000 AXNT20 KNHC 142355 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SAT MAR 14 2009 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 5N8W 3N15W CROSSING THE EQUATOR NEAR 24W EXTENDING TO 2S34W AND INTO NE BRAZIL NEAR 4S41W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS S OF 3N BETWEEN 5N-12N...AND WITHIN 160 NM N OF AXIS BETWEEN 10W-16W. SIMILAR CONVECTION IS FOUND WHERE THE ITCZ AXIS MEETS NE BRAZIL. ...DISCUSSION... GULF OF MEXICO... A QUASI-STATIONARY FRONT EXTENDS FROM SE LOUISIANA TO A 1011 MB LOW CENTERED NEAR 20.5N96W THEN THE FRONT CONTINUES MAINLY N ALONG THE EASTERN SLOPE OF THE SIERRA MADRE MOUNTAINS. THE FRONT IS AT THE LEADING EDGE OF A WIDE BAND OF CLOUDINESS WITH EMBEDDED SHOWERS AND ISOLATED TSTMS. LOW LEVEL CONVERGENCE AND DEEP LAYERED ATMOSPHERIC LIFT ARE SUPPORTING THIS CONVECTIVE ACTIVITY WHICH IS AFFECTING THE N GULF STATES MAINLY WEST OF THE FLORIDA PANHANDLE AND THE WESTERN PORTION OF THE GULF. NLY SURFACE WINDS OF 20 TO 25 KT ARE BEHIND THE FRONT PER AN EARLIER QSCAT PASS AND SFC DATA. THE STRONGEST WINDS ARE NOTED S OF 25N. TO THE SE OF THE FRONT...MODERATE SUBSIDENCE IS RESULTING IN GENERALLY FAIR WEATHER CONDITIONS ACROSS MUCH OF THE S-CENTRAL AND ERN GULF...INCLUDING THE FLORIDA PENINSULA WHERE THIS PATTERN IS EXPECTED TO PERSIST INTO EARLY NEXT WEEK. SE-S WINDS OF 15-20 KT ARE BLOWING AHEAD OF THE FRONT. ALOFT...A RIDGE WITH AXIS EXTENDING FROM THE YUCATAN PENINSULA TO THE SE CONUS COVERS MUCH OF THE GULF WATERS WHILE A CUT-OFF LOW IS OVER THE FOUR CORNER IN THE SW U.S.. SWLY WINDS BETWEEN THESE TWO UPPER-LEVEL FEATURES ARE TRANSPORTING ABUNDANT MID/UPPER LEVEL MOISTURE ACROSS THE NORTHERN GULF REGION. THE FRONT WILL MOVE SLOWLY E REACHING FROM SE LOUISIANA TO WESTERN BAY OF CAMPECHE BY SUN NIGHT...AND FROM THE WESTERN FL PANHANDLE TO BAY OF CAMPECHE BY MON AFTERNOON. CARIBBEAN SEA... THE COMBINATION OF STRONG HIGH PRES BUILDING S OVER THE WESTERN ATLC AND LOWER SFC PRESSURE OVER N SOUTH AMERICA IS PRODUCING FRESH TO STRONG WINDS ACROSS MUCH OF THE BASIN. THESE WEATHER CONDITIONS ARE EXPECTED TO PERSIST THROUGH MONDAY. GENERALLY FAIR WEATHER CONDITIONS ARE OBSERVED ACROSS MUCH OF THE CARIBBEAN REGION...WHERE DEEP LAYERED DRY AIR IS PRESENT. HOWEVER...SHALLOW MOISTURE EMBEDDED IN THE TRADE WIND FLOW IS MOVING ACROSS THE REGION PRODUCING ISOLATED TO SCATTERED PASSING SHOWERS. THESE PATCHES OF LOW LEVEL MOISTURE ARE MORE CONCENTRATED OVER THE EASTERN CARIBBEAN...PARTICULARLY BETWEEN 12N-16N...AND JUST SOUTH OF THE CAYMAN ISLANDS. SIMILAR CLOUDS ARE ALREADY AFFECTING THE N LEEWARD ISLANDS. ATLANTIC OCEAN... A STATIONARY FRONT CLIPS THE FAR NW PORTION OF THE FORECAST AREA AND NE FLORIDA. MOST OF THE SHOWER ACTIVITY ASSOCIATED WITH THIS FRONT IS OVER THE SE CONUS. A 1026 MB SFC HIGH IS LOCATED SW OF BERMUDA NEAR 31N67W WITH RIDGE ENVELOPING MUCH OF THE WEST AND CENTRAL ATLC AND THE N CARIBBEAN SEA...INCLUDING THE GREATER ANTILLES...THE EASTERN GULF OF MEXICO AND THE STATE OF FLORIDA. ALOFT...A RIDGE ALSO DOMINATES MUCH OF THE AREA RESULTING IN GENERALLY FAIR WEATHER CONDITIONS. FARTHER TO THE E...AN UPPER LEVEL LOW LOCATED NEAR 31N35W SUPPORTS A 1007 MB SFC LOW LOCATED NEAR 30N36W. A SFC TROUGH IS ASSOCIATED WITH THIS LOW AND LIES ALONG 30N31W 24N30W 16N37W. ATMOSPHERIC INSTABILITY...UPPER LEVEL DIFFLUENCE...AND LOW LEVEL CONVERGENCE IN THE VICINITY OF THE SURFACE LOW AND TROUGH ARE HELPING TO INDUCE AND AREA OF SCATTERED SHOWERS AND ISOLATED TSTMS N OF 26N BETWEEN 25W-31W. THE REMAINDER OF THE E ATLC AND WEST AFRICA ARE UNDER THE INFLUENCE OF A NARROW SFC RIDGE WITH MOSTLY FAIR WEATHER. A BAND OF TRANSVERSE HIGH CLOUDS ASSOCIATED WITH A JET-STREAM BRANCH IS NOTED S AND SE OF THE AFOREMENTIONED UPPER-LEVEL LOW. ACROSS THE DEEP TROPICS...A BROAD UPPER LEVEL RIDGE ANCHORED ON A HIGH CENTERED NEAR 9N19W IS ENHANCING THE CONVECTION ASSOCIATED WITH THE ITCZ...MAINLY E OF 16W. $$ GR