Tuesday, June 20, 2023

Tropical Storm Bret Expected to Affect Lesser Antilles on Thursday




Latest trends suggest it will stay at tropical storm strength and then actually weaken to a depression again over water, maybe even dissipate. I'd still keep an eye on it, but for now, it looks like it is not strengthening as rapidly as before, and like that upper-level trough will weaken it after it crosses the Lesser Antilles.  

As far as our local weather, forecast looks on track, High near 80 for next couple days, Low in mid-60's, about a 40-50% chance of rain and thunderstorms, not an all-day washout. 

Then storms become more isolated as we get into the weekend, more typical summer conditions, High in the lower 80's for Friday, upper 80's for Saturday. 

And that looks like the pattern for next week, only a minimal chance of an isolated shower or thunderstorm here and there, mix of sun and clouds, Highs climbing up close to 90 most days. Lows should be in upper 60's. Monday might see a slight increase in rain chances, but most people probably will not notice it, weak frontal boundary may pass through the region with minimal impact. Back to the seasonal High near 90, Low near 70, 20% chance of rain by Tuesday. 

000

WTNT33 KNHC 210236

TCPAT3


BULLETIN

Tropical Storm Bret Advisory Number   7

NWS National Hurricane Center Miami FL       AL032023

1100 PM AST Tue Jun 20 2023


...BRET STRENGTHENS A LITTLE MORE....


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION

-----------------------------------------------

LOCATION...12.5N 50.2W

ABOUT 730 MI...1170 KM E OF THE WINDWARD ISLANDS

MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H

PRESENT MOVEMENT...W OR 280 DEGREES AT 17 MPH...28 KM/H

MINIMUM CENTRAL PRESSURE...1003 MB...29.62 INCHES



WATCHES AND WARNINGS

--------------------

CHANGES WITH THIS ADVISORY:


None.


SUMMARY OF WATCHES AND WARNINGS IN EFFECT:


A Tropical Storm Watch is in effect for...

* Barbados

* Dominica

* Martinique

* St. Lucia


A Tropical Storm Watch means that tropical storm conditions are

possible within the watch area, generally within 48 hours.


Interests elsewhere in the Lesser Antilles should monitor the

progress of Bret.  Additional tropical storm watches or warnings

will likely be required for these and other islands on Wednesday.


For storm information specific to your area, please monitor

products issued by your national meteorological service.



DISCUSSION AND OUTLOOK

----------------------

At 1100 PM AST (0300 UTC), the center of Tropical Storm Bret was

located near latitude 12.5 North, longitude 50.2 West. Bret is

moving toward the west near 17 mph (28 km/h), and this general

motion is expected to continue for the next several days.  On the

forecast track, the center of Bret is expected move across portions

of the Lesser Antilles Thursday afternoon and Thursday night, and

then move across the eastern Caribbean Sea on Friday.


Maximum sustained winds have increased to near 50 mph (85 km/h) 

with higher gusts.  Some additional strengthening is forecast during 

the next day or so, and Bret is expected to be a tropical storm 

when it reaches the Lesser Antilles Thursday and Thursday night.


Tropical-storm-force winds extend outward up to 45 miles (75 km)

from the center.


The estimated minimum central pressure is 1003 mb (29.62 inches).



HAZARDS AFFECTING LAND

----------------------

Key messages for Bret can be found in the Tropical Cyclone

Discussion under AWIPS header MIATCDAT3, WMO header WTNT43 KNHC and

on the web at hurricanes.gov/text/MIATCDAT3.shtml


WIND:  Tropical storm conditions are possible within the watch

area by Thursday.


RAINFALL:  Through Saturday, storm total rainfall amounts of 3 to 6

inches with maximum amounts of 10 inches possible across portions of

the Lesser Antilles from Guadeloupe south to St Vincent and the

Grenadines, including Barbados.  The heavy rainfall could lead to

flash flooding, especially across areas of higher terrain.  Isolated

urban flooding is also possible.



NEXT ADVISORY

-------------

Next intermediate advisory at 200 AM AST.

Next complete advisory at 500 AM AST.


$$

Forecaster Beven


589 

WTNT23 KNHC 210235

TCMAT3


TROPICAL STORM BRET FORECAST/ADVISORY NUMBER   7

NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032023

0300 UTC WED JUN 21 2023


NOTICE... LAND-BASED TROPICAL CYCLONE WATCHES AND WARNINGS ARE NO

LONGER INCLUDED IN THE TROPICAL CYCLONE FORECAST/ADVISORY...(TCM).

CURRENT LAND-BASED COASTAL WATCHES AND WARNINGS CAN BE FOUND IN THE

MOST RECENTLY ISSUED TROPICAL CYCLONE PUBLIC ADVISORY...(TCP).


TROPICAL STORM CENTER LOCATED NEAR 12.5N  50.2W AT 21/0300Z

POSITION ACCURATE WITHIN  20 NM


PRESENT MOVEMENT TOWARD THE WEST OR 280 DEGREES AT  15 KT


ESTIMATED MINIMUM CENTRAL PRESSURE 1003 MB

MAX SUSTAINED WINDS  45 KT WITH GUSTS TO  55 KT.

