000
AXNT20 KNHC 182318
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON MAR 18 2013

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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL 
ANALYSIS.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2245 UTC.

...ITCZ/MONSOON TROUGH... 

THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL 
ATLC NEAR 9N13W AND CONTINUES TO 4N17W WHERE THE ITCZ CONTINUES 
ALONG 2N23W 1N28W THEN S OF THE EQUATOR INTO SOUTH AMERICA NEAR 
34W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION 
ARE WITHIN 150 NM N OF THE MONSOON TROUGH/ITCZ BETWEEN 16W-24W. 

...DISCUSSION...

GULF OF MEXICO...                                                
A BROAD UPPER TROUGH IS MOVING ACROSS THE MISSISSIPPI VALLEY 
AND NW GULF N OF 25N W OF 88W. AN UPPER RIDGE EXTENDING FROM THE 
CARIBBEAN DOMINATES THE REMAINDER OF THE GULF. THE COMBINATION 
OF THE UPPER RIDGE AND UPPER TROUGH IS GENERATING SCATTERED 
SHOWERS/THUNDERSTORMS OVER THE E GULF N OF 24N E OF 87W TO 
INLAND OVER FLORIDA MAINLY S OF LINE FROM DAYTONA BEACH TO 
TAMPA. A WEAK 1006 MB LOW IS JUST OFF THE COAST OF TEXAS/NE 
MEXICO WITH A SURFACE TROUGH EXTENDING N ALONG THE COAST OF 
TEXAS TO BETWEEN HOUSTON AND CORPUS CHRISTI AND S TO TAMPICO 
MEXICO. THE REMAINDER OF THE GULF IS UNDER CLEAR SKIES THIS 
EVENING. A COLD FRONT WILL ENTER THE NE GULF TONIGHT AND WILL 
REACH FROM FLORIDA BIG BEND TO S TEXAS TUE BEFORE STALLING FROM 
SW FLORIDA TO THE TEXAS/MEXICO BORDER TUE NIGHT THEN DISSIPATE 
ON WED. HIGH PRESSURE WILL BUILD ACROSS THE N GULF THU AND FRI. 
ANOTHER COLD FRONT WILL APPROACH THE NW GULF ON SAT.

CARIBBEAN SEA...                                                 
A BROAD UPPER RIDGE DOMINATES THE CARIBBEAN ANCHORED INLAND OVER 
SOUTH AMERICA WITH AN UPPER RIDGE AXIS EXTENDING FROM COLOMBIA 
ACROSS E CUBA/WINDWARD PASSAGE INTO THE W ATLC. EASTERLY TRADE 
WINDS ACROSS THE CARIBBEAN ARE USHERING IN SOME ISOLATED LOW 
LEVEL SHOWERS DOTTING THE CARIBBEAN BASIN. FRESH TO STRONG TRADE 
WINDS IN THE CENTRAL CARIBBEAN WILL WEAKEN TUE THROUGH FRI AS 
THE W ATLC RIDGE SHIFTS E. FRESH TO STRONG E WINDS ARE EXPECTED 
IN THE GULF OF HONDURAS OVERNIGHT TONIGHT AND ON TUE NIGHT. 

ATLANTIC OCEAN...                                             
THE UPPER RIDGE OVER THE CARIBBEAN DOMINATES THE W INTO THE 
CENTRAL ATLC WITH A RIDGE AXIS EXTENDING ACROSS E CUBA/WINDWARD 
PASSAGE TO ALONG THE US EASTERN SEABOARD. SCATTERED SHOWERS AND 
POSSIBLE ISOLATED THUNDERSTORMS ARE MOVING ACROSS THE FLORIDA 
PENINSULA INTO THE FAR W ATLC FROM 25N-29N W OF 78W. A SURFACE 
RIDGE DOMINATES THE W AND CENTRAL ATLC ANCHORED BY A PAIR OF 
1024 MB SURFACE HIGHS NEAR 28N63W AND 27N52W. AN UPPER TROUGH IS 
MOVING THROUGH THE E ATLC SUPPORTING A SURFACE TROUGH THAT 
EXTENDS THROUGH 32N22W ALONG 26N25W 21N34W TO 20N50W. THIS 
SURFACE TROUGH REMAINS EMBEDDED WITHIN AN AREA OF DRY AIR THUS 
NO ASSOCIATED SHOWERS. W ATLC SURFACE RIDGE WILL SHIFT E THROUGH 
TUE. A COLD FRONT WILL MOVE OFF THE NE FLORIDA COAST TUE 
REACHING FROM 32N75W TO S FLORIDA TUE THEN STALL FROM BERMUDA TO 
THE BAHAMAS WED. REINFORCING COLD AIR WILL SWEEP ACROSS NW ATLC 
AND MERGE WITH THE FRONT THU. THE FRONT WILL THEN WEAKEN AS IT 
DRIFTS S THROUGH FRI BEFORE STALLING ALONG 22N SAT.

FOR ADDITIONAL INFORMATION PLEASE VISIT 
HTTP://WWW.HURRICANES.GOV/MARINE

$$
PAW