000 AXNT20 KNHC 180515 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT SUN MAR 18 2007 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN 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. ...ITCZ... ITCZ AXIS IS ALONG 9N12W 5N20W 3N26W TO NEAR EQ48W. CONVECTION HAS DECREASED CONSIDERABLY DURING THE PAST 24 HRS. ONLY ISOLATED MODERATE CONVECTION NOTED WITHIN 90 NM EITHER SIDE OF THE AXIS. ...DISCUSSION... GULF OF MEXICO... A WELL DEFINED UPPER LEVEL TROUGH WITH IT'S AXIS ALONG 75W HAS BEGUN TO SHIFT EWD. UPPER WINDS OVER THE GULF AREA ARE NWLY AT 40 TO 60 KT. A 1025 MB HIGH LOCATED ALONG THE COAST OF LOUISIANA IS MOVING SLOWLY EWD. NLY WINDS TO 20 KT CONTINUE E OF 90W TONIGHT WHILE N OF 25N W OF 90W WINDS HAVE SHIFTED TO E AND SE 10 TO 15 KT. S OF 25N W OF 90W WINDS ARE MOSTLY N TO NE 10 TO 15 KT. LATEST WATER VAPOR IMAGERY SHOWS VERY DRY AIR OVER THE SRN HALF OF THE GULF RESULTING IN CLEAR SKIES. THE CENTER OF THE SURFACE HIGH IS EXPECTED TO SHIFT EASTWARD OVER THE NEXT COUPLE OF DAYS...BUT HIGH PRESSURE RIDGE WILL REMAIN IN CONTROL OF THE GULF THROUGH TUE. CARIBBEAN... A COLD FRONT LIES OVER SE CUBA AND CONTINUES TO MOVE ESE. A MODERATE NLY FLOW IS EVIDENT BEHIND THE FRONT OVER THE NW CARIBBEAN WITH SCATTERED TO BROKEN CLOUDS AND ISOLATED SHOWERS. CONSIDERABLE CLOUDINESS IS NOTED OVER HAITI AND WRN PORTIONS OF THE DOMINICAN REPUBLIC. EARLIER CONVECTION HAS DIMINISHED AND MOVED NE OVER ATLC WATERS. ELY TRADES DOMINATE THE ERN CARIBBEAN WITH SCATTERED CLOUDS AND ISOLATED WEAK SHOWERS. IN THE UPPER ATMOSPHERE A BROAD ANTICYCLONE COVERS THE ERN HALF OF THE CARIBBEAN WHILE OVER THE WRN HALF THE FLOW ALOFT IS MOSTLY SWLY. HIGH LEVEL CLOUDINESS FROM EARLIER CONVECTION OVER COLOMBIA AND WRN VENEZUELA WAS BEING ADVECTED N AND NE OVER THE ERN PORTION. SW ATLANTIC... STRONG UPPER TROUGH WITH AXIS ALONG 75W ROTATING RAPIDLY EWD. BROAD SWATH OF VERY DRY UPPER LEVELS OVER BAHAMAS SHIFTING E. STRONG DIFFLUENT PATTERN ALOFT E OF TROUGH AXIS AIDING ISOLATED CONVECTION S OF 25N BETWEEN 60W AND 70W. A COLD FRONT LIES OVER THE SE BAHAMAS TONIGHT AND SE CUBA. THE FRONT IS MOVING SE 15 KT. MULTILAYERED CLOUDINESS 200 NM WIDE IS ASSOCIATED WITH THE FRONT WITH EMBEDDED SHOWERS AND TSTMS. MOST OF THE ENERGY WITH THIS FEATURE IS SHIFTING N OF 30N AHEAD OF THE FRONT AND MOST FRONTAL CONVECTION HAS BEEN ON THE DECLINE THE PAST FEW HRS. OVER THE ATLC S OF 20N W OF 40W LATEST SATELLITE PICTURES SHOW SCATTERED TO BROKEN LOW AND MID CLOUDS MOVING W 20 KT WITH ISOLATED LIGHT SHOWERS. ERN ATLANTIC... A CLOSED UPPER LOW THAT WAS JUST N OF THE CANARY ISLANDS HAS FLATTENED OUT AND BECOME STATIONARY. SCATTERED CONVECTION NEAR THE CENTER HAS DECREASED INDICATING THE SYSTEM HAS WEAKENED THE PAST 24 HR. WATER VAPOR IMAGERY SHOWS A NARROW BAND OF CIRRUS ASSOCIATED WITH A JET STREAM ALONG 16N40W EWD OVER THE CAPE VERDE ISLANDS. QUIKSCAT DATA SHOWS WIND VELOCITIES 60 TO 80 KT WITH THIS JET. ON THE SURFACE STRONG HIGH PRESSURE CENTERED WELL N OF THE REGION ALONG 30W EXTENDS S TO 10N E OF 50W. THE RIDGE IS RESPONSIBLE FOR A MODERATE TO FRESH NE FLOW OF COOL AIR. THE AIR PICKS UP MOISTURE FROM THE ATLC AND PRODUCES SCATTERED TO BROKEN LOW AND MID CLOUDINESS THROUGHOUT THIS REGION. $$ RRG