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Atlantic Tropical Weather Discussion (Text)

000
AXNT20 KNHC 290559
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT TUE JUL 29 2014

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL  
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF 
SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE 
EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE 
IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL 
ANALYSIS.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0545 UTC.

...SPECIAL FEATURE...                                   

A DISTURBANCE OVER THE CENTRAL TROPICAL ATLANTIC HAS BECOME 
BETTER ORGANIZED DURING THE PAST SEVERAL HOURS. THE SYSTEM IS 
ASSOCIATED WITH A 1010 MB LOW EMBEDDED IN THE MONSOON TROUGH 
NEAR 9N35W. RAINBANDS OF SCATTERED MODERATE CONVECTION ARE FROM 
5N-14N BETWEEN 31W-42W. THERE IS A MEDIUM CHANCE OF FURTHER 
DEVELOPMENT OF THIS DISTURBANCE WITHIN 48 HOURS. SEE THE LATEST 
NHC TROPICAL WEATHER OUTLOOK UNDER AWIPS/WMO HEADERS 
MIATWOAT/ABNT20 KNHC FOR MORE DETAILS.

...TROPICAL WAVES... 

A TROPICAL WAVE CAME OFF THE WEST AFRICAN COAST MONDAY EVENING. 
ITS AXIS IS CURRENTLY NEAR 18W OR ABOUT 250 NM E OF THE CAPE 
VERDE ISLANDS. THE NORTHERN ENVIRONMENT OF THE WAVE IS EMBEDDED 
IN THE DRY SAHARAN AIR LAYER WHILE S OF 13N THE WAVE IS 
ASSOCIATED WITH DEEP LAYER MOISTURE. A CLUSTER OF MODERATE 
CONVECTION AND ISOLATED TSTMS IS IN THE SOUTHERN WAVE 
ENVIRONMENT FROM 5N-10N BETWEEN 17W-23W. SCATTERED MODERATE 
CONVECTION IS ELSEWHERE FROM 5N-10N BETWEEN 14W-23W.

A TROPICAL WAVE IS W-NW OF AN AREA OF DISTURBED WEATHER OVER THE 
CENTRAL ATLC. THE AXIS OF THE WAVE EXTENDS FROM 17N41W TO 8N39W 
MOVING W AT 10 KT DURING THE PAST 24 HOURS. MOST OF THE WAVE 
ENVIRONMENT IS IN THE DRY SAHARAN AIR LAYER WHICH IS HINDERING 
THE DEVELOPMENT OF DEEP CONVECTION. 

...ITCZ/MONSOON TROUGH...                                     

MONSOON TROUGH EXTENDS FROM THE COAST OF WEST AFRICA NEAR 10N15W 
TO 8N21W 8N29W TO A 1010 MB LOW NEAR 9N35W TO 6N42W. THE 
INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 6N42W TO THE 
COAST OF N-NE SOUTH AMERICA NEAR 5N52W. AREAS OF CONVECTION ARE 
ASSOCIATED WITH TROPICAL WAVES. SEE THE SECTIONS ON TROPICAL 
WAVES AND SPECIAL FEATURES FOR DETAILS.

...DISCUSSION...

GULF OF MEXICO...                                               

A BROAD MID-UPPER LEVEL TROUGH EXTENDS ACROSS THE EASTERN CONUS 
SUPPORTING A STATIONARY FRONT THAT EXTENDS FROM A 1008 MB LOW 
OVER SOUTH CAROLINA SW ACROSS CENTRAL GEORGIA TO LOUISIANA TO 
TEXAS. A PRE-FRONTAL TROUGH IS OVER THE NE BASIN EXTENDING FROM 
31N83W TO 29N88W AND SUPPORTING SCATTERED SHOWERS AND TSTMS N OF 
27N E OF 90W. OVER THE SW GULF...A CLUSTER OF MODERATE 
CONVECTION AND TSTMS IS S OF 21N E OF 95W ASSOCIATED WITH THE 
NORTHERN PORTION OF A TROPICAL WAVE MOVING INTO E PACIFIC 
WATERS. THE REST OF THE GULF IS BEING INFLUENCED BY RIDGING 
ALOFT WHICH IS SUPPORTING A 1019 MB HIGH NEAR 26N92W. DRY AIR 
SUBSIDENCE FROM ALOFT ALONG WITH SURFACE HIGH PRESSURE PROVIDE A 
GENERAL STABLE ENVIRONMENT THAT SUPPORT FAIR WEATHER ELSEWHERE 
IN THE GULF. VARIABLE WINDS OF 5-15 KT PREVAILS ACROSS THE GULF 
N OF 21N WHILE WINDS UP TO 20 KT ARE OVER THE BAY OF CAMPECHE IN 
ASSOCIATION WITH THE TROPICAL WAVE. THE STATIONARY FRONT WILL 
TRANSITION TO A COLD FRONT LATER THIS MORNING AND MOVE INTO THE 
NE GULF WHERE IT IS EXPECTED TO TRANSITION BACK INTO A 
STATIONARY FRONT LATER DURING THE DAY. THE FRONTAL SYSTEM IS 
EXPECTED TO DISSIPATE OVER THE EASTERN GULF WED MORNING. SURFACE 
RIDGING WILL PREVAIL ELSEWHERE DURING THIS PERIOD.

