000
AGXX40 KNHC 280509
MIMATS

MARINE WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 
130 AM THU SEP 28 2006

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

TWO LARGE FEATURES DOMINATE THE MID LEVELS TONIGHT..ONE A 
LONGWAVE TROUGH OVER THE ERN TWO THIRDS OF THE CONUS AND THE 
OTHER A RIDGE CENTERED NEAR 34N45W. A NEW SURGE OF COLD AIR IS 
PLUNGING SWD OVER THE CENTRAL PLAINS ACCORDING TO THE WATER 
VAPOR IMAGERY AND FAIRLY CLOSE TO THE GFS MODEL POSITION. ON THE 
SURFACE TONIGHT T.D. NINE HAS FORMED OVER MID OCEAN NEAR 27N54W 
MOVING NW AND EXPECTED TO BECOME A TRPL STORM LATER THIS 
MORNING. THE T.D. IS CAUGHT UNDER A UPPER RIDGE NOTED ABOVE AND 
IS IN A FAIRLY GOOD ENVIRONMENT. A DISSIPATING FRONT WAS OVER S 
FL AND IS EXPECTED TO BECOME STATIONARY. THREE WEAK TRPCL WAVES 
WERE NOTED ON THE MAP TONIGHT NEAR 45W..59W..AND 82W.

LATER DAY 1 LOOK FOR MID LEVEL HEIGHTS TO CONTINUE FALLING W OF 
70W AS THE COLD SURGE HEADS SWD. THE MID LEVEL RIDGE TRIES TO 
MOVE E BUT A CUTOFF LOW NEAR 25N32W BLOCKS IT'S MOVEMENT. ON THE 
SURFACE THE GFS DOES A POOR JOB OF DEPICTING THE TRPCL STORM 
WITH A CLOSED 1016 MB ISOBAR AND LIGHT WINDS. A WEAK COLD FRONT 
HEADS FOR THE NW GULF COAST BUT GRADIENTS ARE WEAK. ONLY WIND 
PROBLEM BESIDES THE T.S. IS OVER THE CENTRAL CARIB WHERE 20 KT 
CAN BE EXPECTED.

FOR DAY 2 THE MID ATLC RIDGE DECIDES TO TAKE A NWD TRACK AND 
SHIFTS TO NEAR 35N52W. MID LEVEL HEIGHTS STOP FALLING W OF 70W 
AS THE COLD AIR ALOFT SHIFTS EWD OVER THE MID ATLC AND NE COAST. 
ON THE SURFACE THE TRPCL STORM HEADS N ALONG 57W AND EXITS THE 
REGION. THE COLD FRONT MOVES TO N CENTRAL FL WITH MOSTLY LIGHT 
WINDS AND A WEAK 1018 MB HIGH FOLLOWING. CARIB WINDS DECREASE 
SLIGHTLY DAY 2 WITH THE ATLC RIDGE BACKING OFF SOME.

OUTLOOK PERIOD...

FOR DAY 3 AN EQUALLY STRONG UPPER TROUGH IS NOTED OVER THE ERN 
ATLC N OF 30N WHICH BLOCKS THE MID ATLC RIDGE FROM MOVING. THIS 
IN TURN HOLDS THE LONGWAVE TROUGH OVER THE ERN CONUS WITH SOME 
INCREASING AMPLITUDE ALONG 88W. ON THE SURFACE DAY 3 THE COLD 
FRONT GRADUALLY DISSIPATES WITH THE FOLLOWING HIGH MOVING TO 
NEAR 30N88W. WINDS OVER THE GULF REMAIN LIGHT. CARIB WINDS 
CHANGE LITTLE AND REMAIN LIGHT TO MODERATE AS WELL AS ATLC WINDS 
W OF 60W.

DAY 4 OR THE FIRST DAY OF OCTOBER FINDS THE LONGWAVE TROUGH OVER 
THE ERN CONUS MOVING EWD TO THE MID ATLC COAST. THE MID ATLC 
RIDGE HOLDS FIRM NEAR 35N50W BLOCKED BY THE STRONG TROUGH THAT 
CUTS OFF NEAR 32N35W. ON THE SURFACE DAY 4 SOME STRENGTHENING OF 
THE MID ATLC SURFACE RIDGE WILL INCREASE ELY TRADES S OF 24N E 
OF 70W. CARIB WINDS REMAIN LIGHT TO MODERATE. SOME INCREASE IN 
NE WINDS OVER THE SE GULF AS THE WEAK HIGH STRENGTHENS A COUPLE 
OF MB.

FINALLY ON DAY 5 THE LARGE UPPER TROUGH OVER THE ERN CONUS MOVES 
ENE AS THE WESTERLIES W OF THE TROUGH BECOME MORE ZONAL. THE 
RIDGE OVER MID OCEAN STAYS PUT NEAR 35N50W BLOCKED BY A CUTOFF 
LOW NEAR 27N35W. A NEW MID LEVEL RIDGE STRENGTHENS OVER THE N 
GULF COAST. ON THE SURFACE DAY 5 THE HIGH OVER THE N GULF COAST 
SHIFTS NE BUT MAINTAINS MODERATE NE WINDS W OF 75W AND OVER THE 
NW CARIB. REMAINDER OF CARIB WILL HAVE MOSTLY MODERATE ELY 
TRADES. THE ATLC RIDGE WEAKENS SOME AND MODERATE ELY TRADES ARE 
CONFINED TO BETWEEN 19N TO 24N FROM 50W TO 70W.  

WARNINGS...
ATLANTIC...
NONE.

CARIBBEAN...
NONE.

GULF OF MEXICO...
NONE.

FORECASTER RRG