000
AXNT20 KNHC 212358
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST SAT FEB 21 2009

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...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2245 UTC.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 04N08W 01N16W 01N16W 01N49W INTO NE 
BRAZIL NEAR 00N50W.  SCATTERED MODERATE CONVECTION WITHIN 30-75 
NM OF AXIS E OF 10W.  SCATTERED MODERATE CONVECTION INLAND OVER 
NE BRAZIL WITHIN 90 NM S OF AXIS W OF 47W.  

...DISCUSSION...
GULF OF MEXICO...
IN THE UPPER LEVELS...LONGWAVE TROUGH DIGS S ACROSS CENTRAL 
TEXAS AND NORTHEAST MEXICO IN SUPPORT OF COLD FRONT BRINGING 
ABUNDANT TROPICAL MOISTURE EMBEDDED IN 80 KT SW JET CORE FROM 
WESTERN BAY OF CAMPECHE TO SE LOUISIANA NEAR NEW ORLEANS. 
MODERATE TO STRONG SUBSIDENCE FOUND OVER SOUTHEAST CORNER OF 
BASIN.  
AT THE SURFACE...HIGH PRESSURE 1030 MB OFF MID ATLC SEABOARD HAS 
RIDGE EXTENDING SW ACROSS CENTRAL GULF PRODUCING MODERATE EAST 
TO SOUTHEAST FLOW THROUGH MOST OF BASIN.  W GULF HAS BROKEN TO 
OVERCAST MULTILAYERED CLOUDS N OF 25N W OF 90W WITH SCATTERED 
SHOWERS AS COLD FRONT ACROSS CENTRAL TEXAS APPROACHES NW 
WATERS.  

CARIBBEAN SEA...
IN THE UPPER LEVEL...WELL DEFINED ANTICYCLONE OVER SURINAME HAS 
RIDGE EXTEND N AND COVER ENTIRE CARIBBEAN WITH DRY AIR MASS DUE 
TO MODERATE TO STRONG SUBSIDING AIR ALOFT.
AT THE SURFACE...TIGHT GRADIENT BETWEEN NORTH CAROLINA 1030 MB 
HIGH PRESSURE AND 1006 MB LOW PRESSURE OVER NORTHERN COLOMBIA 
CAUSING TRADEWINDS TO INCREASE ALONG COAST OF COLOMBIA TO GALE 
FORCE.  PATCHES OF BROKEN LOW CLOUDS AND ISOLATED SHOWERS DOT 
EASTERN CARIBBEAN S OF 13N AND GULF OF HONDURAS ISLANDS. 

ATLANTIC OCEAN...
IN THE UPPER LEVELS...BROAD UPPER LEVEL RIDGE AXIS ALONG 58W 
MAINTAINS DRY SUBSIDING AIR MASS OVER W OF 45W S OF 30N.  LARGE 
UPPER LEVEL CYCLONE OVER EASTERN ATLC AT 30N26W WITH AXIS SW 
07N43W.
AR THE SURFACE...COLD FRONT EXTENDS FROM 32N57W TO CENTRAL 
BAHAMAS NEAR 24N73W. SOUTHERNMOST EDGE OF FRONT STALLING AND 
LIKELY SHIFTING NORTH AS WARM FRONT WITHIN NEXT 24-36 HRS WITH 
SCATTERED SHOWERS WITHIN 240 NM NW OF FRONT.

$$
WALLY BARNES