CARIBBEAN SEA...                                               

WITH THE EXCEPTION TO THE FAR WESTERN AND SW CARIBBEAN...LOWER 
TO MIDDLE LEVEL DRY AIR DOMINATES ACROSS THE REGION ALONG WITH 
STRONG DEEP LAYER ENVIRONMENTAL WIND SHEAR. THESE TWO FACTORS 
PROVIDE OVERALL STABILITY...THUS SUPPORTING CLEAR SKIES. A 
DIFFLUENT ENVIRONMENT ALOFT OVER THE GREATER ANTILLES ALONG WITH 
PATCHES OF LOW-LEVEL MOISTURE SUPPORT SHOWERS AND TSTMS OVER 
COASTAL WATERS OF WESTERN CUBA N OF 21N...SCATTERED SHOWERS OVER 
CENTRAL AND WESTERN HISPANIOLA AND PASSING SHOWERS OVER EASTERN 
PUERTO RICO. CLOUDINESS AS WELL AS ISOLATED SHOWERS AND TSTMS 
ASSOCIATED WITH THE PASSAGE OF A TROPICAL WAVE ARE ALONG CENTRAL 
AMERICA COASTAL WATERS N OF 9N W OF 81W. OTHERWISE...A CONTINUAL 
TIGHT PRESSURE GRADIENT BETWEEN A LOW OVER NORTHERN COLOMBIA AND 
HIGH PRESSURE FROM THE ATLC EXTENDING INTO THE CARIBBEAN SUPPORT 
TRADES OF 20-25 KT S OF 17N BETWEEN 66W-82W WITH NEAR GALE FORCE 
WINDS ALONG THE COAST OF COLOMBIA. A TROPICAL WAVE IS EXPECTED 
TO ENTER THE EASTERN CARIBBEAN THU MORNING AHEAD OF A POSSIBLE 
TROPICAL CYCLONE. SEE THE SPECIAL FEATURES SECTION FOR MORE 
DETAILS.

...HISPANIOLA...                                                 

CURRENTLY...A DIFFLUENT ENVIRONMENT ALOFT SUPPORTS CLOUDINESS 
AND POSSIBLE ISOLATED SHOWERS ACROSS HAITI AND WESTERN DOMINICAN 
REPUBLIC. MOSTLY FAIR WEATHER IS FORECAST FOR TUE...HOWEVER 
MODEL GUIDANCE PREDICTS SHOWERS ACROSS PORTIONS OF THE ISLAND 
MOST OF THE DAY WEDNESDAY.

ATLANTIC OCEAN...                                               

A MID-UPPER LEVEL TROUGH OVER THE EASTERN CONUS ALONG WITH THE 
SE PERIPHERY OF A RIDGE GENERATE A DIFFLUENT ENVIRONMENT ALOFT 
OVER THE SW N ATLC WATERS WHICH ALONG MODERATE DEEP LAYER 
MOISTURE IN THE REGION SUPPORT SHOWERS AND TSTMS NW OF FREEPORT 
FROM 26N-29N BETWEEN 77W-80W. OVER THE E ATLC...A MID-UPPER 
LEVEL LOW N OF THE AREA CONTINUE TO SUPPORT A SURFACE TROUGH 
FROM 30N27W TO 27N28W WITH NO CONVECTION ASSOCIATED WITH IT. THE 
REMAINDER BASIN IS FAIRLY DRY AND UNDER THE INFLUENCE OF SURFACE 
RIDGING ANCHORED BY A 1026 MB HIGH NEAR 33N53W. THESE TWO 
FACTORS SUPPORTS FAIR WEATHER ELSEWHERE IN THE BASIN. 
OTHERWISE...SEE ABOVE THE SPECIAL FEATURES AND TROPICAL WAVES 
SECTIONS. SURFACE RIDGING WILL DOMINATE ACROSS THE CENTRAL AND 
EASTERN ATLC THE TUE AND WED. A FRONTAL BOUNDARY IS EXPECTED TO 
MOVE ACROSS THE SW N ATLC TODAY THROUGH THU MORNING. ANOTHER 
FRONTAL SYSTEM IS EXPECTED TO SINK INTO THE NORTHERN CENTRAL 
ATLC BY EARLY THU.

FOR ADDITIONAL INFORMATION PLEASE VISIT 
WWW.HURRICANES.GOV/MARINE

$$
RAMOS