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Atlantic Tropical Weather Discussion (Text)

000
AXNT20 KNHC 200004
TWDAT 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL 
805 PM EDT SAT APR 19 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.

...SPECIAL FEATURE...                                           
N-NE GALE FORCE WINDS ARE FORECAST TO BEGIN SUN MORNING ON THE 
SW N ATLANTIC WATERS N OF 29N BETWEEN 20 AND 60 NM OF SHORE 
ASSOCIATED WITH A FRONTAL SYSTEM. GALE WINDS ARE EXPECTED TO 
SUBSIDE BY SUN AFTERNOON. PLEASE SEE THE HIGH SEAS FORECAST 
UNDER AWIPS/WMO HEADERS MIAHSFAT2/ FZNT02 KNHC.

...ITCZ/MONSOON TROUGH...                                     
THE MONSOON TROUGH EXTENDS ACROSS AFRICA WITH THE WESTERNMOST 
PART OF THE AXIS BEING AT SW SENEGAL. THE ITCZ BEGINS NEAR 
05N11W AND CONTINUES ALONG 01N25W 01N36W TO THE NORTHERN COAST 
OF BRAZIL NEAR 0N50W. CLUSTERS OF MODERATE TO ISOLATED STRONG 
CONVECTION ARE FROM 02S-05N BETWEEN 14W-26W. SCATTERED MODERATE 
CONVECTION IS ELSEWHERE WITHIN 150 NM N AND S OF THE ITCZ W OF 
26W. 

...DISCUSSION...                                                

GULF OF MEXICO...                                               
SURFACE AND UPPER LEVEL RIDGING AS WELL AS DRY AIR SUBSIDENCE 
DOMINATE ACROSS THE GULF WATERS...THUS SUPPORTING STABILITY AND 
FAIR WEATHER CONDITIONS. THE SURFACE RIDGE IS ANCHORED BY A 1021 
MB HIGH S OF THE BORDER BETWEEN TEXAS AND LOUISIANA NEAR 29N93W 
AND PROVIDES THE GULF WITH N-NE WIND FLOW OF 10-15 KT. SURFACE 
RIDGING IS EXPECTED TO PREVAIL THROUGH MONDAY. BY TUE 
MORNING...A HIGH PRESSURE CENTER IS EXPECTED TO DEVELOP OVER THE 
NW GULF AHEAD OF THE NEXT COLD FRONT WHICH IS EXPECTED TO ENTER 
THIS REGION OF THE BASIN TUE AFTERNOON.

CARIBBEAN SEA...                                                
NEARLY WESTERLY FLOW AND DRY AIR DOMINATE THE CARIBBEAN AT THE 
UPPER LEVELS. A BROAD SURFACE RIDGE COVERING MUCH OF THE ATLC 
EXTENDS INTO THE NORTHERN BASIN THUS INCREASING THE PRESSURE 
GRADIENT TO SUPPORT TRADE WINDS OF 20 KT ACROSS THE CENTRAL AND 
EASTERN CARIBBEAN. A RELAXED PRESSURE GRADIENT OVER THE NW AND 
SW CARIBBEAN SEA SUPPORT LIGHTER NE WINDS RANGING FROM 5-15 KT. 
A WESTWARD-MOVING MOIST AIRMASS HAS REACHED JAMAICA AND CENTRAL-
EASTERN CUBA WHERE IT IS SUPPORTING SHOWERS AND TSTMS. WET 
TRADES ARE ALSO ACROSS THE EASTERN CARIBBEAN WHICH MAY ENHANCE 
SCATTERED SHOWERS TONIGHT. 

...HISPANIOLA...                                                
CURRENTLY FAIR WEATHER IS ACROSS THE ISLAND SUPPORTED BY DRY AIR 
AT THE LOWER LEVELS AND ALOFT. EXCEPT FOR THE TYPICAL AFTERNOON 
SHOWERS...FAIR WEATHER IS EXPECTED THE NEXT TWO DAYS.

ATLANTIC OCEAN...                                               
A DEEP LAYER CYCLONIC CIRCULATION IS OVER THE SOUTHEASTERN U.S. 
WITH AN ASSOCIATED TROUGH EXTENDING SOUTHWARD TO N OF CUBA. 
TROUGHINESS ALOFT IS SUPPORTING A FRONTAL SYSTEM ASSOCIATED WITH 
A 1011 MB LOW OVER JACKSONVILLE NEAR 30N81W. A COLD FRONT 
EXTENDS FROM A TRIPLE POINT ALONG 30N79W 26N79W TO THE STRAITS 
OF FLORIDA NEAR 23N82W. AHEAD OF THE FRONT...A SQUALL LINE 
EXTENDS FROM 30N74W TO 27N75W TO EASTERN-CENTRAL ANDROS NEAR 
24N77W. SATELLITE IMAGERY AND LIGHTING DATA INDICATE THERE ARE 
SHOWERS AND TSTMS WITHIN 80 NM E OF THE FRONT N OF 26N AND 
WITHIN 160 NM E OF THE SQUALL LINE N OF 24N. BOTH LOW LEVEL 
MOISTURE CONVERGENCE AND UPPER LEVEL DIFFLUENCE SUPPORT THIS 
CONVECTION. GALE FORCE WINDS ASSOCIATED WITH THIS FRONTAL SYSTEM 
ARE FORECAST TO BEGIN SUN MORNING AND SUBSIDE SUN AFTERNOON. 
PLEASE SEE SPECIAL FEATURE SECTION. THE LOW WILL CONTINUE TO 
SHIFT NE AND THE ASSOCIATED COLD FRONT WILL CONTINUE TO DRIFT 
EASTWARD ACROSS THE SW N ATLC THROUGH TUE MORNING. 
OTHERWISE...THE REMAINDER OF THE ATLC IS DOMINATED BY A SURFACE 
RIDGE ANCHORED BY A 1029 MB HIGH NEAR 32N53W WHICH IS EXPECTED 
TO DRIFT SE INTO THE AREA OF DISCUSSION BY SUN 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