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000
ABNT20 KNHC 271138
TWOAT

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
800 AM EDT SAT AUG 27 2016

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

The National Hurricane Center is issuing advisories on Tropical
Storm Gaston, located about 800 miles east-southeast of Bermuda.

A weak area of low pressure located south of Andros Island in the
Bahamas continues to produce disorganized showers and thunderstorms
mainly to the south and east of its center. Upper-level winds are
not conducive for significant development during the next day or so
while the low moves west-northwestward through the Straits of
Florida at about 10 mph. Environmental conditions could become a
little more conducive for some development when the system moves
across the eastern Gulf of Mexico next week. Heavy rains are likely
to continue over portions of eastern and central Cuba today. Gusty
winds and locally heavy rainfall are likely over portions of the
Bahamas, and will spread into parts of southern Florida and the
Florida Keys later this weekend. Interests elsewhere in Florida and
the eastern Gulf of Mexico should continue to monitor the progress
of this disturbance.
* Formation chance through 48 hours...low...20 percent
* Formation chance through 5 days...medium...40 percent

A weak trough of low pressure located about a hundred miles south of
the coast of southwestern Louisiana is producing disorganized shower
and thunderstorm activity over the north-central Gulf of Mexico.
Conditions are not expected to be conducive for development before
this system reaches the coast of Texas on Sunday. However, heavy
rainfall is possible along the Gulf Coast from Louisiana to
southeastern Texas during the next few days. For additional
information, please see products from your local National Weather
Service office.
* Formation chance through 48 hours...low...10 percent
* Formation chance through 5 days...low...10 percent

An area of low pressure centered about 130 miles southwest of
Bermuda is producing winds of around 35 mph. While shower and
thunderstorm activity has increased a little near the center during
the past few hours, any significant development of this system is
likely to be slow to occur due the proximity of dry air. This low
is expected to move westward and then west-northwestward at about 10
mph toward the coast of the Carolinas during the next few days. For
additional information on this system, see High Seas Forecasts
issued by the National Weather Service.
* Formation chance through 48 hours...low...30 percent
* Formation chance through 5 days...low...30 percent

&&

High Seas Forecasts issued by the National Weather Service can be
found under AWIPS header NFDHSFAT1, WMO header FZNT01 KWBC, and
on the Web at http://www.opc.ncep.noaa.gov/shtml/NFDHSFAT1.shtml.

$$
Forecaster Brennan

Summary for Tropical Storm GASTON (AT2/AL072016)

...GASTON EXPECTED TO STRENGTHEN TODAY...
 As of 5:00 AM AST Sat Aug 27
 the center of GASTON was located near 27.9, -52.0
 with movement NW at 15 mph.
 The minimum central pressure was 995 mb
 with maximum sustained winds of about 65 mph.

Tropical Storm GASTON Public Advisory Number 19

Issued at 500 AM AST SAT AUG 27 2016  

000
WTNT32 KNHC 270852
TCPAT2

BULLETIN
TROPICAL STORM GASTON ADVISORY NUMBER  19
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL072016
500 AM AST SAT AUG 27 2016

...GASTON EXPECTED TO STRENGTHEN TODAY...


SUMMARY OF 500 AM AST...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...27.9N 52.0W
ABOUT 820 MI...1325 KM ESE OF BERMUDA
MAXIMUM SUSTAINED WINDS...65 MPH...100 KM/H
PRESENT MOVEMENT...NW OR 310 DEGREES AT 15 MPH...24 KM/H
MINIMUM CENTRAL PRESSURE...995 MB...29.39 INCHES


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


DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
At 500 AM AST (0900 UTC), the center of Tropical Storm Gaston was
located near latitude 27.9 North, longitude 52.0 West.  Gaston is
moving toward the northwest near 15 mph (24 km/h).  A northwestward
heading with a decrease in forward speed is expected during the
next couple of days.

Maximum sustained winds are near 65 mph (100 km/h) with higher
gusts.  Strengthening is forecast during the next 48 hours, and
Gaston is expected to become a hurricane by tonight.

Tropical-storm-force winds extend outward up to 150 miles (240 km)
from the center.

