000
AXNT20 KNHC 031043
TWDAT 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL 
805 AM EDT WED APR 03 2013

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 
1015 UTC.

...THE ITCZ/THE MONSOON TROUGH... 

THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL 
ATLC NEAR 12N16W AND CONTINUES ALONG 5N19W TO 2N25W WHERE THE 
ITCZ BEGINS AND CONTINUES ALONG 1N30W THEN S OF THE EQUATOR NEAR 
36W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION 
ARE FROM 8N TO S OF THE EQUATOR E OF 20W TO THE PRIME MERIDIAN. 
CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 1N-4N BETWEEN 
22W-29W. 

...DISCUSSION...

GULF OF MEXICO...                                                
A BROAD UPPER RIDGE COVERS THE CARIBBEAN AND GULF OF MEXICO WITH 
AN UPPER TROUGH MOVING ACROSS THE CENTRAL PLAIN STATES TO N 
MEXICO WITH A SHORTWAVE MOVING OVER E TEXAS AND THE FAR NW GULF 
SUPPORTING A FRONTAL BOUNDARY THAT EXTENDS ACROSS S LOUISIANA 
TO A 1008 MB LOW NEAR PORT ARTHUR TEXAS AND A COLD FRONT 
EXTENDING FROM THE LOW INTO THE GULF WATERS THEN INLAND S OF 
GALVESTON. A SECOND SURFACE LOW FORMED ALONG THE PREVIOUS SURFACE 
TROUGH AT 03/0600 UTC. AT 03/0900 UTC THE SURFACE TROUGH EXTENDS 
FROM 27N87W TO A 1007 MB SURFACE LOW NEAR 28N94W THEN SW INTO NE 
MEXICO NEAR 25N98W. SCATTERED SHOWERS/THUNDERSTORMS ARE N OF 
SURFACE TROUGH TO THE FRONTAL BOUNDARY BETWEEN 87W-96W WITH 
SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS N OF THE 
FRONTAL BOUNDARY TO INLAND OVER THE N GULF COAST. SE SURFACE 
FLOW OVER THE REMAINDER OF THE W GULF IS BANKING LOW CLOUDS WITH 
SCATTERED SHOWERS AND A POSSIBLE ISOLATED THUNDERSTORM N OF 23N 
W OF 90W. INCREASING WINDS AND SEAS WILL CONTINUE TODAY AS THE 
LOW PRESSURE SYSTEM IN NW GULF DEEPENS TONIGHT AND THU THEN 
TRACKS E-NE ACROSS THE N GULF. THE LOW WILL DRAG A COLD FRONT 
ACROSS THE GULF THU AND FRI THEN SE OF THE AREA LATE FRI. GENTLE 
TO MODERATE E-SE WINDS ACROSS THE REGION SAT WILL BECOME 
MODERATE TO FRESH SE SUN.

CARIBBEAN SEA...                                                
A BROAD UPPER RIDGE DOMINATES MOST OF THE CARIBBEAN ANCHORED 
INLAND OVER SOUTH AMERICA. A WEAK BENIGN UPPER TROUGH IS MOVING 
ACROSS THE LESSER ANTILLES. RELATIVE TIGHT PRESSURE GRADIENT 
EXISTS BETWEEN THE LOWER PRESSURE OF SOUTH AMERICA AND THE 
SURFACE RIDGE OVER THE W ATLC PRODUCING FRESH TO STRONG EASTERLY 
TRADE WINDS ACROSS THE CENTRAL CARIBBEAN WITH MODERATE TRADE 
WINDS ELSEWHERE. CONVERGENCE OVER THE SW CARIBBEAN BETWEEN THE 
EASTERLY SURFACE FLOW AND THE SW FLOW ALOFT ARE GENERATING  
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS INLAND OVER COLOMBIA 
AND WITHIN 30 NM ALONG THE COAST. WATER VAPOR IMAGERY INDICATES 
A SWATH OF STRONG SUBSIDENCE ACROSS MOST OF THE BASIN GIVING THE 
CARIBBEAN FAIR CONDITIONS ACROSS THE REMAINDER OF THE AREA. 
TRADE WINDS WILL PREVAIL THROUGH FRI. HIGH PRESSURE CENTERED 
OVER THE CENTRAL ATLC IS ENHANCING TRADE WINDS OVER A BROAD AREA 
OF THE TROPICAL ATLC. FRESH TO STRONG SE WINDS ARE EXPECTED IN 
THE GULF OF HONDURAS THROUGH THU. A WEAK COLD FRONT IS EXPECTED 
TO REACH THE YUCATAN CHANNEL FRI THEN DISSIPATE OVER THE NW 
CARIBBEAN SAT. MODERATE TO FRESH E TRADE WINDS WILL PREVAIL 
ACROSS THE REGION THIS WEEKEND.

ATLANTIC OCEAN...                                               
THE UPPER TROUGH EXTENDS OVER THE W ATLC N OF 25N FROM 58W-75W 
SUPPORTING A WEAK COLD FRONT THAT ENTERS THE REGION NEAR 32N63W 
TO 29N67W WHERE IT DISSIPATES TO 27N73W. A SURFACE TROUGH IS S 
OF THE FRONT EXTENDING FROM 25N68W TO OVER HAITI NEAR 19N72W. A 
SHARP UPPER RIDGE IS TO THE E EXTENDING FROM 24N53W TO BEYOND 
32N50W PROVIDING DIFFLUNCE ALOFT TO GENERATE SCATTERED SHOWERS 
AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN 60/75 NM OF LINE FROM 
23N63W TO BEYOND 32N56W. AN UPPER TROUGH AXIS OVER THE E ATLC 
EXTENDS THROUGH 32N21W TO 25N42W SUPPORTING A COLD FRONT ALONG 
THE COAST OF AFRICA THROUGH 32N10W TO 28N12W WHERE IT DISSIPATES 
TO 23N18W. A LARGE SURFACE RIDGE COVERS THE REMAINDER OF THE 
ATLC BETWEEN THE ABOVE FRONTS AND ANCHORED BY A 1028 MB HIGH 
NEAR 30N41W. THE W ATLC COLD FRONT AND SURFACE TROUGH TO MERGE 
INTO SINGLE ENTITY FROM 30N59W TO 22N70W BY THIS EVENING AND 
SHIFT E OF THE FORECAST AREA THU. A LOW PRESSURE SYSTEM MOVING 
OUT OF THE GULF OF MEXICO TONIGHT AND THU WILL INCREASE WINDS 
AND SEAS IN N WATERS THU AND FRI. THE LOW WILL SWEEP A COLD 
FRONT OVER THE REGION FRI THROUGH SAT NIGHT. GENTLE TO MODERATE 
E-NE WINDS WILL PREVAIL ACROSS THE REGION SUN.

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

$$
PAW