Atlantic Tropical Weather Discussion

000
AXNT20 KNHC 211103
TWDAT 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL 
805 AM EDT MON APR 21 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1145 UTC.

...ITCZ/MONSOON TROUGH...                                     
THE MONSOON TROUGH EXTENDS ACROSS AFRICA TO THE COAST OF SENEGAL 
AND THE EXTENDS OVER THE EASTERN TROPICAL ATLANTIC ALONG 14N17W 
TO 06N21W. THE ITCZ BEGINS FROM THERE AND CONTINUES JUST S OF 
THE EQUATOR WEST OF 35W TO THE NORTHERN COAST OF BRAZIL NEAR 
03S40W. SCATTERED MODERATE ISOLATED STRONG CONVECTION EXISTS 
SOUTH OF WEST AFRICA EAST OF 10W. 

...DISCUSSION...                                                

GULF OF MEXICO...                                               
A 1021 MB SURFACE HIGH IS ANALYZED ALONG THE FLORIDA PANHANDLE-
ALABAMA BORDER WITH A WEAK NORTH-SOUTH SURFACE PRESSURE GRADIENT 
ACROSS THE GULF OF MEXICO. CORRESPONDINGLY...SURFACE WINDS ARE 
GENERALLY GENTLE TO MODERATE BREEZE CONDITIONS OUT OF THE 
NORTHEAST IN THE EASTERN GULF AND SOUTHEAST IN THE WESTERN GULF. 
NO SIGNIFICANT DEEP CONVECTION OR SHOWERS ARE CURRENTLY 
OCCURRING.  RELATIVELY THICK CIRRUS IS BLOWING EASTWARD ACROSS 
THE WESTERN GULF AS UPPER-LEVEL DEBRIS CLOUDINESS FROM DEEP 
CONVECTION OVER CENTRAL MEXICO LATE YESTERDAY.  OVER THE NEXT 
COUPLE OF DAYS...THE WINDS WILL DROP OFF EVEN MORE AS THE WEAK 
SURFACE HIGH DRIFTS SOUTHWESTWARD INTO THE NORTH CENTRAL GULF.  
NO SIGNIFICANT DEEP CONVECTION OR SHOWERS ARE EXPECTED FOR THE 
NEXT DAY...THOUGH LATE TUESDAY AND EARLY WEDNESDAY SOME 
CONVECTION COULD DEVELOP IN THE NORTHERN GULF OF MEXICO AHEAD OF 
AN ADVANCING COLD FRONT.

CARIBBEAN SEA... 
THE TAIL END OF A COLD FRONT EXTENDS ACROSS THE CENTRAL BAHAMAS 
TO EASTERN CUBA WITH A DISSIPATING COLD FRONT INDICATED FROM 
THERE TO NEAR THE CAYMAN ISLANDS.  A MODERATE NORTH-SOUTH 
SURFACE PRESSURE GRADIENT EXISTS ACROSS THE CARIBBEAN AND THE 
EASTERLY TRADEWINDS ARE GENTLE TO FRESH BREEZE CONDITIONS...WITH 
THE USUAL EXCEPTION OF STRONGER NE WINDS OF 25 KT NORTH OF 
COLOMBIA. OVER THE NEXT COUPLE OF DAYS...THE SURFACE PRESSURE 
GRADIENT WEAKENS AND WINDS FURTHER SLACKEN. ENHANCED TOTAL 
PRECIPITABLE WATER IS OBSERVED WITH THE TPW IMAGERY ACROSS THE 
EASTERN BAHAMAS...EASTERN CUBA...AND THE NORTHWESTERN CARIBBEAN. 
ADDITIONALLY...A WEAK MAXIMA IN MOISTURE...POSSIBLY AN EARLY 
SEASON WEAK TROPICAL WAVE...ALSO IS REACHING THE WINDWARD 
ISLANDS.  WHILE THE FRONTAL BOUNDARY SHOULD DISSIPATE NEAR THE 
BAHAMAS SHORTLY...THE RESIDUAL MOISTURE AND CONVERGENCE MAY 
CONTINUE TO AID THE DEVELOPMENT OF SCATTERED DEEP CONVECTION IN 
THE EASTERN BAHAMAS...EASTERN CUBA...HISPANIOLA...AND JAMAICA 
DURING THE NEXT COUPLE OF DAYS. ADDITIONALLY...THE WEAK MAXIMA 
IN MOISTURE IS SUGGESTED BY THE GFS TO MOVE NORTHWESTWARD AND 
MAY ENHANCE SHOWERS AND WIDELY SCATTERED DEEP CONVECTION OVER 
THE LESSER ANTILLES AND PUERTO RICO. HOWEVER...SUCH CONVECTIVE 
ACTIVITY IS NOT EXPECTED TO BE WIDESPREAD...AS SUBSIDENT UPPER-
LEVEL WESTERLY FLOW COVERS THE CARIBBEAN AS IS TYPICAL FOR THIS 
TIME OF YEAR.

