Atlantic Tropical Weather Outlook


000
ABNT20 KNHC 191151
TWOAT

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
700 AM EST Tue Nov 19 2019

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

A broad area of low pressure located about 250 miles northeast of
the northern Leeward Islands is gradually becoming better organized
and the associated shower and thunderstorm activity has been
developing closer to the center since yesterday. If this trend
continues, then a tropical or subtropical depression or storm could
form in the next day or so while the system moves northwestward and
then northward over the open Atlantic. The low is forecast to
interact with a frontal system by midweek and further development is
unlikely after that time. For more information, see High Seas
Forecasts issued by the National Weather Service.
* Formation chance through 48 hours...high...80 percent.
* Formation chance through 5 days...high...80 percent.

&&
High Seas Forecasts issued by the National Weather Service can be
found under AWIPS header NFDHSFAT1, WMO header FZNT01 KWBC, and
online at ocean.weather.gov/shtml/NFDHSFAT1.php

$$
Forecaster Latto

Summary for Tropical Storm Sebastien (AT5/AL202019)

...TROPICAL STORM SEBASTIEN FORMS... ...EXPECTED TO REMAIN OVER OPEN WATERS...
 As of 11:00 AM AST Tue Nov 19
 the center of Sebastien was located near 20.1, -58.7
 with movement NNW at 8 mph.
 The minimum central pressure was 1008 mb
 with maximum sustained winds of about 45 mph.

Tropical Storm Sebastien Public Advisory Number 1

Issued at 1100 AM AST Tue Nov 19 2019  

000
WTNT35 KNHC 191500
TCPAT5

BULLETIN
Tropical Storm Sebastien Advisory Number   1
NWS National Hurricane Center Miami FL       AL202019
1100 AM AST Tue Nov 19 2019

...TROPICAL STORM SEBASTIEN FORMS...
...EXPECTED TO REMAIN OVER OPEN WATERS...


SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...20.1N 58.7W
ABOUT 275 MI...445 KM NE OF THE LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
PRESENT MOVEMENT...NNW OR 330 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...1008 MB...29.77 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 1100 AM AST (1500 UTC), the center of Tropical Storm Sebastien
was located near latitude 20.1 North, longitude 58.7 West. Sebastien
is moving toward the north-northwest near 8 mph (13 km/h). A turn to
the north is expected on Wednesday followed by a turn to the
northeast and an increase in forward speed Wednesday night.

Maximum sustained winds are near 45 mph (75 km/h) with higher gusts.
Some slight strengthening is possible over the next day or so.
Sebastien is expected to become absorbed by a cold front in a
couple of days.

Tropical-storm-force winds extend outward up to 105 miles (165 km)
from the center.

The estimated minimum central pressure is 1008 mb (29.77 inches).


HAZARDS AFFECTING LAND
----------------------
None


NEXT ADVISORY
-------------
Next complete advisory at 500 PM AST.

$$
Forecaster Latto

Tropical Storm Sebastien Forecast Advisory Number 1

Issued at 1500 UTC TUE NOV 19 2019  

561 
WTNT25 KNHC 191504 CCA
TCMAT5

TROPICAL STORM SEBASTIEN FORECAST/ADVISORY NUMBER   1
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL202019
1500 UTC TUE NOV 19 2019

CORRECTED GUSTS AT INITIAL TIME

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

TROPICAL STORM CENTER LOCATED NEAR 20.1N  58.7W AT 19/1500Z
POSITION ACCURATE WITHIN  30 NM

PRESENT MOVEMENT TOWARD THE NORTH-NORTHWEST OR 330 DEGREES AT   7 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 1008 MB
MAX SUSTAINED WINDS  40 KT WITH GUSTS TO  50 KT.
34 KT....... 90NE   0SE   0SW   0NW.
12 FT SEAS.. 90NE   0SE   0SW   0NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT.  RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 20.1N  58.7W AT 19/1500Z
AT 19/1200Z CENTER WAS LOCATED NEAR 19.8N  58.5W

FORECAST VALID 20/0000Z 21.0N  59.2W
MAX WIND  40 KT...GUSTS  50 KT.
34 KT... 90NE  90SE   0SW   0NW.

FORECAST VALID 20/1200Z 22.2N  60.0W
MAX WIND  45 KT...GUSTS  55 KT.
34 KT... 90NE 130SE   0SW   0NW.

FORECAST VALID 21/0000Z 23.5N  60.0W
MAX WIND  45 KT...GUSTS  55 KT.
34 KT...100NE 140SE   0SW   0NW.

FORECAST VALID 21/1200Z 25.5N  58.3W...POST-TROP/EXTRATROP
MAX WIND  45 KT...GUSTS  55 KT.
34 KT...100NE 150SE   0SW   0NW.

FORECAST VALID 22/1200Z...DISSIPATED

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 20.1N  58.7W

NEXT ADVISORY AT 19/2100Z

$$
FORECASTER LATTO



Tropical Storm Sebastien Forecast Discussion Number 1

Issued at 1100 AM AST Tue Nov 19 2019  

000
WTNT45 KNHC 191501
TCDAT5

Tropical Storm Sebastien Discussion Number   1
NWS National Hurricane Center Miami FL       AL202019
1100 AM AST Tue Nov 19 2019

Satellite imagery indicates that the overall cloud pattern of the
disturbance has improved since yesterday, and that the low has
become well-defined. In addition, a late-arriving ASCAT-B
scatterometer pass showed 35-38 kt winds extending 90 n mi from the
center in the northeastern quadrant. This pass also revealed that
the low was nearly closed at the surface, and since the
scatterometer may not have resolved the small scale of the low-level
center it is likely that the surface low is indeed closed. Based on
these data, advisories are being initiated on Tropical Storm
Sebastian with an initial advisory intensity of 40 kt.

