000
AXNT20 KNHC 061727
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST WED MAR 06 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1645 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE COAST OF LIBERIA NEAR 5N9W 
TO 3N13W. THE ITCZ BEGINS FROM 3N13W AND CONTINUES ALONG 2N30W 
EQ44W 1S47W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS 
FROM EQ-2N BETWEEN 9W-15W. SIMILAR ACTIVITY IS WITHIN 120 NM 
NORTH OF THE AXIS BETWEEN 14W-23W...AND WITHIN 100 NM EITHER 
SIDE OF THE AXIS BETWEEN 27W-45W. 

...DISCUSSION...

GULF OF MEXICO...
A COLD FRONT CONTINUES TO BISECT THE GULF OF MEXICO TODAY. AS OF 
1500 UTC...THE FRONT EXTENDS FROM FLORIDA NEAR 28N80W TO THE BAY 
OF CAMPECHE ALONG 25N85W 23N95W 18N95W. THE FRONT IS FAIRLY DRY 
WITH ONLY A SMALL LINE OF ISOLATED SHOWERS ALONG THE AXIS. THE 
AREAS BOTH AHEAD AND BEHIND THE FRONT ARE UNDER CLEAR SKIES DUE 
TO DRY AIR ALOFT COVERING THE BASIN EXCEPT DIRECTLY NEAR THE 
FRONT. MAINLY ZONAL WESTERLY FLOW IS ACROSS THE BASIN BETWEEN AN 
UPPER LEVEL RIDGE TO THE SOUTH COVERING THE CARIBBEAN...AND AN 
UPPER LEVEL TROUGH COVERING THE EASTERN CONUS CENTERED OVER 
VIRGINIA...WHICH IS SUPPORTING THE COLD FRONT. SURFACE RIDGING 
HAS ALREADY BEGUN TO BUILD IN NORTHWEST OF THE FRONT AROUND A 
1030 MB HIGH OVER TEXAS. THE STRONG PRESSURE GRADIENT BETWEEN 
THIS HIGH PRESSURE AND THE FRONT IS HELPING SUPPORT NORTH TO 
NORTHEAST WINDS OF 15-20 KT ACROSS THE NORTHERN GULF. THE FRONT 
IS EXPECTED TO CONTINUE MOVING SE...AND SHOULD EXIT THE BASIN 
LATER TONIGHT AS THE SURFACE RIDGE MOVES EAST ACROSS THE AREA.

CARIBBEAN SEA...
FAIR CONDITIONS SPREAD ACROSS A LARGE PORTION OF THE CARIBBEAN 
TODAY DUE TO MODERATELY DRY AIR ALOFT AROUND AN UPPER LEVEL 
RIDGE COVERING THE BASIN CENTERED NEAR 9N57W. AN AREA OF 
LOW-LEVEL MOISTURE IS PRESENT FROM THE WINDWARD PASSAGE TO THE 
COASTS OF HONDURAS AND NICARAGUA WHERE LOW-LEVEL CLOUDS AND 
POSSIBLE ISOLATED SHOWERS ARE PRESENT. A FEW ISOLATED SHOWERS 
ARE ALSO IN THE NE CORNER OF THE CARIBBEAN DUE TO A STATIONARY 
FRONT EXTENDING FROM THE CENTRAL ATLC INTO THE AREA ALONG 18N62W 
TO 16N68W. TRADEWIND FLOW OF 15-20 KT IS PRESENT THROUGHOUT THE 
CENTRAL AND EASTERN PORTIONS OF THE BASIN. THE FRONT IN THE GULF 
OF MEXICO WILL REACH THE NW CARIBBEAN LATER TONIGHT BRINGING A 
WIND SURGE AND POSSIBLE ISOLATED SHOWERS TO THAT AREA. LITTLE 
CHANGE IS EXPECTED ELSEWHERE.

ATLANTIC OCEAN...
THE COLD FRONT IN THE GULF OF MEXICO ALSO EXTENDS THROUGH A 
SMALL PORTION OF THE SOUTHWEST NORTH ATLC ENTERING THE 
DISCUSSION AREA NEAR 32N74W CONTINUING TO THE FLORIDA COAST NEAR 
28N80W...AS OF 1500 UTC. SCATTERED SHOWERS/ISOLATED 
THUNDERSTORMS ARE WITHIN 30 NM OF THE AXIS NORTH OF 29N...WITH 
ISOLATED SHOWERS ALONG THE REMAINDER OF THE AXIS. GALE FORCE 
WINDS ARE ALSO BOTH AHEAD AND BEHIND THE FRONT NORTH OF 29N. THE 
REMAINDER OF THE SOUTHWEST NORTH ATLC IS DOMINATED BY SURFACE 
RIDGING AROUND A 1019 MB HIGH NEAR 27N65W. THE RIDGE IS 
SUPPORTED BY A BROAD UPPER LEVEL RIDGE CENTERED NEAR 9N57W. 
FARTHER EAST...A LARGE UPPER LEVEL TROUGH CENTERED NORTH OF THE 
DISCUSSION AREA WITH AXIS ALONG 38W SUPPORTS A SECOND FRONTAL 
BOUNDARY. IT ENTERS AS A COLD FRONT NEAR 32N31W AND CONTINUES TO 
20N54W WHERE IT BECOMES STATIONARY INTO THE NE CARIBBEAN NEAR 
18N62W. POSSIBLE ISOLATED SHOWERS ARE UP TO 200 NM EAST OF THE 
AXIS. THE FAR EAST ATLC IS DOMINATED BY A SECOND 1018 MB SURFACE 
HIGH CENTER NEAR 21N32W. THE SURFACE RIDGE IS SUPPORTED BY AN 
UPPER LEVEL RIDGE ALONG 18W. 

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

$$
WALTON