000
AXNT20 KNHC 190511
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST THU FEB 19 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0445 UTC.

...THE ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 6N9W CROSSING THE EQUATOR NEAR 
18W THEN ALONG 3S30W AND INTO NE BRAZIL NEAR 4S38W. SCATTERED 
MODERATE CONVECTION IS FROM THE EQUATOR TO 4N E OF 23W TO THE 
COAST OF AFRICA. 

...DISCUSSION...

GULF OF MEXICO...
A 1023 MB SURFACE HIGH IN THE W ATLC EXTENDS A RIDGE ACROSS THE 
FLORIDA PENINSULA AND SRN GULF PRODUCING MOSTLY FAIR WEATHER S 
OF 27N. SCATTERED MULTI-LAYERED CLOUDS WITH EMBEDDED ISOLATED 
SHOWERS AND THUNDERSTORMS ARE OBSERVED OVER THE NRN GULF WATERS 
AHEAD OF A COLD FRONT THAT...AS OF 0300 UTC... WAS POSITIONED 
ALONG THE TEXAS COAST AND INLAND OVER MEXICO. THIS FRONT IS 
FORECAST TO MOVE INTO THE NW GULF IN THE NEXT FEW HOURS AND 
SURGE ACROSS THE REGION THROUGH THURS NIGHT. STRONG N TO NE 
WINDS...SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED IN 
CONJUNCTION WITH THE FRONTAL PASSAGE. ALOFT...STRONG WNW FLOW 
AROUND AN UPPER RIDGE WITH AXIS ALONG 100W IS TRANSPORTING UPPER 
LEVEL MOISTURE ACROSS THE NRN GULF WATERS WHILE THE SRN 
GULF...INCLUDING SE MEXICO AND THE YUCATAN PENINSULA REMAINS 
MOSTLY CLEAR UNDER MODERATE TO STRONG SUBSIDENCE. 

CARIBBEAN SEA...
A FRONTAL BOUNDARY EXTENDS ACROSS THE CENTRAL ATLC TO THE NRN 
LEEWARD ISLANDS. SCATTERED SHOWERS ASSOCIATED WITH THIS BOUNDARY 
LINGER OVER THE NRN LEEWARD ISLANDS AND EASTERN PUERTO RICO.
LOW-LEVEL CONVERGENCE ACROSS THE CENTRAL AND WRN CARIBBEAN IS 
GENERATING ISOLATED SHOWERS WITHIN 70 NM OF A LINE FROM 15N65W 
TO 13N81W. THESE SHOWERS LACK DEEP CONVECTION UNDER STRONG 
SUBSIDENCE IN THE MID TO UPPER LEVELS ACROSS MUCH OF THE BASIN. 
HIGH PRESSURE IN THE W ATLANTIC WILL MAINTAIN STRONG TRADE WIND 
FLOW ACROSS THE CARIBBEAN THROUGH THU WITH THE NEXT COLD FRONT 
FORECAST TO REACH WRN CUBA AND THE NW CARIBBEAN EARLY FRIDAY.

ATLANTIC OCEAN...
AN INTENSE EXTRATROPICAL LOW PRESSURE SYSTEM IN THE NORTH 
CENTRAL ATLC EXTENDS A COLD FRONT SOUTHWARD THAT ENTERS THE 
DISCUSSION AREA NEAR 31N42W AND CONTINUES ALONG 23N50W TO 20N54W 
WHERE IT BECOMES STATIONARY TO THE LEEWARD ISLANDS NORTH OF 
GUADELOUPE. A BAND OF MULTI-LEVEL CLOUDS AND SCATTERED SHOWERS 
IS NOTED WITHIN 100 NM OF THE FRONT...WITH THE STRONGEST 
CONVECTION N OF 26N. GALE FORCE WIND CONDITIONS ARE OBSERVED 
WITHIN 180 NM AHEAD OF THE FRONT N OF 28N AND BEHIND THE FRONT 
TO 56W N OF 29N. SOUTH OF THE FRONT...A SFC TROUGH FROM 19N52W 
TO 10N52W DEPICTS AN AREA OF SCATTERED SHOWERS. A 1023 MB HIGH 
PRESSURE SYSTEM HAS MOVED INTO THE W ATLC BEHIND THE FRONT. COLD 
AIR STRATOCUMULUS CLOUDS COVER THE REGION BETWEEN THE FRONT AND 
77W. SCATTERED SHOWERS ARE MOVING OFF THE N COAST OF FLORIDA 
AHEAD OF A STRONG COLD FRONT OVER THE SE CONUS. THIS FRONT IS 
EXPECTED TO MOVE OFFSHORE LATE TONIGHT AS THE HIGH PRESSURE 
SHIFTS E INTO THE CENTRAL ATLC. SW FLOW WILL INCREASE AHEAD OF 
THE FRONT REACHING GALE FORCE CONDITIONS N OF 29N AND W OF 74W 
LATER TODAY. A SFC RIDGE EXTENDS ACROSS THE EAST ATLC PROVIDING 
FAIR WEATHER EAST OF THE AFOREMENTIONED FRONT. THE SRN PERIPHERY 
OF THIS RIDGE IS ALSO PRODUCING A LARGE AREA OF MODERATE TO 
FRESH TRADE WINDS ACROSS THE TROPICS MAINLY EAST OF 45W. 
 

$$
WADDINGTON