Tropical Weather Discussion
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295
AXNT20 KNHC 201805
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
205 PM 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 1200 UTC surface analysis and satellite imagery through
1715 UTC.

...SPECIAL FEATURES...

At 20/1800 UTC, major Hurricane Maria is located near 18.4N 66.9W
or about 13 nm W of Arecibo, Puerto Rico. The present movement of
Maria is northwest at 10 kt. The estimated minimum central
pressure is 961 mb. Maximum sustained winds are 100 kt with gusts
to 120 kt, Category 3. Numerous strong convection is within 120
nm of the center. Scattered moderate to isolated strong convection
is elsewhere within 210 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 20/1800 UTC, Tropical Storm Jose is located about 121 nm SSE
of Nantucket Massachusetts near 39.2N 69.3W, moving northeast at 7
kt. The estimated minimum central pressure is 976 mb. Maximum
sustained winds are 60 kt with gusts to 75 kt. Scattered moderate
convection lays on the NW quadrant of the storm from 38N-42N
between 70W-73W. Jose is a large system. Tropical-storm-force
winds extend outward up to 178 nm from the center. Please see the
latest NHC Forecast/Advisory under AWIPS/WMO headers
MIATCMAT2/WTNT22 KNHC for more details.

...GALE WARNING...

A 1007 mb low in the central Atlc, the remnants of former
tropical cyclone Lee, is located near 18N46W. Scattered moderate
convection is over the NE quadrant from 17N-25N between 42W-45W
Gale-force winds ore over 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.

...TROPICAL WAVES...

A tropical wave is in the E Atlantic with axis extending from
21N34W to 06N33W, moving west at 20 kt. The wave is in a region of
moderate low to middle level moisture N of 13N, and abundant
moisture S of 13N, as shown by SSMI TPW imagery. A well defined
surface reflection is also noted. Widely scattered moderate
convection is from 05N-13N between 28W-40W.

A tropical wave is in the W Caribbean with axis extending from
20N85W to 07N88W, moving west at 20 kt. SSMI TPW imagery
indicates the presence of some dry air intrusion in the wave
environment. That along with strong subsidence aloft, and strong
vertical wind shear, produces a lack of convection over the NW
Caribbean.

...ITCZ/MONSOON TROUGH...

The monsoon trough extends from the African coast near 12N16W to
12N28W to 08N40W to 10N45W to 09N49W. The ITCZ extends from
09N49W to 08N59W. Aside from the convection associated with the
tropical wave, isolated moderate convection is from 05N-10N
between 30W-38W.

...DISCUSSION...

GULF OF MEXICO...

A 1016 mb high is centered over the NE Gulf of Mexico near 28N87W.
10-15 kt anticyclonic surface winds are over the Gulf. Lightning
detection imagery indicates thunderstorms over the NW Gulf, SE
Texas, and SW Louisiana. The northern extent of a tropical wave is
over the the Bay of Campeche, S of 20N95W. Scattered showers are
within 90 nm of this wave. the remainder of the Gulf of Mexico has
mostly fair weather. In the upper levels, an upper level high is
centered over the W Gulf near 22N95W. Expect little change over
the next 24 hours.

CARIBBEAN SEA...

The eye of category 4 Hurricane Maria has recently moved off the
NW coast of Puerto Rico. Maria is forecast to pass just north of
the northeast coast of the Dominican Republic tonight and
Thursday. See the special features section for further details.
The eastern extent of the Pacific monsoon trough is over Costa
Rica and Panama. Clusters of scattered moderate convection are
over the SW Caribbean S of 12N. Scatterometer data shows mainly
light to gentle trade winds west of 75W. Of note in the upper
levels, a sharp upper level trough is over the NW Caribbean with
axis from central Cuba near 22N89W to central Honduras near
14N87W. Some scattered showers are Just E of the trough axis due
to upper level diffluence.

...HISPANIOLA...

A hurricane warning is in effect for the NE Dominican Republic. A
tropical storm warning is in effect for the N coast of Haiti. A
dangerous storm surge accompanied by large and destructive waves
will raise water levels by as much as 4-6 feet above normal tide
levels in the hurricane warning area in the Dominican Republic,
and 1-3 ft elsewhere along the northern coasts of the Dominican
Republic and Haiti. Please see the latest NHC Forecast/Advisory.
Scattered moderate to isolated strong convection is over E
Hispaniola E of 70W, spreading W, due to Maria. Expect the entire
island to be under feeder bands over the the next 24 hours.

ATLANTIC OCEAN...

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 above. A surface trough
over the central Atlantic extends from 31N44W to 25N45W. Scattered
moderate convection is observed within 120 nm east of the trough
north of 25N. The remainder of the basin remains under the
influence of a broad surface ridge centered north of the area.

For additional information please visit
http://www.hurricanes.gov/marine

$$
Formosa




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