000 AXNT20 KNHC 051707 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST FRI DEC 05 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 1645 UTC. ...THE ITCZ... THE ITCZ AXIS IS ANALYZED ALONG 6N10W 6N21W 4N32W 4N43W 5N54W. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM S OF THE ITCZ AXIS BETWEEN 9W-13W. SCATTERED MODERATE CONVECTION IS ALSO S OF 8N BETWEEN 31W-40W. ...DISCUSSION... GULF OF MEXICO... STRONG WESTERLY AND SOUTHWESTERLY FLOW ALOFT COVERS THE GULF REGION...AS A DEEP LAYER TROUGH SLOWLY MOVES EASTWARD OVER THE E AND S CONUS. AN ASSOCIATED SURFACE FRONT IS PRESENT ACROSS THE GULF REGION...EXTENDING FROM THE N FLORIDA PENINSULA NEAR 29N82W TO 26N90W TO A 1019 MB SURFACE LOW NEAR 21N96W TO E MEXICO NEAR 20N97W TO THE NW ACROSS PORTIONS OF CENTRAL AND N MEXICO. ALSO...A SURFACE TROUGH IN THE BAY OF CAMPECHE EXTENDS FROM THE 1019 MB SURFACE LOW NEAR 21N96W TO 20N95W TO 19N95W. THE AFOREMENTIONED FRONT IS MOVING SOUTHWARD AS A COLD FRONT E OF 93W...AND IS NEARLY STATIONARY W OF 93W AS THE STRONGEST UPPER LEVEL ENERGY TRANSLATES EASTWARD OVER THE SE CONUS. LOW LEVEL CONVERGENCE IN THE VICINITY OF THE FRONT...COMBINED WITH ATMOSPHERIC LIFT IN MOIST WESTERLY AND SOUTHWESTERLY FLOW ALOFT...IS SUPPORTING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WITHIN 60 NM EITHER SIDE OF THE FRONT. INCREASED N TO NE SURFACE WINDS ARE ADVECTING A RELATIVELY COOLER AND DRIER AIRMASS ACROSS THE N AND W GULF IN THE WAKE OF THE FRONT. THIS AIRMASS IS BEING SUPPORTED BY A 1037 MB SURFACE HIGH IN NE OKLAHOMA NEAR 36N95W. DEEP LAYER DRY AIR IS INHIBITING DEEP CONVECTION OVER THE SE GULF...WHERE GENERALLY FAIR WEATHER PREVAILS. ADDITIONALLY...STRONG N TO NE SURFACE WINDS ARE BLOWING THROUGH THE ISTHMUS OF TEHUANTEPEC RESULTING IN GALE FORCE WINDS IN THE EAST PACIFIC REGION. CARIBBEAN SEA... AN UPPER RIDGE EXTENDS FROM N COLOMBIA NEAR 11N73W TO AN UPPER HIGH S OF HISPANIOLA NEAR 15N72W TO THE NE CARIBBEAN NEAR 19N68W TO THE W ATLC. UPPER LEVEL DIVERGENCE SW OF THE UPPER HIGH IS COMBINING WITH DEEP MOISTURE OVER THE SW CARIBBEAN TO RESULT IN SCATTERED SHOWERS S OF 12N W OF 79W. THIS ACTIVITY IS BEING ENHANCED BY LOW LEVEL CONVERGENCE IN THE VICINITY OF A SURFACE TROUGH EXTENDING FROM 14N81W TO A 1011 MB SURFACE LOW NEAR 10N82W TO N PANAMA NEAR 9N82W. ALSO...A DISSIPATING SURFACE STATIONARY FRONT OVER THE NW CARIBBEAN EXTENDS FROM E OF THE YUCATAN PENINSULA NEAR 19N87W TO CENTRAL CUBA NEAR 22N78W TO THE W ATLC...WITH SCATTERED SHOWERS WITHIN 60 NM EITHER SIDE OF THIS DISSIPATING STATIONARY FRONT. NEAR AND E OF THE AFOREMENTIONED UPPER RIDGE...FAIR WEATHER CONDITIONS PERSIST OVER THE E CARIBBEAN WHERE DEEP LAYER SUBSIDENCE IS ENHANCING STABLE ATMOSPHERIC CONDITIONS IN THE PRESENCE OF DEEP LAYER DRY AIR. ATLANTIC OCEAN... WESTERLY AND SOUTHWESTERLY FLOW ALOFT CONTINUES TO INCREASE OVER THE W ATLC AS THE DEEP TROUGH OVER THE E AND S CONUS TRANSLATES EASTWARD. A SURFACE COLD FRONT EXTENDS FROM THE N FLORIDA PENINSULA NEAR 29N82W TO 32N79W TO NE OF THE DISCUSSION AREA. LOW LEVEL CONVERGENCE IS SUPPORTING SCATTERED SHOWERS ALONG AND WITHIN 60 NM E OF THIS COLD FRONT. TO THE E...A DISSIPATING SURFACE STATIONARY FRONT EXTENDS FROM CENTRAL CUBA NEAR 22N78W TO 26N63W TO 30N55W. DEEP LAYER DRY AIR IS INHIBITING DEEP CONVECTION IN THE VICINITY OF THIS WEAKENING STATIONARY FRONT. TO THE E OF THESE FRONTS...THE FLOW ALOFT IS MORE AMPLIFIED... WITH AN UPPER RIDGE AXIS EXTENDING FROM THE NE CARIBBEAN NEAR 19N68W TO 27N65W TO 32N60W TO N OF THE DISCUSSION AREA...AND AN UPPER TROUGH AXIS EXTENDING FROM 28N50W TO 32N45W TO NE OF THE DISCUSSION AREA. THIS UPPER TROUGH IS ASSOCIATED WITH A 1012 MB SURFACE LOW NEAR 27N48W AND A SURFACE TROUGH EXTENDING FROM 28N50W TO 29N47W TO 25N46W TO 23N50W. LOW LEVEL CONVERGENCE NEAR THIS SURFACE LOW AND SURFACE TROUGH IS SUPPORTING SCATTERED SHOWERS FROM 24N-31N BETWEEN 44W-50W. ALSO...A SURFACE TROUGH OVER THE CENTRAL ATLC EXTENDS FROM 19N42W TO 15N45W TO 10N47W...WITH LOW LEVEL CONFLUENCE SUPPORTING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WITHIN 90 NM EITHER SIDE OF THIS SURFACE TROUGH. FARTHER TO THE E...NUMEROUS SHOWERS N OF 23N BETWEEN 26W-35W ARE BEING SUPPORTED BY UPPER LEVEL DIVERGENCE E OF A SHARP UPPER TROUGH WITH THE AXIS EXTENDING FROM 22N30W TO 27N35W TO 32N37W TO NW OF THE DISCUSSION AREA...AND BY ATMOSPHERIC INSTABILITY. FARTHER TO THE S...AN UPPER RIDGE IS S OF 14N BETWEEN THE AFRICAN COAST AND 58W...WITH AN UPPER HIGH NEAR 9N20W. UPPER LEVEL DIVERGENCE ASSOCIATED WITH THE UPPER HIGH AND UPPER RIDGE IS ENHANCING THE CONVECTION ASSOCIATED WITH THE ITCZ. $$ COHEN