000
AXNT20 KNHC 291738
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI MAR 29 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1700 UTC.

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

THE MONSOON TROUGH PASSES THROUGH COASTAL LIBERIA NEAR 5N10W TO 
4N15W EQ20W. THE ITCZ CONTINUES FROM EQ21W TO EQ30W EQ40W EQ47W. 
A CLUSTER OF MODERATE TO ISOLATED STRONG CONVECTION IS FROM 2N 
TO 6N BETWEEN 12W AND 17W. SMALLER CLUSTERS OF SIMILAR 
CONVECTION ARE WITHIN 220 NM N OF THE ITCZ AXIS BETWEEN 27W AND 
40W...ALSO WITHIN 100 NM S OF THE ITCZ W OF 40W.
 
...DISCUSSION...
                                            
THE GULF OF MEXICO... 
SURFACE RIDGING CONTINUES OVER THE GULF ANCHORED BY A 1028 MB 
HIGH PRESSURE LOCATED OVER NW SOUTH CAROLINA NEAR 34N81W. THE 
HIGH PRESSURE IS PROVIDING EASTERLY WINDS OF 10-15 KT E OF 90W 
AND SOUTHEASTERLY WINDS OF THE SAME MAGNITUDE W OF 90W. THE 
SURFACE WIND FLOW OVER THE WESTERN GULF IS BANKING LOW LEVEL 
CLOUDS ALONG THE E COAST OF MEXICO FROM S OF MATAMOROS TO THE 
CITY OF VERACRUZ. METAR OBSERVATIONS IN THIS REGION HAVE 
REPORTED HAZE AND FOG WHICH MIGHT AFFECT THE VISIBILITY 
OFFSHORE. SATELLITE COMPOSITE TOTAL PRECIPITABLE WATER      
IMAGERY INDICATE THE POSSIBILITY OF ISOLATED SHOWERS WITHIN 70 
NM OF THE E COAST OF MEXICO. NEARLY WESTERLY FLOW SPREAD OVER 
THE BASIN IN THE MIDDLE TO UPPER LEVELS. CLEAR SKIES AND FAIR 
WEATHER DOMINATE THE REMAINDER OF THE BASIN ASSISTED BY A TONGUE 
OF DRY AIR ALOFT EMBEDDED IN MIDDLE TO UPPER FLOW. OVER THE 
COURSE OF 24 HOURS...RETURN FLOW WILL SPREAD ACROSS THE BASIN AS 
A NEW HIGH PRESSURE BUILDS OVER THE SOUTHEASTERN CONUS AND THEN 
DISPLACES OVER THE W ATLC. NO VARIATIONS IN WIND MAGNITUDE ARE 
EXPECTED. 

THE CARIBBEAN SEA... 
AS OF 1500 UTC...THE TAIL OF A COLD FRONT LOCATED OVER THE 
CENTRAL ATLC IS MOVING ACROSS PUERTO RICO AND THEN ACROSS THE 
MONA PASSAGE WHERE IT TRANSITIONS TO A SHEARLINE ALONG 17N68W 
17N71W 16N74W 15N77W 13N80W. RAINSHOWERS ARE OCCURRING OVER THE 
ISLAND OF PUERTO RICO AS INDICATED BY RADAR IMAGERY AS WELL AS 
WITHIN 100 NM OF THE ISLAND S COAST. SATELLITE COMPOSITE TOTAL 
PRECIPITABLE WATER IMAGERY INDICATE THE POSSIBILITY OF 
RAINSHOWERS OVER THE MONA PASSAGE AS WELL AS WITHIN 50 NM EITHER 
SIDE OF THE SHEARLINE. RAINSHOWERS MAY ALSO BE WITHIN 150 NM OF 
THE COASTS OF VENEZUELA AND COLOMBIA ASSISTED BY MIDDLE TO UPPER 
LEVEL MOISTURE ADVECTION FROM BRAZIL AS WELL AS AN AREA OF 
SURFACE LOW PRESSURE OVER COLOMBIA. WESTERLY WINDS SPREAD ACROSS 
THE CARIBBEAN IN THE MIDDLE TO UPPER LEVELS AND DRY AIR EMBEDDED 
IN THIS FLOW IS PROVIDING FAIR WEATHER TO THE REMAINDER 
CARIBBEAN WATERS. IN TERMS OF WINDS...20 KT NORTHEASTERLY WIND 
DOMINATE THE REGION W OF 68W WHILE EASTERLY TRADEWINDS IN THE 
RANGE OF 10-15 KT SPREAD E OF 68W. OVER THE COURSE OF 24 
HOURS...WINDS OVER THE CENTRAL CARIBBEAN ARE EXPECTED TO AUGMENT 
TO NEAR GALE FORCE AS A TIGHTER PRESSURE GRADIENT BUILDS OVER 
THE BASIN DUE TO THE DEVELOPMENT OF A HIGH PRESSURE CENTER OVER 
THE W ATLC. 

THE ATLANTIC OCEAN...
A COLD FRONT EXTENDS ACROSS THE CENTRAL ATLC TO THE NE CARIBBEAN 
ALONG 30N36W 25N47W 20N56W 18N65W THEN ACROSS PUERTO RICO TO THE 
MONA PASSAGE. THIS FRONT IS BEING SUPPORTED BY A BROAD MIDDLE TO 
UPPER LEVELS TROUGH COVERING THE WESTERN AND CENTRAL ATLC.  
RAINSHOWERS ARE POSSIBLE WITHIN 80 NM OF THE COLD FRONT N OF 25N 
AS WELL AS WITHIN 140 NM E OF THE FRONT S OF 22N. THE HEAVIEST 
RAINSHOWERS ARE OCCURRING WITHIN 100 NM OFF THE COAST OF NORTHERN 
PUERTO RICO. A BROAD SURFACE RIDGE SPREADS E OF THE COLD FRONT 
IN THE EASTERN ATLC N OF 19N ANCHORED BY A 1023 MB HIGH PRESSURE 
NEAR 28N19W. OVER THE COURSE OF 24 HOURS...THE COLD FRONT WILL 
CONTINUE TO MOVE ACROSS THE CENTRAL ATLC WATERS WHILE A NEW HIGH 
PRESSURE BUILDS BEHIND IT OVER THE SOUTHEASTERN CONUS...THEN 
DRIFTING TO THE WEST ATLC.

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

$$
NR