000
AXNT20 KNHC 180514
TWDAT 

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

...THE ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 7N11W 3N15W CROSSING THE EQUATOR 
NEAR 23W THEN ALONG 1S30W AND INTO NE BRAZIL NEAR 3S42W. 
SCATTERED MODERATE CONVECTION IS WITHIN 50 NM N OF THE AXIS 
BETWEEN 13W-18W. CLUSTERS OF MODERATE CONVECTION ARE FROM 1N-3N 
BETWEEN 26W-28W AND FROM 1N-3N BETWEEN 32W-40W. SCATTERED 
MODERATE TO STRONG CONVECTION IS ALONG THE COAST OF BRAZIL S OF 
2N AND W OF 41W.

...DISCUSSION...

GULF OF MEXICO...
A 1025 MB SFC HIGH OFF THE COAST OF THE CAROLINAS EXTENDS A SFC 
RIDGE ACROSS FLORIDA AND THE GULF OF MEXICO PRODUCING MOSTLY 
FAIR WEATHER. SCATTERED MULTI-LAYERED CLOUDS ARE OBSERVED OVER 
THE WRN 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 LATER THIS AFTERNOON AS THE HIGH PRESSURE SHIFTS SE INTO 
THE W ATLC. ALOFT...A RIDGE EXTENDS NE FROM THE PACIFIC 
GENERATING STRONG NW FLOW IN THE NRN GULF. MODERATE SUBSIDENCE S 
OF 26N IS MAINTAINING MOSTLY CLEAR CONDITIONS ACROSS THE SRN 
GULF THIS MORNING.

CARIBBEAN SEA...
A COLD FRONT EXTENDS FROM THE ATLC ALONG THE N COAST OF PUERTO 
RICO AND ACROSS HISPANIOLA. SCATTERED SHOWERS ARE WITHIN 40 NM 
OF THE FRONT...AFFECTING THE GREATER ANTILLES AND THE CARIBBEAN 
N OF 17N. 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 
IS MOVING ACROSS THE CENTRAL CARIBBEAN AND IS ANALYZED FROM 
16N69W TO THE VENEZUELAN COAST NEAR 11N70W. THIS TROUGH IS 
GENERATING A LARGE AREA OF LOW/MID CLOUDS WITH ISOLATED SHOWERS 
S OF 16N BETWEEN 65W-73W. STRONG SWLY FLOW ALOFT IS SUPPORTING 
CONVECTION ALONG THIS FEATURE. PATCHY CLOUDS COVER THE CARIBBEAN 
W OF 73W DUE TO STRONG SUBSIDENCE ALOFT. EXPECT TRADE WIND FLOW 
TO INCREASE TO 25 KT...30 KT ALONG THE COAST OF COLOMBIA AND SW 
OF THE MONA PASSAGE...AS HIGH PRESSURE MOVES INTO THE W ATLC.

ATLANTIC OCEAN...
AN INTENSE 962 MB EXTRATROPICAL LOW PRESSURE SYSTEM WITH 
HURRICANE FORCE WINDS IS SPINNING OVER THE N CENTRAL ATLC NEAR 
38N54W. THIS SYSTEM EXTENDS A COLD FRONT THAT ENTERS THE 
DISCUSSION AREA NEAR 31N50W AND CONTINUES ALONG 25N55W 21N60W TO 
THE N COAST OF PUERTO RICO AND INTERIOR HISPANIOLA. MULTI-LEVEL 
CLOUDS AND SCATTERED SHOWERS ARE NOTED WITHIN 50 NM OF THE 
FRONT. ANOTHER BAND OF LOW CLOUDS AND POSSIBLE EMBEDDED SHOWERS 
IS AHEAD OF THE FRONT WITHIN 40 NM OF A LINE 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 FILL IN THE W ATLC BEHIND THE FRONT. EXPECT HIGH PRESSURE 
TO BUILD IN THIS REGION OVER THE NEXT 24 HOURS. EAST OF THE 
FRONT...A SFC RIDGE EXTENDS FROM A 1029 MB HIGH NEAR 33N26W 
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