000 AXNT20 KNHC 171803 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SAT MAR 17 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1730 UTC. ...ITCZ... ITCZ AXIS IS ALONG 7N12W 3N25W EQ35W AND INTO NE BRAZIL NEAR 3S43W. THE ITCZ REMAINS FAIRLY ACTIVE WITH SCATTERED MODERATE/ISOLATED STRONG CONVECTION NOTED WITHIN 90NM N AND 150NM S OF THE AXIS BETWEEN 15W-26W. ISOLATED CLUSTERS OF MODERATE CONVECTION ARE WITHIN 150 NM EITHER SID OF AXIS BETWEEN 30W-38W. SCATTERED MODERATE IS NEAR THE COAST OF BRAZIL FROM 5S-2S BETWEEN 36W-41W. ...DISCUSSION... GULF OF MEXICO... BRISK NLY WINDS ARE OVER MUCH OF THE GULF E OF 95W AS HIGH PRES BUILDS IN FROM THE N BEHIND THE COLD FRONT PUSHING THROUGH THE NW CARIBBEAN. SCATTERED TO BROKEN COOL AIR STRATOCUMULUS CLOUDS ARE OVER THE GULF WATERS S OF 27N. MOSTLY CLEAR SKIES ARE N OF 27N WITH A BIT COOLER SSTS AND DRIER LOW LEVEL AIR IN PLACE. NW TO WNW UPPER FLOW IS OVER THE GULF ON THE SW PORTION OF THE LONGWAVE UPPER TROF OVER THE ERN U.S. THIS HAS ADVECTED VERY DRY MID/UPPER AIR OVER MUCH OF THE GULF. SFC WINDS WILL GRADUALLY VEER OVER THE NEXT COUPLE OF DAYS AS HI PRES N OF THE AREA SLIDES E. MODELS SHOW VERY LITTLE IN THE WAY OF PRECIP AFFECTING THE GULF OVER THE NEXT COUPLE OF DAYS WITH SFC RIDGE AXIS OVER THE N PORTION. CARIBBEAN... COLD FRONT HAS PUSHED INTO THE NW CARIB AND AS OF 17/1500 UTC EXTENDS FROM CENTRAL CUBA TO THE GULF OF HONDURAS ALONG 22N80W 16N88W. THIS MORNINGS QUIKSCAT PASS SHOWED A SPEED GRADIENT IN THE NLY FLOW AROUND THE BOUNDARY. SATELLITE IMAGERY SUGGESTS A PREFRONTAL TROUGH MAY BE REESTABLISHING ITSELF BETWEEN THE FAR NE COAST OF NICARAGUA AND THE WINDWARD PASSAGE...AND WILL LIKELY ADD THIS TO THE 1800 UTC MAP. ASSOCIATED SCATTERED SHOWERS WITH EMBEDDED TSTMS ARE OVER THE CARIB WATERS AND ADJACENT LAND AREAS N OF 16N BETWEEN 73W-78W. MODERATE NE WINDS ARE OVER THE SW CARIBBEAN AROUND THE COLOMBIAN LOW...WHILE MODERATE ESE FLOW DOMINATES E OF 72W ON THE SW PORTION OF ATLC HI PRES. IN THE UPPER LEVELS...FLOW IS MOSTLY WLY IN THE NW CARIB AT THE BASE OF THE TROUGHING OVER THE ERN U.S. FLOW IS MORE SW TO WSW ELSEWHERE WITH A RIDGE AXIS EXTENDING NE FROM NE SOUTH AMERICA. THIS UPPER FLOW IS ADVECTING A FEW THIN PATCHES OF HIGH CLOUD THROUGH THE BASIN...ORIGINATING OVER ITCZ CONVECTION IN THE EPAC AND COLOMBIA. MODERATE ELY WINDS WILL DOMINATE MUCH OF THE AREA THE NEXT COUPLE OF DAYS EXCEPT MORE NE BEHIND FRONT IN NW PORTION. FRONT WILL SLOWLY WASH OUT OVER THE NEXT DAY OR SO. WESTERN AND CENTRAL ATLANTIC... LARGE UPPER TROUGH OVER THE ERN U.S. HAS AN ASSOCIATED COLD FRONT THAT ENTERS THE AREA NEAR 32N72W AND CONTINUES THROUGH THE NRN BAHAMAS TO THE COAST OF CUBA NEAR 23N81W. BROKEN TO OVERCAST DEEP LAYER CLOUDINESS...WITH EMBEDDED SHOWERS AND TSTMS ARE MAINLY AHEAD OF THE FRONT N OF 22N BETWEEN 70W-75W. BRISK NW TO N SFC WINDS ARE BEHIND THE FRONT...IN ADDITION TO BROKEN COOL AIR STRATOCUMULUS CLOUDS. STRONG S TO SW WINDS ARE E OF THE FRONT MAINLY N OF 26N. ANOTHER LOW LEVEL CONFLUENT ZONE NOTED AHEAD OF THE FRONT...WHERE A SFC TROUGH IS ANALYZED ALONG 25N68W 22N58W. ASSOCIATED SCATTERED MODERATE CONVECTION IS FROM 23N-26N BETWEEN 60W-65W. THIS CONVECTION IS ALSO BEING SUPPORTED BY UPPER DIFFLUENCE BETWEEN THE TROUGH OVER THE ERN U.S. AND RIDGING IN THE CENTRAL ATLC/N OF THE LEEWARD ISLANDS. A SEPARATE REMNANT FRONTAL TROUGH REMAINS THROUGH THE CENTRAL ATLC ALONG 32N45W 25N49W...ASSOCIATED WITH DEEP LAYER LOW NEAR 39N49N. ISOLATED SHOWERS POSSIBLE WITHIN 30 NM EITHER SIDE OF THE TROUGH. REMAINDER OF E ATLC AREA GENERALLY DOMINATED BY FAIR WEATHER...AND MODERATE TRADES S OF A STRONG 1042 MB HIGH JUST N OF THE AZORES. THERE IS AN UPPER LOW SPINNING IN THE FAR NE PORTION OF THE AREA NEAR 32N17W...WITH ITS ASSOCIATED BROKEN TO OVERCAST MID TO HIGH CLOUDS/MOISTURE AFFECTING THE CANARY ISLANDS. $$ WILLIS