000
AXNT20 KNHC 071709
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST WED MAR 07 2012

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
1500 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF 
SIERRA LEONE AT 7.5N12.5W TO 3N17W. THE ITCZ CONTINUES FROM 
3N17W ALONG 1N25W 2N38W 1S47W. SCATTERED MODERATE CONVECTION IS 
FROM 2N-5N BETWEEN 35W-50W.    

...DISCUSSION...

GULF OF MEXICO...
UPPER LEVEL RIDGING PREVAILS OVER THE GULF OF MEXICO DURING THE 
MORNING HOURS SUPPORTING A STRONG SURFACE RIDGE JUST N OF THE 
AREA ANCHORED BY A 1040 MB HIGH CENTERED NEAR 37N68W. THE 
PRESSURE GRADIENT BETWEEN THIS STRONG HIGH PRESSURE AND LOWER 
PRESSURE ACROSS THE TROPICAL BELT IS MAINTAINING FRESH TO STRONG 
E-SE WINDS OVER THE GULF WATERS. DRY AND STABLE CONDITIONS FROM 
HIGH PRESSURE IS LIMITING CONVECTIVE ACTIVITY TO ISOLATED LOW 
TOPPED SHOWERS MAINLY OVER THE SE GULF WATERS. THE SURFACE RIDGE 
IS EXPECTED TO WEAKEN AND SHIFT EWD OVER THE NEXT COUPLE OF 
DAYS...WITH WINDS DIMINISHING ACROSS THE BASIN BY THE END OF THE 
WEEK. 

CARIBBEAN SEA...
AN UPPER LEVEL TROUGH PREVAILS OVER THE WESTERN CARIBBEAN WATERS 
WHILE AN UPPER LEVEL RIDGE PREVAILS OVER THE EASTERN PORTION. 
THOUGH THE SURFACE BOUNDARY IE SHEARLINE OVER THE WESTERN 
CARIBBEAN HAS DISSIPATED...THE UPPER LEVEL TROUGH CONTINUES TO 
SUPPORT BROAD LOW LEVEL TROUGHING OVER THE REGION. THE PRESSURE 
GRADIENT BETWEEN THIS BROAD LOW LEVEL TROUGHING AND STRONG HIGH 
PRESSURE MENTIONED ABOVE IS MAINTAINING STRONG TO NEAR GALE 
WINDS OVER THE SW CARIBBEAN WATERS...WITH GALE FORCE WINDS OFF 
THE COAST OF COLOMBIA. FRESH TO STRONG TRADEWINDS PREVAIL ACROSS 
THE REMAINDER OF THE CARIBBEAN WATERS. WEAK LOW LEVEL FORCING 
OVER THE SW CARIBBEAN...AND A STABLE AIRMASS OVER THE EASTERN 
CARIBBEAN WATERS IS LIMITING CONVECTION TO LOW TOPPED TRADEWIND 
SHOWERS. STRONGER SPEED CONVERGENCE AT LOW LEVELS IS RESULTING 
IN SCATTERED STRONGER CONVECTIVE ACTIVITY OVER THE NW CARIBBEAN 
WATERS. THERE IS NOT MUCH CHANGE IN THIS PATTERN THROUGH FRI 
WHEN THE RIDGE N OF THE AREA WILL WEAKEN AND START TO SHIFT 
EASTWARD. 

ATLANTIC OCEAN...
A STRONG SURFACE HIGH PRESSURE 1040 MB IS CENTERED N OF THE SW N 
ATLC WATERS NEAR 37N68W. THE PRESSURE GRADIENT BETWEEN THIS 
FEATURE AND TROUGHING OVER THE SW CARIBBEAN IS MAINTAINING FRESH 
TO STRONG TRADEWINDS ACROSS MUCH OF THE SW N ATLC WATERS. AN 
UPPER LEVEL TROUGH IS ALOFT OF THIS AREA. A LINGERING SHEAR LINE 
EXTENDS ACROSS THE AREA FROM 31N52W TO THE CENTRAL BAHAMAS. LOW 
LEVEL CONVERGENCE ASSOCIATED WITH THIS SHEAR LINE COMBINED WITH 
UPPER LEVEL DIVERGENCE E OF THE TROUGH AXIS IS ENHANCING 
CONVECTIVE ACTIVITY ALONG THE SHEAR LINE E OF THE BAHAMAS. THE 
SHEARLINE IS EXPECTED TO DISSIPATE OVER THE NEXT 24 TO 36 HOURS. 
AN UPPER LEVEL LOW CENTERED NEAR 31N34W IS SUPPORTING A SURFACE 
TROUGH ALONG 30N37W TO 23N38W. SCATTERED SHOWERS ARE WITHIN 240 
NM E OF THE AXIS.  

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

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AL