Sebastien will not be in an ideal environment for significant
intensification, as it will be battling dry air to its west and
about 20 kt of northwesterly shear for the next couple of days.
However, due to the presence of an upper trough to the west of the
system, a diffluent environment aloft may aid in some slight
strengthening over the next day or so. After that time, the
storm will begin to interact with an approaching cold front,
and some additional intensification may occur due to baroclinic
processes. The cyclone is then expected to become absorbed by the
front in about 48 hours. The various intensity guidance solutions
are in decent agreement, and the official forecast is near the mean
of these forecasts. There are some timing variations among the
models on when the cyclone will become absorbed by the front, and it
is possible that the storm could be absorbed sooner than indicated.

The initial motion is 330/07 kt. Sebastien will be steered to
the northwest in the near term around a deep-layer ridge over the
central Atlantic. By Wednesday, the cyclone should turn north, and
then should accelerate northeastward by Wednesday night as the
cyclone gets caught up in the flow between the retreating ridge and
ahead of the approaching cold front. The model guidance is in good
agreement on this scenario, and on the official forecast track the
cyclone will remain over open waters for the duration of its
existence.


FORECAST POSITIONS AND MAX WINDS

INIT  19/1500Z 20.1N  58.7W   40 KT  45 MPH
 12H  20/0000Z 21.0N  59.2W   40 KT  45 MPH
 24H  20/1200Z 22.2N  60.0W   45 KT  50 MPH
 36H  21/0000Z 23.5N  60.0W   45 KT  50 MPH
 48H  21/1200Z 25.5N  58.3W   45 KT  50 MPH...POST-TROP/EXTRATROP
 72H  22/1200Z...DISSIPATED

$$
Forecaster Latto

Tropical Storm Sebastien Wind Speed Probabilities Number 1

Issued at 1500 UTC TUE NOV 19 2019


000
FONT15 KNHC 191500
PWSAT5
                                                                    
TROPICAL STORM SEBASTIEN WIND SPEED PROBABILITIES NUMBER   1        
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL202019               
1500 UTC TUE NOV 19 2019                                            
                                                                    
AT 1500Z THE CENTER OF TROPICAL STORM SEBASTIEN WAS LOCATED NEAR    
LATITUDE 20.1 NORTH...LONGITUDE 58.7 WEST WITH MAXIMUM SUSTAINED    
WINDS NEAR 40 KTS...45 MPH...75 KM/H.                               
                                                                    
Z INDICATES COORDINATED UNIVERSAL TIME (GREENWICH)                  
   ATLANTIC STANDARD TIME (AST)...SUBTRACT 4 HOURS FROM Z TIME      
   EASTERN  DAYLIGHT TIME (EDT)...SUBTRACT 4 HOURS FROM Z TIME      
   CENTRAL  DAYLIGHT TIME (CDT)...SUBTRACT 5 HOURS FROM Z TIME      
                                                                    
WIND SPEED PROBABILITY TABLE FOR SPECIFIC LOCATIONS                 
                                                                    
CHANCES OF SUSTAINED (1-MINUTE AVERAGE) WIND SPEEDS OF AT LEAST     
   ...34 KT (39 MPH... 63 KM/H)...                                  
   ...50 KT (58 MPH... 93 KM/H)...                                  
   ...64 KT (74 MPH...119 KM/H)...                                  
FOR LOCATIONS AND TIME PERIODS DURING THE NEXT 5 DAYS               
                                                                    
PROBABILITIES FOR LOCATIONS ARE GIVEN AS OP(CP) WHERE               
    OP  IS THE PROBABILITY OF THE EVENT BEGINNING DURING            
        AN INDIVIDUAL TIME PERIOD (ONSET PROBABILITY)               
   (CP) IS THE PROBABILITY OF THE EVENT OCCURRING BETWEEN           
        12Z TUE AND THE FORECAST HOUR (CUMULATIVE PROBABILITY)      
                                                                    
PROBABILITIES ARE GIVEN IN PERCENT                                  
X INDICATES PROBABILITIES LESS THAN 1 PERCENT                       
PROBABILITIES FOR 34 KT AND 50 KT ARE SHOWN AT A GIVEN LOCATION WHEN
THE 5-DAY CUMULATIVE PROBABILITY IS AT LEAST 3 PERCENT.             
PROBABILITIES FOR 34...50...64 KT SHOWN WHEN THE 5-DAY              
64-KT CUMULATIVE PROBABILITY IS AT LEAST 1 PERCENT.                 
                                                                    
                                                                    
  - - - - WIND SPEED PROBABILITIES FOR SELECTED LOCATIONS - - - -   
                                                                    
               FROM    FROM    FROM    FROM    FROM    FROM    FROM 
  TIME       12Z TUE 00Z WED 12Z WED 00Z THU 12Z THU 12Z FRI 12Z SAT
PERIODS         TO      TO      TO      TO      TO      TO      TO  
             00Z WED 12Z WED 00Z THU 12Z THU 12Z FRI 12Z SAT 12Z SUN
                                                                    
FORECAST HOUR    (12)   (24)    (36)    (48)    (72)    (96)   (120)
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
LOCATION       KT                                                   
                                                                    
$$                                                                  
FORECASTER LATTO                                                    

Tropical Storm Sebastien Graphics


Tropical Storm Sebastien 5-Day Uncertainty Track Image
5-Day Uncertainty Track last updated Tue, 19 Nov 2019 15:01:57 GMT

Tropical Storm Sebastien 34-Knot Wind Speed Probabilities
Wind Speed Probabilities last updated Tue, 19 Nov 2019 15:24:20 GMT