000
AGXX40 KNHC 010657
MIMATS

MARINE WEATHER DISCUSSION  
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
300 AM EDT THU JUL 31 2008

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

AT THE MOMENT...A RELATIVELY ZONAL MID LEVEL PATTERN CAN BE 
FOUND OVER MUCH OF THE NORTH ATLANTIC N OF 30N WITH A WEAK AND 
FLAT RIDGE TO ITS S CENTERED NEAR 25N.  THE SURFACE REFLECTION 
OF THE RIDGE CURRENTLY EXTENDS FROM 30N35W WEST-SOUTHWESTWARD TO 
25N60W AND THEN DUE W INTO THE GULF OF MEXICO.  OVER THE 
WEEKEND...LOOK FOR THE UPPER PATTERN TO BEGIN TO AMPLIFY AS 
TROUGHING BUILDS OVER THE GREAT LAKES AND EASTERN CONUS AND A 
DEEP ANTICYCLONE ESTABLISHES ITSELF NEAR 30N45W. THE MODELS 
DIFFER ON THE STRENGTH OF THE TROUGHING OVER THE SE CONUS.  
WHILE THE 00Z GFS HAS TRENDED WEAKER WITH THE SURFACE REFLECTION 
OF THIS SYSTEM COMPARED TO ITS 18Z RUN...THE 00Z GFS STILL 
APPEARS TO HAVE CONVECTIVE FEEDBACK ISSUES IN THE 18Z/02 TO 
18Z/04 TIME FRAME.  THE NAM IS ALSO ON THE STRONGER EDGE OF THE 
GUIDANCE WITH THE TROUGHING IN THE GULF OF MEXICO...BUT IS ALONE 
FAVORING THE W GULF FOR A SURFACE SYSTEM.  WITH THE ECMWF 
TRENDING TOWARD A MORE AMPLIFIED PATTERN LIKE THE GFS...THINK A 
SCALED DOWN VERSION OF THE GFS THAT ACCOUNTS FOR ITS FEEDBACK 
ISSUES IS ACCEPTABLE FOR NOW.  

LOOK FOR THE TROUGH PASSING THROUGH THE E CONUS TO MOVE OFFSHORE 
ON FRI...WITH SW WINDS FOUND N OF 28N AND W OF 70W THROUGH THE 
WEEKEND.  AGAIN...THE GFS IS FAVORED WITH THIS TROUGH.  

IN THE CARIBBEAN...EXPECT THE TROPICAL WAVE NEAR 68W TO PROGRESS 
W INTO THE YUCATAN THROUGH TUE.  LOOK FOR CONVECTION TO 
ACCOMPANY THE NORTHERN EDGE OF THE TROPICAL WAVE AS IT TRACKS IN 
THE DIFFLUENT REGION ON THE SE SIDE OF AN UPPER LEVEL LOW 
CURRENTLY OVER CUBA.  OTHERWISE...LOOK FOR MODERATE TO STRONG E
TRADE WINDS OVER THE S CENTRAL CARIBBEAN WITH LIGHT TO MODERATE 
E TRADE WINDS OVER THE REMAINDER OF THE REGION.

FARTHER E...THE TROPICAL WAVE ALONG 31W WITH ITS EMBEDDED LOW 
PRESSURE SYSTEM WILL TRACK WEST-NORTHWESTWARD TOWARD THE ISLANDS 
BY TUE.  THE GFS IS SLIGHTLY FASTER CARRYING THE SYSTEM W THAN 
THE ECMWF.  FOR NOW...THE GFS SOLUTION LOOKS 
REASONABLE...ESPECIALLY AS THE ANTICYCLONE BUILDS TO ITS NW OVER 
THE WEEKEND...HELPING TO PROPEL IT WEST-NORTHWESTWARD BY THE END 
OF THE PERIOD.


WARNINGS...
ATLANTIC...
NONE.

CARIBBEAN...
NONE.

GULF OF MEXICO...
NONE. 

.FORECASTER SCHAUER CLARK. TROPICAL PREDICTION CENTER.