000 AXNT20 KNHC 200611 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST THU DEC 20 2007 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND THE ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS... WEATHER OBSERVATIONS...AND RADAR. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0545 UTC ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 5N9W 3N25W 4N35W 2N45W AND INTO SOUTH AMERICA NEAR THE EQUATOR AT 50W. CLUSTERS OF MODERATE TO STRONG CONVECTION ARE WITHIN 50 NM EITHER SIDE OF THE AXIS BETWEEN 17W-24W. SIMILAR CONVECTION IS WITHIN 150 NM N OF THE AXIS BETWEEN 28W-33W. WIDESPREAD MODERATE TO STRONG CONVECTION IS FROM 2N-6N BETWEEN 35W-45W. UPPER DIFFLUENCE IS ENHANCING THIS CONVECTIVE ACTIVITY. DISCUSSION... GULF OF MEXICO... HIGH PRES REMAINS IN CONTROL OF THE WEATHER PATTERN ACROSS THE GULF GIVING THE AREA LIGHT TO MODERATE E TO SE WINDS WITH THE RETURN FLOW BRINGING INCREASED MOISTURE TO THE W GULF. UPPER-LEVEL OUTFLOW FROM CONVECTIVE ACTIVITY ALONG THE TEXAS/LOUISIANA BORDER IS SPREADING OVER THE NW GULF. THE REMAINDER OF THE GULF REMAINS TRANQUIL WITH PATCHES OF LOW LEVEL CLOUDS UNDER STRONG SUBSIDENCE FROM AN UPPER RIDGE. A SUBTROPICAL JET WITH CORE WINDS OF NEAR 120 KT IS RIDING ON THE N PERIPHERY OF THE RIDGE FROM THE EPAC ACROSS N MEXICO AND THE N GULF WATERS DRAWING UPPER-LEVEL MOISTURE ACROSS THE AREA. THE NEXT COLD FRONT IS FORECAST TO ENTER THE REGION THIS WEEKEND. STRONG WINDS AND HIGH SEAS WILL BUILD IN THE GULF FOLLOWING THE FRONTAL PASSAGE. CARIBBEAN SEA... A SFC TROUGH STRETCHES FROM EASTERN CUBA ACROSS THE CAYMAN ISLANDS TO NORTHERN BELIZE NEAR 18N88W. ASSOCIATED LOW CLOUDS WITH EMBEDDED SHOWERS REMAIN OVER THE NW CARIBBEAN/GULF OF HONDURAS. ALOFT...STRONG SUBSIDENCE AND DRY STABLE AIR DOMINATE THE CENTRAL AND EASTERN CARIBBEAN. UPPER-LEVEL MOISTURE IS BEING DRIVEN NWD ACROSS THE WINDWARD ISLANDS BETWEEN A SHORT-WAVE TROUGH OVER THE LESSER ANTILLES AND A RIDGE OVER THE TROPICAL ATLC. SATELLITE IMAGERY SHOWS SHALLOW CONVECTION OVER THE ABC ISLANDS AT THE BASE OF THE SHORT-WAVE TROUGH. MODERATE TO FRESH ELY TRADE WINDS WILL CHANGE LITTLE THROUGH SATURDAY. ATLANTIC OCEAN... A SFC RIDGE EXTENDS FROM A 1024 MB SURFACE HIGH OVER GEORGIA COVERING THE W ATLC. A BAND OF LOW LEVEL MOISTURE JUST CLIPS THE DISCUSSION AREA N OF 30N ALONG 76W/77W. THIS MOISTURE IS ASSOCIATED WITH A COLD FRONT WELL NORTH OF THE AREA. THE SUBTROPICAL JET OVER THE NORTHERN GULF OF MEXICO CONTINUES TO PUSH HIGH CLOUDS/MOISTURE OVER THE W ATLC. FARTHER EAST...A COLD FRONT ENTERS THE REGION NEAR 31N45W AND STRETCHES SW TO 24N71W...THEN CONTINUES ACROSS THE BAHAMAS AND CENTRAL CUBA AND INTO THE CARIBBEAN AS A SFC TROUGH. A BROKEN BAND OF MAINLY LOW LEVEL CLOUDS WITH ISOLATED SHOWERS/THUNDERSTORMS IS BEHIND THE FRONT. FAIR WEATHER STRATOCUMULUS CLOUDS ARE BEING TRANSPORTED AROUND A 1028 MB SFC HIGH CENTERED NEAR 29N42W. AN UPPER-LEVEL RIDGE DOMINATES THE CENTRAL ATLC. A DEEP-LAYERED TROUGH IS OVER THE E ATLC. AN ASSOCIATED FRONTAL BOUNDARY EXTENDS OVER THE CANARY ISLANDS TO 19N20W. UPPER WESTERLY ZONAL FLOW COVERS THE TROPICAL ATLC. $$ GR/RJW