000 AXNT20 KNHC 211816 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST THU FEB 21 2008 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1645 UTC ...ITCZ... ITCZ AXIS IS CENTERED ALONG 5N9W 1N47W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS WITHIN 240 NM OF THE ITCZ AXIS BETWEEN 5W AND 15W AND BETWEEN 35W AND 50W. ...DISCUSSION... GULF OF MEXICO... AN UPPER RIDGE...ORIGINATING OVER THE W CARIBBEAN...DOMINATES THE UPPER LEVELS. UPPER MOISTURE...IN THE FORM OF THIN BROKEN CIRRUS...IS STREAMING E ACROSS THE RIDGE N OF LINE 22N97W 26N90W 25N81W WITH SOMEWHAT DRIER AIR NOTED S OF THE SAME LINE. AT THE LOW LEVELS A WARM FRONT EXTENDS FROM SW FL TO THE MISSISSIPPI DELTA AND IS LIFTING N AND NE WITH TIME. BROKEN LOW AND MID LEVEL CLOUDS ARE NOTED NE OF THE WARM FRONT WITH CONVECTION FLARING NEAR 30N87W. CARIBBEAN... AN UPPER LEVEL ANTICYCLONE IS CENTERED NEAR 14N76W WITH ANTICYCLONIC FLOW DOMINATING THE UPPER LEVELS OF THE CARIBBEAN W OF 70W. AN UPPER LEVEL TROUGH EXTENDS W OF THE AREA E OF 70W WITH AN EMBEDDED UPPER CYCLONE AT 14N67W. BROKEN CIRRIFORM CLOUDS ARE STREAMING E ACROSS THE AREA N OF 15N W OF 70W. AT THE LOW LEVELS THE SUBTROPICAL ATLC RIDGE IS PUSHING LOCALLY BROKEN LOW AND MID LEVELS CLOUDS...WITH EMBEDDED SHOWERS...W ACROSS THE WATERS N OF 12N WITH THE CLOUDS TURNING NW OVER THE AREA W OF 80W. ATLANTIC... AN UPPER RIDGE IS NOTED OVER THE AREA W OF 73W WITH BROKEN CIRRUS SPREADING E ACROSS THE RIDGE. AN UPPER TROUGH IS NOTED ALONG 32N68W 26N70W. AN ASSOCIATED SURFACE FRONT IS ALONG 32N61W 26N74W BECOMING QUASI STATIONARY TO 25.5N80W...HIGH PRES IS NEAR 31N71W 1025 MB. DIFFLUENCE E OF THE UPPER TROUGH IS ENHANCING CONVECTION ALONG THE SURFACE FRONT WITH THE ACTIVITY IN DECREASING AT THE MOMENT. AN TROPICAL UPPER TROUGH DOMINATES THE CENTRAL ATLC EXTENDING THROUGH UPPER CYCLONES AT 34N33W AND 18N47W AND 14N61W. DRY UPPER AIR IS NOTED WITHIN 270 NM EITHER SIDE OF THE TROUGH AXIS. BROKEN LOW AND MID LEVEL CLOUDS AND EMBEDDED SHOWERS ARE NOTED WITHIN 150 NM W AND WITHIN 240 NM E SEMICIRCLES OF THE CYCLONE AT 18N47W. AT THE LOW LEVELS A RIDGE EXTENDS ALONG 32N44W 25N70W. AN UPPER RIDGE EXTENDS W OFF THE AFRICAN COAST OVER THE TROPICAL ATLC E OF 40W WITH A DENSE MOISTURE PLUME WITHIN 420 NM EITHER SIDE OF LINE 8N43W 21N26W TO BEYOND 35N2W. $$ NELSON