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Special Tropical Weather Outlook
NWS National Hurricane Center Miami FL
510 AM EDT Thu Sep 17 2020
For the North Atlantic...Caribbean Sea and the Gulf of Mexico:
Special Tropical Weather Outlook issued to update the discussion of
the low pressure system over the southwestern Gulf of Mexico.
The National Hurricane Center is issuing advisories on Tropical
Depression Sally, located inland over southeastern Alabama, on
Hurricane Teddy, located over the central tropical Atlantic, and on
Tropical Storm Vicky, located over the eastern tropical Atlantic.
1. Thunderstorm activity has continued to increase and become better
organized this morning in association with a well-defined low
pressure system located over the southwestern Gulf of Mexico.
Upper-level winds are gradually becoming more conducive for
development and, if this recent development trend continues,
a tropical depression or a tropical could form later today. The
low is expected to meander over the southwestern Gulf of Mexico for
the next day or so before moving slowly northward to
northeastward on Friday and Saturday. An Air Force Reserve
reconnaissance aircraft is scheduled to investigate the disturbance
* Formation chance through 48 hours...high...90 percent.
* Formation chance through 5 days...high...90 percent.
2. An elongated area of low pressure located a few hundred miles
south-southwest of the Cabo Verde Islands is producing disorganized
shower and thunderstorm activity. Environmental conditions are
expected to be conducive for development during the next few days,
and a tropical depression could form before upper-level winds become
less favorable over the weekend. The low is forecast to move
west-northwestward at 10 to 15 mph during the next several days.
* Formation chance through 48 hours...medium...40 percent.
* Formation chance through 5 days...medium...60 percent.
3. A non-tropical area of low pressure is located over the far
northeastern Atlantic Ocean a few hundred miles east-northeast of
the Azores. This system is forecast to move east-southeastward and
then northeastward at about 10 mph over the next day or two, and its
chances of acquiring some subtropical characteristics before it
reaches the coast of Portugal late Friday appear to be decreasing.
For more information on this system, see High Seas Forecasts issued
by Meteo France.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 5 days...low...10 percent.
High Seas Forecasts issued by Meteo France can be found under WMO
header FQNT50 LFPW and available on the web at