34 KT....... 40NE  30SE   0SW  40NW.

12 FT SEAS.. 60NE  30SE   0SW  60NW.

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 12.5N  50.2W AT 21/0300Z

AT 21/0000Z CENTER WAS LOCATED NEAR 12.4N  49.5W


FORECAST VALID 21/1200Z 12.9N  52.3W

MAX WIND  50 KT...GUSTS  60 KT.

50 KT... 20NE   0SE   0SW   0NW.

34 KT... 80NE  40SE   0SW  60NW.


FORECAST VALID 22/0000Z 13.3N  54.7W

MAX WIND  55 KT...GUSTS  65 KT.

50 KT... 30NE   0SE   0SW  30NW.

34 KT... 90NE  50SE  10SW  70NW.


FORECAST VALID 22/1200Z 13.7N  57.5W

MAX WIND  55 KT...GUSTS  65 KT.

50 KT... 30NE   0SE   0SW  30NW.

34 KT... 90NE  50SE  20SW  70NW.


FORECAST VALID 23/0000Z 14.0N  60.6W

MAX WIND  55 KT...GUSTS  65 KT.

50 KT... 30NE   0SE   0SW  30NW.

34 KT... 90NE  50SE  30SW  70NW.


FORECAST VALID 23/1200Z 14.3N  63.9W

MAX WIND  50 KT...GUSTS  60 KT.

50 KT... 30NE   0SE   0SW  30NW.

34 KT...100NE  50SE  40SW  80NW.


FORECAST VALID 24/0000Z 14.6N  67.6W

MAX WIND  45 KT...GUSTS  55 KT.

34 KT... 90NE  50SE  40SW  70NW.


EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 125 NM

ON DAY 4 AND 175 NM ON DAY 5...AND FOR INTENSITY NEAR 15 KT EACH DAY


OUTLOOK VALID 25/0000Z 15.0N  75.0W

MAX WIND  30 KT...GUSTS  40 KT.


OUTLOOK VALID 26/0000Z...DISSIPATED


REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 12.5N  50.2W


INTERMEDIATE PUBLIC ADVISORY...WTNT33 KNHC/MIATCPAT3...AT 21/0600Z


NEXT ADVISORY AT 21/0900Z


$$

FORECASTER BEVEN


000

FONT13 KNHC 210236

PWSAT3


TROPICAL STORM BRET WIND SPEED PROBABILITIES NUMBER   7             

NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032023               

0300 UTC WED JUN 21 2023                                            


AT 0300Z THE CENTER OF TROPICAL STORM BRET WAS LOCATED NEAR LATITUDE

12.5 NORTH...LONGITUDE 50.2 WEST WITH MAXIMUM SUSTAINED WINDS NEAR  

45 KTS...50 MPH...85 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           

        00Z WED 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       00Z WED 12Z WED 00Z THU 12Z THU 00Z FRI 00Z SAT 00Z SUN

PERIODS         TO      TO      TO      TO      TO      TO      TO  

             12Z WED 00Z THU 12Z THU 00Z FRI 00Z SAT 00Z SUN 00Z MON


FORECAST HOUR    (12)   (24)    (36)    (48)    (72)    (96)   (120)

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 

LOCATION       KT                                                   


PT GALLINAS    34  X   X( X)   X( X)   X( X)   1( 1)   3( 4)   X( 4)


CURACAO        34  X   X( X)   X( X)   X( X)   2( 2)   1( 3)   X( 3)


CAPE BEATA     34  X   X( X)   X( X)   X( X)   1( 1)   3( 4)   X( 4)


PONCE PR       34  X   X( X)   X( X)   X( X)   3( 3)   1( 4)   X( 4)


AGUADILLA PR   34  X   X( X)   X( X)   X( X)   2( 2)   1( 3)   X( 3)


VIEQUES PR     34  X   X( X)   X( X)   X( X)   3( 3)   1( 4)   X( 4)


SAINT THOMAS   34  X   X( X)   X( X)   X( X)   3( 3)   1( 4)   X( 4)


SAINT JOHN     34  X   X( X)   X( X)   X( X)   3( 3)   X( 3)   X( 3)


SAINT CROIX    34  X   X( X)   X( X)   X( X)   5( 5)   X( 5)   X( 5)


SAINT MAARTEN  34  X   X( X)   X( X)   1( 1)   3( 4)   X( 4)   X( 4)


SABA           34  X   X( X)   X( X)   1( 1)   4( 5)   X( 5)   X( 5)


ST EUSTATIUS   34  X   X( X)   X( X)   2( 2)   3( 5)   X( 5)   X( 5)


ST KITTS-NEVIS 34  X   X( X)   X( X)   2( 2)   4( 6)   X( 6)   X( 6)


BARBUDA        34  X   X( X)   X( X)   2( 2)   3( 5)   X( 5)   X( 5)