The estimated minimum central pressure based on data from the
NASA/NOAA Global Hawk aircraft is 995 mb (29.39 inches).


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


NEXT ADVISORY
-------------
Next complete advisory at 1100 AM AST.

$$
Forecaster Berg


Tropical Storm GASTON Forecast Advisory Number 19

Issued at 0900 UTC SAT AUG 27 2016  

000
WTNT22 KNHC 270852
TCMAT2
 
TROPICAL STORM GASTON FORECAST/ADVISORY NUMBER  19
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL072016
0900 UTC SAT AUG 27 2016
 
THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.
 
TROPICAL STORM CENTER LOCATED NEAR 27.9N  52.0W AT 27/0900Z
POSITION ACCURATE WITHIN  15 NM
 
PRESENT MOVEMENT TOWARD THE NORTHWEST OR 310 DEGREES AT  13 KT
 
ESTIMATED MINIMUM CENTRAL PRESSURE  995 MB
MAX SUSTAINED WINDS  55 KT WITH GUSTS TO  65 KT.
50 KT....... 50NE  30SE   0SW  30NW.
34 KT.......130NE  80SE  40SW 100NW.
12 FT SEAS..240NE 120SE 150SW 180NW.
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 27.9N  52.0W AT 27/0900Z
AT 27/0600Z CENTER WAS LOCATED NEAR 27.6N  51.5W
 
FORECAST VALID 27/1800Z 28.8N  53.6W
MAX WIND  60 KT...GUSTS  75 KT.
50 KT... 60NE  40SE  20SW  40NW.
34 KT...130NE  90SE  60SW 100NW.
 
FORECAST VALID 28/0600Z 29.9N  55.0W
MAX WIND  70 KT...GUSTS  85 KT.
64 KT... 30NE  20SE   0SW  20NW.
50 KT... 60NE  50SE  40SW  50NW.
34 KT...130NE 110SE  80SW 100NW.
 
FORECAST VALID 28/1800Z 30.6N  56.0W
MAX WIND  80 KT...GUSTS 100 KT.
64 KT... 35NE  30SE  20SW  30NW.
50 KT... 70NE  60SE  50SW  50NW.
34 KT...140NE 120SE  90SW 110NW.
 
FORECAST VALID 29/0600Z 31.2N  56.8W
MAX WIND  85 KT...GUSTS 105 KT.
50 KT... 70NE  70SE  50SW  60NW.
34 KT...140NE 130SE 100SW 110NW.
 
FORECAST VALID 30/0600Z 32.5N  55.6W
MAX WIND  90 KT...GUSTS 110 KT.
50 KT... 80NE  80SE  70SW  60NW.
34 KT...140NE 150SE 120SW 110NW.
 
EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 150 NM
ON DAY 4 AND 200 NM ON DAY 5...AND FOR INTENSITY NEAR 15 KT EACH DAY
 
OUTLOOK VALID 31/0600Z 34.5N  50.5W
MAX WIND  85 KT...GUSTS 105 KT.
 
OUTLOOK VALID 01/0600Z 37.0N  43.5W
MAX WIND  75 KT...GUSTS  90 KT.
 
REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 27.9N  52.0W
 
NEXT ADVISORY AT 27/1500Z
 
$$
FORECASTER BERG
 
 

Tropical Storm GASTON Forecast Discussion Number 19

Issued at 500 AM AST SAT AUG 27 2016  

000
WTNT42 KNHC 270853
TCDAT2

TROPICAL STORM GASTON DISCUSSION NUMBER  19
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL072016
500 AM AST SAT AUG 27 2016

Recent microwave data indicate that Gaston's center is now well
embedded near the middle of the central dense overcast.  The
microwave images also show that a partial mid-level ring has formed,
but it remains open to the north-northeast.  Even though Gaston's
structure appears to be improving, the maximum winds remain 55 kt
based on Dvorak Current Intensity numbers from TAFB and SAB.

