000 AXNT20 KNHC 071749 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST SAT MAR 07 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 1200 UTC SURFACE ANALYSIS...AND SATELLITE IMAGERY THROUGH 1715 UTC. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 7N9W 3N12W CROSSING THE EQUATOR NEAR 20W EXTENDING TO 2S26W AND INTO NE BRAZIL NEAR 3S40W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS S OF 2N BETWEEN 19W-25W. SCATTERED MODERATE CONVECTION IS FROM THE EQUATOR TO 5N BETWEEN 47W-51W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL RIDGE DOMINATES MUCH OF THE GULF AND THE SE CONUS WITH MODERATE TO STRONG SUBSIDENCE IN PLACE OVER THE REGION. SOUTHEASTERLY SURFACE FLOW OF UP TO 25 KT RESIDES ON THE WRN PERIPHERY OF A SURFACE RIDGE THAT EXTENDS FROM A 1032 MB HIGH IN THE W ATLC NEAR 30N71W. EASTERLY WINDS OF 15-20 KT CONTINUE THROUGH THE STRAITS OF FLORIDA AND ACROSS THE SE PORTION OF THE GULF S OF 24N. THE SURFACE HIGH IS FORECAST TO REMAIN NEARLY STATIONARY AND AS A RESULT...THE OVERALL WEATHER PATTERN ACROSS THE GULF WILL CHANGE LITTLE THROUGH MONDAY. CARIBBEAN SEA... FRESH TO STRONG NE-E WINDS ASSOCIATED WITH A 1032 MB SURFACE HIGH CENTERED IN THE W ATLC NEAR 30N71W ARE TRANSPORTING PATCHES OF SHALLOW MOISTURE ACROSS CUBA...HISPANIOLA...AND THE NW CARIBBEAN SEA. THESE WINDS ARE RESULTING IN ADVECTING ISOLATED SHOWERS ACROSS THE CARIBBEAN WATERS MAINLY N OF 18N. ALSO...A GALE WARNING IS IN EFFECT FOR THE SW CARIBBEAN FROM 10N-13N BETWEEN 75W-77W OFF THE COLOMBIAN COAST. THE INCREASED SURFACE WINDS ARE THE RESULT OF A TIGHTENING SURFACE PRESSURE GRADIENT BETWEEN THE AFOREMENTIONED HIGH OVER THE W ATLC AND LOWER PRESSURE OVER NRN SOUTH AMERICA. ALOFT...STRONG SUBSIDENCE IS RESULTING FROM CONFLUENCE IN WESTERLY UPPER LEVEL FLOW AND IS LIMITING AND DEEP CONVECTION ACROSS THE REGION. ATLANTIC OCEAN... A DEEP LAYERED TROUGH REMAINS OVER THE CENTRAL ATLC WITH AN UPPER LOW CENTERED NEAR 25N55W. THIS TROUGH SUPPORTS A COMPLEX AREA OF LOW PRESSURE WITH A DISSIPATING 1010 MB LOW CENTERED NEAR 30N51W. A STATIONARY FRONT MEANDERS S-SW TO A PARTIALLY OCCLUDED 1012 MB LOW NEAR 24N55W. THE ASSOCIATED COLD FRONT EXTENDS SW ALONG 20N54W TO 15N60W. LOW-LEVEL CONVERGENCE IS GENERATING SCATTERED SHOWERS WITHIN 90 NM OF THE COLD FRONT. A PRE-FRONTAL SURFACE TROUGH IS ANALYZED FROM 26N49W TO 21N50W WITH SCATTERED SHOWERS WITHIN 120 NM ON EITHER SIDE OF THE TROUGH. SCATTERED MODERATE CONVECTION IS N OF 23N BETWEEN 44W-56W WITH THIS COMPLEX LOW PRESSURE AREA. ALL OF THIS ACTIVITY IS BEING SUPPORTED BY UPPER LEVEL DIVERGENCE E OF THE UPPER TROUGH. ACROSS THE W ATLC...A RELATIVELY COOLER AND DRIER AIRMASS IS ASSOCIATED WITH A 1032 MB HIGH CENTERED NEAR 30N71W. BROKEN COLD AIR STRATOCUMULUS CLOUDS ARE NOTED ACROSS THE W ATLC INTO THE BAHAMAS AND CUBA UNDER A PREVAILING NE FLOW. ACROSS THE E ATLC...AN UPPER LOW IS LOCATED NEAR 28N22W. ATMOSPHERIC INSTABILITY ASSOCIATED WITH THIS UPPER LOW IS SUPPORTING SCATTERED SHOWERS FROM 25N TO BEYOND 32N BETWEEN 11W-23W. HOWEVER...SUBSIDENCE ASSOCIATED WITH A SURFACE RIDGE IS INHIBITING DEEP CONVECTION ACROSS MUCH OF THE E ATLC. AN UPPER-LEVEL RIDGE CENTERED NEAR 6N24W DOMINATES MUCH OF THE DEEP TROPICS AND IS AIDING IN SUPPORTING CONVECTION ALONG THE ITCZ. $$ HUFFMAN