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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 HTTP://WWW.HURRICANES.GOV/MARINE

$$ NR

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