000 AXNT20 KNHC 190521 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0345 UTC. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 6N9W 3N19W 1N26W CROSSING THE EQUATOR NEAR 31W TO 3S40W. CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE FROM 4N TO THE EQUATOR BETWEEN 1W-12W AND 21W-36W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 150 NM N OF THE ITCZ AXIS E OF 20W TO THE COAST OF W AFRICA. ...DISCUSSION... GULF OF MEXICO... THE GULF HAS ONCE AGAIN BECOME ACTIVE AS A COLD FRONT ENTERS THE GULF AT 19/0300 UTC NEAR THE TEXAS/LOUISIANA BORDER EXTENDING S ALONG 27N94W TO INLAND OVER MEXICO JUST N OF TAMPICO. VERY NARROW BANDS OF SHOWERS/THUNDERSTORMS ARE ALONG AND WITHIN 45 NM E OF THE FRONT TO INLAND OVER LOUISIANA. BROKEN/OVERCAST LOW CLOUDS WITH POSSIBLE ISOLATED SHOWERS ARE W OF THE FRONT TO INLAND OVER TEXAS AND NE MEXICO. AN ASSOCIATED UPPER LOW IS MOVING ACROSS CENTRAL TEXAS. A FAIRLY STRONG SURFACE RIDGE IS OVER THE W ATLC AND COUPLED WITH THE LOW PRESSURE SYSTEM OVER THE FAR 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 OVER THE FLORIDA STRAITS. AN INTERESTING NOTE...MIGRATORY BIRDS ARE OBSERVED ON RADAR COVERING THE FLORIDA STRAITS FROM CUBA ACROSS THE FLORIDA KEYS INTO FLORIDA BAY AND AS FAR N AS FORT MYERS. 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 NE CARIBBEAN CREATING A SHEAR AXIS ACROSS THE CARIBBEAN FROM THE CENTRAL LESSER ANTILLES TO S OF JAMAICA NEAR 16N80W. THE WEAKENING FRONTAL BOUNDARY ASSOCIATED WITH THE UPPER TROUGH ENTERS THE CARIBBEAN OVER THE N LEEWARD ISLANDS TO JUST S OF HISPANIOLA WITH PATCHES OF LOW CLOUDS WITH POSSIBLE ISOLATED SHOWERS N OF 16N E OF 70W INTO THE ATLC WATERS. 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 EXPECTED TO MOVE THROUGH ATLC PASSAGES TONIGHT THROUGH FRI. ATLANTIC OCEAN... HIGH AMPLITUDE UPPER RIDGE COVERS THE W ATLC W OF 70W ACROSS FLORIDA INTO THE GULF OF MEXICO. A SURFACE RIDGE ANCHORED N OF THE REGION COVERS THE W ATLC W OF 60W INTO THE FAR E GULF OF MEXICO. A STORM SYSTEM REMAINS OVER THE N/CENTRAL ATLC WITH THE UPPER TROUGH OVER THE AREA N OF 17N FROM 40W-70W AND THE ASSOCIATED COLD FRONT ENTERING THE REGION NEAR 32N43W ALONG 23N49W TO THE N LEEWARD ISLANDS WHERE IT WEAKENS AND BECOMES NEAR STATIONARY INTO THE NE CARIBBEAN. SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS ARE WITHIN 120 NM E OF THE FRONT N OF 23N AND GALE FORCE WINDS ARE BOTH E AND W OF THE FRONT...SEE MIAHSFAT2 FOR MORE DETAILS. A POST-FRONTAL SURFACE TROUGH EXTENDS FROM 31N50W TO 26N60W WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF 27N FROM 48W-56W. STRONG SUBSIDENCE AND DRY STABLE AIR COVER MOST OF THE REGION THUS LIMITING ANY FURTHER AREA OF SHOWERS. ZONAL WSW UPPER FLOW COVERS THE REMAINDER OF THE ATLC E OF 40W AND SURFACE RIDGE COVERING THE E ATLC E OF 45W AND ANCHORED BY A 1027 MB HIGH NEAR THE AZORES. $$ WALLACE