000
AGXX40 KNHC 091724
MIMATS

MARINE WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
130 PM EDT THU JUL 09 2009

MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA 
AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W.

UPPER LEVELS...
LARGE AMPLITUDE TROUGH WITH AXIS ALONG 84W DIGS FURTHER S 
EFFECTIVELY FORCING BROAD ATLC RIDGE CENTER NE.  RIDGE NEW 
POSITION WILL CURTAIL THE FRESH TO STRONG BREEZE THE SW N ATLC 
HAS BEEN EXPERIENCING THROUGHOUT ENTIRE LAST WEEK.  ATLC RIDGE 
BLOCKS TROUGH FROM FURTHER EASTWARD INTRUSION AND DEFLECT IT NE 
WHILE RIDGE EXPANDS W INTO GULF OF MEXICO.  UPSTREAM RIDGE 
INTRUDING INTO GULF OF MEXICO FROM THE W BRING VERY DRY AIR MASS 
INTO NW PART OF BASIN.  CARIBBEAN ALSO REMAINS VERY DRY N OF 13N.

SURFACE...
CREST OF WEAK TROPICAL WAVE ALONG 95W MOVING W INTO AREA OF 
CONFLUENT FLOW ALOFT EXPECTED TO WEAKEN AS IT CROSSES BAY OF 
CAMPECHE.  ABUNDANT MOISTURE LEFT BEHIND BY WAVE S OF 20N 
COMBINE LOW LEVEL CONVERGENT FLOW WITH DIFFLUENT FLOW ALOFT 
DEVELOPING SCATTERED MODERATE CONVECTION OVER E SIDE OF YUCATAN 
PENINSULA THROUGH THIS AFTERNOON EXPECTED TO BECOME ISOLATED 
TONIGHT AS CONFLUENCE ALOFT DIMINISHES. 
 
WEAK FRONTAL BOUNDARY ACROSS EXTREME NW PORTION OF SW N ATLC AND 
INTO GULF OF MEXICO N OF 27N E OF 91W REMAINS ACTIVE WITH 
SCATTERED TSTMS.  DAYTIME HEATING AND MODERATE DIFFLUENT FLOW 
ALOFT ADDS ISOLATED STRONG TSTMS OVER N AND CENTRAL FLORIDA 
PENINSULA.  ELSEWHERE...GULF OF MEXICO AND SW N ATLC REMAIN 
DRY.  FRESH BREEZE ON SW PERIPHERY OF ATLC RIDGE MAY BUILD SEAS 
TO 8 FT...EXCEPT HIGHER WIND AND SEAS IN PASSAGES.  

TIGHT PRES GRADIENT BETWEEN ATLC RIDGE AND 1009 MB LOW PRES OVER 
COLOMBIA MAINTAINS FRESH TO STRONG BREEZE ACROSS MOST OF CENTRAL 
CARIBBEAN THROUGH FORECAST PERIOD...IF ANYTHING GETTING STRONGER 
AS RIDGE BUILDS W LATE IN PERIOD. 

WARNINGS

ATLC...
.NONE. 

CARIBBEAN...
.NONE.

GULF OF MEXICO...
.NONE.

FORECASTER WALLY BARNES. TROPICAL PREDICTION CENTER.