[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 082146
TWDAT

Tropical Weather Discussion...UPDATED
NWS National Hurricane Center Miami FL
546 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 1200 UTC surface analysis and satellite imagery through
2100 UTC.

...SPECIAL FEATURES...

Recently upgraded Hurricane Michael is centered near 22.2N 85.2W
at 08/2100 UTC, or about 25 nm NW of the western tip of Cuba, or
450 nm S of Apalachicola, Florida moving N or 355 degrees at 08
kt. The estimated minimum central pressure is 978 mb. The maximum
sustained wind speed has increased to 70 kt with gusts to 85 kt.
Satellite imagery shows that the cloud and convective structure of
Michael continues to improve. The upper- level outflow is also
increasing over all quadrants of Michael as noted by the fanning
outward of the cirrus clouds. The satellite imagery shows numerous
strong convection within 90 nm of the center in the NE and SE
quadrants. Scattered strong convection is elsewhere within 120 mm
of the center in the NE quadrant, and within 60 nm of the center
in the W semicircle. Scattered moderate to strong convection is
seen from 18N to 23N between 81W and 84W, including western Cuba.
Similar activity is along the coast of western Cuba west of 83W,
and spreads northward to over the southeastern Gulf of Mexico near
25N. Scattered moderate convection is quickly spreading northward
over much of the eastern Gulf of Mexico north of 23N and E of
86W. Latest NHC forecast has Michael forecast 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, and move across the eastern Gulf of Mexico Tue and Tue
night. Michael 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. Michael is forecast to become a major hurricane by Tue or Tue
night. Very heavy rainfall is forecast over western Cuba, with
maximum isolated amounts of 12 inches, possibly leading to life-
threatening flash floods and mudslides. Isolated maximum amounts
of 12 inches are also possible in the Florida panhandle and Big
Bend region into the Carolinas. The Public Advisories are under
WMO header WTNT34 KNHC, and under AWIPS header MIATCPAT4. The
Forecast/Advisories are under WMO header WTNT24 KNHC, and AWIPS
header MIATCMAT4.

Tropical Storm Leslie is north of the area near 33.8N 45.0W 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.
he Public Advisories are under WMO header WTNT33 KNHC, and under
AWIPS header MIATCPAT3. The Forecast/Advisories are under WMO
header WTNT23 KNHC, and under AWIPS header MIATCMAT3.

A 1010 mb low is over the far eastern Atlantic near 09N26W. The
low is along a tropical wave axis that is along 26W from 03N to
15N. This system is roughly located several hundred miles
southwest of the Cabo Verde Islands. It is moving westward at 10
to 15 kt. Satellite imagery shows scattered moderate isolated
strong convection becoming organized with time from 06N to 13N
between 24W and 31W. This system has a medium potential to form
into a tropical depression during next few days while it moves
west-northwestward. However, by late this week, strong upper-
level winds are expected to become unfavorable for development.
See 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.

CARIBBEAN SEA...

Hurricane Michael is centered near 22.2N 85.2W, or 25 nm NW of
the western tip of Cuba 978 mb at 5 PM EDT, moving northward at
at 08 kt. The estimated minimum central pressure is 978 mb. Maximum
sustained wind speed is 70 kt with gusts to 85 knots. Micheal is
forecast to move into the southeastern Gulf of Mexico this
evening. Micheal is bringing very heavy rainfall over western Cuba
as well as to the Yucatan Channel and vicinity waters. See
Special Features above for more details on Tropical Storm Michael.

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. High pressure covers the rest of the area outside the
above described troughs. Tropical storm-force wind speeds from
Hurricane Michael may clip the waters offshore N Florida Wed night
and on Thu as the cyclone tracks northeastward towards the Mid-
Atlantic region.


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

$$
Aguirre
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