000 AXNT20 KNHC 190506 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 AM 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0445 UTC. ...THE ITCZ... ITCZ IS CENTERED ALONG 9N13W 5N26W 5N34W 5N42W 4N51W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 3N-8N BETWEEN 16W-26W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS ALSO FROM 2N-8N BETWEEN 27W-33W. SIMILAR CONVECTION IS FROM 5N-11N BETWEEN 34W-50W. ...DISCUSSION... GULF OF MEXICO... A 1026 MB SURFACE HIGH IS E OF THE FLORIDA PENINSULA NEAR 30N79W...WITH THE ANTICYCLONIC FLOW AROUND THIS HIGH RESULTING IN E TO SE SURFACE WINDS OF 10 TO 20 KT ACROSS MUCH OF THE GULF REGION. SUBSIDENCE ASSOCIATED WITH THIS HIGH IS RESULTING IN ATMOSPHERIC STABILITY AND FAIR WEATHER CONDITIONS ACROSS MUCH OF THE GULF REGION. THIS STABILITY IS BEING ENHANCED BY THE PRESENCE OF AN UPPER HIGH OVER THE CENTRAL GULF CENTERED NEAR 25N86W...WITH RELATIVELY LIGHT AND BROAD ANTICYCLONIC FLOW ALOFT...AND DEEP LAYER DRY AIR...ACROSS THE GULF REGION. CARIBBEAN SEA... WESTERLY CONFLUENT FLOW ALOFT IS RESULTING IN SUBSIDENCE AND ATMOSPHERIC STABILITY ACROSS THE CARIBBEAN REGION...WHERE GENERALLY DEEP LAYER DRY AIR IS PRESENT. THESE FACTORS ARE RESULTING IN FAIR WEATHER CONDITIONS ACROSS MUCH THE CARIBBEAN REGION. THE SOUTHERN PERIPHERY OF THE ANTICYCLONIC FLOW AROUND THE AFOREMENTIONED 1026 MB SURFACE HIGH E OF THE FLORIDA PENINSULA NEAR 30N79W IS BRINGING FRESH TRADEWINDS TO THE CARIBBEAN REGION. UPPER LEVEL MOISTURE IS STREAMING NORTHWARD FROM SOUTH AMERICA ACROSS THE SW CARIBBEAN...WITH ISOLATED SHOWERS OVER THE SW CARIBBEAN S OF 10N W OF 76W...INCLUDING PORTIONS OF N COLOMBIA AND S PANAMA. ATLANTIC OCEAN... ACROSS THE W ATLC...A 1026 MB SURFACE HIGH IS CENTERED E OF THE FLORIDA PENINSULA NEAR 30N79W...WHICH IS BRINGING SUBSIDENCE AND FAIR WEATHER CONDITIONS TO MUCH OF THE W ATLC. NORTHERLY UPPER LEVEL FLOW TO THE E OF THE UPPER HIGH OVER THE GULF OF MEXICO IS ADVECTING UPPER LEVEL MOISTURE ACROSS THE W ATLC. FARTHER TO THE E...A SURFACE TROUGH OVER THE CENTRAL ATLC EXTENDS FROM A 1014 MB SURFACE LOW NEAR 32N57W TO 27N58W TO A 1012 MB SURFACE LOW NEAR 24N60W TO 22N63W. LOW LEVEL CONVERGENCE ASSOCIATED WITH THE SURFACE LOWS AND SURFACE TROUGH IS RESULTING IN SCATTERED SHOWERS N OF 23N BETWEEN 56W-61W. THIS ACTIVITY IS BEING ENHANCED BY INSTABILITY IN THE VICINITY OF AN UPPER TROUGH WITH AN AXIS EXTENDING FROM 20N67W TO 27N57W TO 32N53W TO N OF THE DISCUSSION AREA. UPPER LEVEL DIVERGENCE IN THE NE QUADRANT OF A 90-100-KT UPPER LEVEL JET MAXIMUM E OF THIS UPPER TROUGH AXIS IS ALSO ENHANCING THE SHOWER ACTIVITY. IN 24 HOURS...ATMOSPHERIC LIFT ASSOCIATED WITH UPPER LEVEL JET MAXIMUM IS FORECAST TO RESULT IN THE DEVELOPMENT OF A 1012 MB SURFACE LOW OVER THE CENTRAL ATLC NEAR 28N48W. ACROSS THE E ATLC...SUBSIDENCE ASSOCIATED WITH A SURFACE RIDGE EXTENDING SOUTHWESTWARD FROM A 1033 MB SURFACE HIGH NEAR 42N19W IS GENERALLY INHIBITING DEEP CONVECTION N OF 13N E OF 32W. HOWEVER...ATMOSPHERIC INSTABILITY ASSOCIATED WITH AN UPPER LOW NEAR 32N20W IS RESULTING IN SCATTERED SHOWERS N OF 29N BETWEEN 15W-22W. FARTHER TO THE S...A SURFACE TROUGH EXTENDS FROM 18N54W TO 15N55W TO 13N55W...WITH CYCLONIC CURVATURE NOTED IN THE LOW LEVEL WIND FIELD IN THE VICINITY OF THIS SURFACE TROUGH. LOW LEVEL CONVERGENCE IS RESULTING IN SCATTERED SHOWERS WITHIN 60 NM EITHER SIDE OF THIS SURFACE TROUGH. ACROSS THE TROPICAL ATLC... AN UPPER RIDGE IS S OF 17N BETWEEN 16W-50W. UPPER LEVEL DIVERGENCE ASSOCIATED WITH THIS UPPER RIDGE IS ENHANCING THE CONVECTION ASSOCIATED WITH THE ITCZ. $$ COHEN