000 AXNT20 KNHC 021741 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT WED APR 02 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 5N10W 2N20W 3N30W 1N40W CROSSING THE EQUATOR NEAR 42W TO 2S45W. THE AXIS REMAINS ACTIVE TODAY WITH SCATTERED MODERATE TO STRONG CONVECTION NOTED WITHIN 210 NM S OF THE AXIS BETWEEN 10W-20W...WITHIN 240 NM S OF THE AXIS BETWEEN 22W-28W AND WITHIN 240 NM N OF THE AXIS BETWEEN 28W-45W. ...DISCUSSION... GULF OF MEXICO... THE REGION CURRENTLY LIES IN A NW TO N MID-UPPER FLOW REGIME ...BETWEEN A LARGE RIDGE OVER THE TROPICAL EPAC AND AN AMPLIFIED TROUGH OVER THE W ATLC AND THE CARIBBEAN. THIS PATTERN IS PRODUCING MODESTLY DRY AIR OVER THE GULF...EXCEPT FOR SOME HIGH LEVEL CLOUDINESS SPREADING OVER THE NW PORTION. AT THE SFC...A SLOW MOVING OR STALLED FRONT IS DRAPED ACROSS THE DEEP SOUTH FROM CENTRAL SOUTH CAROLINA TO THE NEW ORLEANS AREA THEN OFF THE LOUISIANA COAST AND BACK INLAND OVER S TEXAS. MOST OF THE ASSOCIATED OVERRUNNING MOISTURE IS INLAND OVER THE SRN STATES. THIS BOUNDARY IS NOT EXPECTED TO MAKE MUCH FURTHER SE PROGRESS DUE TO THE LACK OF UPPER SUPPORT. HOWEVER...THE NEXT BOUNDARY IS ANTICIPATED TO BE STRONGER AND ENTER THE NW WATERS BY FRI NIGHT. ELSEWHERE...LIGHT TO MODERATE ELY FLOW IS TRANSPORTING SCATTERED SHOWERS AND ISOLATED TSTMS ACROSS THE FL STRAITS AND A SMALL PORTION OF THE SE GULF. CARIBBEAN SEA... A LARGE AMPLIFIED MID-UPPER TROUGH EXTENDS ACROSS THE CENTRAL AND WRN CARIBBEAN FROM THE BAHAMAS THRU THE WINDWARD PASSAGE TO COSTA RICA. INSTABILITY ASSOCIATED WITH A VORTICITY MAXIMUM OVER THE SRN BAHAMAS AND DIFFLUENCE TO THE E OF THE AXIS IS GENERATING SCATTERED SHOWERS AND TSTMS N OF 17N BETWEEN 70W-78W. DRY STABLE AIR...DUE TO CONFLUENCE ALOFT W OF THE AXIS...HAS SPREAD WELL S FROM THE YUCATAN CHANNEL TO NRN COLOMBIA. IN THE LOW LEVELS...A WEAK TROUGH CONTINUES TO TRACK QUICKLY WWD ALONG 75W. THIS FEATURE IS ENHANCING THE AFOREMENTIONED SHOWER/TSTM ACTIVITY...WHICH IS MAINLY E OF THE SFC TROUGH AXIS SHEARED BY STRONG WLY FLOW ALOFT. TRADE WINDS ARE STRONG E OF THE TROUGH AXIS AND LIGHT TO MODERATE TO ITS W. AS A SIDE NOTE...THE UW-CIMSS MIMIC-TPW PRODUCT REVEALS THE PROGRESS OF THE LOW-LEVEL TROUGH WELL...WHICH IS LIKELY A COMBINATION OF SOME TROPICAL MOISTURE AND A MID-LATITUDE SURGE THAT ROTATED AROUND THE SUBTROPICAL RIDGE. ATLANTIC OCEAN... A SHORTWAVE UPPER TROUGH IS NEARLY CUT OFF OVER THE SRN BAHAMAS WHILE ANOTHER SHORTWAVE SKIRTS THE N WATERS ALONG 77W. THE NRN SHORTWAVE...COMBINED WITH A SFC TROUGH OFF THE FL E COAST ALONG 31N77W 27N79W...IS PRODUCING QUITE A BIT OF TSTM ACTIVITY. LIGHTNING DATA IS VERY IMPRESSIVE SHOWING A SWATH OF STRIKES FROM THE NW BAHAMAS NORTH-NORTHEASTWARD WITHIN 240 NM E OF THE SFC TROUGH AXIS. LESS OF A LIGHTING DISPLAY IS OCCURRING IN ASSOCIATION WITH THE SRN BROADER TROUGH S OF 23N BETWEEN 68W-75W. DEEP LAYER SUBSIDENT RIDGING LIES OVER THE CENTRAL ATLC. THE TIGHT PRES GRADIENT...TO THE S OF THE RELATED 1032 MB SFC HIGH NEAR 32N55W...IS PRODUCING STRONG TRADES S OF 25N AS NOTED IN RECENT SCATTEROMETER DATA. WINDS ARE STRONGEST JUST W OF A DYING COLD FRONT FROM 32N30W TO 25N35W CONTINUING TO 20N45W. A 1210Z ASCAT PASS SHOWS SOME EVIDENCE OF A WEAK SFC LOW ALONG THE FRONT...WILL RE-EXAMINE FOR THE 18Z ANALYSIS. WHILE DEEP MOISTURE IS MINIMAL ALONG THE FRONT THERE IS SOME CONVECTIVE ACTIVITY CLIPPING THE N PORTION...N OF 29N BETWEEN 27W-29W RELATED TO THE UPPER TROUGH. IN THE TROPICS...A SPRAWLING UPPER HIGH IS CENTERED NEAR 8N28W. DIFFLUENT FLOW TO THE S OF THE HIGH IS ENHANCING CLUSTERS OF CONVECTION IN THE ITCZ. $$ CANGIALOSI