000
AXNT20 KNHC 202227
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI APR 20 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2215 UTC.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 8N10W 4N20W 2N31W 1N40W CROSSING THE 
EQUATOR TO INLAND OVER SOUTH AMERICA NEAR 50W. SCATTERED 
MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 150 NM N OF THE 
ITCZ AXIS FROM 23W-34W AND WITHIN 150 NM S OF THE ITCZ AXIS FROM 
28W-35W. CLUSTERS OF SIMILAR CONVECTION ARE WITHIN 180 NM OF THE 
AXIS FROM 35W-48W. 

...DISCUSSION...

GULF OF MEXICO...
BROAD UPPER RIDGE COVERS THE GULF EXTENDING FROM SOUTH AMERICA 
ACROSS THE CARIBBEAN INTO THE GULF THROUGH THE YUCATAN CHANNEL 
TO OVER THE SE US. THIS CONTINUES TO PUMP TROPICAL MOISTURE 
ACROSS MEXICO AND THE W GULF GENERATING ONLY SCATTERED HIGH 
CLOUDS. DISSIPATING FRONTAL BOUNDARY EXTENDS FROM A 1012 MB LOW 
IN THE W ATLC ACROSS FLORIDA NEAR LAKE OKEECHOBEE TO ALONG THE 
COAST OF LOUISIANA. DRY AIR AT THE LOWER LEVELS ARE LIMITING 
SHOWERS. LIGHT EASTERLY WINDS DOMINATE THE ENTIRE AREA. SURFACE 
RIDGE IS BUILDING S FROM OVER THE E US BRIDGING THE DYING 
FRONTAL BOUNDARY AND ENCOMPASSES THE GULF AND SHALL REMAIN 
THROUGH THE WEEKEND. 

CARIBBEAN SEA...
DEEP LAYERED TROUGH OVER THE W ATLC DRAPES A DISSIPATING COLD 
FRONT ACROSS E CUBA NEAR 20N76W TO OFF THE COAST OF HONDURAS 
NEAR 16N84W. BROKEN/OVERCAST LOW CLOUDS WITH ISOLATED SHOWERS 
ARE WITHIN 120 NM SE OF THE FRONT. THE UPPER LEVELS HOWEVER ARE 
DOMINATED BY A BROAD UPPER RIDGE ANCHORED INLAND OVER SOUTH 
AMERICA. THIS UPPER RIDGE IS PUMPING TROPICAL MOISTURE ACROSS 
THE S CARIBBEAN GENERATING SHOWERS/THUNDERSTORMS OVER COLOMBIA 
AND NW VENEZUELA INTO THE COASTAL WATERS FROM 68W-76W. THE ITCZ 
AXIS EXTENDS OVER PANAMA GENERATING SIMILAR ACTIVITY INLAND AND 
ALONG THE COASTAL WATERS OF PANAMA E OF 82W. 

ATLANTIC OCEAN...
THE DEEP LAYERED TROUGH COVERS THE W ATLC INTO THE CENTRAL ATLC 
N OF 20N E OF 47W TO FLORIDA WITH THE ASSOCIATED COLD FRONT 
EXTENDING THROUGH 32N56W OVER THE TURKS AND CAICOS TO E CUBA 
NEAR 20N76W AND DISSIPATES IN THE CARIBBEAN. EMBEDDED WITHIN 
THIS BROAD UPPER TROUGH IS A 1`012 MB LOW OFF THE COAST OF 
FLORIDA NEAR 29N79W WITH A DISSIPATING FRONTAL BOUNDARY 
EXTENDING W ACROSS FLORIDA NEAR LAKE OKEECHOBEE. BROAD UPPER 
RIDGE COVERS THE E/CENTRAL ATLC FROM 30W-47W WITH ENOUGH 
DIFFLUENCE TO GENERATE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS 
E OF THE FRONT WITHIN 75 NM OF LINE FROM 20N65W TO BEYOND 
32N48W. A DEEP LAYERED LOW IS NE OF THE AREA OFF THE COAST OF 
GIBRALTAR WITH THE UPPER LOW COVERING THE AREA N OF 23N E OF 
25W. HIGH PRESSURE COVERS THE E ATLC N OF 20N FROM AFRICA COAST 
TO 45W ANCHORED BY A 1023 MB HIGH NEAR 33N29W. DRY AIR DOMINATES 
THE E ATLC AS WELL AS THE TROPICAL ATLC...LIMITING SHOWER 
ACTIVITY AND PUSHING THE ITCZ TO THE S.  

$$
WALLACE