GUADELOUPE     34  X   X( X)   1( 1)   6( 7)   5(12)   X(12)   X(12)


AVES           34  X   X( X)   X( X)   3( 3)  20(23)   X(23)   X(23)

AVES           50  X   X( X)   X( X)   X( X)   4( 4)   X( 4)   X( 4)


DOMINICA       34  X   X( X)   1( 1)  20(21)  11(32)   X(32)   X(32)

DOMINICA       50  X   X( X)   X( X)   3( 3)   3( 6)   X( 6)   X( 6)


MARTINIQUE     34  X   X( X)   X( X)  20(20)  10(30)   X(30)   X(30)

MARTINIQUE     50  X   X( X)   X( X)   2( 2)   1( 3)   X( 3)   X( 3)


SAINT LUCIA    34  X   X( X)   2( 2)  31(33)  11(44)   X(44)   X(44)

SAINT LUCIA    50  X   X( X)   X( X)   8( 8)   4(12)   X(12)   X(12)

SAINT LUCIA    64  X   X( X)   X( X)   1( 1)   1( 2)   X( 2)   X( 2)


SAINT VINCENT  34  X   X( X)   1( 1)  14(15)   9(24)   X(24)   X(24)

SAINT VINCENT  50  X   X( X)   X( X)   3( 3)   2( 5)   X( 5)   X( 5)


BARBADOS       34  X   X( X)   4( 4)  24(28)   1(29)   X(29)   X(29)

BARBADOS       50  X   X( X)   X( X)   7( 7)   X( 7)   X( 7)   X( 7)

BARBADOS       64  X   X( X)   X( X)   1( 1)   X( 1)   X( 1)   X( 1)


GRENADA        34  X   X( X)   X( X)   2( 2)   3( 5)   X( 5)   X( 5)


$$                                                                  

FORECASTER BEVEN


000

WTNT43 KNHC 210236

TCDAT3


Tropical Storm Bret Discussion Number   7

NWS National Hurricane Center Miami FL       AL032023

1100 PM AST Tue Jun 20 2023


Bret has become a little better organized this evening, with 

increased convection near and north of the center and some outer 

bands developing in the eastern semicircle.  This development has 

lead to satellite intensity estimates from TAFB and SAB increasing 

to 45 kt, and that will be the initial intensity for this advisory. 

Unfortunately, the ASCAT overpasses this evening again managed to 

miss Bret.


Satellite imagery continues to suggest some vertical wind shear is 

undercutting Bret's otherwise favorable looking outflow pattern and 

slowing the rate of intensification.  This shear is expected to 

continue for the next 36 h or so, and the storm is forecast to 

continue to slowly strengthen during this time. The new intensity 

forecast calls for Bret to have a 55-kt intensity when it passes 

near or over the Lesser Antilles around the 48-h point.   After 

that, stronger shear associated with an upper-level trough over the 

eastern Caribbean should stop intensification and cause Bret to 

weaken.  Indeed, the global models continue to forecast the system 

to degenerate to a tropical wave by 96 h.  The new intensity 

forecast will continue to have a 96 h point followed by dissipation 

before 120 h.  However, it will show a faster weakening from 72-96 h 

than the previous forecast.


The initial motion is westward or 280/15 kt.  There is again little 

change to either the track forecast guidance or the track forecast 

since the last advisory, with low- to mid-level ridging north of 

Bret expected to steer the cyclone westward through dissipation. 

Users are reminded that NHC's track forecasts have average errors 

of about 60 n mi at 48 hours, and it is too soon to know exactly 

where Bret's center will move across the Lesser Antilles chain.



KEY MESSAGES:


1. Bret is forecast to approach the Lesser Antilles through

Thursday morning and then move across the islands Thursday

afternoon and Thursday night as a tropical storm, bringing a risk of

flooding from heavy rainfall, strong winds, and dangerous waves

along the coast.


2. Given the uncertainty in the track and intensity forecasts, it

is too early to specify the location and magnitude of where Bret's

associated hazards could occur.  A Tropical Storm Watch has been

issued for Barbados, Dominica, Martinique, and St. Lucia, and 

additional watches and warnings are likely for these and other 

islands in the Lesser Antilles on Wednesday.



FORECAST POSITIONS AND MAX WINDS


INIT  21/0300Z 12.5N  50.2W   45 KT  50 MPH

 12H  21/1200Z 12.9N  52.3W   50 KT  60 MPH

 24H  22/0000Z 13.3N  54.7W   55 KT  65 MPH

 36H  22/1200Z 13.7N  57.5W   55 KT  65 MPH

 48H  23/0000Z 14.0N  60.6W   55 KT  65 MPH

 60H  23/1200Z 14.3N  63.9W   50 KT  60 MPH

 72H  24/0000Z 14.6N  67.6W   45 KT  50 MPH

 96H  25/0000Z 15.0N  75.0W   30 KT  35 MPH

120H  26/0000Z...DISSIPATED


$$

Forecaster Beven

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