[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 092315
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Fri Oct 9 2020

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
2300 UTC.

...SPECIAL FEATURES...

At 5 pm CDT, the eyewall of Delta moved onshore on the southwestern
coast of Louisiana, about 25 miles SSE of Cameron, Louisiana with
maximum sustained winds of 90 kt. An hour later, at 6 pm CDT, the
hurricane made landfall near Creole, Louisiana. Delta is a category
2 hurricane on the Saffir-Simpson Hurricane Wind Scale. The minimum
central pressure estimated from Air Force Reserve reconnaissance
aircraft data was 970 mb. Hurricane conditions and life-threatening
storm surge is expected in the landfall area. Heavy rainfall
will lead to significant flash flooding and minor to major river
flooding in parts of Louisiana today and Saturday. Additional
flooding is expected across portions of the central Gulf Coast
into the Lower Mississippi Valley. On the forecast track, the
center of Delta will move across central and northeastern
Louisiana tonight and Saturday morning. After that time, the
system is forecast to moves across northern Mississippi into the
Tennessee Valley. Some weakening is possible before landfall,
with rapid weakening expected after landfall. Delta is forecast
to weaken to a tropical storm tonight and to a tropical
depression on Saturday. Please, read the latest NHC Public
Advisory, at https://www.nhc.noaa.gov/text/MIATCPAT1.shtml, and
the Forecast/ Advisory, at
https://www.nhc.noaa.gov/text/MIATCMAT1.shtml, for more details.

...TROPICAL WAVES...

A tropical wave is along 33W/34W from 02N-17N, moving W at 15-20
kt. Scattered moderate convection is noted from 07N-10N between
32W-36W. Environmental conditions could be conducive for some
slow development of the system this weekend or early next week
while it is located over the tropical Atlantic well east of the
Lesser Antilles. Upper-level winds are forecast to become
unfavorable for further development by the middle of next week.
This system has a low chance of tropical cyclone formation
through 5 days.

An eastern Caribbean tropical wave axis extends along 63W/64W
from 05N-22N, moving W at 10 kt. Currently, convection is
limited near the wave axis. Moisture associated with this wave
will reach Puerto Rico tonight into Sat increasing the likelihood
of showers and thunderstorms.

Another tropical wave is moving across the Caribbean Sea with
axis along 76W, from 20N southward, moving westward 10 to 15
knots. The wave is helping to induce some convective activity
over Jamaica and southern regional waters, particularly from
15N-18N between 75W-78W.

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the Atlantic Ocean just N of Dakar,
Senegal, then continues SW to near 08N31W. The ITCZ extends from
07N40W to 10N52W. Scattered moderate convection is seen from
06N-10N between 40W-50W, and from from 09N-13N between 50W-58W.
The 925 mb streamlines and winds suggest the presence of a trough
in this area.

GULF OF MEXICO...

Please, see the Special Features section above for details on
Hurricane Delta. The most recent scatterometer data indicated
that the fresh to strong winds associated with the periphery of
the hurricane extend outward, covering the waters N of 23N W of
88W. Delta will weaken to a tropical storm near 31.1N 92.5W Sat
morning, then reach 33.1N 91.0W Sat afternoon. Delta will weaken
to a tropical depression near 34.4N 89.2W Sun morning and be near
35.9N 87.1W Sun afternoon. It is expected to become a remnant
low in Kentucky Mon morning and dissipate Mon afternoon. In its
wake, weak high pressure will build across the Gulf waters into
early next week. Swell from Delta will spread across the Gulf
into the weekend.

CARIBBEAN SEA...

An upper-level low is centered over the NW Caribbean. This
system, along with abundant moisture at low to middle levels is
supporting scattered showers and thunderstorms over the NW
Caribbean, Cuba, the Yucatan Peninsula and northern Central
America. Plenty of moisture in a gentle to moderate SE wind flow
will dominate the NW Caribbean and adjacent land areas on Sat.

For the forecast, building high pressure over the northwest
Atlantic will support fresh trade winds and moderate seas over
the south-central Caribbean, and gentle to moderate trade winds
and slight seas elsewhere into Sat. Winds and seas will diminish
across the basin through early next week as the high pressure
shifts east. A tropical wave may impact Atlantic waters east of
the Leeward Islands Tue and Wed.

ATLANTIC OCEAN...

A weak cold front enters the forecast area near 31N58W, and extends
SW to near 27N71W, then continues as a stationary front to NE Florida.
Scattered showers are along the frontal boundary. A surface trough
is ahead of the front and stretches from 31N52W to 25N58W to
20N62W. Scattered moderate convection is ahead of the trough
axis. Another surface trough is near 40W from 20N-27N. Scattered
showers are near the trough. The remainder of the Atlantic is
under the influence of a 1027 high pressure located over the
Azores.

For the forecast west of 65W, the aforementioned front will dissipate
into Sat. North of the boundary, moderate to fresh east winds will
prevail for the first half of the weekend, before weak high pressure
building over the area leads to lesser winds for the start of next
week.

$$
GR
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