000
AXNT20 KNHC 171045
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT MAR 17 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL 
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN 
SECTIONS OF SOUTH AMERICA...AND THE 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 
0900 UTC.

...ITCZ...

ITCZ AXIS IS ALONG 2N9W 4N15W 3N21W 2N24W 4N30W EQ38W EQ47W. THE 
ITCZ HAS BECOME QUITE ACTIVE DURING THE PAST 12 HRS WITH 
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ALONG 
THE AXIS AND WITHIN 60 NM OF THE AXIS. 
  

...DISCUSSION...

GULF OF MEXICO...
A SHARP UPPER LEVEL TROUGH AXIS IS ALONG 85W AND CONTINUES TO 
DIG SEWD. A COLD FRONT EXTENDS FROM S FLORIDA SW TO WRN CUBA AND 
NE YUCATAN. THE FRONT IS MOVING SE 20 KT. NLY WINDS OF 20 TO 25 
KT ARE MAINLY E OF 90W THIS MORNING AND 15 TO 20 KT W OF 90W. 
HIGH PRESSURE IS BUILDING SE OVER THE AREA AND WILL SLOWLY MOVE 
EWD OVER THE NEXT 24 HR.

CARIBBEAN...
A SHORT-WAVE TROUGH IN THE MID LEVELS WAS ALONG 73W MOVING E 30 
KT. THE TROUGH IS SUPPORTING SCATTERED SHOWERS AND TSTMS OVER SE 
CUBA..THE SE BAHAMAS AND WRN HAITI THIS MORNING. A BROAD RIDGE 
DOMINATES THE ERN PORTION OF THE CARIBBEAN. STRONG SWLY WINDS OF 
50 TO 60 KT ARE ADVECTING UPPER LEVEL MOISTURE AND HIGH CLOUDS 
FROM CONVECTION OVER NRN SOUTH AMERICA. TRADE WINDS HAVE 
DECREASED OVER THE N CENTRAL CARIB AS THE ATLC RIDGE RECEDES 
EWD. MODERATE ELY WINDS CONTINUE OVER THE ERN PORTION. A COLD 
FRONT WILL MOVE SE OVER THE NW CARIBBEAN TODAY WITH INCREASING 
NLY WINDS OF 20 KT AND INCREASING ROUGH SEAS. A CHANCE OF 
SHOWERS AND TSTMS CAN BE EXPECTED ALONG THE FRONT. DRIER AND 
SLIGHTLY COOLER WEATHER WILL FOLLOW THE FRONT.

WESTERN AND CENTRAL ATLANTIC...
A BAND OF TSTMS EXTENDS FROM 31N75W S TO JUST NE OF THE BAHAMAS 
AND IS MOVING E 20 KT. THE TSTMS ARE AHEAD OF A COLD FRONT THAT 
EXTENDS FROM 31N76W TO SE FL. AN OLD FRONTAL BOUNDARY EXTENDS 
FROM NEAR 31N42W DIFFUSE TO 23N54W. ISOLATED CONVECTION 
CONTINUES ALONG THE BOUNDARY NEAR 30N43W. NEW CONVECTION HAS 
DEVELOPED IN A SMALL AREA WITHIN 60 NM OF 23N63W OUT AHEAD OF 
THE MID LEVEL TROUGH ALONG 73W. 

EASTERN ATLANTIC...
A STRONG HIGH WAS LOCATED WELL N OF THE REGION ALONG 30W AND 
EXTENDS SW OVER THE REGION. THE RIDGE IS PRODUCING STRONG NE 
WINDS WHICH IS MOSTLY DEVOID OF CLOUDINESS N OF THE CAPE VERDE 
ISLANDS AND E OF 32W. THE AIR PICKS UP MOISTURE AS IT MOVES SW 
OVER THE ATLC AND BROKEN LOW AND MID LEVEL CLOUDINESS DEVELOPS W 
OF 32W. THE CLOUDS CONTINUE WWD BECOMING MOSTLY SCATTERED W OF 
55W. THE ENTIRE AREA N OF 8N IS DEVOID OF ANY CONVECTION. A 
SUBTROPIC JET IS EVIDENT FROM NEAR 15N61W TO 18N47W THEN HEADS 
ESE TO 12N17W. A BAND OF CIRRUS CLOUDS ACCOMPANY THE JET MOSTLY 
W OF 40W. THE CIRRUS THINS OUT E OF 40W INDICATING A MOSTLY DRY 
UPPER ATMOSPHERE OVER THE ERN REGION. A UPPER LOW WAS LOCATED 
NEAR 31N20W MOVING S 20 KT AND WILL BE AFFECTING THE WRN CAPE 
VERDE ISLANDS LATER TODAY WITH SCATTERED SHOWERS AND TSTMS. 

$$
RRG