000 AXNT20 KNHC 191037 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT WED MAR 19 2008 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND THE 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1015 UTC. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 6N9W 5N12W 1N26W 2N36W CROSSING THE EQUATOR NEAR 50W. CLUSTERS OF SCATTERED/NUMEROUS STRONG CONVECTION ARE FROM 4N TO S OF THE EQUATOR E OF 7W ACROSS THE PRIME MERIDIAN. SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 90 NM OF LINE FROM EQ24W TO 3N38W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 150 NM N OF THE ITCZ AXIS BETWEEN 21W-26W AND FROM 2N TO S OF THE EQUATOR BETWEEN 8W-13W. ...DISCUSSION... GULF OF MEXICO... AT 19/0900 UTC...A COLD FRONT CONTINUES TO MOVE ACROSS THE GULF ENTERING OVER LOUISIANA JUST E OF VERMILION BAY EXTENDING S ALONG 25N92W TO INLAND OVER MEXICO JUST N OF TUXPAN. A PRE-FRONTAL SURFACE TROUGH EXTENDS FROM NEAR NEW ORLEANS LOUISIANA ALONG 26N91W TO 21N94W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE BETWEEN THE SURFACE TROUGH AND THE COLD FRONT. BROKEN/OVERCAST LOW CLOUDS WITH POSSIBLE ISOLATED SHOWERS ARE WITHIN 150 NM W OF THE FRONT. THE ASSOCIATED UPPER LOW IS MOVING FROM TEXAS INTO OKLAHOMA. A FAIRLY STRONG SURFACE RIDGE IS OVER THE W ATLC TO OVER FLORIDA AND COUPLED WITH THE LOW PRESSURE SYSTEM OVER THE W GULF IS PRODUCING A TIGHT PRESSURE GRADIENT OVER THE REMAINDER OF THE GULF OF MEXICO WITH GALE FORCE WINDS OVER THE N/CENTRAL GULF...SEE MIAHSFAT2 FOR MORE DETAILS. A BROAD HIGH AMPLITUDE UPPER RIDGE COVERS THE GULF E OF THE FRONT AND THE E U.S. ANCHORED BY AN UPPER HIGH BETWEEN THE FLORIDA KEYS AND CUBA. CARIBBEAN SEA... THE UPPER RIDGE COVERING MOST OF THE GULF OF MEXICO EXTENDS INTO THE NW CARIBBEAN...A SECOND UPPER RIDGE COVERS THE S CARIBBEAN ANCHORED OVER SOUTH AMERICA...AND THE UPPER TROUGH OVER THE CENTRAL ATLC DIPS INTO THE E CARIBBEAN CREATING A SHEAR AXIS ACROSS THE CARIBBEAN FROM THE N WINDWARD ISLANDS S OF JAMAICA TO NEAR 19N84W. THE WEAKENING FRONTAL BOUNDARY ASSOCIATED WITH THE UPPER TROUGH ENTERS THE CARIBBEAN OVER THE LEEWARD ISLANDS TO S OF HISPANIOLA WITH PATCHES OF LOW CLOUDS WITH POSSIBLE ISOLATED SHOWERS OVER THE LEEWARD/VIRGIN ISLANDS AND PUERTO RICO. STRONG SUBSIDENCE AND DRY STABLE AIR REMAINS OVER THE REMAINDER OF THE REGION. MODERATE/STRONG EASTERLY TRADE WINDS WILL REMAIN OVER THE AREA THROUGH FRI WITH GALE FORCE WINDS ALONG THE COLOMBIAN COAST. DANGEROUS LARGE N SWELL ARE MOVING THROUGH ATLC PASSAGES INTO THE CARIBBEAN AND ARE EXPECTED TO CONTINUE THROUGH FRI. ATLANTIC OCEAN... HIGH AMPLITUDE UPPER RIDGE COVERS THE W ATLC W OF 70W TO ACROSS FLORIDA INTO THE GULF OF MEXICO. A SURFACE RIDGE ANCHORED N OF THE REGION COVERS THE W ATLC W OF 57W TO OVER FLORIDA. THE STORM SYSTEM REMAINS OVER THE N/CENTRAL ATLC WITH THE UPPER TROUGH OVER THE AREA N OF 16N FROM 40W-70W AND THE ASSOCIATED COLD FRONT ENTERING THE REGION NEAR 32N41W ALONG 23N47W TO THE LEEWARD ISLANDS WHERE IT CONTINUES TO WEAKEN INTO THE NE CARIBBEAN. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 120 NM E OF THE FRONT N OF 25N AND GALE FORCE WINDS ARE BOTH E AND W OF THE FRONT...SEE MIAHSFAT2 FOR MORE DETAILS. A POST-FRONTAL SURFACE TROUGH EXTENDS THROUGH 32N49W TO 24N55W WITH SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS N OF 28N BETWEEN THE FRONT AND THE SURFACE TROUGH. STRONG SUBSIDENCE AND DRY STABLE AIR COVER MOST OF THE REGION THUS LIMITING ANY FURTHER AREA OF SIGNIFICANT SHOWERS. ZONAL WSW UPPER FLOW COVERS THE REMAINDER OF THE ATLC E OF 40W AND SURFACE RIDGE COVERING THE E ATLC E OF 40W AND ANCHORED BY A HIGH WELL N OF THE REGION. $$ WALLACE