000 AXNT20 KNHC 231413 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 AM EST SAT FEB 23 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1115 UTC ...ITCZ... ITCZ AXIS IS CENTERED ALONG 5N10W 1N21W 4N30W 4N40W 1N48W. SCATTERED MODERATE ISOLATED STRONG CONVECTION NOTED WITHIN 330 NM N AND WITHIN 240 NM S OF THE ITCZ AXIS BETWEEN 28W AND 30W. ISOLATED MODERATE OBSERVED S OF 8N BETWEEN 39W AND 51W. ...DISCUSSION... GULF OF MEXICO... AN UPPER TROUGH IS SWINGING E ACROSS THE N CENTRAL GULF ATTM ACCOMPANIED BY DRY UPPER AIR GENERALLY W OF A LINE FROM 30N870W TO 20N97W. AN UPPER ANTICYCLONE OVER THE SE BAHAMAS RIDGES W OVER THE GULF OF MEXICO TO A CREST ALONG POINTS 20N95W 28N81W. UPPER LEVEL MOISTURE...ORIGINATING FROM FORMER CONVECTION OVER THE E PACIFIC NEAR 15N95W AND OVER CENTRAL AMERICA BETWEEN 85W AND 95W...IS STREAMING NE UNDER THIS RIDGE. AT 09 UTC A SURFACE COLD FRONT EXTENDS FROM 30N89W SW TO THE CENTRAL GULF NEAR 26N90W THEN BECOMES STATIONARY THROUGH A WEAK LOW PRES IN THE BAY OF CAMPECHE NEAR 20N94W THEN TURNS W AND NW BACKING UP AGAINST THE MEXICAN MOUNTAINS FROM 20N98W TO S TEXAS NEAR 28N100W. UPPER DIFFLUENCE E OF THE THE UPPER TROUGH IS STILL ENHANCING CONVECTION AHEAD OF THE SURFACE FRONT ALONG LINE FROM 27N88W TO BEYOND 30N81W WITH LIGHTNING DATA STILL REGISTERING HITS OVER THE GULF ALONG THIS LINE. A 75 NM WIDE BAND OF OVERCAST LOW CLOUDS...AND VISIBILITIES ESTIMATED IN THE 3-5 NM RANGE IN FOG...IS NOTED FROM 29N90W TO 24N97W. E OF THE FRONT...THE ATLC SUBTROPICAL RIDGE EXTENDS W OVER THE AREA WITH ITS AXIS ALONG 24N TO NEAR 88W. CARIBBEAN... AN UPPER ANTICYCLONE IS CENTERED NEAR 21N73W WITH ITS ANTICYCLONIC ENVELOPE DOMINATING THE CARIBBEAN W OF 67W. THE WESTERN PORTION OF A CENTRAL ATLC UPPER TROUGH STILL EXTENDS INTO THE EASTERN CARIBBEAN BUT APPEARS TO BE FILLING WITH TIME. THIN BROKEN CIRRIFORM CLOUDS ARE NOTED OVER THE NW CARIBBEAN ALONG THE UPPER RIDGE. DRY UPPER AIR IS INDICATED ELSEWHERE ALOFT. AT THE LOW LEVELS THE ATLC SUBTROPICAL RIDGE EXTENDS W ACROSS THE NW CARIBBEAN WITH ITS AXIS ROUGHLY JUST N OF THE AREA ALONG 24N. LOCALLY BROKEN LOW TRADE WINDS CLOUDS WITH EMBEDDED SHOWERS ARE NOTED E OF 70W WITH CLOUDINESS BECOMING BROKEN TO OVERCAST ROM JAMAICA TO W CUBA. ATLANTIC... AN UPPER ANTICYCLONE IS CENTERED OVER THE SE BAHAMAS WITH A RIDGE EXTENDING NE TO BEYOND 32N68W. A MOISTURE PLUME IS NOTED ALONG THE RIDGE N OF POINTS 25N80W 25N54W. THE CENTRAL SUB-TROPICAL ATLC IS DOMINATED ALOFT BY AN UPPER TROUGH EXTENDING THROUGH CYCLONES ALONG 36N14W 22N40W 15N55W. DRY UPPER AIR IS NOTED OVER THE SW SEMICIRCLES OF EACH OF THESE CYCLONES WHILE SHOWERS ARE ENHANCED OVER THE NE SEMICIRCLE. THE TROPICAL E ATLC IS DOMINATED ALOFT BY AN ANTICYCLONE AT 5N14W WITH A RIDGE EXTENDING W TO NEAR 1N40W. UPPER DIFFLUENCE ALONG THIS RIDGE AXIS IS ENHANCING CONVECTION NEAR 2N23W WITH THE DEBRIS MOISTURE SPREADING N TO ALONG 18N BETWEEN 15W AND 28W. A WELL DEFINED 300 NM WIDE MOISTURE PLUME...ORIGINATING FROM CONVECTION OVER S AMERICA NEAR 2S50W...STREAMS NE ALONG THE TROPICAL UPPER RIDGE...ROUGHLY ALONG 3N48W 20N25W THEN TURNS E ACROSS AFRICA ALONG 29N9W 27N1W. AT THE LOW LEVELS A HIGH PRES IS AT 39N33W 1030 MB WITH A RIDGE SW THROUGH THE STRAITS OF FLORIDA. A SURFACE FRONT HAS STALLED JUST OFFSHORE THE NE FLORIDA COAST WITH SHOWERS AND A FEW TSTMS VERIFIED BY LIGHTNING DATA NEAR 29N80W. LOCALLY BROKEN STRATOCUMULUS IS MOVING ANTICYCLONICALLY ACROSS THE WATERS SE OF THE LOW LEVEL RIDGE. $$ NELSON