000 AXNT20 KNHC 200531 CCA TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 AM EST SAT 20 DEC 2003 ...CORRECTED FOR DATE... TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...GULF OF MEXICO...CARIBBEAN SEA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE EQUATOR TO 32N INCLUDING NORTHERN SECTIONS OF SOUTH AMERICA. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY... WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0445 UTC. SPECIAL FEATURES... NONE. TROPICAL WAVES/ITCZ... AXIS OF ITCZ-RELATED CLOUDS/CONVECTION IS CENTERED ALONG 5N1W 6N10W 3N40W 1N50W. SCATTERED MODERATE TO STRONG CONVECTION FROM 2N-6N BETWEEN 22W-33W. WIDELY SCATTERED MODERATE CONVECTION WITHIN 60 NM EITHER SIDE OF AXIS FROM 38W-46W. MIDDLE/UPPER LEVEL SYNOPTIC FEATURES... GULF OF MEXICO... A BROAD MID/UPPER LEVEL LONGWAVE TROUGH CONTINUES TO DOMINATE THE E HALF OF THE UNITED STATES AND GLFMEX AS IT MOVES SLOWLY EWD. THE TROUGH HAS AMPLIFIED SWD DURING THE LAST 24 HOURS AS SHORTWAVE DISTURBANCES EMBEDDED WITHIN THE LARGER SCALE FLOW DROP SEWD FROM THE CENTRAL UNITED STATES AND MEXICO. THE MEAN AXIS NOW STRETCHES FROM THE NE UNITED STATES SW ACROSS N FLORIDA TO THE BAY OF CAMPECHE. AS A RESULT OF THE AMPLIFICATION...THE SUBTROPICAL JET AND VEIL OF ASSOCIATE UPPER LEVEL MOISTURE/CLOUDS WHICH WAS OVER THE S GLFMEX YESTERDAY HAS MOVED E OF THE AREA WITH CONVERGENT FLOW ON THE BACKSIDE OF THE TROUGH NOW PRODUCING MODERATE SUBSIDING AND DRY AIR OVER THE ENTIRE GLFMEX. CARIBBEAN... THE ANTICYCLONE WHICH WAS LOCATED OVER THE E CARIBBEAN YESTERDAY HAS MOVED EWD INTO THE CENTRAL ATLC WITH SW TO W UPPER LEVEL FLOW NOW COVERING THE ENTIRE CARIBBEAN AHEAD OF AN APPROACHING TROUGH OVER THE GLFMEX. AN 80+ KT UPPER JET EXTENDS AROUND THE E FLANK OF THE TROUGH FROM THE YUCATAN PENINSULA OVER CENTRAL CUBA. MID/UPPER LEVEL CLOUDINESS AND A FEW ISOLATED SHOWERS ACCOMPANY THE JET WITH THE REST OF THE CARIBBEAN REMAINING UNDER MODERATE TO STRONG SUBSIDENCE AND A VERY DRY AIR MASS. THE AMPLIFYING UPSTREAM TROUGH WILL PRODUCE INCREASINGLY DIVERGENT FLOW OVER THE NW CARIBBEAN DURING THE NIGHT AND A FEW SHOWERS/THUNDERSTORMS ARE ALREADY BEGINNING TO DEVELOP ALONG A STATIONARY FRONT FROM THE WINDWARD PASSAGE TO NICARAGUA. CLOUDINESS AND SHOWERS/THUNDERSTORMS LIKELY INCREASE OVERNIGHT AND DURING THE DAY NW OF A LINE FROM NICARAGUA NEWD TO HISPANIOLA. ATLANTIC... A HIGH AMPLITUDE TROUGH-RIDGE-TROUGH PATTERN CONTINUES OVER MUCH OF THE ATLC WATERS WITH A LARGE MID-LATITUDE TROUGH OVER THE E UNITED