W and 75W. The center of Jose is expected
to pass well to the east of the New Jersey coast today, and pass
offshore of southeastern Massachusetts Thursday. Please see the
latest NHC Forecast/Advisory under AWIPS/WMO headers
MIATCMAT2/WTNT22 KNHC for more details.


A 1008 mb low in the central Atlc, or the remnants of former
tropical cyclone Lee, are located near 18N46W. Showers and
thunderstorms have significantly decreased near the low pressure
area the last couple of hours. Scattered moderate convection and
tstms are in the NE quadrant of the low center from 17N to 25N
between 40W and 46W. Gale-force winds prevails in the NE quadrant
of the low...within 270 nm of the center. An increase in the
organization of the deep convection would result in the
regeneration of Lee as it moves northward over the central
Atlantic Ocean. There is a medium chance for tropical cyclone re-
development within the next 48 hours.


A tropical wave is in the E Atlc with axis extending from 18N27W
to 06N27W, moving west at 20 kt. CIRA LPW imagery show dry air has
increased in the wave environment the last couple of hours due to
intrusion of Saharan dry air and dust. This is limiting the
convection to scattered moderate SW of the wave axis from 05N to
12N between 28W and 32W.

A tropical wave is in the W Caribbean with axis extending from
20N85W to 07N88W, moving west at 20 kt. CIRA TPW imagery
indicates the presence of dry air in the wave environment that
along with strong subsidence from aloft, and strong vertical wind
shear support lack of convection in the far NW Caribbean W of 84W.


The monsoon trough extends southwest from the African coast near
12N16W to 11N28W to 08N42W. The ITCZ extends from 08N42W to
09N48W to 09N59W. Aside from the convection associated with the
tropical wave, scattered moderate convection is from 04N to 11N
between 32W and 40W.



Weak surface ridging prevails over the Gulf of Mexico basin with
light and variable winds over most of the basin. Ridging aloft
over the entire Gulf along with dry air subsidence continue to
support clear skies, except for scattered showers and tstms over
the Bay of Campeche due to proximity of a tropical wave that
already moved over the EPAC waters S of Mexico. Winds will shift
from SE to E Thursday afternoon.


Category 4 Hurricane Maria is moving across Puerto Rico this
morning. The eye of Maria is forecast to exit Puerto Rico by the
north during the afternoon hours, and pass just north of the
northeast coast of the Dominican Republic tonight and Thursday.
See the special features section for further details. Low level
wind convergence east of a tropical wave in the western Caribbean
is producing a large area of isolated showers and tstms in the SW
Caribbean from S of 15N W of 77W. Scatterometer data shows mainly
light to gentle trade winds west of 71W, with the remainder of
the basin N of 12N experiencing cyclonic winds associated with
Hurricane Maria.


Scattered showers are in the Mona Passage and E Dominican Republic
adjacent waters. Mostly fair weather prevails across the island.
However, weather conditions will deteriorate across the Island
this morning associated with the rainbands of Hurricane Maria
moving across Puerto Rico. These showers will increase as the
system moves NW very close of the Island on Thu.


Please refer to Special Features section for more information on
Hurricanes Maria and Tropical Storm Jose. There is a gale warning
associated with the remnants of former tropical cyclone Lee along
with scattered moderate convection. See gale warning section
above. A surface trough over the central Atlantic extends from
32N41W to 30N42W to 25N44W. Scattered moderate convection is
observed east of the trough north of 23N between 38W-44W. The
remainder of the basin remains under the influence of a broad
surface ridge centered north of the area.

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