000
AXNT20 KNHC 220539
TWDAT 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 0515 UTC.

...THE ITCZ...
ITCZ AXIS IS CENTERED 6N11W 3N20W CROSSING THE EQUATOR NEAR 28W 
TO NE BRAZIL NEAR 3S43W. SCATTERED MODERATE CONVECTION IS S OF 
4N BETWEEN 15W-36W.

...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. LIGHTNING DATA AND DOPPLER RADAR SHOW A 
NARROW LINE OF SCATTERED SHOWERS AND ISOLATED TSTMS ALONG THE 
BOUNDARY. BUOY OBS AND QUIKSCAT DATA REVEAL W TO NW WINDS NEAR 
20 KT IN THE VICINITY OF THE FRONT. SFC HIGH PRESSURE CENTERED 
OVER THE SW GULF NEAR 24N95W 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 IS STALLED FROM W CUBA TO THE 
CENTRAL YUCATAN PENINSULA. MOIST SWLY UPPER FLOW AND SLIGHT 
LOW-LEVEL CONVERGENCE ALONG THE BOUNDARY IS LEADING TO ISOLATED 
SHOWERS AND TSTMS OVER THE NW CARIBBEAN. A MORE SIGNIFICANT AREA 
OF UNSETTLED WEATHER LIES OVER THE EXTREME SW CARIBBEAN S OF 11N 
BETWEEN 81W AND 84W. 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 
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 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 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 32N39W TO 30N44W THEN ANALYZED AS A TROUGH 
TO 26N57W. A WEAK LOW HAS BROKEN OFF FROM THE BASE OF THE TROUGH 
AND IS NOW BEING CARRIED WWD BY THE LOW-LEVEL FLOW. WHILE LITTLE 
SIGNIFICANT PRECIP IS NOTED ALONG THE FRONT...STRONG NE FLOW IS 
NOTED N OF THE BOUNDARY. A NARROW SWATH OF SCATTERED SHOWERS AND 
TSTMS ARE LOCATED IN THE UPPER DIFFLUENT ZONE N OF 23N BETWEEN 
25W-36W. AN UPPER JET EXTENDING NE FROM THE WINDWARD ISLANDS TO 
20N30W IS ADVECTING SOME MOISTURE WITHIN 240 NM E OF THE JET 
AXIS. OTHERWISE...THE E ATLC IS DOMINATED BY A STRONG AZORES 
HIGH.

$$
CANGIALOSI