...HISPANIOLA...                                                
NO SIGNIFICANT DEEP CONVECTION IS OCCURRING OVER HAITI AND 
DOMINICAN REPUBLIC.  ENHANCED TOTAL PRECIPITABLE WATER IS 
OBSERVED WITH THE TPW IMAGERY ACROSS THE EASTERN 
BAHAMAS...EASTERN CUBA...AND THE NORTHWESTERN CARIBBEAN. WHILE 
THE FRONTAL BOUNDARY SHOULD DISSIPATE NEAR THE BAHAMAS 
SHORTLY...THE RESIDUAL MOISTURE AND CONVERGENCE MAY CONTINUE TO 
AID THE DEVELOPMENT OF SCATTERED DEEP CONVECTION IN HISPANIOLA 
DURING THE NEXT COUPLE OF DAYS. HOWEVER...SUCH CONVECTIVE 
ACTIVITY IS NOT EXPECTED TO BE WIDESPREAD...AS SUBSIDENT UPPER-
LEVEL WESTERLY FLOW COVERS THE CARIBBEAN AS IS TYPICAL FOR THIS 
TIME OF YEAR.

ATLANTIC OCEAN... 
A 1009 MB SURFACE LOW IS SOUTHEAST OF NORTH 
CAROLINA NEAR 32N73W WITH A COLD FRONT EXTENDING SOUTHWARD TO 
EASTERN CUBA AND A SECONDARY TROUGH EXTENDING SOUTHWESTWARD TO 
THE NORTHWESTERN BAHAMAS.  A PRE-FRONTAL SQUALL LINE IS ABOUT 
120 NM AHEAD OF THE FRONT NORTH OF 25N.  SURFACE WINDS REACH UP 
TO 30 KT IN THE NORTHERLY FLOW JUST OFFSHORE OF NORTHEASTERN 
FLORIDA.  ALL OF THIS IS SUPPORTED BY A VIGOROUS UPPER-LEVEL 
CUTOFF LOW AT ABOUT THE SAME LOCATION AS THE SURFACE LOW.  THE 
UPPER-LEVEL LOW SHOULD LIFT OUT AND BECOME AN OPEN TROUGH AS IT 
QUICKLY MOVES NORTHEASTWARD.  WHILE THE BAROCLINICITY OF THE 
COLD FRONT WEAKENS SOME...LARGE AMOUNTS OF MOISTURE AND UPPER-
LEVEL FORCING SHOULD CONTINUE TO PROVIDE THE POTENTIAL FOR AT 
LEAST SCATTERED DEEP CONVECTION AHEAD AND ALONG THE FRONT FOR 
THE NEXT COUPLE OF DAYS.  WHILE THE NORTHERLY FLOW BEHIND THE 
FRONT SHOULD GRADUALLY WEAKEN...THE SOUTHWESTERLY WINDS AHEAD OF 
THE FRONT SHOULD STRENGTHEN UP TO STRONG BREEZE OR NEAR GALE 
CONDITIONS FOR THE NEXT TWO DAYS.   FARTHER TO THE EAST...A 
ANOTHER COLD FRONT MAY JUST REACH AROUND 30N EAST OF 40W LATE 
TODAY...THOUGH THE POTENTIAL FOR DEEP CONVECTION WITH THIS FRONT 
APPEARS MINIMAL AND WINDS REMAIN LIGHT ACROSS THE FRONT.  
ELSEWHERE...THE REMAINDER OF THE ATLANTIC IS DOMINATED BY A 
SURFACE RIDGE ANCHORED BY A 10253 MB HIGH NEAR 29N51W WHICH IS 
EXPECTED TO DRIFT EASTWARD OVER THE NEXT TWO DAYS.  FAIR WEATHER 
IS OVER THE CENTRAL AND EASTERN ATLANTIC BEING SUPPORTED BY DRY 
AIR SUBSIDENCE FROM THE MIDDLE LEVELS. 

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

$$
LANDSEA