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Atlantic Tropical Weather Discussion (Text)

000
AXNT20 KNHC 210002
TWDAT 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL 
805 PM EDT SUN APR 20 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2345 UTC.

...ITCZ/MONSOON TROUGH...                                     
THE MONSOON TROUGH EXTENDS ACROSS AFRICA TO THE COAST OF SENEGAL 
AND THE EXTENDS OVER THE E TROPICAL ATLC ALONG 13N16W TO 06N20W. 
THE ITCZ BEGINS NEAR 05N20W AND CONTINUES JUST S OF THE EQUATOR 
ALONG 30W AND 40W TO THE NORTHERN COAST OF BRAZIL NEAR 01S45W. 
SCATTERED MODERATE CONVECTION IS FROM 02S-02N BETWEEN 31W-44W. 

...DISCUSSION...                                                

GULF OF MEXICO...                                               
SURFACE AND UPPER LEVEL RIDGING AS WELL AS DRY AIR SUBSIDENCE 
FROM THE MIDDLE LEVELS DOMINATE ACROSS THE GULF WATERS...THUS 
SUPPORTING STABILITY AND FAIR WEATHER CONDITIONS. THE SURFACE 
RIDGE IS ANCHORED BY A 1021 MB HIGH OFF THE ALABAMA COAST NEAR 
29N87W AND PROVIDES THE GULF WITH N-NE WIND FLOW OF 10-15 KT.  
SURFACE RIDGING IS EXPECTED TO PREVAIL THROUGH WEDNESDAY WITH  
WINDS RANGING FROM 5-15 KT. THE TAIL OF A COLD FRONT ALONG THE 
EASTERN CONUS IS FORECAST TO EXTEND ALONG THE NORTHERN GULF 
COAST TUE EVENING ENHANCING SHOWERS FROM LOUISIANA TO GEORGIA. 

CARIBBEAN SEA...                                                 
A DEEP LAYER CYCLONIC CIRCULATION IS OVER THE WESTERN ATLC 
WATERS CENTERED NEAR 33N75W WITH AN ASSOCIATED TROUGH EXTENDING 
SW TO NORTHERN CUBA. TROUGHINESS ALOFT SUPPORTS A FRONTAL SYSTEM 
ASSOCIATED WITH A 1009 MB LOW NEAR 31N76W. A COLD FRONT EXTENDS 
FROM A TRIPLE POINT SW ACROSS THE CENTRAL BAHAMAS TO CENTRAL 
CUBA NEAR 20N78W WHERE IT TRANSITIONS TO A DISSIPATING 
STATIONARY FRONT TO SAN PEDRO SULA HONDURAS. LOW LEVEL MOISTURE 
CONVERGENCE AHEAD OF THE FRONT IS SUPPORTING A CLUSTER OF 
MODERATE CONVECTION AND TSTMS OVER EASTERN CUBA AND NORTHERN 
ADJACENT WATERS. SHOWERS ARE ALSO NOTED OVER HISPANIOLA WITH 
TSTMS OCCURRING OVER CENTRAL HAITI...THIS ACTIVITY BEING 
ENHANCED BY A WESTWARD MOVING MOIST AIRMASS THAT ENTERED THE 
ISLAND IN THE AFTERNOON. SCATTERED SHOWERS ARE WITHIN 120 NM OF 
THE COAST OF COSTA RICA AND WITHIN 80 NM OFF THE COAST OF 
COLOMBIA. ALOFT...NEARLY WESTERLY FLOW AND DRY AIR DOMINATE THE 
CARIBBEAN WHICH IS SUPPORTING FAIR WEATHER ELSEWHERE. A BROAD 
SURFACE RIDGE COVERING MUCH OF THE ATLC WATERS EXTENDS INTO THE 
NORTHERN CENTRAL AND EASTERN  BASIN THUS INCREASING THE PRESSURE 
GRADIENT TO SUPPORT TRADE WINDS OF 20 KT. A RELAXED PRESSURE 
GRADIENT OVER THE NW AND SW CARIBBEAN SEA SUPPORT LIGHTER E-NE 
WINDS RANGING FROM 5-15 KT. THE STATIONARY BOUNDARY WILL 
CONTINUE TO WEAKEN OVERNIGHT WHILE THE COLD FRONT LIFTS NE OVER 
THE ATLC WATERS. LINGERING MOISTURE IS FORECAST TO ENHANCE 
SHOWERS THE NEXT DAY OR SO.

...HISPANIOLA...                                                
SHOWERS NOTED OVER HISPANIOLA WITH TSTMS OCCURRING OVER CENTRAL 
HAITI...THIS ACTIVITY IS BEING ENHANCED BY A WESTWARD MOVING 
MOIST AIRMASS THAT ENTERED THE ISLAND IN THE AFTERNOON. HIGH 
MOISTURE ASSOCIATED WITH A FRONTAL SYSTEM MOVING ACROSS CENTRAL 
CUBA WILL CONTINUE TO ENHANCE SHOWERS OVER THE ISLAND AND 
ADJACENT WATERS DURING THE NEXT TWO DAYS.

ATLANTIC OCEAN...                                               
A DEEP LAYER CYCLONIC CIRCULATION IS OVER THE WESTERN ATLC 
WATERS CENTERED NEAR 33N75W WITH AN ASSOCIATED TROUGH EXTENDING 
SW TO NORTHERN CUBA. TROUGHINESS ALOFT SUPPORTS A FRONTAL SYSTEM 
ASSOCIATED WITH A 1009 MB LOW NEAR 31N76W. A COLD FRONT EXTENDS 
FROM A TRIPLE POINT ALONG 30N72W TO THE CENTRAL BAHAMAS NEAR 
24N75W TO CENTRAL CUBA NEAR 20N78W WHERE IT TRANSITIONS TO A 
DISSIPATING STATIONARY OVER THE NW CARIBBEAN. BEHIND THE 
FRONT...A SURFACE TROUGH EXTENDS FROM 31N74W TO W FREEPORT WITH 
NO CONVECTION ASSOCIATED WITH IT. AHEAD OF THE FRONT...A SQUALL 
LINE EXTENDS FROM 29N69W TO 24N73W. SATELLITE IMAGERY AND 
LIGHTING DATA INDICATE THERE ARE SHOWERS AND TSTMS WITHIN 240 NM 
E OF THE SQUALL LINE N OF 24N. BOTH LOW LEVEL MOISTURE 
CONVERGENCE AND UPPER LEVEL DIFFLUENCE SUPPORT THIS CONVECTION.  
THE LOW WILL CONTINUE TO SHIFT NE AND THE ASSOCIATED COLD FRONT 
WILL CONTINUE TO DRIFT EASTWARD ACROSS THE ATLC THROUGH WED 
MORNING. OTHERWISE...THE REMAINDER OF THE ATLC IS DOMINATED BY A 
SURFACE RIDGE ANCHORED BY A 1025 MB HIGH NEAR 29N45W WHICH IS 
EXPECTED TO DRIFT SW BY MON AFTERNOON. FAIR WEATHER IS OVER THE 
CENTRAL AND EASTERN ATLC BEING SUPPORTED BY DRY AIR SUBSIDENCE 
FROM THE MIDDLE LEVELS. 

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

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NR