000 AXNT20 KNHC 191755 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST FRI DEC 19 2008 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND 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 1715 UTC. ...THE ITCZ... ITCZ IS CENTERED ALONG 6N6W 4N26W 7N39W 4N52W. CLUSTERS OF SCATTERED TO STRONG MODERATE CONVECTION ARE FROM 2N-8N BETWEEN 21W-40W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 6N-11N BETWEEN 54W-59W. ...DISCUSSION... GULF OF MEXICO... A 1025 MB SURFACE HIGH IS E OF THE FLORIDA PENINSULA IN THE W ATLC NEAR 29N76W...WITH THE ANTICYCLONIC FLOW AROUND THIS HIGH RESULTING IN SE TO S SURFACE WINDS OF 10 TO 20 KT ACROSS MUCH OF THE GULF REGION. SUBSIDENCE ASSOCIATED WITH THIS HIGH IS RESULTING IN FAIR WEATHER CONDITIONS ACROSS MUCH OF THE GULF REGION THIS AFTERNOON. THIS STABILITY IS BEING ENHANCED BY AN UPPER HIGH OVER THE E GULF CENTERED NEAR 25N80W...WITH LIGHT AND BROAD ANTICYCLONIC FLOW ALOFT...AND DEEP LAYER DRY AIR. CARIBBEAN SEA... CONFLUENCE IN WESTERLY FLOW ALOFT IS GENERATING STRONG DRY AIR IN SUBSIDENCE ACROSS THE CARIBBEAN REGION. THESE FACTORS ARE RESULTING IN FAIR WEATHER CONDITIONS ACROSS MUCH THE CARIBBEAN REGION. THE SOUTHERN PERIPHERY OF THE AFOREMENTIONED SURFACE HIGH PRESSURE IN THE W ATLC NEAR 29N76W IS BRINGING NE TO E SURFACE WINDS OF 15 TO 25 KT TO THE CARIBBEAN BASIN. A SMALL AREA OF ISOLATED SHALLOW SHOWERS ARE BEING USHERED IN ON THESE NE WINDS ACROSS THE SW CARIBBEAN AND COASTAL NICARAGUA S OF 15N AND W OF 81W. ELSEWHERE...UPPER LEVEL MOISTURE IS STREAMING NORTHWARD FROM SOUTH AMERICA ACROSS THE SE CARIBBEAN...WITH ISOLATED SHOWERS POSSIBLE S OF 14N AND E OF 68W. ATLANTIC OCEAN... A 1025 MB SURFACE HIGH IS CENTERED NEAR 29N76W IN THE W ATLC... WHICH IS BRINGING SUBSIDENCE AND FAIR WEATHER CONDITIONS TO MUCH OF THE W ATLC W OF 65W. AN UPPER HIGH IS CENTERED OVER THE SRN FLORIDA PENINSULA ADVECTING MOISTURE WITHIN NW UPPER LEVEL FLOW ACROSS THE W ATLC. FARTHER TO THE E...A PAIR OF SURFACE TROUGHS ARE OVER THE CENTRAL ATLC. ONE EXTENDS FROM 26N59W TO A 1015 MB SURFACE LOW NEAR 23N61W TO 20N62W. LOW LEVEL CONVERGENCE IS RESULTING IN ISOLATED SHOWERS WITHIN 60 NM NW OF THIS SURFACE TROUGH. THE SECOND SURFACE TROUGH EXTENDS FROM 30N50W TO 25N52W WITH SCATTERED SHOWERS E OF THE TROUGH IN AN AREA OF UPPER DIFFLUENCE FROM 25N-30N BETWEEN 43W-50W. AN UPPER TROUGH IS SUPPORTING THESE TWO SURFACE TROUGHS WITH AXIS EXTENDING FROM 32N50W TO 21N60W AND INTO THE NE CARIBBEAN. ACROSS THE E ATLC...SUBSIDENCE ASSOCIATED WITH A SURFACE RIDGE EXTENDING SW FROM A 1035 MB SURFACE HIGH NEAR 44N15W IS INHIBITING DEEP CONVECTION N OF 15N AND E OF 40W. HOWEVER...AN UPPER LOW IS NEAR 30N19W AND IS GENERATING SCATTERED SHOWERS FROM 27N-32N BETWEEN 18W-23W. FARTHER TO THE S IN THE DEEP TROPICAL ATLC...A SURFACE TROUGH EXTENDS FROM 20N54W TO 12N55W WITH LOW LEVEL CONVERGENCE NEAR THE TROUGH RESULTING IN SCATTERED SHOWERS S OF 16N BETWEEN 50W-61W AND ACROSS THE SRN WINDWARD ISLANDS. IN THE UPPER LEVELS...A RIDGE IS S OF 16N BETWEEN 30W-60W. UPPER LEVEL DIVERGENCE ASSOCIATED WITH THIS UPPER RIDGE IS ENHANCING THE CONVECTION ALONG THE ITCZ. $$ HUFFMAN