[Tropical] Tropical Weather Outlook and Summary

[EMWIN Server]

ABNT20 KNHC 121142
TWOAT

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 AM EDT Sun Sep 12 2021

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

Showers and thunderstorms associated with a broad area of low
pressure over the southwestern Bay of Campeche have increased
overnight and are showing signs of organization. Environmental
conditions are conducive for additional development, and a tropical
depression is expected to form later today or tonight while the
system moves northwestward and then northward near the coast of
northeastern Mexico.  Additional development is possible through the
middle of next week if the system remains over water, and  interests
along the western and northwestern Gulf coast should monitor the
progress of this disturbance as watches may be required for portions
of the coasts of northeastern Mexico and Texas later this morning or
this afternoon. An Air Force Hurricane Hunter aircraft is currently
en route to investigate the system this morning.

Regardless of development, the disturbance will continue to produce
heavy rain across portions of southern Mexico today, which may lead
to flash flooding and mudslides.  By late today, heavy rain is
expected to reach portions of the Texas and Louisiana coasts, with
a heavy rain threat continuing across those coastal areas through
the middle of the week. Localized significant rainfall amounts are
possible, potentially resulting in areas of flash, urban, and
isolated river flooding.
* Formation chance through 48 hours...high...90 percent.
* Formation chance through 5 days...high...90 percent.

Disorganized showers and a few thunderstorms continue in
association with a tropical wave located near the Cabo Verde
Islands.  Environmental conditions are becoming less conducive for
development, and the chances of tropical depression formation are
decreasing while the system moves westward over the far eastern
tropical Atlantic.  By the middle of the week, stronger upper-level
winds and marginally warm ocean temperatures are expected to limit
additional development.  This disturbance could bring locally heavy
rain across the Cabo Verde Islands today.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 5 days...low...20 percent.

A non-tropical area of low pressure is located over the far
northeastern Atlantic a few hundred miles east-northeast of the
Azores. This system is forecast to move south-southeastward towards
warmer waters, which could allow the low to gradually acquire some
tropical or subtropical characteristics during the next couple of
days.  After that time, the system is forecast to move inland over
Portugal ending any further development chance.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 5 days...low...20 percent.

Another tropical wave is forecast to move off the west coast of
Africa in a couple of days. Gradual development of this system is
possible thereafter, and a tropical depression could form by the
middle of the week while it moves westward across the eastern
tropical Atlantic Ocean.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 5 days...medium...60 percent.

An area of low pressure is expected to form north of the
southeastern or central Bahamas in a few days resulting from a
tropical wave interacting with an upper-level trough.  Gradual
development of this system is possible, and a tropical depression
could form later this week several hundred miles southeast of the
Carolinas while it moves northwestward across the western Atlantic.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...medium...50 percent.

$$
Forecaster Brown
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