000
AXNT20 KNHC 172338
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST TUE FEB 17 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 
2315 UTC.

...THE ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 4N8W 1N20W CROSSING THE EQUATOR 
AT 38W...AND INTO NE BRAZIL NEAR 2S45W. SCATTERED MODERATE TO 
ISOLATED STRONG CONVECTION IS WITHIN 150 NM N OF THE AXIS 
BETWEEN 21W-28W AND BETWEEN 32W-39W. SCATTERED MODERATE 
CONVECTION IS ALSO WITHIN 150 NM OF THE NE BRAZIL COAST BETWEEN 
40W-50W. 

...DISCUSSION...

GULF OF MEXICO...
A 1027 MB HIGH OVER SOUTH CAROLINA EXTENDS A RIDGE ACROSS THE 
FLORIDA PENINSULA AND 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. THE HIGH PRESSURE WILL MOVE SE INTO THE W 
ATLC OVER THE NEXT 24 HOURS ALLOWING THE NEXT COLD FRONT TO 
ENTER THE NW GULF WED AFTERNOON. IN THE UPPER LEVELS...A RIDGE 
EXTENDS FROM THE E PACIFIC REGION ACROSS MEXICO AND THE GULF 
GENERATING NW FLOW...ALLOWING MODERATE SUBSIDENCE S OF 26N AND 
PROMOTING STABLE ATMOSPHERIC CONDITIONS ACROSS THE SRN GULF AND 
YUCATAN PENINSULA THIS EVENING.  

CARIBBEAN SEA...
THE TAIL END OF A COLD FRONT EXTENDING FROM THE W ATLC IS OVER 
NRN HISPANIOLA WITH BROKEN LOW CLOUDS AND ISOLATED SHOWERS 
WITHIN 90 NM SE OF THE FRONT. HIGH PRESSURE NW OF THE COLD 
FRONT...CENTERED OVER SOUTH CAROLINA...COVERS CUBA AND THE NW 
CARIBBEAN. NE WINDS AROUND THE SRN PERIPHERY OF THIS HIGH ARE 
TRANSPORTING SCATTERED COLD AIR STRATOCUMULUS CLOUDS FROM THE W 
ATLC INTO THE NW CARIBBEAN W OF 75W. FURTHER E...A SURFACE 
TROUGH REMAINS OVER THE ERN CARIBBEAN WITH AXIS ALONG 68W/69W S 
OF 17N. THIS TROUGH IS GENERATING A LARGE AREA OF LOW/MID CLOUDS 
WITH ISOLATED SHOWERS OVER THE ABC ISLANDS. THE TRADE WINDS WILL 
START TO INCREASE ACROSS THE BASIN OVER THE NEXT 24 HOURS AS 
HIGH PRESSURE OVER THE W ATLC TIGHTENS THE PRESSURE GRADIENT 
OVER THE CARIBBEAN. IN THE UPPER LEVELS...A TROUGH IS ACROSS 
CENTRAL AMERICA AND THE WRN CARIBBEAN W OF 80W WHILE A RIDGE 
EXTENDS FROM THE WRN TROPICAL ATLC ACROSS THE ERN AND CENTRAL 
CARIBBEAN TO 80W. STRONG SUBSIDENCE IS NOTED OVER THE WRN 
CARIBBEAN W OF 75W. 

ATLANTIC OCEAN...
A VERY STRONG EXTRATROPICAL CYCLONE WITH HURRICANE FORCE WINDS 
IN THE WRN SEMICIRCLE IS SPINNING OVER THE W-CENTRAL ATLC OCEAN 
NEAR 37N58W. THE ATTENDANT COLD FRONT ENTERS THE FORECAST AREA 
NEAR 32N52W THEN CONTINUES SW ALONG 23N60W TO 20N70W AND ACROSS 
NRN HISPANIOLA. A WELL DEFINED BAND OF LOW/MID CLOUDS WITH 
EMBEDDED SHOWERS IS WITHIN 90 NM E OF THE FRONT. THIS SHOWER 
ACTIVITY WILL CONTINUE TO IMPACT HISPANIOLA AND PUERTO RICO 
THROUGH THE EVENING. THE REMAINDER OF THE ATLC IS UNDER THE 
INFLUENCE OF A RIDGE ANCHORED ON A HIGH LOCATED WELL N OF 
REGION. THIS HIGH IS GENERATING MOSTLY FAIR WEATHER WITH 
MODERATE TO FRESH NE TRADE WINDS NOTED ACROSS THE TROPICS. 
ALOFT...AN AMPLIFIED TROUGH/RIDGE/TROUGH PATTERN DOMINATES THE 
ATLC OCEAN BASIN. THE DEEP LAYERED TROUGH OVER THE W ATLC 
SUPPORTS THE ABOVE MENTIONED COLD FRONT. A RIDGE EXTENDS OVER 
THE CENTRAL ATLC TO BEYOND THE AZORES ISLANDS. E OF THE 
RIDGE...ANOTHER DEEP LAYERED TROUGH AXIS STRETCHES FROM THE 
MADEIRA ISLANDS TO THE CAPE VERDE ISLANDS. W-NW UPPER-LEVEL FLOW 
COVERS THE DEEP TROPICS S OF 20N. 

$$
HUFFMAN