000
AXNT20 KNHC 180459
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT TUE MAR 18 2008

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL 
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN 
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
0345 UTC.

...THE ITCZ...

ITCZ AXIS IS CENTERED ALONG 5N8W 3N14W 2N21W CROSSING THE 
EQUATOR NEAR 27W TO 5S38W. SCATTERED/NUMEROUS STRONG CONVECTION 
IS N OF 3N TO INLAND OVER SW AFRICA BETWEEN THE PRIME MERIDIAN 
AND 2W. CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE 
FROM 7N TO S OF THE EQUATOR BETWEEN 11W-30W. 

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LOW IS OVER NW MEXICO AND W TEXAS WITH A DEVELOPING 
FRONTAL SYSTEM MOVING ACROSS CENTRAL TEXAS. THIS FRONT IS 
EXPECTED TO MOVE INTO THE NW GULF LATE TUE. A SURFACE RIDGE 
ANCHORED OVER E VIRGINIA COVERS THE E GULF INTO THE W ATLC AND 
IS PRODUCING A TIGHT PRESSURE GRADIENT OVER THE GULF OF MEXICO 
WITH GALE FORCE WINDS EXPECTED IN THE NEXT FEW HOURS OVER THE W 
GULF. HEAVY SHOWERS/SEVERE THUNDERSTORMS REMAIN INLAND OVER 
TEXAS MOVING NNE TO THE CENTRAL MISSISSIPPI VALLEY. THIS 
ACTIVITY IS EXPECTED TO ENTER THE GULF LATE THIS MORNING 
PRECEDING THE FRONT. ABROAD HIGHLY AMPLIFIED UPPER RIDGE COVERS 
THE GULF AND THE E U.S. INTO THE W ATLC WITH THE AXIS ALONG 86W. 
CURRENTLY LOW CLOUDS ARE BEING BANKED ALONG THE TEXAS AND 
LOUISIANA COAST IN RESPONSE TO THE RETURN FLOW AROUND THE 
SURFACE RIDGE. 

CARIBBEAN SEA...
UPPER TROUGH OVER THE CENTRAL ATLC DIPS INTO THE NE CARIBBEAN N 
OF 17N W OF 75W WHILE THE REMAINDER OF THE CARIBBEAN IS UNDER A 
BROAD UPPER RIDGE. STRONG SUBSIDENCE AND DRY STABLE AIR IS 
CURRENTLY OVER THE REGION. HOWEVER...THE ASSOCIATED COLD FRONT 
IS APPROACHING THE GREATER ANTILLES AND WILL ENTER THE NE 
CARIBBEAN OVER THE NEXT FEW HOURS AND DISSIPATE ON WED. 
MODERATE/STRONG EASTERLY TRADE WINDS REMAIN OVER THE AREA 
USHERING IN SOME SCATTERED PATCHES OF LOW CLOUDS WITH POSSIBLE 
ISOLATED SHOWERS MAINLY S OF 15N. WITH THE EXCEPTION OF THE 
APPROACHING FRONT...LITTLE CHANGE IS EXPECT ACROSS THE CARIBBEAN 
THROUGH FRI. 

ATLANTIC OCEAN...
HIGH AMPLITUDE UPPER RIDGE COVERS THE W ATLC W OF 75W ACROSS 
FLORIDA INTO THE GULF OF MEXICO. A SURFACE RIDGE ANCHORED OVER E 
VIRGINIA COVERS THE W ATLC W OF 67W INTO THE GULF OF MEXICO. THE 
STRONG STORM SYSTEM IS OVER THE N/CENTRAL ATLC WITH THE UPPER 
TROUGH OVER THE AREA N OF 17N FROM 45-75W AND THE ASSOCIATED 
WELL DEFINED COLD FRONT ENTERING THE REGION NEAR 32N47W ALONG 
22N60W ACROSS CUBA NEAR 21N75W DISSIPATING RAPIDLY OVER THE FAR 
E GULF OF MEXICO. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE 
WITHIN 90 NM E OF THE FRONT AND GALE FORCE WINDS BOTH E AND W OF 
THE FRONT...SEE MIAHSFAT2 FOR MORE DETAILS. STRONG SUBSIDENCE 
AND DRY STABLE AIR COVER MOST OF THE REGION THUS LIMITING 
FURTHER AREA OF SHOWERS. BROAD UPPER TROUGH COVERS THE E ATLC N 
OF 24N E OF 34W WITH A WEAK UPPER LOW CENTERED NEAR 33N30W AND A 
SURFACE TROUGH EXTENDING FROM 31N33W TO 25N35W. BROAD SURFACE 
RIDGE COVERS THE E ATLC E OF 40W WITH A WEAKNESS IN THE REGION 
OF THE SURFACE TROUGH. 

$$
WALLACE