000
AXNT20 KNHC 221040
TWDAT 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT WED APR 22 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.

...THE ITCZ...
ITCZ AXIS IS CENTERED 5N10W 3N15W CROSSING THE EQUATOR NEAR 28W 
TO NE BRAZIL NEAR 3S43W. SCATTERED MODERATE CONVECTION IS S OF 
4N BETWEEN 14W-38W.

...DISCUSSION...

THE GULF OF MEXICO...
A LARGE DEEP LAYER TROUGH OVER THE EASTERN CONUS...WHICH 
PROVIDED SUPPORT FOR A COLD FRONT THAT MOVED THROUGH THE SE GULF 
TUE...IS DRAGGING A REINFORCING COLD FRONT FROM THE FLORIDA BIG 
BEND TO SE LOUISIANA. THE FRONT IS MAINLY DRY IN NATURE AS 
SATELLITE IMAGERY ONLY INDICATES LITTLE CLOUD COVER ALONG THE 
BOUNDARY.  BUOY OBS AND AN EARLIER QUIKSCAT DATA REVEAL W TO NW 
WINDS OF 15-20 KT IN THE VICINITY OF THE FRONT. SFC HIGH 
PRESSURE CENTERED OVER THE SW GULF NEAR 24N91W COUPLED WITH DEEP 
LAYER DRY AIR IS PROMOTING MAINLY FAIR WEATHER AND LIGHT WINDS 
OVER THE REMAINDER OF THE GULF. THE HIGH IS EXPECTED TO BUILD NE 
AND AMPLIFY OVER THE W ATLC...WHICH WILL INCREASE E TO SE FLOW 
OVER MUCH OF THE AREA BY THE END OF THE WEEK.

THE CARIBBEAN SEA... 
THE TAIL END OF A W ATLC FRONT EXTENDS FROM W CUBA TO THE 
BELIZE. MOIST SWLY UPPER FLOW AND SLIGHT LOW-LEVEL CONVERGENCE 
ALONG THE BOUNDARY IS LEADING TO A FEW SHOWERS OVER THE NW 
CARIBBEAN. A MORE SIGNIFICANT AREA OF UNSETTLED WEATHER LIES 
OVER THE EXTREME SW CARIBBEAN S OF 11N W OF 81W. THIS CONVECTIVE 
ACTIVITY IS PARTIALLY TIED TO THE ITCZ AND FURTHER ENHANCED BY 
AN UPPER DIFFLUENT PATTERN. STRONG WLY FLOW ALOFT IS ADVECTING 
SOME MOISTURE FROM THIS AREA INTO THE CENTRAL AND ERN CARIBBEAN 
BUT IT APPEARS TO BE ONLY IN THE FORM OF MID-HIGH LEVEL CLOUDS. 
TRADE WINDS REMAIN IN THE 20-30 KT RANGE OVER THE S CARIBBEAN... 
STRONGEST NEAR THE COAST OF COLOMBIA WHERE THERE IS A 
TOPOGRAPHIC ENHANCEMENT. THESE STRONG WINDS ARE EXPECTED TO 
EXPAND W OVER THE NEXT FEW DAYS AS STRONG HIGH PRES TAKES SHAPE 
OVER THE W ATLC.

THE ATLANTIC OCEAN...
SCATTERED SHOWERS AND ISOLATED TSTMS ARE WITHIN 300 NM E OF A 
COLD FRONT EXTENDING FROM 32N73W TO W CUBA. THIS ACTIVITY IS 
BEING ENHANCED BY STRONG SWLY UPPER FLOW AND A DIFFLUENT PATTERN 
BETWEEN THE ASSOCIATED TROUGH OVER THE ERN CONUS AND A RIDGE 
OVER THE CENTRAL ATLC. SLY 20-30 KT WINDS ARE N OF 28N WITHIN 
420 NM E OF THE FRONT DUE TO THE TIGHT PRESSURE GRADIENT BETWEEN 
THE FRONT AND STRONG HIGH PRES NE OF BERMUDA. OVER THE CENTRAL 
ATLC...DEEP LAYER TROUGHING REMAINS WELL DEFINED PROVIDING 
SUPPORT FOR A FRONT EXTENDING FROM 32N38W TO 30N45W THEN 
ANALYZED AS A TROUGH TO 27N58W. A WEAK LOW HAS BROKEN OFF FROM 
THE BASE OF THE TROUGH AND IS NOW BEING CARRIED WWD BY THE 
LOW-LEVEL FLOW. LITTLE SIGNIFICANT PRECIP IS ASSOCIATED WITH THE 
FRONT/LOW. HOWEVER...THE TIGHT PRESSURE GRADIENT BETWEEN THE 
FRONT AND HIGH PRES TO ITS N IS PRODUCING STRONG NE FLOW. A 
NARROW SWATH OF SCATTERED SHOWERS AND TSTMS ARE LOCATED NEAR THE 
UPPER TROUGH AXIS...WHICH HAS A WEAK SURFACE CONNECTION...N OF 
28N BETWEEN 32W-37W. AN UPPER JET EXTENDING NE FROM THE WINDWARD 
ISLANDS TO 20N30W IS ADVECTING SOME MOISTURE WITHIN 240 NM E OF 
THE JET AXIS. 

$$
CANGIALOSI