000 AXNT20 KNHC 041743 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST FRI MAR 04 2011 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTION OF SOUTH AMERICA...AND 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... THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ANALYZED FROM THE COAST OF LIBERIA NEAR 05N09W TO 02N20W TO 01N30W CONTINUING S OF THE EQUATOR TO THE COAST OF BRAZIL NEAR 02S43W. SCATTERED MODERATE CONVECTION IS WITHIN 90 NM S OF THE AXIS BETWEEN 27W AND 36W. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 270 NM N OF THE AXIS BETWEEN 28W AND 38W. SIMILAR CONVECTION IS FROM 03N TO 07N BETWEEN 38W AND 44W. ...DISCUSSION... GULF OF MEXICO... A WEAK UPPER RIDGE EXTENDS ACROSS THE AREA REACHING FROM NEAR THE COAST OF S CENTRAL LOUISIANA TO MEXICO NEAR 19N95W IN THE BAY OF CAMPECHE. WATER VAPOR SATELLITE IMAGERY INDICATES MAINLY DRY AND STABLE AIR ACROSS THE BASIN. THE EXCEPTION IS IN THE CENTRAL GULF WHERE A SHEAR AXIS EXTENDS FROM JUST S OF LOUISIANA NEAR 28N91W TO THE YUCATAN CHANNEL NEAR 22N85W. THIS SHEAR AXIS IS THE REMNANTS OF A STATIONARY FRONT AND SURFACE LOW WHICH DISSIPATED OVER THE AREA DURING THE OVERNIGHT HOURS. SCATTERED SHOWERS ARE WITHIN 180-240 NM NE OF THIS AXIS WITH ISOLATED TSTMS ALSO POSSIBLE. LIGHT TO FRESH SE WINDS EXIST TO THE W OF THIS BOUNDARY WITH FRESH TO STRONG E OF THE BOUNDARY. THE SHEAR AXIS WILL DISSIPATE TONIGHT WITH A COLD FRONT PUSHING INTO THE NW GULF FROM THE TEXAS COAST SAT AFTERNOON. THE FRONT WILL REACH FROM SE LOUISIANA TO THE BAY OF CAMPECHE SAT NIGHT AND WILL QUICKLY WEAKEN AS IT MOVES INTO THE E GULF SUN...MOVING E OF THE AREA BY MON MORNING. LATEST MODEL GUIDANCE IS TRENDING WEAKER AND SLOWER WITH THE FRONT ALTHOUGH GALE FORCE WINDS ARE STILL FORECAST BEHIND IT IN THE SW GULF BEGINNING AROUND 06Z SAT NIGHT. CARIBBEAN SEA... AN UPPER TROUGH REACHES FROM CENTRAL CUBA TO THE E COAST OF NICARAGUA NEAR 12N83W. SW FLOW EXISTS AHEAD OF THE TROUGH OVER THE REMAINDER OF THE BASIN WITH A MAINLY DRY AND STABLE ATMOSPHERE THROUGHOUT ALOFT. THE REMNANTS OF A STATIONARY FRONT ARE IN THE WINDWARD PASSAGE EXTENDING SW TO JAMAICA. THIS BOUNDARY WILL CONTINUE TO DISSIPATE THIS AFTERNOON. A WEAK SURFACE TROUGH REMAINS IN THE E CARIBBEAN FROM NEAR 16N64W TO 12N68W. SCATTERED SHOWERS ARE OCCURRING WITHIN 90-120 NM EITHER SIDE OF THE TROUGH AXIS. THIS TROUGH WILL DISSIPATE DURING THE NEXT 24 HOURS. ELSEWHERE WIDESPREAD SHOWERS REMAIN OVER THE W CARIBBEAN WITH FRESH TO STRONG TRADE WINDS IN THE LEE OF CUBA. FRESH TO STRONG WINDS ALSO EXIST NEAR THE COAST OF COLOMBIA WHERE THERMAL LOW PRES IS DEVELOPING OVER COLOMBIA AND HIGHER PRES EXISTS TO THE NE CREATING A TIGHT GRADIENT. WINDS WILL DIMINISH ACROSS THE BASIN THIS WEEKEND AS HIGH PRES NE OF THE AREA RETREATS WEAKENING THE GRADIENT. ATLANTIC OCEAN... A STRONG 1044 MB SURFACE HIGH IS MOVING ACROSS THE FAR NE CONUS AND INTO MARITIME CANADA EARLY THIS AFTERNOON. A VERY TIGHT PRES GRADIENT EXITS S OF THIS HIGH AND INTO THE NW PORTION OF THE AREA WITH 20-30 KT WINDS OCCURRING E OF FLORIDA THROUGH THE BAHAMAS AND NE OF CUBA. A STATIONARY FRONT EXTENDS FROM 31N57W TO JUST NE OF HAITI NEAR 20N73W. SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING WITHIN 90-120 NM EITHER SIDE OF THE FRONT MAINLY N OF 24N. WIDESPREAD SHOWERS ARE ALSO OCCURRING THROUGHOUT THE AREA NW OF THE FRONT WITH COLDER AIR ALOFT MOVING OVER THE RELATIVELY WARMER SEA SURFACE. THE FRONT WILL BECOME LESS DEFINED ON SAT DISSIPATING BY SUN NIGHT. WINDS WILL DIMINISH SAT NIGHT AND SUN AS THE NEXT COLD FRONT APPROACHES THE NW PORTION FROM THE CONUS. THE FRONT WILL PUSH SE OFF THE GEORGIA/FLORIDA COAST SUN NIGHT WEAKENING AS IT MOVES OVER THE CENTRAL BAHAMAS MON. A WEAK SURFACE TROUGH IS NE OF THE LESSER ANTILLES FROM NEAR 21N63W TO 18N61W JUST E OF BARBUDA. SCATTERED SHOWERS ARE OCCURRING WITHIN 60 NM W OF THE TROUGH AND 90-120 NM NE OF THE TROUGH. FARTHER EAST...A WEAK SURFACE TROUGH EXTENDS FROM 30N39W TO 27N36W AND WAS CAPTURED NICELY BY A 1256Z ASCAT PASS WHICH INDICATED ONLY 5-15 KT WINDS. THIS FEATURE WILL DISSIPATE LATER TODAY. ELSEWHERE ACROSS THE BASIN AN UPPER ANTICYCLONE HAS FORMED NEAR 05N31W WITH A RIDGE AXIS COVERING THE AREA ALONG 05/06N. CONVECTION ALONG THE ITCZ IS BEING ENHANCED ON THE SW SIDE OF THE ANTICYCLONE AS DESCRIBED ABOVE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ LEWITSKY