000
AXNT20 KNHC 062327
TWDAT 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL 
805 PM EDT SAT APR 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2245 UTC.

...ITCZ/MONSOON TROUGH... 

THE MONSOON TROUGH EXTENDS FROM A 1007 MB SURFACE LOW OVER 
SOUTHERN SENEGAL NEAR 13N16W INTO THE TROPICAL EASTERN ATLC 
ALONG 5N18W EQ29W 1S31W. THE ITCZ BEGINS NEAR 1S31W AND 
CONTINUES INTO BRAZIL NEAR 3S40W. SCATTERED MODERATE/ISOLATED 
STRONG CONVECTION IS FROM 3S-4N BETWEEN 21W-26W. SIMILAR 
ACTIVITY IS FROM 2N-5N BETWEEN 41W-44W.

...DISCUSSION...

GULF OF MEXICO...       
PRIMARILY ZONAL WESTERLY FLOW COVERS THE 
GULF OF MEXICO AROUND BROAD UPPER RIDGING. THE UPPER RIDGE 
CONTINUES TO SUPPORT SURFACE RIDGING AROUND A 1021 MB HIGH 
CENTERED JUST SOUTH OF THE FLORIDA PANHANDLE NEAR 29N87W...AS OF 
2100 UTC. FAIR CONDITIONS AND LIGHT ANTI-CYCLONIC FLOW IS AROUND 
THE HIGH CENTER INCREASING IN SPEED TO NEAR 15 KT AROUND THE 
PERIPHERY OF THE BASIN FARTHER AWAY FROM THE HIGH. THE RIDGE IS 
EXPECTED TO EAST ALLOWING RETURN FLOW TO INCREASE OVER THE 
WESTERN GULF AND EVENTUALLY SPREAD EASTWARD BEFORE A COLD FRONT 
MOVES OFF THE TEXAS COAST LATER NEXT WEEK AROUND THURSDAY 
MORNING. 

CARIBBEAN SEA... 
A SHORTWAVE UPPER TROUGH IS MOVING THROUGH THE 
WEST ATLC AND INTO THE NW CARIBBEAN SUPPORTING A COLD FRONT THAT 
ENTERS THE AREA OVER EASTERN CUBA NEAR 21N76W AND CONTINUES TO 
NICARAGUA ALONG 17N81W 12N84W...AS OF 2100 UTC. ISOLATED SHOWERS 
ARE WITHIN 60 NM EITHER SIDE OF THE AXIS WITH A CLUSTER OF 
SHOWERS/THUNDERSTORMS ALONG THE FRONT OVER CUBA. NORTHERLY WINDS 
OF 15-20 KT ARE NORTHWEST OF THE AXIS WITH LIGHTER WINDS TO THE 
IMMEDIATE EAST. TRADEWIND FLOW OF 15-20 KT COVERS THE REMAINDER 
OF THE EASTERN AND CENTRAL CARIBBEAN. AN UPPER LEVEL RIDGE 
COVERS THIS PORTION OF THE BASIN TOO HELPING PROVIDE FAIR 
CONDITIONS. THE FRONT IS EXPECTED TO STALL SHORTLY AND WILL 
BEGIN TO DISSIPATE. SOME MOISTURE WILL REMAIN NEAR THE FRONT AND 
ALONG THE NORTHERN ISLANDS AS THE REMAINDER OF THE FRONT MOVES 
EAST JUST NORTH OF THE BASIN ACROSS THE ATLC.

ATLANTIC OCEAN... 
A SHORTWAVE UPPER TROUGH ALONG 71W SUPPORTS A 
1013 MB FRONTAL LOW NEAR 29N73W. A COLD FRONT EXTENDS SOUTH OF 
THE LOW TO EASTERN CUBA...WHILE A WARM FRONT EXTENDS TO THE NE 
TO NEAR 32N64W. A PRE-FRONTAL SURFACE TROUGH IS ALSO EAST OF THE 
SYSTEM ALONG 30N67W TO 24N72W. SHOWERS/THUNDERSTORMS ARE UP TO 
250 NM EAST OF THE AXIS WITH SCATTERED SHOWERS UP TO 90 NM WEST 
OF THE AXIS. ISOLATED SHOWERS ARE ALSO 180 NM EAST OF THE COLD 
FRONT. HIGH PRESSURE WILL BUILD ACROSS THE WEST ATLC AS THE LOW 
PRESSURE/FRONTAL SYSTEM MOVES QUICKLY TOWARDS THE NE. THE 
CENTRAL ATLC IS DOMINATED BY BROAD SURFACE RIDGING ANCHORED BY A 
1033 MB HIGH NEAR 36N39W. IT IS SUPPORTED ALONG BY AN UPPER 
LEVEL RIDGE EXTENDING FROM THE EASTERN CARIBBEAN TO NORTH OF THE 
AZORES ISLANDS. A NARROW UPPER TROUGH IS JUST TO THE EAST 
EXTENDING FROM NEAR 40N21W TO 23N33W 4N52W. THE UPPER TROUGH 
SUPPORTS A DISSIPATING COLD FRONT ALONG 32N27W 29N34W. POSSIBLE 
ISOLATED SHOWERS ARE ALONG THE AXIS. 

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

$$
WALTON