000 AXNT20 KNHC 142327 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST TUE MAR 14 2006 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...WEATHER OBSERVATIONS... RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2245 UTC. ...THE ITCZ... ITCZ IS CENTERED ALONG 6N10W 2N40W INTO S AMERICA NEAR 1S48W. SCATTERED MODERATE CONVECTION WITHIN 75 NM EITHER SIDE OF THE AXIS W OF 39W. ...DISCUSSION... GULF OF MEXICO... STRONG MIDDLE TO UPPER LEVEL RIDGE REMAINS IN CONTROL OVER MOST OF THE GLFMEX WITH MEAN AXIS EXTENDING FROM A ANTICYCLONE OVER THE BAY OF CAMPECHE NEWD OVER THE W ATLC NEAR BERMUDA. FURTHER N...MIDDLE TO UPPER LEVEL TROUGH LIES OVER THE E U.S. WITH ATTENDANT SURFACE COLD FRONT PUSHING SWD OVER THE GLFMEX CURRENTLY FROM N FLORIDA TO VERACRUZ MEXICO. THE FRONT CONTINUES INLAND OVER INTERIOR MEXICO ALONG THE E SLOPES OF THE SIERRA MADRE ORIENTAL MOUNTAINS. LACKING APPRECIABLE DYNAMICS...ONLY A NARROW BAND OF SCATTERED SHOWERS ACCOMPANIES THE FRONT. AS THE UPPER TROUGH PROGRESSES EWD INTO THE W ATLC OVER THE NEXT 24 HOURS...THE UPPER FLOW WILL BECOME INCREASINGLY ZONAL. AS SUCH...THE COLD FRONT WILL WEAKEN AS IT PUSHES SWD OVER THE REMAINDER OF THE GULF AND BECOME DIFFUSE AS IT CLEARS THE S FLORIDA PENINSULA LATE TONIGHT INTO EARLY WED. STILL...LOW LEVEL MOISTURE POOLING ALONG THE BOUNDARY WILL CONTINUE TO SUPPORT A NARROW BAND OF LOW CLOUDINESS AND SCATTERED SHOWERS PRIMARILY OVER THE E GULF AND CENTRAL FLORIDA TONIGHT THROUGH EARLY TUE. ELSEWHERE OVER THE GULF AND FLORIDA...THE SUBTROPICAL RIDGE HAS BEEN SHUNTED E OF THE AREA BY THE APPROACHING COLD FRONT RESULTING IN MUCH WEAKER SLY TO WLY FLOW. DEWPOINTS REMAIN IN THE 60S AND 70S AHEAD OF THE FRONT CREATING SUMMER-LIKE CONDITIONS. CARIBBEAN SEA... AFOREMENTIONED UPPER LEVEL ANTICYCLONE OVER THE BAY OF CAMPECHE NOSES SEWD OVER CENTRAL AMERICA INTO COLOMBIA. OVER THE E CARIBBEAN...A LARGE UPPER CUTOFF LOW CONTINUES TO DRIFT SWD FROM THE ATLC OVER HISPANIOLA AND PUERTO RICO. CONFLUENT FLOW ON THE BACK/WEST SIDE OF THE UPPER LOW IS ENHANCING AN ALREADY DRY/STABLE ENVIRONMENT ALOFT WITH STRONG SUBSIDENCE NOTED IN WATER VAPOR IMAGERY OVER THE ENTIRE CARIBBEAN...CENTRAL AMERICA...AND N PORTIONS OF S AMERICA. E OF THE UPPER LOW...THE FLOW IS BECOMING INCREASINGLY DIFFLUENT BUT REMAINS VERY DRY ALOFT. STILL...ENHANCED SHOWER AND TSTMS ACTIVITY IS NOTED ALONG THE LEADING EDGE OF A SAL/AFRICAN DUST OUTBREAK NEARING THE LESSER ANTILLES. CURRENTLY...THE STRONGEST ACTIVITY EXTENDS FROM MARTINIQUE SWD INTO N GUYANA AND NE VENEZUELA. WIDELY SCATTERED SHOWER ACTIVITY IS NOTED ELSEWHERE OVER THE CARIBBEAN E OF 70W. THIS ACTIVITY IS EXPECTED TO SLOWLY EXPAND WESTWARD KEEPING SHOWERS/TSTMS OVER THE SE CARIBBEAN THROUGH WED. ELSEWHERE...THE SCREAMING EAGLE OVER THE CARIBBEAN YESTERDAY HAS BECOME DIFFUSE IN SATELLITE IMAGERY WITH NO SIGNIFICANT WEATHER. BRISK TRADES CONTINUE ACROSS MUCH OF THE CARIBBEAN SEA BUT ARE EXPECTED TO GRADUALLY WEAKEN OVER THE NEXT FEW DAYS AS HIGH PRES OVER THE W ATLC SHIFT EWD. ATLANTIC OCEAN... A HIGH-OVER-LOW TYPE PATTERN EXISTS OVER THE W HALF OF THE ATLC WITH MIDDLE TO UPPER LEVEL RIDGING OBSERVED OVER THE W ATLC FROM W CUBA NEWD OVER BERMUDA AND A LARGE UPPER-LEVEL CUTOFF LOW JUST NW OF PUERTO RICO 20N67W. FURTHER E...A BROAD/FLAT TROUGH PREVAILS OVER THE E ATLC WITH THE SUBTROPICAL JET...ESTIMATED TO TO 120 KT...BETWEEN 15N-25N FROM THE E CARIBBEAN INTO AFRICA OVER MAURITANIA. LOOKING UPSTREAM...PROGRESSIVE MID/UPPER LEVEL TROUGH IS OBSERVED MOVING EWD FROM THE E U.S. INTO THE W ATLC WATERS WITH ATTENDANT SURFACE COLD FRONT TRAILING FROM THE MID-ATLANTIC COAST SWD OVER N FLORIDA. THE BULK OF THE UPPER DYNAMICS/LIFT IS CONFINED N OF THE AREA LEAVING ONLY A NARROW BAND OF SCATTERED SHOWERS ALONG THE FRONT. ELSEWHERE...DEEP CONVECTION REMAINS ABSENT OVER ALL BUT THE ITCZ OWING TO THE NEAR DOMINANCE OF MODERATE TO STRONG SUBSIDENCE AND DRY/STABLE CONDITIONS ALOFT ACROSS THE ENTIRE ATLANTIC. CLOUDS/CONVECTION ARE ESPECIALLY SCARCE OVER THE SE PART OF THE AREA WHERE SATELLITE IMAGERY CONTINUES TO SHOW A STRONG SAHARAN AIR LAYER AND AFRICAN DUST OUTBREAK GENERALLY SE OF A LINE FROM CANARY ISLANDS TO THE SE CARIBBEAN. THE HIGHEST CONCENTRATION OF DUST IS S OF 20N E OF 40W INCLUDING THE CAPE VERDE ISLANDS. VISIBILITY MAY BE OCCASIONALLY REDUCED BELOW 5 SM WITHIN THIS AREA. ELSEWHERE AT THE SURFACE...SUBTROPICAL RIDGE EXTENDS E/W ACROSS THE AREA ALONG 26N/27N WITH A 1024 MB HIGH PRES APPROXIMATELY 500 NM SE OF BERMUDA NEAR 27N58W. $$ RHOME