000 AXNT20 KNHC 111756 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SUN MAR 11 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 CENTERED ALONG 7N11W 4N25W EQ43W AND INTO NE BRAZIL NEAR 2S47W. SCATTERED CLUSTERS OF MODERATE CONVECTION ARE WITHIN 120 NM EITHER SIDE OF THE AXIS E OF 31W. SIMILAR ACTIVITY IS FROM 4S-EQ BETWEEN 34W-45W...WHICH INCLUDES THE ACTIVITY NEAR THE NE COAST OF BRAZIL. A REGION OF SCATTERED MODERATE IS ALSO NORTH OF THE AXIS FROM 3N-5N BETWEEN 44W-53W. ...DISCUSSION... GULF OF MEXICO... WEAK SFC HIGH PRES RIDGING CONTINUES TO DOMINATE THE GULF FROM A 1025 MB CENTER OVER SW GEORGIA. LIGHT TO MODERATE ELY WINDS E OF 90W BEND MORE SELY IN THE WRN GULF. SIMILAR TO SLIGHTLY STRONGER E/SE WINDS EXPECTED THROUGH EARLY WEEK AS HIGH PRESSURE N OF THE AREA PUSHES E AND OFFSHORE THE MID ATLANTIC STATES. IN THE UPPER LEVELS...STRONG NEARLY ZONAL FLOW DOMINATES MUCH OF THE BASIN BETWEEN RIDGING EXTENDING N FROM THE SW CARIBBEAN AND A COUPLE OF SHORTWAVE TROUGHS PUSHING THROUGH THE CONUS AND OFF THE E COAST. THESE STIFF WINDS ARE ADVECTING ABUNDANT UPPER LEVEL MOISTURE/HIGH CLOUDS FROM THE EPAC ACROSS CENTRAL MEXICO INTO THE GULF EXCEPT FOR THE FAR NE PORTION WHERE DRY AIR EXISTS. INCREASING DEEP LAYER MOISTURE WITH POSSIBLE SHOWERS EXPECTED IN THE WRN GULF EARLY TO MID WEEK...AHEAD OF THE UPPER LOW TO REMAIN QUASI-STATIONARY OVER WRN TEXAS AND RETURN FLOW AROUND THE SFC HIGH NE OF THE AREA. CARIBBEAN... A CLUSTER OF MODERATE CONVECTION FORMED JUST OFFSHORE SRN NICARAGUA AND COSTA RICA THIS MORNING...BUT THIS AREA HAS BEEN DIMINISHING IN BOTH COVERAGE AND INTENSITY OVER THE LAST COUPLE HOURS. THIS IS ONE OF THE ONLY NOTABLE CONVECTIVE CLUSTERS NOTICED IN THE CARIBBEAN OVER THE PAST SEVERAL WEEKS. ELSEWHERE THE WEATHER REMAINS DOMINATED BY DRY STABLE AIR ALOFT THAT IS ROTATING AROUND UPPER RIDGING OVER THE BASIN. OVERALL FAIR WEATHER AND TYPICAL ISOLATED SHOWERS DRIVEN BY MODERATE TRADES ARE THE THEME ACROSS THE SEA TODAY. MORE OF THE SAME...TRANQUIL WEATHER AND MODERATE TO FRESH TRADES...IS THE FORECAST FOR THE NEXT COUPLE OF DAYS. WESTERN ATLANTIC... THE MESSY...COMPLEX WEATHER SITUATION OVER THE WRN ATLC THE LAST FEW DAYS HAS EVOLVED AND SORTED ITSELF OUT QUITE A BIT. LIGHT TO MODERATE NE WINDS ARE FOUND OVER MUCH OF THE AREA W OF 68W OR BEHIND THE COLD FRONT THAT ENTERS THE AREA NEAR 32N65W AND CONTINUES SSW TO 26N68W...WHERE IT LOSES MUCH OF ITS THERMAL CONTRAST AND CONTINUES SW AS A TROUGH TO NEAR 22N72W. THE FRONT IS ASSOCIATED WITH THE 1009 MB SFC LOW JUST N OF THE AREA NEAR 33N65W. MOST OF THE CONVECTION IN THE AREA IS ASSOCIATED WITH THE PREFRONTAL TROUGH ANALYZED ALONG 29N63W 23N66W TO THE COAST OF HISPANIOLA NEAR 19N72W. THE TROUGH IS MARKED BY CONFLUENT SW INTO SE FLOW...AND BROKEN TO OVERCAST DEEP LAYER CLOUDINESS WITH EMBEDDED SHOWERS/TSTMS WITHIN 150 NM OF THE AXIS. THE CONVECTION IS ALSO SUPPORTED BY A CLEAR UPPER DIFFLUENT ZONE AHEAD OF THE DOMINATING SHORTWAVE UPPER TROUGH MOVING THROUGH THE AREA. LOOKING AHEAD...THE LOW PRES SYSTEM IS EXPECTED TO CONTINUE DEEPENING AS IT TRACKS RATHER QUICKLY TO THE N. HOWEVER...THE ASSOCIATED TRAILING FRONTAL TROUGH WILL REMAIN IN THE REGION FOR THE NEXT COUPLE OF DAYS. THE MODERATE ELY SWELL FROM THIS STORM THAT IS CURRENTLY AFFECTING EXPOSED FLORIDA BEACHES NORTH OF THE BAHAMA SHADOW ZONE WILL SUBSIDE SLOWLY THROUGH MIDWEEK. EASTERN ATLANTIC... STRONG HIGH PRESSURE RIDGING CONTINUES TO DOMINATE THE SFC PATTERN ACROSS MUCH OF THE CENTRAL AND EASTERN ATLC. THIS HIGH IS PRODUCING MODERATE TO FRESH TRADE WINDS AND FAIR WEATHER ACROSS A GOOD PORTION OF THE AREA. IN THE MID AND UPPER LEVELS...STRONG RIDGING ALSO DOMINATES WITH A HIGH CENTER NEAR 21N31W. DRY AND STABLE AIR ALOFT RESULTING IN STRONG SUBSIDENCE IS AIDING IN THE WIDESPREAD FAIR WEATHER. THE TRADE WINDS ARE SET TO PICK UP AGAIN FROM W TO E STARTING TODAY INTO NEXT WEEK AS STRONG HIGH PRES REBUILDS E ACROSS THE ATLC OCEAN. UPPER RIDGING WILL ALSO REMAIN IN CONTROL SUPPORTING THE CONTINUATION OF FAIR WEATHER. $$ WILLIS