000
AXNT20 KNHC 200005
TWDAT 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SUN APR 19 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...
FROM 2N AT THE PRIME MERIDIAN...CROSSING THE EQUATOR ALONG
4W TO 3S20W 4S30W INTO NORTHEASTERN BRAZIL NEAR 3S44W. 
ISOLATED MODERATE SHOWERS TO LOCALLY STRONG THUNDERSTORMS
FROM 2.5N TO 5N BETWEEN 13W AND 18W.

...DISCUSSION...

THE GULF OF MEXICO...
MIDDLE LEVEL TO UPPER LEVEL FLOW CROSSES INTERIOR MEXICO...HITS 
THE SIERRA MADRE ORIENTAL MOUNTAIN RANGE...AND VOILA SHOWERS AND 
THUNDERSTORMS HAVE ERUPTED ALONG THE RANGE FROM JUST OFF THE 
WESTERN PART OF THE ISTHMUS OF TEHUANTEPEC NORTHWARD TO A SPOT
A LITTLE BIT TO THE EAST OF SALTILLO IN THE STATE OF COAHUILA.
BROAD AND GRADUAL MIDDLE LEVEL TO UPPER LEVEL ANTICYCLONIC FLOW 
COVERS THE GULF OF MEXICO. A DEEP LAYER TROUGH THAT IS MOVING 
FROM THE CENTRAL U.S.A. EASTWARD REACHES AS FAR TO THE SOUTH AS 
THE NORTH CENTRAL GULF WATERS...SPARKING SOME PRECIPITATION 
THERE. THIS TROUGH SUPPORTS THE MOST CURRENT COLD FRONT THAT 
PASSES THROUGH SOUTHWESTERN LOUISIANA TO THE LOWER TEXAS COAST.
 
THE CARIBBEAN SEA... 
BROAD MIDDLE TO UPPER LEVEL NORTHWESTERLY-TO-WESTERLY WIND FLOW 
COVERS THE ENTIRE AREA. UPPER LEVEL SOUTHWESTERLY WIND FLOW
MOVES FROM EXTREME NORTHWESTERN VENEZUELA ACROSS THE REST OF THE 
CARIBBEAN SEA...AND EXITS THE AREA AS IT PASSES ON TOP OF THE 
EASTERN CARIBBEAN SEA ISLANDS...FROM THE GUADELOUPE PASSAGE 
SOUTHWARD. DEEP LAYER CYCLONIC FLOW COVERS THE CARIBBEAN SEA
TO THE NORTH OF 15N TO THE EAST OF 71W...AS A DEEP LAYER TROUGH 
FROM THE ATLANTIC OCEAN EXTENDS INTO THE NORTHEASTERN CORNER OF 
THE AREA. 

THE ATLANTIC OCEAN...
A WESTERN ATLANTIC OCEAN DEEP LAYER TROUGH SUPPORTS A COLD FRONT 
THAT EXTENDS FROM A 1017 MB LOW PRESSURE CENTER NEAR 28N56W TO 
23N60W TO THE MONA PASSAGE. THIS DEEP LAYER TROUGH IS THE SAME 
ONE WHOSE SOUTHERN END REACHES INTO THE NORTHEASTERN CARIBBEAN 
SEA. A WARM FRONT EXTENDS FROM THE 28N56W LOW PRESSURE CENTER
TO 31N51W. ISOLATED MODERATE SHOWERS AND POSSIBLE THUNDERSTORMS
ARE WITHIN 30 NM OR LESS ON EITHER SIDE OF 13N60W 16N58W 
19N56W...AND WITHIN 60 NM OR LESS ON EITHER SIDE OF 22N55W 
27N53W BEYOND 32N50W. A SURFACE RIDGE IS ALONG 16N51W 22N43W 
27N38W BEYOND A 1029 MB HIGH PRESSURE CENTER NEAR 33N26W. 
AN UPPER LEVEL TROUGH EXTENDS FROM A BROAD CYCLONIC CIRCULATION 
CENTER NEAR 27N20W TO 13N28W.

$$
MT