[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 090005
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
805 PM EDT Mon Oct 8 2018

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 1800 UTC surface analysis and satellite imagery through
2330 UTC.

...SPECIAL FEATURES...

The center of Hurricane Michael at 09/0000 UTC is near 22.7N
85.2W, or about 100 km NW of the western tip of Cuba, or about 785
km to the S of Apalachicola in Florida. MICHAEL is moving N, or
355 degrees, 10 knots. The estimated minimum central pressure is
970 mb. The maximum sustained wind speeds are 75 knots with gusts
to 90 knots. Scattered to numerous strong rainshowers are within
120 nm of the center in the NW semicircle, and within 170 nm to
280 nm of the center in the SE quadrant. Widely scattered to
scattered moderate and isolated strong rainshowers are elsewhere
from 18N into the Gulf of Mexico between 77W in Cuba and 88W in
the Gulf of Mexico. MICHAEL is forecast to continue to push wind,
rain, and higher sea heights/storm surge with it, as it continues
its forecast movement into the NE corner of the Gulf of Mexico.
Michael is forecast to become a major hurricane by Tuesday or
Tuesday night. Expect periods of comparatively heavier rainfall
amounts during the next 48 hours or so along the northward path of
MICHAEL. Isolated maximum amounts of 12 inches may reach western
sections of Cuba, possibly leading to life- threatening flash
floods and mudslides. Isolated maximum amounts of 12 inches are
also possible in the Florida panhandle and in the Florida Big Bend
region into the Carolinas. The PUBLIC ADVISORIES are being
transmitted via the WMO header WTNT34 KNHC, and via the AWIPS
header MIATCPAT4. The FORECAST/ADVISORIES are being transmitted
via the WMO header WTNT24 KNHC, and via the AWIPS header
MIATCMAT4.

Tropical Storm Leslie is north of the area near 33.8N 45.8W at
08/2100 or about 950 nm W of the Azores moving SE, or 130 degrees
at 12 kt. The estimated minimum central pressure is 986 mb. The
maximum sustained wind speed has increased to 50kt with gusts to
60 kt. Latest satellite imagery shows banding features wrapping
around the center mainly in the eastern semicircle, with some
evidence of the bands wrapping attempting to wrap around in the
western semicircle. The bands consists of the scattered moderate
isolated strong type intensity from 33N to 35N, and within 60 nm
of the center in the S quadrant. Scattered moderate convection is
seen from 35N to 37N between 44W and 47W, and in an outer rainband
within 30 nm either side of a line from 33N42W to 35N42W to
36N44W. Leslie is forecast to maintain its southeast or east-
southeast motion at a slightly slower forward speed during the
couple of days, with a turn toward the east-northeast forecast for
Thu. The latest NHC forecast has Leslie becoming a minimal
hurricane at 18 UTC on Wed near a position of 28.2N 41.7W.
The PUBLIC ADVISORIES for LESLIE are transmitted via the WMO
header WTNT33 KNHC, and via the AWIPS header MIATCPAT3. The
FORECAST/ADVISORIES for LESLIE are transmitted via the WMO header
WTNT23 KNHC, and via the AWIPS header MIATCMAT3.

A 1011 mb low pressure center is about several hundred miles to
the southwest of the Cabo Verde Islands. The low pressure center
is becoming better defined. Environmental conditions are expected
to be conducive for further development. It is likely that a
tropical depression may form within a day or two, while the
system moves generally west-northwestward. Strong upper level
winds are expected to limit further development later in the week.
The chance for development into a tropical cyclone is high.
Scattered moderate isolated strong convection becoming organized
with time from 06N to 13N between 24W and 31W. Please read the
latest NHC Tropical Weather Outlook, under AWIPS/WMO headers
MIATWOAT/ABNT20 KNHC, for more details.

...TROPICAL WAVES...

A central Atlantic tropical wave is along 41W from 04N to 18N.
A 1011 mb low is along the wave near 12N41W. This system is
moving westward at about 15 kt. Scattered moderate convection is
within 60 nm of the low in the NE quadrant, but is being sheared
by strong southwest winds aloft.

A Caribbean Sea tropical wave that earlier was over the eastern
Caribbean was analyzed near 70W as depicted by model diagnostic
guidance. It is moving westward at 15 kt. Scattered showers and
thunderstorms are from 15N to 18N within 60 nm either side of the
wave.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis passes through the coastal regions of
Guinea-Bissau near 12N16W to 10N22W to the Special Features
1010 mb low at 09N26W and to 08N35W. The ITCZ axis extends from
the 1011 mb low near 12N41W, that is associated with the tropical
wave along 26W, to 09N49W and to 08.5N56W. Outside from
convection associated with the Special Features tropical wave
along 26W and with the tropical wave along 41W, scattered
moderate convection is along and within 60 nm south of the
monsoon trough between 31W and 35W. Scattered moderate convection
is also over the far eastern Atlantic from 03N to 09N between
15W and 21W, and just inland the coast of Africa from 04N to 06N.

GULF OF MEXICO...