STATES AND EXTREME W ATLC...A WELL DEFINED RIDGE OVER THE CENTRAL ATLC EXTENDING NWD FROM A ANTICYCLONE NEAR 21N55W TO BEYOND 32N50W...AND A WEAKENING TROUGH OVER THE E ATLC EXTENDING SWD FROM A LARGE UPPER LOW OVER THE AZORES INTO THE DEEP TROPICAL ATLC ALONG 20N30W 13N40W 6N50W THEN INLAND OVER S AMERICA. A SUBTROPICAL JET FROM 80-120 KT EXTENDS FROM THE NW CARIBBEAN NEWD OVER CUBA AND THE BAHAMAS INTO THE W ATLC BEYOND 30N70W. MID/UPPER LEVEL MOISTURE WITH THE JET ALONG WITH INCREASING UPPER DYNAMICS/LIFT IS PRODUCING A LARGE AREA OF PRIMARILY MID/HIGH LEVEL CLOUDINESS AND ISOLATED SHOWERS/THUNDERSTORMS FROM CUBA NEWD OVER BERMUDA. SHOWERS/THUNDERSTORMS WITHIN THIS AREA SHOULD INCREASE DURING THE NIGHT AS THE TROUGH AMPLIFIES AND BECOME MORE NEGATIVELY TILTED. THE AFOREMENTIONED MOISTURE CONTINUES NEWD OVER EXITING THE AREA NEAR BERMUDA AROUND THE N PERIPHERY OF THE LARGE CENTRAL ATLC RIDGE LEAVING MUCH OF THE CENTRAL ATLC UNDER VERY STRONG SUBSIDENCE AND DRY AIR. SHIFTING EWD...MOIST SLY FLOW AROUND THE E SIDE OF THE TROUGH FROM THE AZORES TO S AMERICA IS PRODUCING MOSTLY HIGH CLOUDINESS AND A FEW ISOLATED SHOWERS FROM THE ITCZ NWD OVER THE CAPE VERDE AND CANARY ISLANDS. SURFACE SYNOPTIC FEATURES... STRONG 1030 MB HIGH PRES REMAINS ANCHORED OVER CENTRAL TEXAS WITH RIDGE EXTENDING SWD ALONG THE COAST MEXICO THROUGH THE BAY OF CAMPECHE AND ALONG CENTRAL AMERICA. NLY FLOW AROUND THE E SIDE OF HIGH CONTINUES TO USHER IN SOME OF THE COOLEST AIR OF THE SEASON BEHIND A STATIONARY FRONT EXTENDING FROM THE W ATLC NEAR 32N56W SW THROUGH THE WINDWARD PASSAGE TO NICARAGUA. REINFORCING COLD FRONT MOVING SWD FROM THE JUST W OF BERMUDA OVER THE CENTRAL BAHAMAS AND W CUBA TO THE W GLFMEX NEAR 22N95W. BROKEN/OVERCAST MULTI-LEVEL CLOUDINESS AND ISOLATED SHOWERS/THUNDERSTORMS WITHIN 400 NM W OF STATIONARY FRONT. 1024 MB HIGH PRES LOCATED OVER THE CNTRL ATLC NEAR 27N51W. E ATLC COLD FRONT ENTERS THE AREA NEAR 32N21W AND EXTENDS SW ALONG 22N30W TO 19N40W. WIDELY SCATTERED MODERATE CONVECTION NORTH OF THE CANARY ISLANDS BETWEEN 10W-22W. SIGNIFICANT CLOUDS/CONVECTION... GULF OF MEXICO... NONE. CARIBBEAN SEA... BROKEN/OVERCAST MULTILEVEL CLOUDINESS WITHIN 400 NM OF STATIONARY FROM WINDWARD PASSAGE TO CENTRAL NICARAGUA. TROPICAL ATLANTIC... SEE ITCZ. EXTENSIVE UPPER LEVEL CLOUDINESS EXTENDS NWD FROM THE ITCZ OVER THE CAPE VERDE ISLANDS SE OF A LINE FROM 10N37W TO 20N27W. SUBTROPICAL ATLANTIC... HIGH CLOUDINESS AND ISOLATED SHOWERS LIE SE OF LINE FROM 20N27W TO 30N20W. $$ RHOME