000
AXNT20 KNHC 060005
TWDAT 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SUN APR 05 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 LIBERIA NEAR 6N10W TO THE EQUATOR ALONG 21W/22W...2S30W
INTO NORTHEASTERN BRAZIL NEAR 6S39W. ISOLATED AND DISORGANIZED
MODERATE SHOWERS ARE SOUTH OF SOUTH OF 6N EAST OF 23W...AND
SOUTH OF 12N BETWEEN 44W AND 56W. STRONG SHOWERS AND 
THUNDERSTORMS ARE OCCURRING IN THE NORTHERN HALF OF FRENCH 
GUIANA.

...DISCUSSION...

THE GULF OF MEXICO...
BROAD UPPER LEVEL ANTICYCLONIC FLOW FROM A RIDGE COVERS THE GULF 
OF MEXICO. THE DEEP LAYER TROUGH THAT SUPPORTS THE CURRENT
COASTAL TEXAS/EXTREME NORTHWESTERN GULF OF MEXICO COLD FRONT
RUNS MOSTLY FROM IOWA TO MISSOURI TO ARKANSAS AND OKLAHOMA.
HIGH LEVEL MOISTURE CURVES ANTICYCLONICALLY ACROSS MORE OR LESS
THE NORTHERNMOST ONE-THIRD OF THE BASIN. A SURFACE TROUGH IS FROM
150 NM TO 250 NM TO THE EAST-SOUTHEAST OF THE COLD 
FRONT...PASSING THROUGH SOUTHEASTERN MISSISSIPPI TO SOUTHEASTERN 
LOUISIANA...TO 28N90W IN THE GULF WATERS TO 25N97W NEAR COASTAL 
NORTHEASTERN MEXICO. THE COLD FRONT PASSES THROUGH THE UPPER 
TEXAS COAST NEAR THE BORDER WITH LOUISIANA TO THE MIDDLE TEXAS 
COAST TO THE TEXAS BORDER WITH MEXICO CROSSING THE FALCON 
RESERVOIR. NO DEEP CONVECTIVE ACTIVITY IS OCCURRING RIGHT NOW 
WITH THIS FEATURE.

THE CARIBBEAN SEA...
A WEAK SURFACE PRESSURE GRADIENT EXISTS IN THE AREA FOR THIS 
MAP. A SURFACE TROUGH IS CROSSING PUERTO RICO...FROM 13N TO 20N
ALONG 66W/67W. BROKEN TO OVERCAST MULTILAYERED CLOUDS AND 
POSSIBLE SHOWERS COVER THE CARIBBEAN SEA FROM 13N TO 17N BETWEEN 
64W AND 68W...AND AROUND PUERTO RICO FROM 17N TO 19N BETWEEN 65W 
AND 68W. MOSTLY MIDDLE LEVEL TO UPPER LEVEL NORTHWESTERLY WINDS 
AND DRY AIR IN SUBSIDENCE COVER THE AREA. LARGE-SCALE
ANTICYCLONIC FLOW FROM THE GULF OF MEXICO RIDGE COVERS THE
AREA WEST OF 71W. A HINT OF MIDDLE LEVEL TO UPPER LEVEL CYCLONIC 
FLOW IS PRESENT TO THE EAST OF 71W...GIVEN THE ATLANTIC OCEAN 
TROUGH THAT CUTS ACROSS THE EASTERN ISLANDS.

THE ATLANTIC OCEAN...
A WESTERN ATLANTIC DEEP LAYER TROUGH SUPPORTS THE CURRENT 
ATLANTIC OCEAN COLD FRONT THAT PASSES THROUGH 32N60W TO 27N66W
TO 25N71W. A DISSIPATING STATIONARY CONTINUES TO 25N75W. 
ISOLATED MODERATE SHOWERS ARE MOVING AWAY FROM THE COAST OF 
SOUTH CAROLINA. SHOWERS AND POSSIBLE THUNDERSTORMS ARE FROM
25N TO 26N BETWEEN 64W AND 66W...AND WITHIN 30 NM ON EITHER
SIDE OF 31N60W 29N64W. THE SOUTHERNMOST EXTENT OF THIS WESTERN 
ATLANTIC OCEAN DEEP LAYER TROUGH CUTS ACROSS THE ISLANDS OF THE
EASTERN CARIBBEAN SEA. A 1018 MB LOW PRESSURE CENTER IS NEAR 
29N42W...UNDER A 28N39W MIDDLE LEVEL TO UPPER LEVEL CYCLONIC 
CIRCULATION CENTER.

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