000 AGXX40 KNHC 040618 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 130 AM EST FRI JAN 04 2008 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. STRONG UPPER TROUGH ALONG 62W MOVING E FAIRLY QUICKLY AS UPPER FLOW BECOMES ZONAL W OF 70W. SORT OF A REX BLOCK OVER THE ERN ATLC WITH HIGH PRES RIDGE CENTERED NEAR 32N32W AND A CLOSED LOW CENTER NEAR 20N40W. ON THE SURFACE TONIGHT A COLD FRONT EXTENDED FROM 31N57W TO 20N70W THEN WAS STATIONARY OVER THE CENTRAL CARIB TO 11N81W. AN ARCTIC AIRMASS WAS CENTERED OVER THE SE CONUS APPROACHING THE COAST. STRONG N AND NE WINDS CONTINUE W OF THE FRONT. A 1034 MB HIGH WAS OVER THE ERN ATLC PRODUCING 20 TO 25 KT WINDS FROM 20N TO 25N E OF 45W. LATER DAY 1 THE STRONG UPPER TROUGH WILL SLOWLY WEAKEN AS IT MOVES E TO 54W. LITTLE CHANGE ELSEWHERE. ON THE SURFACE LATER DAY 1 SLOW WEAKENING OF THE ARCTIC AIRMASS AS IT MOVES EWD OFF THE SE COAST. COLD FRONT MOVES TO 31N50W 19N64W. LITTLE CHANGE TO OVERALL WINDS. FOR DAY 2 AS WEAKENING UPPER TROUGH EXITS THE REGION IT GRADUALLY DISSIPATES BUT NOT BEFORE WACKING THE REX BLOCK AND OPENING UP THE CLOSED UPPER LOW. THUS A STRONG ZONAL FLOW PREVAILS N OF 25N WITH WEAK EMBEDDED SHORTWAVES ALONG 70W AND 100W. ON THE SURFACE DAY 2 THE OLD COLD FRONT BEGINS TO LOOSE IDENTITY OVER THE ERN ATLC NEAR 40W. OLD ARCTIC AIRMASS CENTERED N OF AREA ALONG 66W. RETURN FLOW SETTING UP W OF 90W AS PRESSURES FALL OVER CENTRAL PLAINS. STRONG NE AND E WINDS PREVAIL BETWEEN 50W AND 90W. OUTLOOK PERIOD... FOR DAY 3 ZONAL FLOW ALOFT BECOMES MORE SWLY W OF 90W AS MID LEVEL HEIGHTS FALL OVER ROCKIES. MID LEVEL RIDGING DEVELOPS OVER GULF EXTENDING OVER ERN SEABOARD WITH WEAK SHORTWAVE PUSHING THROUGH RIDGE ALONG DELMARVA. ON THE SURFACE DAY 3 FRONT OVER ERN ATLC DISSIPATING WHILE OLD ARCTIC AIRMASS MODIFYING OVER ATLC WATERS. GRADIENT WEAKENING AND WINDS OVER REGION SLOWLY DECREASING TO MOSTLY 15 TO 20 KT. RETURN FLOW CONTINUES OVER WRN GULF. FOR DAY 4 WITH MID LEVEL RIDGE HOLDING ALONG ERN SEABOARD..SHORTWAVES DROPPING SE OVER CENTRAL ATLC CARVING OUT LARGE SCALE TROUGH ALONG 50W. MID LEVEL HEIGHTS CONTINUE FALLING OVER SRN PLAINS AS NEXT TROUGH MOVES OUT OF SRN ROCKIES. ON THE SURFACE DAY 4 OLD AIRMASS OVER W CENTRAL ATLC WILL CONTINUE TO PRODUCE 15 TO 20 KT WINDS OVER MOST OF REGION. RETURN FLOW OF 20 KT W OF 90W CONTINUES. FOR DAY 5 INCREASING AMPLITUDE TO MID LEVEL FEATURES CONTINUES WITH RIDGE EXTENDING FROM NW CARIB NE TO 40N65W. MID LEVEL TROUGHING CONTINUES OVER W CENTRAL ATLC. NEXT STRONG SHORTWAVE DROPS INTO S CENTRAL PLAINS. ON THE SURFACE DAY 5 WEAK FRONTAL TROUGH SETS UP OVER ERN ATLC FROM 31N42W TO 20N52W. OLD AIRMASS OVER WRN ATLC WILL MAINTAIN BRISK NE AND E WINDS W OF TROUGH TO 90W AND CARIB. SLY WINDS TO 20 KT OVER GULF W OF 90W WITH NEXT COLD FRONT MOVING TO SE TX LATE. WARNINGS... ATLANTIC... NONE. CARIBBEAN... GALE WARNING... GULF OF MEXICO... NONE. FORECASTER RRG