000
AXNT20 KNHC 160549
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SAT MAY 16 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...

FROM THE LIBERIA COAST NEAR 6N10W TO 3N14W TO THE EQUATOR ALONG 
23W...TO 3S36W INTO NORTHEASTERN BRAZIL NEAR 7S41W. ISOLATED AND 
DISORGANIZED MODERATE SHOWERS ARE TO THE SOUTH OF 4N TO THE EAST 
OF 20W...AND TO THE SOUTH OF 3N BETWEEN 20W AND 50W.

...DISCUSSION...

THE GULF OF MEXICO...
LARGE SCALE UPPER LEVEL ANTICYCLONIC FLOW MOVES FROM THE EASTERN 
PACIFIC OCEAN ACROSS MEXICO INTO THE GULF OF MEXICO. SOME OF THE 
CYCLONIC FLOW THAT HAS BEEN ASSOCIATED WITH THE BAHAMAS-TO-CUBA-
SOUTHWESTERN CARIBBEAN SEA TROUGH OF YESTERDAY HAS MOVED INTO 
THE SOUTHEASTERN CORNER OF THE GULF OF MEXICO. MOST OF THE UPPER 
LEVEL NORTHWESTERLY WIND FLOW THAT IS ON THE EASTERN SIDE OF THE 
RIDGE REACHES 85W...AND INSTEAD OF PASSING THROUGH THE YUCATAN 
CHANNEL...THAT FLOW MOVES TOWARD THE SMALL CYCLONIC CIRCULATION 
CENTER THAT HAS MOVED INTO THE STRAITS OF FLORIDA. MODERATE TO 
STRONG SHOWERS AND THUNDERSTORMS HAVE DEVELOPED FROM SOUTH 
CENTRAL TEXAS INTO NORTHEASTERN MEXICO IN ADVANCE OF A DEEP 
LAYER TROUGH THAT IS MOSTLY IN TEXAS BUT THAT ENTERS FAR 
NORTHEASTERN MEXICO A SURFACE TROUGH IS ALONG 83W/84W TO THE 
SOUTH OF 28N. ISOLATED MODERATE SHOWERS ARE IN THE AREA FROM
THE GULF OF TEHUANTEPEC TO 23N100W. A SURFACE TROUGH CONTINUES
TO RUN THROUGH CENTRAL MEXICO IN THE SAME AREA AS THE CONVECTIVE
PRECIPITATION.

THE CARIBBEAN SEA...
A MIDDLE LEVEL TO UPPER LEVEL TROUGH EXTENDS FROM THE STRAITS OF
FLORIDA...ACROSS CUBA TO 150 NM TO THE WEST OF JAMAICA...INTO 
THE SOUTHWESTERN CORNER OF THE AREA. THIS TROUGH HAS PERSISTED 
IN MORE OR LESS THE SAME AREA FOR AT LEAST THE LAST 48 HOURS OR 
SO. MOIST UPPER LEVEL SOUTHWESTERLY WIND FLOW IS ON THE EASTERN 
SIDE OF THE TROUGH ACROSS THE REMAINDER OF THE CARIBBEAN SEA TO 
THE EAST OF 70W. THE CYCLONIC FLOW AROUND THE TROUGH COVERS THE 
AREA ROUGHLY FROM THE MONA PASSAGE TO THE COAST OF NORTHERN 
COLOMBIA. ISOLATED MODERATE SHOWERS ARE IN THE AREA TO THE NORTH 
OF THE LINE FROM THE WESTERN TIP OF CUBA TO 16N82W TO SOUTHERN 
HAITI. 

THE ATLANTIC OCEAN...
A DEEP LAYER TROUGH EXTENDS FROM A 32N53W CYCLONIC CIRCULATION 
CENTER TO 26N54W TO 22N62W. THIS TROUGH SUPPORTS A SURFACE COLD 
FRONT THAT EXTENDS FROM A 1003 MB GALE CENTER NEAR 35N53W TO
30N50W 26N56W 24N62W...CONTINUING AS A STATIONARY FRONT TO 
25N71W. A PRE-FRONTAL TROUGH IS WITHIN 150 NM TO THE EAST OF THE 
FRONT FROM 23N TO 33N. MODERATE SHOWERS ARE TO THE NORTH OF 24N 
BETWEEN 48W AND 55W. 

PASSES THROUGH 32N54W TO 28N60W TO 27N65W. 
A STATIONARY FRONT CONTINUES FROM 27N65W TO 30N70W AND 33N75W. 
PRECIPITATION IS DISSIPATING WITHIN A 30 NM RADIUS OF 26N54W. 
SHOWERS AND POSSIBLE THUNDERSTORMS STILL ARE FROM 30N TO 31N 
BETWEEN 50W AND 51W. THE REMNANTS OF AN EARLIER MIDDLE LEVEL
TO UPPER LEVEL TROUGH ARE ALONG THE LINE FROM 33N24W TO 22N32W.

$$
MT