000 AXNT20 KNHC 062346 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST WED DEC 06 2006 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA... CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA... NORTHEASTERN 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2345 UTC. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 11N15W 5N30W 6N45W 4N54W. SMALL CLUSTERS OF SCATTERED MODERATE CONVECTION NOTED WITHIN 90 NM OF THE AXIS BETWEEN 29W AND 50W. ...DISCUSSION... THE GULF OF MEXICO... UPPER FLOW REMAINS MOSTLY ZONAL ACROSS THE GULF THIS EVENING...ADVECTING QUITE A BIT OF MID TO UPPER MOISTURE ACROSS THE AREA OUTSIDE OF THE BAY OF CAMPECHE...WHERE VERY DRY AIR HAPPENS TO BE PRESENT. AVAILABLE BUOY/SHIP DATA AND SATELLITE IMAGERY SUGGEST A SFC TROUGH HAS FORMED OVER THE GULF BETWEEN PANAMA CITY FLORIDA AND THE YUCATAN CHANNEL. THIS IS REFLECTED ON THE 2100 UTC MAP. THERE IS NO DEEP CONVECTION ASSOCIATED WITH THIS TROUGH...THOUGH SCATTERED SHOWERS EXPECTED WITHIN 60 NM OF THE AXIS. THE TROUGH IS PRODUCING A KINK IN THE ISOBARS AROUND THE 1025 MB HIGH OVER SW GEORGIA. WINDS/SEAS HAVE SUBSIDED SUBSTANTIALLY OVER THE GULF OVER THE LAST 24 HOURS...BUT EXPECTED TO INCREASE THU/FRI BEHIND THE NEXT COLD FRONT. MOST OF THE PRECIP/CONVECTION ASSOCIATED WITH THIS FRONT EXPECTED TO BE LIMITED TO THE FAR WRN PORTION OFF S TEXAS AND MEXICO. THE CARIBBEAN SEA... A DYING STATIONARY FRONT EXTENDS FROM W CUBA TO NW HONDURAS ALONG 24N80W 21N85W 16N88W. THE BOUNDARY APPEARS RATHER DISCONTINUOUS AND THUS WAS REMOVED FROM THE 2100 UTC MAP. A SFC TROUGH EXTENDS N FROM NRN COLOMBIA THROUGH HAITI. SOME OF THIS MAY BE MORE DUE TO THE NATURAL TRADE FLOW THROUGH THE CARIBBEAN AND AROUND THE ADJACENT LAND MASSES. DEEP CONVECTION IS NON EXISTENT ACROSS THE CARIBBEAN THIS EVENING...WITH EXTENSIVE DRY MID TO UPPER AIR CONTINUING OVER THE AREA. UPPER RIDGING DOMINATES THE WRN AND CENTRAL CARIBBEAN WHILE A WEAKENING UPPER TROUGH IS OVER THE ERN CARIBBEAN. OVERALL E TO NE SFC FLOW IS IN THE 15-20 KT RANGE ACROSS THE CARIBBEAN...WHICH IS EXPECTED TO PERSIST INTO THU. THIS FLOW CONTINUES TO ADVECT SCATTERED TO BROKEN LOWER CLOUDS WITH ISOLATED SHOWERS THROUGH THE CARIBBEAN. A BIT STRONGER NE FLOW DEVELOPS IN THE NW PORTION LATE FRI INTO SAT AS STRONG HIGH PRESSURE BUILDS N OF THE AREA. THE ATLANTIC OCEAN... A DYING STATIONARY FRONT IS OVER THE SW NORTH ATLC FROM THE BAHAMAS TO 29N60W. A COLD FRONT EXISTS FROM THIS POINT TO 32N50W. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM SE OF THE COLD FRONT PORTION...N OF 28N BETWEEN 50W-55W. THE REMAINDER OF THE FRONT IS MARKED BY BROKEN TO OVERCAST LOWER CLOUDS WITH POSSIBLE LIGHT RAIN SHOWERS WITHIN 90 NM. THE SFC GRADIENT OVER THE AREA OFF THE FLORIDA COAST HAS WEAKENED TODAY WITH HIGH PRESSURE NEARING FROM GEORGIA...THOUGH NE WINDS AND WAVES INCREASE BEHIND THE NEXT FRONT FRI AND SAT. SFC OBS AND SATELLITE IMAGERY STILL SUGGEST A SFC TROUGH EXTENDS N THROUGH THE TURKS AND CAICOS ISLANDS TO 25N71W. SCATTERED SHOWERS POSSIBLE WITHIN 120NM OF THIS FEATURE. UPPER FLOW OVER THE WRN ATLC IS ZONAL...AND IS ADVECTING HIGH MOISTURE/CLOUDS E FROM THE FLORIDA COAST. A WEAKENING UPPER LOW/TROUGH NEAR THE LEEWARD ISLANDS HAS SCATTERED SHOWERS/TSTMS FROM 7N-20N BETWEEN 55W-61W. THIS AREA IS ALSO BEING SUPPORTED BY UPPER DIFFLUENT AIR BETWEEN THE UPPER LOW OVER THE LEEWARDS AND THE UPPER RIDGE EXTENDING N THROUGH THE TROPICAL ATLC...WHOSE AXIS IS ALONG 53W. A PRONOUNCED UPPER LOW IS SEEN SPINNING OVER THE E ATLC WATERS NEAR 20N32W...WHICH HAS ABUNDANT UPPER MOISTURE TO ITS S AND SE THROUGH AFRICA. THE E AND CENTRAL ATLC SFC PATTERN IS DOMINATED BY A 1033MB HIGH NEAR 33N23W. $$ WILLIS