000
AXNT20 KNHC 091113
TWDAT 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT THU APR 09 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1015 UTC.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 5N8W 2N15W CROSSING THE EQUATOR NEAR 
18W AND EXTENDING TO 2S24W INTO NE BRAZIL NEAR 3S40W. SCATTERED 
MODERATE TO STRONG CONVECTION IS FROM 1N-5N BETWEEN 2W-8W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION IS WITHIN 240 NM 
OF AXIS BETWEEN 10W-20W.

...DISCUSSION...

GULF OF MEXICO...
SFC HIGH PRES CONTINUES TO SHIFT E NOW CENTERED OVER THE FAR SE 
WATERS NEAR THE DRY TORTUGAS. SLY RETURN FLOW TO THE W OF THE 
HIGH HAS MODIFIED THE COOL AIRMASS THAT WAS IN PLACE EARLIER 
THIS WEEK. WINDS ARE STRONGEST OVER THE W WATERS IN RESPONSE TO 
BROAD LOW PRES OVER THE PLAINS AND ROCKIES. THIS LOW PRESSURE 
SYSTEM WILL DRAG A COLD FRONT NEAR OR OVER THE NW GULF FRI. 
ALOFT...STRONG W TO NW FLOW LIES OVER THE REGION...BETWEEN 
RIDGING OVER THE CENTRAL CONUS AND LARGE SCALE TROUGHING OVER 
THE W ATLC...ADVECTING SOME PACIFIC HIGH LEVEL CLOUDINESS INTO 
THE WRN GULF. 

CARIBBEAN SEA...
A STATIONARY FRONT IS DISSIPATING FROM THE WINDWARD PASSAGE TO 
NICARAGUA. PATCHY LOW-MID LEVEL CLOUDS AND EMBEDDED ISOLATED 
SHOWERS ARE WITHIN 180 NM W OF THE FRONT. NLY WINDS HAVE 
DIMINISHED BELOW 20 KT NEAR THE FRONT. IN FACT...THE ONLY AREA 
OF 20 KT WINDS ARE NEAR THE COAST OF COLOMBIA. A WEAK INVERTED 
SFC TROUGH HAS MOVED ACROSS THE LESSER ANTILLES ALONG 64W FROM 
13N-18N. LOW-LEVEL CLOUDS AND EMBEDDED SCATTERED SHOWERS ARE 
WITHIN 180 NM E OF THE TROUGH AXIS. SIMILAR ACTIVITY IS 
OCCURRING OVER THE ISLAND OF HISPANIOLA ASSOCIATED WITH REMNANT 
TROUGHING AND LOCAL UPSLOPE CONDITIONS. ALL OF THE AREAS 
OUTLINED ARE SHALLOW IN NATURE CAPPED BY DRY AIR IN THE MID AND 
UPPER LEVELS.   

ATLANTIC OCEAN...
A LARGE SCALE MID-UPPER TROUGH OVER THE W ATLC IS PROVIDING SOME 
SUPPORT FOR A STATIONARY FRONT EXTENDING FROM 32N59W TO 26N65W 
THROUGH THE WINDWARD PASSAGE. LOW-LEVEL CONVERGENCE AND UPPER 
DIFFLUENCE IS PRODUCING SCATTERED SHOWERS WITHIN 180 NM E OF THE 
FRONT N OF 26N AND ISOLATED ACTIVITY WITHIN 180 NM EITHER SIDE S 
OF 26N. THIS FRONT IS EXPECTED TO STALL AND GRADUALLY DISSIPATE 
OVER THE NEXT DAY OR TWO. A WEAK SFC RIDGE IS BUILDING E OVER 
THE W ATLC BEHIND THE FRONT. DESPITE THE DECREASE IN WINDS OVER 
THE W ATLC...SEAS REMAIN QUITE ELEVATED N OF THE BAHAMAS IN NW 
SWELL. FARTHER E...AN UPPER LOW CENTERED NEAR 23N40W IS 
PRODUCING MULTILAYER CLOUDINESS AND EMBEDDED ISOLATED SHOWERS 
FROM 20N-24N BETWEEN 38W-43W. AN ASSOCIATED WEAK LOW-LEVEL 
TROUGH ALONG 52W FROM 22N-27N IS PRODUCING LITTLE SENSIBLE 
WEATHER. A SW TO W UPPER JET WITH CORE WINDS NEAR 100 KT 
ORIGINATES JUST E OF THE BASE OF THE UPPER TROUGH FROM 15N61W TO 
14N40W TO 23N31W TO 26N15W GENERATING AND ADVECTING MID-HIGH 
LEVEL CLOUDINESS WITHIN 300 NM SE OF THE JET AXIS. 

$$
CANGIALOSI