000 AGXX40 KNHC 070508 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 130 AM EDT SAT APR 7 2007 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. IT SEEMS LIKE THIS WINTER/SPRING SEASON HAS BEEN CHARACTERIZED BY STRONG SHORTWAVES IN THE NRN BRANCH THAT MOVE TO THE ERN GREATLAKES..TAP MORE COLD AIR AND ENLARGE TO LARGE CYCLONIC CIRCULATIONS BEFORE TRANSITING EWD. THE SAME SYNARIO HAS DEVELOPED TONIGHT. THIS FEATURE DOMINATES THE ENTIRE REGION W OF 60W. A MID LEVEL RIDGE IS DEVELOPING ALONG 50W IN RESPONSE TO THE LARGE TROUGH. ON THE SURFACE TONIGHT A COLD FRONT HAS MOVED RAPIDLY SE AND EXTENDS FROM 31N73W TO W CENTRAL CUBA SW TO BELIZE. A POLAR AIRMASS EXTENDS OVER THE GULF WITH 20 KT WINDS. A SUBTROPIC RIDGE IS OVER THE ERN ATLC WITH 20 KT TRADES S OF 15N. LATER DAY 1 THE MID LEVEL FLOW TIGHTENS AS COLD AIR ALOFT SPILLS S OVER THE TN VALLEY. WEAK SHORTWAVE IN THE SRN BRANCH OVER THE WRN GULF WILL MOVE E TODAY. ON THE SURFACE LATER DAY 1 WINDS OF 20 TO 25 KT N OF 28N BETWEEN 55W AND 80W ASSOCIATED WITH CYCLONIC CIRCULATION AND THE COLD FRONT. FAIRLY STRONG POLAR AIRMASS EXTENDS SE OVER THE GULF WITH GUSTY WINDS TO 20 KT. ATLC TRADES 20 KT S OF 18N. FOR DAY 2 LARGE CYCLONIC CIRCULATION MOVING E OFF CANADIAN MARITIMES WITH MID LEVEL FLOW BECOMING MORE ZONAL S OF 35N. FLAT MID LEVEL RIDGE OVER CARIB EXTENDS NE ALONG 45W. ON THE SURFACE DAY 2 ATLC COLD FRONT LOOSES STEAM AS IT DRIFTS EWD TO 31N52W 21N70W. POLAR AIRMASS WEAKENING BUT REMAINS OVER N GULF COAST. INVERTED TROUGH OVER NW GULF TIGHTENS GRADIENT N OF 27N W OF 90W WITH NE WINDS INCREASING 20 TO 25 KT..SOMEWHAT LESS THAN GFS RUN OF 24 HRS AGO. CARIB WINDS INCREASE SOME TO 20 KT E OF 80W. OUTLOOK PERIOD... FOR DAY 3 A SECONDARY SUPPLY OF COLD AIR ALOFT HANGS BACK OVER THE OH VALLEY AS THE STRONG CYCLONIC CIRCULATION LIFTS NE. MID LEVEL FLOW S OF 35N REMAINS STRONG WLY. ON THE SURFACE DAY 3 A WARM FRONTAL BOUNDARY OVER THE N GULF SLOWLY WORKS IT'S WAY NWD AS WHATS LEFT OF THE POLAR AIRMASS MOVES E OFF THE SE COAST. NE WINDS OF 20 KT PERSIST N OF THE FRONT. ELSEWHERE THE ATLC FRONT STALLS AND BEGINS TO WEAKEN ALONG 31N54W 21N70W..SEPARATING THE DRIER AIRMASS ON THE W SIDE FROM THE ATLC RIDGE CENTERED NEAR 29N42W. FOR DAY 4 THE LAST OF THE MID LEVEL COLD AIR MOVES OFF THE NE COAST WITH RIDGING DEVELOPING ALONG 90W. A NEW SHORTWAVE MOVES INTO THE N CENTRAL PLAINS WHILE A WEAKER SHORTWAVE MOVES E IN THE SRN BRANCH TO 85W. ON THE SURFACE DAY 4 THE WRM FRONT OVER THE N GULF MOVES INLAND AS SURFACE PRESSURES FALL OVER THE PLAINS. SLY WINDS INCREASE TO 20 TO 25 KT OVER THE GULF. THE ATLC FRONT BECOMES DIFFUSE ALONG 31N50W 22N66W. OLD POLAR AIR 1019 MB NEAR 28N68W AND SUBTROPIC AIRMASS 1021 MB NEAR 29N41W WILL MAINTAIN ELY TRADES S OF 17N AT 15 TO 20 KT. FOR DAY 5 SRN BRANCH SHORTWAVE RACES NE TO OFF THE N CAR COAST AHEAD OF A STRONG SHORTWAVE MOVING SE OVER THE MO VALLEY. THIS SYSTEM WILL BE A FACTOR IN OUR REGION DAY 5 WITH MID LEVEL HEIGHTS FALLING W OF 80W. ON THE SURFACE DAY 5 A COLD FRONT MOVES INTO THE NW GULF WITH WINDS 20 TO 25 KT. 20 TO 25 KT SLY WINDS AHEAD OF THE FRONT SPREAD OVER THE ERN GULF AND SW ATLC W W OF 75W. THE ATLC FRONT DISSIPATES AS BOTH HIGH PRES SYSTEMS BEGINS TO MERGE OVER THE CENTRAL ATLC. ELY TRADES REMAIN ABOUT THE SAME DAY 5. WARNINGS... ATLANTIC... NONE. CARIBBEAN... NONE. GULF OF MEXICO... NONE. FORECASTER RRG