000 AXNT20 KNHC 110540 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT WED APR 11 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 0515 UTC. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 9N13W 5N20W 3N30W 1N40W EQ48W. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 240 NM N OF THE AXIS W OF 41W. SCATTERED MODERATE IS WITHIN 180 NM EITHER SIDE OF AXIS BETWEEN 30W-41W AND WITHIN 150 NM EITHER SIDE BETWEEN 18W-24W. ...DISCUSSION... GULF OF MEXICO AND SW ATLC... VERY ACTIVE WEATHER CONTINUES THIS MORNING IN THE E GULF AND THE EXTREME SW ATLC. THE MAIN PLAYER IS AN UPPER SHORTWAVE WHICH STRETCHES FROM SRN MISSISSIPPI TOWARD THE YUCATAN PENINSULA. UPPER DIFFLUENCE TO THE E OF THIS AXIS IS PROVIDING THE SUPPORT FOR THE SHOWERS AND TSTMS N OF 24N BETWEEN 73W-86W. HOWEVER ...THE HEAVIEST RAINFALL IS CONCENTRATED FROM 25N-27N BETWEEN 77W-84W...WHICH INCLUDES S FLA AND THE WRN BAHAMAS. THIS CONCENTRATION OF RAIN IS BEING ENHANCED BY A SFC BOUNDARY ...ANALYZED AS A TROUGH AT 03Z...ANALYZED ALONG 30N75W 25N80W 27N89W. THIS FEATURE LIES TO THE S...WARM SECTOR...OF A STATIONARY OR SLOW MOVING WARM FRONT DRAPED ACROSS N FLA. DOPPLER RADAR RAINFALL ESTIMATES SHOW ACCUMULATIONS UP TO 5 INCHES IN S FLA WITH MORE ON THE WAY. MUCH QUIETER WEATHER IS IN PLACE ACROSS THE CENTRAL AND WRN GULF...W OF 88W...AS ABUNDANT DRY SINKING AIR TO THE W OF THE SHORTWAVE DOMINATES. COMPUTER MODELS SHOW THE MOISTURE SWATH PUSHING OFF TO THE E AND BREAKING APART AS THE UPPER SHORTWAVE FLATTENS OVER THE NEXT DAY OR TWO. A WEAK COLD FRONT IS EXPECTED TO PUSH INTO THE NW GULF LATER THIS MORNING AND BECOME DIFFUSE ON THU AS IT HEADS SE. ANOTHER COLD FRONT...THIS ONE EXPECTED TO BE MUCH STRONGER...IS FORECAST TO MOVE INTO THE NW GULF FRI NIGHT INCREASING THE CHANCE OF RAIN AND BRINGING A MUCH COOLER AIRMASS THIS WEEKEND. THE CARIBBEAN SEA... A BROAD MID TO UPPER LEVEL RIDGE COVERS THE REGION ANCHORED BY AN UPPER HIGH CENTERED OVER THE S CENTRAL CARIB NEAR 12N74W. DIFFLUENCE ON THE W SIDE OF THIS UPPER ANTICYCLONE IS ENHANCING CLUSTERS OF MODERATE CONVECTION OVER PANAMA...COSTA RICA AND NICARAGUA. SIMILAR OR EVEN SLIGHTLY STRONGER ACTIVITY HAS DEVELOPED OVER THE NE YUCATAN AND THE CHANNEL ASSOCIATED WITH UPPER ENERGY AHEAD OF A SHORTWAVE TROUGH IN THE GULF. A BROKEN LAYER OF CIRRUS...ADVECTED BY UPPER SWLY FLOW...LIES ROUGHLY W OF 70W. ELSEWHERE...MODEST SUBSIDENCE IS KEEPING CONDITIONS FAIRLY TRANQUIL. AT THE SFC...HIGH PRES NE OF THE AREA IS PRODUCING MODERATE ELY TRADES ACROSS THE E AND CENTRAL CARIB VEERING TO THE SE IN THE NW CARIB IN RESPONSE TO THE FRONTAL SYSTEM IN THE GULF. LOW-LEVEL MOISTURE PATCHES REMAIN VERY THIN SO OUTSIDE OF THE AREAS OUTLINED FAIR SKIES ARE THE RULE. NO SIGNIFICANT CHANGES ARE EXPECTED OVER THE NEXT COUPLE OF DAYS AS MOST OF THE WX FEATURES REMAIN N OF THE REGION. CENTRAL AND EASTERN ATLANTIC... A 1025 MB NEAR 33N30W CONTROLS THE SFC PATTERN ACROSS THIS AREA PRODUCING A LARGE AREA OF MODERATE TRADES IN THE TROPICS. IN THE MID AND UPPER LEVELS...THE FLOW IS FAIRLY ZONAL IN THE SUBTROPICS AND THEN CURVES MORE TO THE N IN THE TROPICS W OF 40W AROUND A BROAD RIDGE CENTERED IN THE S CARIB. PATCHES OF MID AND HIGH LEVEL CLOUDS ARE BEING STEERED BY THE STRONG ZONAL FLOW N OF 22N W OF 26W. E OF THERE...THE ATMOSPHERE SUBSTANTIALLY DRIES OUT IN AN UPPER CONFLUENT ZONE TO THE S OF A STRONG UPPER LOW 240 NM W OF PORTUGAL. THIS LOW HAS ASSOCIATED TROUGHING THAT EXTENDS WELL SW ALONG 32N16W 17N29W 4N38W. A 100-120 KT JET ORIGINATES AT THE BASE OF THIS TROUGH AND RACES NE TO THE COAST OF AFRICA NEAR 20N16W. A PLUME OF MOISTURE EXISTS TO THE SE OF THE JET AXIS WHILE UPPER CONFLUENCE IS ENHANCING DRY AIR TO THE W OF THE AXIS. THIS JET IS ALSO PROVIDING A FAVORABLE ENVIRONMENT FOR CONVECTION IN THE ITCZ WHICH IS PARTICULARLY ACTIVE W OF 41W. $$ CANGIALOSI