Two outflow jets are emanating away to the east and southwest of
Gaston, but the outflow remains restricted to the south and
northwest.  Still, the shear has decreased substantially from what
it was a day or two ago, and it should remain generally low for the
next 48 hours.  In addition, sea surface temperatures ahead of
Gaston are expected to be at least 28C for several more days.
Therefore, strengthening is anticipated through day 3, followed by
gradual weakening on days 4 and 5 due to increasing westerly shear.
Although the intensity models all agree on this general scenario,
there is a little more spread in the peak intensities than has been
noted in previous advisories.  On the high end, the Florida State
Superensemble still shows Gaston approaching major hurricane
intensity, while the LGEM model is at the other extreme being about
20 kt lower.  The updated NHC intensity forecast is near the middle
of the guidance and ends up just a little lower than the previous
forecast.

Gaston is moving northwestward, or 310 degrees at 13 kt, between a
mid-tropospheric high to its northeast and a mid-/upper-level low
to its southwest.  The cyclone is expected to maintain a
northwestward heading but steadily decelerate during the next 48
hours.  After that time, Gaston should recurve sharply
east-northeastward and accelerate through the end of the forecast
period as it gets picked up by the mid-latitude westerlies.  The
track guidance has trended westward through 48 hours, delaying
Gaston's recurvature just a bit, and it is then a little faster by
days 4 and 5.  The NHC track forecast has been adjusted accordingly
and is close to the TVCN multi-model consensus.

FORECAST POSITIONS AND MAX WINDS

INIT  27/0900Z 27.9N  52.0W   55 KT  65 MPH
 12H  27/1800Z 28.8N  53.6W   60 KT  70 MPH
 24H  28/0600Z 29.9N  55.0W   70 KT  80 MPH
 36H  28/1800Z 30.6N  56.0W   80 KT  90 MPH
 48H  29/0600Z 31.2N  56.8W   85 KT 100 MPH
 72H  30/0600Z 32.5N  55.6W   90 KT 105 MPH
 96H  31/0600Z 34.5N  50.5W   85 KT 100 MPH
120H  01/0600Z 37.0N  43.5W   75 KT  85 MPH

$$
Forecaster Berg


Tropical Storm GASTON Wind Speed Probabilities Number 19

Issued at 0900 UTC SAT AUG 27 2016


000
FONT12 KNHC 270852
PWSAT2
                                                                    
TROPICAL STORM GASTON WIND SPEED PROBABILITIES NUMBER  19           
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL072016               
0900 UTC SAT AUG 27 2016                                            
                                                                    
AT 0900Z THE CENTER OF TROPICAL STORM GASTON WAS LOCATED NEAR       
LATITUDE 27.9 NORTH...LONGITUDE 52.0 WEST WITH MAXIMUM SUSTAINED    
WINDS NEAR 55 KTS...65 MPH...100 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           
        06Z SAT 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 64 KT ARE SHOWN WHEN THE 5-DAY CUMULATIVE         
PROBABILITY IS AT LEAST 1 PERCENT.                                  
                                                                    
                                                                    
  - - - - WIND SPEED PROBABILITIES FOR SELECTED LOCATIONS - - - -   
                                                                    
               FROM    FROM    FROM    FROM    FROM    FROM    FROM 
  TIME       06Z SAT 18Z SAT 06Z SUN 18Z SUN 06Z MON 06Z TUE 06Z WED
PERIODS         TO      TO      TO      TO      TO      TO      TO  
             18Z SAT 06Z SUN 18Z SUN 06Z MON 06Z TUE 06Z WED 06Z THU
                                                                    
FORECAST HOUR    (12)   (24)    (36)    (48)    (72)    (96)   (120)
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
LOCATION       KT                                                   
                                                                    
SANTA CRUZ AZO 34  X   X( X)   X( X)   X( X)   X( X)   X( X)   3( 3)
 
$$                                                                  
FORECASTER BERG                                                     

Tropical Storm GASTON Graphics


Tropical Storm GASTON 5-Day Uncertainty Track Image
5-Day Uncertainty Track last updated Sat, 27 Aug 2016 08:53:47 GMT

Tropical Storm GASTON 34-Knot Wind Speed Probabilities
Wind Speed Probabilities last updated Sat, 27 Aug 2016 09:06:38 GMT
LightningRing