Hurricane Michael is over the far northwestern Caribbean Sea,
moving northward at 06 kt. Michael is forecast to continue to
increase its northward motion through Tue night, followed by a
northeastward motion on Wed and Thu. On this forecast track, the
center of Michael will pass near the western tip of Cuba within
the next couple of hours and move into the southeastern Gulf of
Mexico by tonight. Michael will move across the eastern Gulf of
Mexico Tue and Tue night, is expected to move inland over the
Florida Panhandle or Florida Big Bend area on Wed, and then move
northeastward across the southeastern United States Wed night and
Thu. Hurricane conditions are expected within the hurricane
warning area along the U.S. Gulf Coast by Wed, with tropical
storm conditions expected by Tue night or early on Wed. Tropical
storm conditions are expected in the tropical storm warning area
by Tue night or early on Wed, and are possible within the
tropical storm watch area by that time. Hurricane conditions are
possible within the hurricane watch area by Wed. Expect for
scattered to numerous strong convection, with strong strong gusty
winds outside the radii of tropical storm force winds, to increase
along and near the track of Michael. Scattered showers and
isolated thunderstorms are over the far western Gulf and over
most of the far northern waters.

A narrow upper-level trough is along 87W north of about 24N. This
features is in between two ridges, one to its west and the other
to its east, that also extends over Hurricane Micheal.
Anticyclonic flow covers the area to the north of Micheal and
west of the trough. At the surface, high pressure ridging noses
southwestward from the Mid-Atlantic to just inland the NE and
north-central Gulf. A weak pressure pattern is present west of
90W. In the wake of Michael, a cold front is forecast to move off
the Texas coast on Wed, and reach from near the western Florida
panhandle to inland far southern Texas by early in Thu. Gentle to
moderate northerly winds are forecast behind the cold front along
with relatively low seas.

Hurricane Michael near 22.2N 85.2W 978 mb at 5 PM
EDT moving N at 8 kt. Maximum sustained winds 70 kt gusts 85 kt.
Michael will move to 23.7N 85.7W Tue morning, 25.7N 86.4W Tue
afternoon, 27.9N 86.6W Wed morning, inland to 30.2N 85.8W Wed
afternoon, and move inland and weaken to a tropical storm near
34.5N 80.5W Thu afternoon. Michael will become extratropical as it
moves to 39.8N 68.8W Fri afternoon, and continue to 46.2N 50.0W
Sat afternoon. Conditions should improve by the end of the week
as Michael speeds off to the N and NE of the area, potentially
dragging a cold front or frontal trough down S of 31N in its wake.

CARIBBEAN SEA...

Hurricane Michael near 22.2N 85.2W 978 mb at 5 PM
EDT moving N at 8 kt. Maximum sustained winds 70 kt gusts 85 kt.
Michael will move to 23.7N 85.7W Tue morning, 25.7N 86.4W Tue
afternoon, 27.9N 86.6W Wed morning, inland to 30.2N 85.8W Wed
afternoon, and move inland and weaken to a tropical storm near
34.5N 80.5W Thu afternoon. Michael will become extratropical as
it moves to 39.8N 68.8W Fri afternoon, and continue to 46.2N
50.0W Sat afternoon. Otherwise and elsewhere, expect moderate
trades, diminishing towards the weekend as the pressure gradient
slackens even more.

An upper-level anticyclone is located near 16N79W, with associated
upper-level anticyclonic flow covering the area between 74W and
83W. An upper-level trough extends from an elongated central
Atlantic low at 23N45W, southwestward to 17N62W and to near
15N67W. Ample available moisture and instability is over the just
about the entire sea, except under the area of the anticyclone.
Scattered showers and thunderstorms are noted elsewhere to the
east of the tropical wave that is near 70W. Expect for this
activity to continue through Wed.

ATLANTIC OCEAN...

An upper-level cyclonic circulation centered at 23N45W, with a
trough extending to the northeastern Caribbean Sea. At the
surface, a trough is analyzed from 25N45W to 19N51W. Only isolated
showers and thunderstorms are within 60 nm of the trough. Another
surface trough is analyzed from near 26N71W to 20N73W. A small
upper-level low is seen at 24N72W. These features acting on a very
moist and unstable atmosphere are resulting in scattered moderate
isolated strong convection from 19N to 26N between 63W and 68W,
and from 22N to 29N between 68W and 74W. The troughs forecast to
move in west to northwest motion across the Bahamas through
tonight, and move to across southern Florida Tue while dampening
out. The pres gradient between this trough and the ridge will
continue to bring fresh to strong winds and higher seas north of
about 24N and west of 64W through most of Tue.

A surface trough extends from near a 1010 mb low just north of
the area at 33N21W southwestward to 28N27W. Only isolated showers
are within 30 to 60 nm of the trough. Yet another surface trough
to the southwest of Tropical Storm Leslie extends from near 31N45W
to 26N52W. Isolated showers and weak isolated thunderstorms are
within 60 nm of the trough. Otherwise, a 1017 mb high center is
near 26N38W.

Hurricane Michael near 22.2N 85.2W 978 mb at 5 PM EDT moving N at
8 kt. Maximum sustained winds 70 kt gusts 85 kt. Michael will
move to 23.7N 85.7W Tue morning, 25.7N 86.4W Tue afternoon, 27.9N
86.6W Wed morning, inland to 30.2N 85.8W Wed afternoon, and move
inland and weaken to a tropical storm near 34.5N 80.5W Thu
afternoon. Michael will become extratropical as it moves to the
39.8N 68.8W Fri afternoon, and continue to the 46.2N 50.0W Sat
afternoon. Otherwise, a trough will move W-NW through the Bahamas
through tonight, moving W of the area thereafter. The pres
gradient between this trough and the ridge will support fresh to
strong winds and higher seas near the trough axis.


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

$$
jl/ja/mt
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