000 AXNT20 KNHC 031740 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT THU APR 03 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 6N10W 2N20W 3N30W 2N40W CROSSING THE EQUATOR NEAR 46W CONTINUING TO 1S48W. SCATTERED MODERATE AND EMBEDDED ISOLATED STRONG CONVECTION IS WITHIN 180 NM N AND 240 NM S OF THE AXIS E OF 24W. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM N AND 210 NM S OF THE AXIS BETWEEN 32W-36W AND FROM THE EQUATOR TO 3N W OF 47W. ...DISCUSSION... GULF OF MEXICO... LITTLE PATTERN CHANGE HAS OCCURRED OVER THE PAST COUPLE OF DAYS WITH A SPRAWLING UPPER HIGH CENTERED OVER THE TROPICAL EPAC AND A NEARLY CUT OFF LOW OVER THE SE BAHAMAS. THIS PATTERN IS KEEPING N TO NW FLOW ALOFT AND MODESTLY DRY AIR...EXCEPT FOR PATCHY HIGH LEVEL CLOUDINESS N OF 27N W OF 88W AND OVER FLORIDA. AT THE SFC...A HIGH PRES RIDGE EXTENDS WWD FROM THE CENTRAL ATLC PROVIDING LIGHT TO MODERATE E TO SE FLOW...EXCEPT SLY 15-20 KT WINDS IN THE NW GULF AHEAD OF A STORM SYSTEM OVER THE CENTRAL PLAINS. DOPPLER RADAR AND VIS IMAGERY DEPICT SCATTERED SHOWERS AND LOW TOPPED TSTMS MOVING THROUGH THE FL STRAITS AND INTO A SMALL PORTION OF THE SE GULF. MAINLY FAIR WEATHER PREVAILS ELSEWHERE. HOWEVER...A CHANGE IS EXPECTED AS THE PRONOUNCED SHORTWAVE OVER THE SW U.S. SHIFTS E SUPPORTING A COLD FRONT THAT IS ANTICIPATED TO MOVE INTO THE NW WATERS TOMORROW EVENING. CARIBBEAN SEA... AN UPPER TROUGH EXTENDS FROM THE SE BAHAMAS TO PANAMA WITH AN EMBEDDED SMALL LOW SPINNING OVER NE CUBA. INSTABILITY/DIFFLUENCE ASSOCIATED WITH THIS UPPER SYSTEM COMBINED WITH A LONG FETCH OF LOW-LEVEL MOISTURE...PRODUCED BY SPEED AND SLIGHT DIRECTIONAL CONVERGENCE...IS PRODUCING SCATTERED SHOWERS AND ISOLATED TSTMS N OF 16N E OF 75W. ACTIVITY IS ISOLATED IN NATURE N OF 14N W OF 75W. PUERTO RICO DOPPLER RADAR SHOWED SCATTERED TO NUMEROUS SHOWERS AND TSTMS OVER THE ISLAND. SIMILAR CONDITIONS ARE LIKELY OCCURRING OVER THE NRN LEEWARD ISLANDS AND THE DOMINICAN REPUBLIC. MODEL GUIDANCE SHOWS THIS MOISTURE SWATH DECREASING OVER THE NEXT DAY OR TWO AS THE UPPER TROUGH/LOW FILLS AND THE LOW-LEVEL MOISTURE STREAM THINS OUT. TRADE WINDS ARE ON THE STRONG SIDE TODAY E OF A SFC TROUGH AXIS FROM 19N83W TO 12N80W. LIGHT ELY WINDS ARE OBSERVED W OF THE AXIS. WESTERN AND CENTRAL ATLANTIC... A STALLED FRONT LIES ACROSS OUR NRN BORDER FROM JUST N OF BERMUDA TO THE FLORIDA/GEORGIA LINE. A WEAK LOW APPEARS TO BE FORMING ALONG THE FRONT NEAR 30N80W...WILL RE-EXAMINE FOR THE 18Z ANALYSIS. LIGHTNING DATA REVEALS NUMEROUS TSTM ACTIVITY NEAR THIS POSSIBLE LOW FROM 29N-32N BETWEEN 76W-80W. FARTHER S...AN UPPER LOW LIES OVER THE SE BAHAMAS PRODUCING SCATTERED SHOWER AND TSTM ACTIVITY OVER THE ERN BAHAMAS AND NEARBY WATERS S OF 23N BETWEEN 63W-74W. OTHERWISE...A STRONG 1030 MB HIGH PRES SYSTEM NEAR 30N52W IS PRODUCING STIFF TRADES S OF 24N. EASTERN ATLANTIC... THE MAIN FEATURE IS A LARGE SCALE CUT OFF LOW NEAR 34N26W. THE SFC LOW WAS ANALYZED 1001 MB AT 12Z...BUT HAS LIKELY DEEPENED TO 998 MB OR SO BASED ON OBS FROM THE AZORES. THIS LOW HAS AN IMPRESSIVE PRESENTATION ON VIS IMAGES...WITH A SECONDARY LOW-MID LEVEL VORTICITY MAXIMUM EVIDENT NEAR 26N34W. A COLD FRONT ENTERS THE AREA NEAR 32N22W TO 25N23W CONTINUING TO 20N28W. SCATTERED SHOWERS ARE POSSIBLE N OF 25N BETWEEN 20W-36W...BUT MOST OF THE DEEPER ACTIVITY LIES JUST N OF THE AREA. IN THE TROPICS...A FLAT UPPER RIDGE LIES ALONG 10N OR SO. ASSOCIATED DIFFLUENCE ALOFT IS ENHANCING CONVECTION IN THE ITCZ E OF 25W. $$ CANGIALOSI