000
AXNT20 KNHC 170523
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0515 UTC.

...THE ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 5N7W 1N20W 1N40W CROSSING THE 
EQUATOR AT 44W...AND INTO NE BRAZIL NEAR 2S50W. WIDELY SCATTERED 
MODERATE CONVECTION IS FROM 2N-3N BETWEEN 19W-22W...FROM EQ-2N 
BETWEEN 27W-35W...AND FROM 2S-2N BETWEEN 44W-49W. 

...DISCUSSION...

GULF OF MEXICO...
A 1029 MB HIGH OVER THE OHIO VALLEY EXTENDS A RIDGE AXIS S TO 
THE YUCATAN PENINSULA PRODUCING ON-SHORE FLOW ALONG THE COASTS 
OF TEXAS AND NE MEXICO. BROKEN TO OVERCAST LOW CLOUDS WITH 
SCATTERED SHOWERS ARE N OF 24N AND W OF 92W. MOSTLY FAIR WEATHER 
IS OVER THE REMAINDER OF THE GULF OF MEXICO IN A RELATIVELY 
COOLER AND DRIER AIR MASS. 15-20 KT E WINDS ARE W OF 90W WHILE 
10-15 KT NE WINDS ARE E OF 90W. IN THE UPPER LEVELS...A RIDGE IS 
OVER THE GULF WITH AXIS OVER MEXICO ALONG 97W. 70-90 KT UPPER 
LEVEL WINDS ARE OVER THE N GULF N OF 28N. SIGNIFICANT UPPER 
LEVEL MOISTURE IS OVER THE N GULF N OF 26N. STRONG SUBSIDENCE 
COVERS THE REMAINDER OF THE GULF. EXPECT... CONTINUED SCATTERED 
SHOWERS OVER THE TEXAS AND LOUISIANA COASTS DUE TO RETURN FLOW 
FOR THE NEXT 24 HOURS.   
 
CARIBBEAN SEA...
THE TAIL END OF A DISSIPATING COLD FRONT IS OVER E CUBA AND THE 
NW CARIBBEAN ALONG 22N77W 20N87W. A SURFACE TROUGH IS OVER THE 
WINDWARD ISLANDS ALONG 67W S OF 16N. SCATTERED SHOWERS ARE FROM 
10N-16N BETWEEN 60W-71W. FRESH TRADEWINDS ARE OVER THE CARIBBEAN 
SEA WITH MORE ISOLATED PATCHES OF BROKEN LOW CLOUDS AND 
SCATTERED SHOWERS. SOME SHOWERS ARE NOTED OVER E CUBA...AND 
INLAND OVER HONDURAS AND NICARAGUA. IN THE UPPER LEVELS...AN 
UPPER LEVEL LOW IS OFF THE COAST OF COSTA RICA NEAR 10N82W. 
SIGNIFICANT MOISTURE IS OVER THE WINDWARD ISLANDS S OF 15N AND E 
OF 63W. STRONG SUBSIDENCE COVERS THE REMAINDER OF THE CARIBBEAN 
AND CENTRAL AMERICA. EXPECT THE UPPER LEVEL LOW TO DRIFT W OVER 
THE NEXT 24 HOURS. ALSO EXPECT THE SURFACE TROUGH TO MOVE W AND 
PRODUCE SHOWERS OVER N COLOMBIA AND THE SE CARIBBEAN FOR THE 
NEXT 24 HOURS. 

ATLANTIC OCEAN...
A 996 MB GALE LOW IS CENTERED IN THE W ATLC NEAR 33N66W. THE 
ATTENDANT COLD FRONT EXTENDS SW ACROSS THE CENTRAL BAHAMAS TO E 
CUBA ALONG 30N63W 22N77W. BROKEN TO OVERCAST LOW CLOUDS AND 
SCATTERED SHOWERS ARE WITHIN 45 NM OF THE FRONT. A SURFACE RIDGE 
AXIS IS OVER THE EASTERN AND CENTRAL ATLANTIC FROM 32N26W TO 
20N53W. A LARGE AREA OF BROKEN LOW CLOUDS ARE FROM EQ-24N 
BETWEEN 20W-48W. IN THE UPPER LEVELS... ZONAL FLOW IS OVER THE 
ATLANTIC N OF 20N. A RIDGE IS S OF 20N BETWEEN 30W-70W. ZONAL 
FLOW IS OVER THE REMAINDER OF THE ATLANTIC. EXPECT THE LOW N OF 
THE AREA TO MOVE NE TO 40N55W IN 24 HOURS AND RAPIDLY DEEPEN TO 
A 962 MB STORM WITH CONVECTION. THE ATTENDANT COLD FRONT WILL 
ENTER THE AREA NEAR 32N47W AND EXTEND S TO THE LEEWARD ISLANDS 
WITH SHOWERS.  

$$
FORMOSA