000
AXNT20 KNHC 180953
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST WED FEB 18 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0930 UTC.

...THE ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 5N8W 2N15W CROSSING THE EQUATOR 
NEAR 23W THEN ALONG 1S30W AND INTO NE BRAZIL NEAR 4S42W. 
SCATTERED MODERATE CONVECTION IS WITHIN 50 NM N OF THE AXIS 
BETWEEN 14W-19W. A CLUSTER OF MODERATE TO STRONG CONVECTION IS 
FROM 4S-2S BETWEEN 21W-24W. CLUSTERS OF MODERATE CONVECTION ARE 
FROM THE EQUATOR TO 3 N BETWEEN 34W-39W. SCATTERED MODERATE TO 
STRONG CONVECTION IS ALONG THE COAST OF BRAZIL S OF 2N AND W OF 
41W.

...DISCUSSION...

GULF OF MEXICO...
A 1023 MB SFC HIGH IN THE W ATLC EXTENDS A RIDGE ACROSS FLORIDA 
AND INTO THE GULF OF MEXICO PRODUCING MOSTLY FAIR WEATHER ACROSS 
THE REGION. SCATTERED MULTI-LAYERED CLOUDS ARE OBSERVED OVER THE 
NORTHERN HALF OF THE GULF WHERE SOUTHERLY RETURN FLOW OF UP TO 
20 KT IS ESTABLISHED AHEAD OF A DEVELOPING LOW PRESSURE SYSTEM 
OVER THE CENTRAL CONUS. THIS SYSTEM WILL PUSH A COLD FRONT INTO 
THE REGION THIS AFTERNOON AS THE HIGH PRESSURE SHIFTS FURTHER 
EAST INTO THE CENTRAL ATLC. EXPECT SCATTERED SHOWERS AND 
THUNDERSTORMS TO MOVE INTO THE NW GULF WITH THE FRONT. STRONG 
WNW FLOW AROUND AN UPPER RIDGE IS TRANSPORTING UPPER LEVEL 
MOISTURE ACROSS THE NRN GULF WHILE THE SRN GULF REMAINS 
RELATIVELY CLEAR UNDER MODERATE SUBSIDENCE ALOFT.

CARIBBEAN SEA...
A COLD FRONT EXTENDS FROM THE ATLC ACROSS PUERTO RICO...THE MONA 
PASSAGE...AND THE DOMINICAN REPUBLIC. SCATTERED SHOWERS ARE 
WITHIN 40 NM OF THE FRONT...AFFECTING THE GREATER ANTILLES AND 
THE CARIBBEAN N OF 16N. THE FRONT IS EXPECTED TO MOVE SE ACROSS 
THE EXTREME NRN LEEWARD ISLANDS TODAY THEN LINGER ACROSS THE NE 
CARIBBEAN AND CENTRAL LEEWARD ISLANDS BEFORE DISSIPATING THU. A 
SFC TROUGH CONTINUES TO MOVE WESTWARD ACROSS THE CENTRAL 
CARIBBEAN GENERATING A LARGE AREA OF LOW/MID CLOUDS WITH 
ISOLATED SHOWERS S OF 15N BETWEEN 65W-75W. PATCHY CLOUDS AND 
FAIR WEATHER COVER THE CARIBBEAN W OF 75W UNDER A STABLE AIRMASS 
ALOFT. HIGH PRESSURE BEHIND THE FRONT WILL MAINTAIN STRONG TRADE 
WIND FLOW ACROSS THE CARIBBEAN.

ATLANTIC OCEAN...
A STRONG EXTRATROPICAL LOW PRESSURE SYSTEM WITH HURRICANE FORCE 
WINDS IS SPINNING OVER THE N CENTRAL ATLC NEAR 40N54W. THE 
ASSOCIATED COLD FRONT ENTERS THE DISCUSSION AREA NEAR 31N49W AND 
CONTINUES ALONG 25N54W 20N60W TO THE EASTERN TIP OF PUERTO RICO 
THROUGH THE MONA PASSAGE AND ACROSS THE DOMINICAN REPUBLIC. 
MULTI-LEVEL CLOUDS AND SCATTERED SHOWERS ARE NOTED WITHIN 90 NM 
OF THE FRONT. A SECOND BAND OF LOW CLOUDS AND EMBEDDED SHOWERS 
SURROUNDS A PRE-FRONTAL TROUGH ANALYZED FROM 30N47W TO 20N54W.   
GALE FORCE WINDS EXTEND UP TO 180 NM E OF THE FRONT N OF 27N AND 
W OF THE FRONT TO 68W N OF 28N. COLD AIR STRATOCUMULUS CLOUDS 
AROUND A 1023 MB SFC HIGH NEAR 31N76W COVER THE W ATLC BEHIND 
THE FRONT. EAST OF THE FRONT...A SFC RIDGE EXTENDS FROM A 1028 
MB HIGH NEAR 33N25W PROVIDING FAIR WEATHER ACROSS THE E ATLC. 
ALOFT...AN AMPLIFIED TROUGH/RIDGE/TROUGH PATTERN DOMINATES THE 
ATLC OCEAN BASIN. THE DEEP LAYERED TROUGH OVER THE W ATLC 
SUPPORTS THE AFOREMENTIONED COLD FRONT. A RIDGE EXTENDS OVER THE 
CENTRAL ATLC TO BEYOND THE AZORES. E OF THE RIDGE...ANOTHER DEEP 
LAYERED TROUGH AXIS STRETCHES FROM THE MADEIRA ISLANDS TO THE 
CAPE VERDE ISLANDS.  

$$
WADDINGTON