000
AXNT20 KNHC 211740
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU MAY 21 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1715 UTC.

...TROPICAL WAVES...
A TROPICAL WAVE IS ALONG 73W SOUTH OF 13N MOVING WEST ABOUT 15 
KT. LOW LEVEL CYCLONIC TURNING IS NOTED OVER N COLOMBIA... 
HOWEVER THAT MAY BE DUE TO A 1008 MB LOW LOCATED W OF THE WAVE. 
SCATTERED SHOWERS ARE WITHIN 120 NM OF THE WAVE AXIS.  

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 7N12W 4N20W 2N30W EQ36W 3S41W.
ISOLATED MODERATE CONVECTION IS OFF THE COAST OF W AFRICA FROM 
1N-5N BETWEEN 10W-15W. SCATTERED MODERATE CONVECTION IS FROM 
1N-4N BETWEEN 27W-37W. 

...DISCUSSION...

THE GULF OF MEXICO...
A 1006 MB LOW IS OVER THE E GULF OF MEXICO NEAR 26N86W. BANDS OF 
WIDELY SCATTERED MODERATE CONVECTION ARE OVER THE NE GULF OF 
MEXICO AND FLORIDA FROM 24N-29N BETWEEN 80W-86W. A TIGHT 
PRESSURE GRADIENT OVER THE NE GULF IS PRODUCING 20-25 KT WINDS N 
OF 27N E OF 90W. THE W GULF OF MEXICO W OF 90W HAS PARTLY CLOUDY 
SKIES WITH 10-15 KT N WINDS. IN THE UPPER LEVELS...AN UPPER 
LEVEL LOW IS CENTERED OVER THE E GULF NEAR 28N85W. THE NE GULF 
AND FLORIDA HAS ABUNDANT UPPER AIR MOISTURE WHILE STRONG 
SUBSIDENCE IS OVER THE REMAINDER OF THE GULF. EXPECT...THE 
SURFACE LOW TO DRIFT NW TO THE CENTRAL GULF OF MEXICO OVER THE 
NEXT 24 HOURS WITH CONVECTION MOSTLY N OF THE CENTER. 

THE CARIBBEAN SEA...
A 1008 MB LOW IS OVER N COLOMBIA NEAR 10N76W. SCATTERED MODERATE 
CONVECTION IS OVER THE GULF OF URABA AND N COLOMBIA FROM 7N-10N 
BETWEEN 76W-78W. FURTHER N...SCATTERED MODERATE TO ISOLATED 
STRONG CONVECTION IS OVER E CUBA...HAITI...AND JAMAICA FROM 
16N-22N BETWEEN 72W-78W...DUE TO UPPER LEVEL DIFFLUENCE SE OF 
THE GULF OF MEXICO UPPER LEVEL LOW. A TROPICAL WAVE IS MOSTLY 
OVER INLAND COLOMBIA PRODUCING SHOWERS. SEE ABOVE. EXPECT... 
CONTINUED CONVECTION FROM THE SW TO NE CARIBBEAN OVER THE NEXT 
24 HOURS.  

THE ATLANTIC OCEAN...
A TIGHT SURFACE PRESSURE GRADIENT IS PRODUCING 20-25 KT WINDS 
ALONG THE COAST OF NE FLORIDA. SCATTERED MODERATE TO ISOLATED 
STRONG CONVECTION IS ALONG THE COAST OF E FLORIDA AND THE N 
BAHAMAS FROM 23N-30N BETWEEN 76W-80W DUE TO UPPER LEVEL 
DIFFLUENCE E OF THE GULF OF MEXICO UPPER LEVEL LOW. A 1015 MB 
LOW IS CENTERED OVER THE CENTRAL ATLANTIC NEAR 28N55W. THE TAIL 
END OF A COLD FRONT IS W OF THE CANARY ISLANDS ALONG 32N17W 
28N20W 25N26W. SCATTERED SHOWERS ARE WITHIN 30 NM OF THE FRONT.  
IN THE UPPER LEVELS...AN UPPER LEVEL LOW IS OVER THE W ATLANTIC 
NEAR 31N64W. ANOTHER UPPER LEVEL LOW IS CENTERED NEAR 30N45W. A 
THIRD UPPER LEVEL LOW IS CENTERED OVER THE E ATLANTIC NEAR 
35N20W. MOSTLY ZONAL FLOW IS OVER THE ATLANTIC FROM 15N-25N.
IN THE TROPICS...UPPER LEVEL HIGH IS CENTERED NEAR 6N20W. A 
RIDGE AXIS EXTENDS W FROM THE UPPER LEVEL HIGH TO 4N50W. 
EXPECT...CONVECTION TO CONTINUE OVER FLORIDA...THE BAHAMAS...AND 
N OF THE LEEWARD ISLANDS FOR THE NEXT 24 HOURS. 

$$
FORMOSA