000 AGXX40 KNHC 240518 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 130 AM EDT MON SEP 24 2007 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. TWO LARGE SCALE FEATURES TONIGHT DOMINATE THE WRN HEMISPHERE. ONE IS A RIDGE OVER THE ERN CONUS..THE OTHER A LARGE TROUGH OVER THE MID ATLC. THE RIDGE HAS PUMPED NWD INTO CANADA WHILE STRONG SWLY FLOW ALOFT IS ERODING THE SW SIDE OF THE RIDGE. ON THE E SIDE OF THE RIDGE LATEST WATER VAPOR LOOP SHOWS ENERGY IN THE WESTERLIES ROTATING SWD ALONG THE SE COAST TONIGHT. LAST WEEK THIS PRODUCED A MID LEVEL TROUGH THAT ROTATED AROUND THE RIDGE AND CLOSED OFF OVER THE ERN GULF. ANYWAY A STRONG SHORTWAVE IS MOVING E OFF THE CANADIAN MARITIMES TONIGHT AND IS BEGINNING TO SIPHON OFF ENERGY FROM THE PERSISTENT TROUGH THAT HAS HUNG AROUND ALL WEEK OVER THE MID ATLC. ON THE SURFACE TONIGHT THE TROPICS ARE GETTING A LITTLE MORE ACTIVE WITH MODERATE WAVES ALONG 38W AND 58W. BOTH SHOW GOOD OUTFLOW AND PERSISTENT CONVECTION. AN OLD TROUGH OVER THE GULF IS NEARLY STATIONARY AND WINDS OVER THE GULF MOSTLY LIGHT. LATER DAY 1 MID LEVEL RIDGE CENTER MOVES TO OH VALLEY WHILE MID ATLC TROUGH WEAKENS AS EXPECTED. LARGE FLAT MID LEVEL RIDGE E OF 60W OVER ERN ATLC. ON THE SURFACE LATER DAY 1 WILL HAVE TO WATCH THE TWO SYSTEMS IN THE TRPL ATLC WATERS FOR POSSIBLE DEVELOPMENT. THE ATLC RIDGE REMAINS WEAK MAINLY E OF 50W AND CONSEQUENTLY TRADES ARE LIGHT TO MODERATE EXCEPT WHERE THE WAVES ARE. CONTINENTAL HIGH PRES REMAINS OVER THE SE COAST AND WINDS ARE LIGHT TO MODERATE W OF 60W. CARIB WINDS LIGHT TO MODERATE. FOR DAY 2 THE MID LEVEL FLOW BEGINS TO FLATTEN OUT BUT MAIN FEATURES CONTINUE TO BE THE RIDGE OVER THE SE COAST AND A LARGE TROUGH OVER THE MID ATLC ALONG 45W. ON THE SURFACE DAY 2 THE PRES GRADIENT REMAINS WEAK OVER THE ATLC N OF 20N WITH MOSTLY LIGHT WINDS. GULF WINDS ALSO LIGHT WITH THE TROUGH DRIFTING W TO 95W. CARIB WINDS LIGHT TO MODERATE WITH WAVE IN ERN SECTION. GFS MODEL PICKS UP ON LOW NEAR 10N44W. OUTLOOK PERIOD... FOR DAY 3 MOST OF THE ENERGY IN THE WESTERLIES STAYS N OF 40N BUT SOME SEEPS INTO THE SRN CONUS WITH ENOUGH PUSH TO DRIVE THE MID LEVEL RIDGE EWD TO 33N63W. MID LEVEL TROUGHING WEAKENS OVER THE ATLC AS HEIGHTS SLOWLY RISE. ON THE SURFACE DAY 3 CONTINENTAL HIGH MOVES E TO NEAR 33N60W WHILE THE ATLC RIDGE SLIDES E OF 45W. GFS LIKES LOW IN TRPL ATLC NEAR 11N48W WITH WINDS TO 25 KT. WEAK LOW IN WRN GULF BUT WINDS MOSTLY LIGHT. CARIB WINDS UNCHANGED. FOR DAY 4 NEXT STRONG SHORTWAVE MOVES INTO MIDWEST LOWERING MID LEVEL HEIGHTS BETWEEN 75W AND 95W N OF 24N. MID LEVEL RIDGE STATIONARY OVER SW ATLC BUT WEAKENING. FLAT PATTERN E OF 50W. ON THE SURFACE DAY 4 GFS MODEL JUMPS ON LOW APPROACHING LESSER ANTILLES LOCATED NEAR 14N54W. A SECOND LOW FURTHER SE NEAR 8N37W HAS WINDS TO 40 KT ACCORDING TO THE GFS WHICH IS OBVIOUSLY OVERDONE. GULF LOW REMAINS WEAK AT 1010 MB BUT STATIONARY COULD SPELL TROUBLE. HIGH PRES OVER ATLC ALONG 55W UNDER MID LEVEL RIDGE CENTER. FOR DAY 5 LARGE AMPLITUDE SHORTWAVE ALONG 78W MOVING EWD IN STRONG MID LEVEL FLOW. MID LEVEL RIDGE BEING ERODED BY SHORTWAVE BUT STILL HOLDING IT'S OWN OVER MID ATLC. MID LEVEL HEIGHTS RISING OVER PLAINS WITH NEW RIDGE DEVELOPING. ON THE SURFACE DAY 5 A COLD FRONT MOVES INTO THE NW GULF WITH WINDS TO 20 KT. GULF LOW DISSIPATING ACCORDING TO GFS MODEL. ALL EYES ON PSBL TRPL DEVELOPMENT E OF LEEWARDS AND FURTHER SE NEAR 40W WHERE GFS MODEL CONTINUES TO LIKE TWO LOWS. HIGH PRES SLIDING SLOWLY EWD TO 55W WITH RIDGE AXIS BACK TO S FL. WINDS OVER THE REGION MOSTLY LIGHT TO MODERATE EXCEPT NEAR LOWS. WARNINGS... ATLANTIC... NONE. CARIBBEAN... NONE. GULF OF MEXICO... NONE. FORECASTER RRG