000 AXNT20 KNHC 111033 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1030 UTC. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 6N10W 4N20W 3N30W 1N40W EQ47W 1S51W. 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 31W-41W. ISOLATED MODERATE IS WITHIN 180 NM N OF THE AXIS E OF 26W. ...DISCUSSION... GULF OF MEXICO AND SW ATLC... THE VERY ACTIVE WEATHER HAS NOW MOSTLY SHIFTED INTO THE SW ATLC WITH LEFT OVER SHOWERS AND TSTMS STILL LYING OVER THE SE GULF AND SOUTH FLORIDA. DOPPLER RADAR STORM TOTAL RAINFALL ESTIMATES SHOW A SWATH OF 2-4 INCHES ACROSS EXTREME S FLA WITH UP TO 8 INCHES LOCALLY. THE MAIN PLAYER IS AN UPPER SHORTWAVE WHICH CONTINUES TO SHIFT E NOW STRETCHING FROM SRN MISSISSIPPI TOWARD THE YUCATAN CHANNEL. UPPER DIFFLUENCE TO THE E OF THIS AXIS IS PROVIDING THE SUPPORT FOR THE SHOWERS AND TSTMS N OF 24N BETWEEN 70W-80W AND FROM 24N-27N BETWEEN 80W-86W. THE HEAVIEST RAINFALL IS CONCENTRATED FROM 25N-27N BETWEEN 75W-79W...WHICH INCLUDES THE WRN BAHAMAS. THIS CONCENTRATION OF RAIN IS BEING ENHANCED BY A NEWLY FORMED 1009 MB SFC LOW ANALYZED NEAR 27N78W. A STATIONARY FRONT EXTENDS N AND E OF THE LOW ALONG 30N76W TO NEAR BERMUDA. A SFC TROUGH IS ANALYZED S AND W OF THE LOW ALONG 25N80W 25N87W. WHILE THIS LOW IS NOT EASILY IDENTIFIABLE IN THE DATA...THE ORGANIZATION OF THE FRONTAL STRUCTURE SUGGESTS A WAVE OF LOW PRES. THIS LOW AND FRONT LIES TO THE S...WARM SECTOR...OF ANOTHER STATIONARY OR SLOW MOVING WARM FRONT DRAPED ACROSS N AND CENTRAL FLA. THERE IS A FAIRLY GOOD SWD DIP IN THIS FRONTAL SYSTEM OVER CENTRAL FLA CLOSELY FOLLOWING THE SFC OBS. MUCH QUIETER WEATHER IS IN PLACE ACROSS THE CENTRAL AND WRN GULF...W OF 86W...AS ABUNDANT DRY SINKING AIR TO THE W OF THE SHORTWAVE AXIS DOMINATES. COMPUTER MODELS SHOW THE MOISTURE SWATH CONTINUING ITS EWD PUSH WITH THE UPPER SHORTWAVE AND SFC LOW OVER THE NEXT COUPLE OF DAYS. A WEAK COLD FRONT IS EXPECTED TO ENTER 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/EARLY SAT INCREASING THE CHANCE OF RAIN AHEAD OF IT AND BRINGING ABOUT A6 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 SCATTERED SHOWERS AND ISOLATED TSTMS OVER COLOMBIA ...PANAMA...COSTA RICA AND NICARAGUA. SIMILAR ACTIVITY IS OVER THE YUCATAN CHANNEL AND WRN CUBA ASSOCIATED WITH UPPER ENERGY AHEAD OF A SHORTWAVE TROUGH IN THE GULF. IT SHOULD BE NOTED THAT THIS ACTIVITY HAS BEEN ON THE WEAKENING TREND OVER THE PAST FEW HOURS EXCEPT FOR THE RECENT BURSTS OVER COLOMBIA. A BROKEN LAYER OF CIRRUS...ADVECTED BY UPPER SWLY FLOW...LIES ROUGHLY BETWEEN 78W-86W. ELSEWHERE...MODEST SUBSIDENCE ALONG AND TO THE E OF THE RIDGE AXIS 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 MODERATE SFC RIDGE WITH THREE EMBEDDED HIGH CENTERS CONTROL THE 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 WITH PATCHES OF MID AND HIGH LEVEL CLOUDS MOSTLY N OF 22N W OF 22W. THE FLOW THEN CURVES MORE TO THE N IN THE TROPICS W OF 35W AROUND A BROAD RIDGE CENTERED IN THE S CARIB KEEPING CONDITIONS RATHER TRANQUIL. FARTHER EAST...SUBSTANTIAL DRY AIR LIES 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 32N15W 15N20W 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 LIES 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 40W. $$ CANGIALOSI