000
AXNT20 KNHC 300504
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT MON APR 30 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0445 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 6N10W 2N21W 3N34W 1N43W 1N52W. 
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE 
WITHIN 120 NM N OF THE ITCZ AXIS FROM 13W-44W AND FROM THE ITCZ 
AXIS TO THE EQUATOR BETWEEN 9W-20W. 

...DISCUSSION...

GULF OF MEXICO...
UPPER RIDGE COVERS THE W GULF EXTENDING FROM THE YUCATAN 
PENINSULA TO OVER TEXAS. AFTERNOON THUNDERSTORMS GENERATED 
INLAND OVER MEXICO ARE SPREADING UPPER LEVEL DEBRIS CLOUDS 
ACROSS THE FAR W GULF FROM THE BAY OF CAMPECHE TO S TEXAS. BROAD 
UPPER TROUGH COVERS THE NE GULF EXTENDING INTO THE W ATLC N OF 
25N E OF 90W. OTHER THAN A SEA BREEZE INDUCED SURFACE TROUGH 
OVER THE FLORIDA PENINSULA...BROAD SURFACE RIDGE COVERS THE SE 
US AND GULF OF MEXICO ANCHORED BY A 1020 MB HIGH OVER THE 
MISSISSIPPI DELTA. THIS COUPLED WITH DRY AIR IS GIVING THE MUCH 
OF THE GULF CLEAR SKIES TONIGHT WITH THE EXCEPTION OF SOME LOW 
LEVEL CLOUDS BANKING ALONG THE TEXAS/MEXICO COAST DUE TO RETURN 
FLOW AROUND THE SURFACE HIGH. HIGH PRESSURE WILL REMAIN IN 
CONTROL OF THE GULF FOR THE FIRST PORTION OF THE WEEK.  

CARIBBEAN SEA...
GENERALLY WESTERLY ZONAL UPPER FLOW DOMINATES THE CARIBBEAN WITH 
AN UPPER E/W RIDGE OVER SOUTH AMERICA INTO THE E PACIFIC REGION. 
MID LEVEL TROUGH AND REMNANT SURFACE TROUGH REMAINS IN THE W 
CARIBBEAN WITH THE SURFACE TROUGH EXTENDING FROM E CUBA NEAR 
20N78W TO 14N81W. THIS IS GENERATING SCATTERED SHOWERS/ISOLATED 
THUNDERSTORMS FROM 14N-18N BETWEEN 79W-84W AND N OF 19N TO OVER 
CUBA FROM 74W-78W. MODERATE EASTERLY TRADE WINDS DOMINATE THE 
CARIBBEAN USHERING IN SOME LOW LEVEL ISOLATED SHOWERS OVER THE 
NE CARIBBEAN N OF 13N E OF 67W...OTHERWISE FAIR WEATHER AND 
CLEAR SKIES TONIGHT FOR THE CARIBBEAN. 

ATLANTIC...
BROAD UPPER TROUGH EXTENDS FROM THE E US INTO THE W ATLC N OF 
25N W OF 61W WITH THE ASSOCIATED COLD FRONT N OF THE REGION. A 
REMNANT SURFACE TROUGH EXTENDS FROM 30N71W TO OVER E CUBA NEAR 
21N77W. THIS IS ENHANCING SCATTERED SHOWERS/ISOLATED 
THUNDERSTORMS TO THE E OF THE SURFACE TROUGH FROM 24N-27N 
BETWEEN 67W-73W. A CUT-OFF UPPER LOW IS IN THE E/CENTRAL ATLC 
NEAR 28N41W COVERING THE AREA N OF 20N FROM 34W-50W. THIS UPPER 
LOW IS EMBEDDED WITHIN SOME VERY DRY AIR THAT DOMINATES MOST OF 
THE ATLC AND IS NOT PRODUCING ANY SHOWER ACTIVITY. AN UPPER 
TROUGH IS OVER THE FAR NE ATLC DIPPING S TO OVER THE CANARY 
ISLANDS WITH THE ASSOCIATED FRONTAL BOUNDARY N OF THE REGION. 
BROAD SURFACE RIDGE COVERS THE ATLC E OF 70W ANCHORED BY A 1030 
MB HIGH JUST SW OF THE AZORES. THIS SURFACE RIDGE COUPLED WITH 
THE DRY AIR IN PLACE IS GIVING MOST OF THE ATLC FAIR WEATHER 
TONIGHT. 

$$
WALLACE