000
AXNT20 KNHC 131803
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU MAR 13 2008

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL 
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN 
SECTIONS OF SOUTH AMERICA...AND THE ATLANTIC OCEAN TO THE 
AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING
INFORMATION IS BASED ON SATELLITE IMAGERY...METEOROLOGICAL 
ANALYSIS... WEATHER OBSERVATIONS...AND RADAR.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1745 UTC.

...THE ITCZ...

ITCZ AXIS IS CENTERED ALONG 08N13W TO 00N25W TO 03S42W.
SCATTERED MODERATE ISOLATED STRONG CONVECTION NOTED WITHIN 150 
NM N AND WITHIN 210 NM S OF AXIS BETWEEN 29W AND 35W AND WITHIN 
30 NM OF AXIS BETWEEN 38W AND 43W. A LARGE CLUSTER OF CONVECTION 
IS DISSIPATING AT THE EQUATOR AND 18W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER ANTICYCLONE IS CENTERED OVER THE BAY OF CAMPECHE AT 
20N93W AND IS SHIFTING E WITH TIME. AN UPPER RIDGE EXTENDS N TO 
A FLAT CREST ALONG 31N BETWEEN 95W AND 85W. UPPER MOISTURE IS 
NOTED OVER THE AREA N OF 25N AND IS SPREADING E IN THE NEARLY 
ZONAL UPPER FLOW. THE UPPER LEVELS ARE DRY OVER THE GULF OF 
MEXICO E OF A LINE FROM 20N95W TO 29N83W...AND EXTENDING E 
ACROSS ALL OF FLORIDA AND THE NW BAHAMAS....BUT SOME OF THE 
UPPER MOISTURE WILL REPLACE THE DRIER AIR TONIGHT. AT THE LOW 
LEVELS A FRONTAL TROUGH...ACCOMPANIED BY A LINE OF SHOWERS...IS 
LIFTING N OVER THE YUCATAN CHANNEL AND THE STRAITS OF FLORIDA S 
OF KEY WEST. A SURFACE RIDGE DISSECTS THE GULF FROM SW GEORGIA 
TO 22N97W. BROKEN TO LOCALLY OVERCAST LOW AND MID LEVELS CLOUDS 
ARE MOVING NE AROUND THE RIDGE OVER THE GULF W OF 90W.

CARIBBEAN SEA...
AN UPPER ANTICYCLONE IS CENTERED NEAR JAMAICA WITH AN UPPER 
RIDGE W TO BELIZE AND A RIDGE EXTENDS E TO HISPANIOLA. A WEAK 
UPPER TROUGH IS OVER THE NE PART. UPPER MOISTURE IN THE FORM OF 
THIN BROKEN CIRRUS IS STREAMING ANTICYCLONICALLY NE ACROSS THE 
CARIBBEAN S OF 14N...IN RESPONSE TO ANOTHER UPPER RIDGE 
ORIGINATING AT 07N50W. OTHERWISE THE UPPER LEVELS ARE DRY OVER 
THE CARIBBEAN. AT THE LOW LEVELS A FRONTAL TROUGH LIES OVER W 
CUBA AND THE YUCATAN CHANNEL AND IS BEGINNING TO LIFT N. WEAK 
SURFACE RIDGING EXTENDS W ACROSS THE NORTHERN CARIBBEAN. A LINE 
OF BROKEN LOW CLOUDS AND SHOWERS IS NOTED WITH 120 NM EITHER 
SIDE OF POINTS 20N74W TO 14N83W.

ATLANTIC OCEAN...
A DEEP LAYERED CYCLONE IS NEAR 29N74W AND IS RACING NE. THE 
ASSOCIATED STATIONARY FRONT LIES ALONG 31N61W 30N70W INTO A 
SURFACE LOW IS ANALYZED AT 29N76.5W 1015 MB AT 1500 UTC. A COLD 
FRONT EXTENDS SW FROM THE LOW ACROSS THE CENTRAL BAHAMAS TO NW 
CUBA AND IS NOW BEGINNING TO LIFT N OVER THE CAY SAL BANK. 
SCATTERED CONVECTION WAS ENHANCED EARLIER NEAR THE SURFACE LOW 
BUT HAS DECREASED CONSIDERABLY THROUGHOUT THE MORNING. CURRENTLY 
OVERCAST MULTILAYERED CLOUDS ARE NOTED N OF 27N BETWEEN 75W AND  
45W. LIGHTNING DATA INDICATES ISOLATED TSTMS ARE EMBEDDED NEAR  
28N68W AND NEAR 29N74W AT THE MOMENT. 

AN UPPER ANTICYCLONE IS NEAR 07N50W RESULTING IN A BROAD UPPER 
RIDGE OVER THE TROPICS W OF 40W. MOIST UPPER AIR IS OBSERVED N 
OF 25N BETWEEN 72W AND 38W AND DRY UPPER AIR IS NOTED GENERALLY 
S OF 25N. AT THE LOW LEVELS A DISSIPATING SURFACE FRONT LIES 
ALONG 31N31W TO 28N43W CONTINUES TO SEPARATE SURFACE HIGH NEAR 
33N30W AND 26N54W. LOW PRES IS NEAR THE AFRICAN COAST AT 19N16W. 

$$
NELSON