000 AXNT20 KNHC 111130 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1115 UTC. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 7N10W 4N21W 2N28W EQ36W 1S43W AND INTO NE BRAZIL NEAR 3S46W. SCATTERED MODERATE CONVECTION IS WITHIN 90 NM N OF THE AXIS BETWEEN 22W-30W. SCATTERED SHOWERS AND TSTMS ARE WITHIN 60 NM EITHER SIDE E OF 22W. ...DISCUSSION... GULF OF MEXICO... WEAK SFC HIGH PRES RIDGING CONTINUES TO DOMINATE MUCH OF THE GULF. THE VERY WEAK SFC TROUGH THAT HAS BEEN STATIONARY FOR THE PAST 36-48 HOURS IN THE CENTRAL GULF HAS NOW DISSIPATED...OR AT LEAST LIFTED OFF THE SFC. LIGHT TO MODERATE ELY WINDS COVER THE REGION THIS MORNING BUT THEY WILL LIKELY INCREASE LATER TODAY AND MON AS A STRONG HIGH PRES SYSTEM IN THE UPPER MIDWEST SURGES SE. IN THE UPPER LEVELS...STRONG 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 MAINLY S OF 26N. DRY STABLE AIR ALOFT COVERS MOST OF THE REGION N OF 26N MAINTAINING FAIR WEATHER. OVER THE NEXT FEW DAYS...THE SYSTEM OF MOST INTEREST IS THE UPPER SHORTWAVE TROUGH THAT IS CURRENTLY OVER COLORADO AND NEW MEXICO. GFS SHOWS THIS SYSTEM CUTTING OFF SHORTLY...IN FACT WV IMAGES SHOW THIS PROCESS ALREADY UNDERWAY...AND MOVING LITTLE OVER THE NEXT COUPLE OF DAYS. THIS WILL LIKELY INCREASE MOISTURE IN THE W GULF AS THE UPPER FLOW VEERS SWLY. CARIBBEAN... AN UPPER LEVEL HIGH CENTERED IN THE SW CARIB NEAR 12N75W IS THE MAIN WEATHER FEATURE IN THE REGION. STRONG WLY FLOW ON THE NRN PERIPHERY OF THE RIDGE IS ADVECTING A SWATH OF HIGH CLOUDS ACROSS THE S GULF...THE YUCATAN PENINSULA AND CUBA. ELSEWHERE QUIET WEATHER PERSISTS WITH PLENTY OF DRY STABLE AIR ALOFT IN PLACE. SLIGHT UPPER LEVEL TROUGHING LIES ABOVE THE LESSER ANTILLES...BUT THE ONLY EFFECT OF THIS IS AN EVEN MORE STABLE ENVIRONMENT DUE TO UPPER CONFLUENT/SUBSIDENT FLOW. FAIR WEATHER AND TYPICAL ISOLATED TRADE WIND SHOWERS IS THE THEME ACROSS THE SEA TODAY. THERE ARE VERY SMALL CLUSTERS OF MODERATE CONVECTION OVER COLOMBIA AND THE ATLC COASTAL WATERS OF COSTA RICA AND W PANAMA ENHANCED BY A DIFFLUENT PATTERN ALOFT. MORE OF THE SAME...TRANQUIL WEATHER AND MODERATE TO FRESH TRADES...IS THE FORECAST FOR THE NEXT COUPLE OF DAYS. WESTERN ATLANTIC... MESSY WEATHER CONTINUES FOR PARTS OF THE REGION. THE SYNOPSIS PRODUCING THIS UNSETTLED WEATHER REMAINS FAIRLY COMPLEX AND FAST EVOLVING...I WILL DO MY BEST TO EXPLAIN IT. STARTING IN THE UPPER LEVELS...A SHORTWAVE TROUGH LIES ALONG 70W N OF 25N. MID TO UPPER LEVEL ENERGY/VORTICITY ASSOCIATED WITH THIS SHORTWAVE IS PRODUCING A SPIN IN THE CLOUDS AND LIKELY SOME SCATTERED SHOWERS N OF 28N BETWEEN 68W-72W. SWLY UPPER LEVEL FLOW TO THE E OF THE AXIS ALONG WITH A HIGHLY DIFFLUENT PATTERN ARE SIGNIFICANT FACTORS FOR THE DEEPER MOISTURE FURTHER E. THE CONTRIBUTING SFC FACTORS...AS OF 09 UTC...CONSIST OF A INTENSIFYING AREA OF LOW PRES JUST E OF BERMUDA AND AN ASSOCIATED COLD FRONT WHICH EXTENDS SWD FROM THE LOW TO 27N68W. A SFC TROUGH...LACKING MUCH THERMAL GRADIENT...CONTINUES S FROM THERE TO HISPANIOLA. THIS PATTERN IS SIGNIFICANTLY DIFFERENT FROM JUST 3 HOURS AGO AS IT IS NOW CLEAR THAT THE LOW NEAR BERMUDA HAS BECOME THE DOMINATE FEATURE WITH THE MOISTURE SWATH MOLDING INTO A BAROCLINIC LEAF PATTERN. A WARM FRONT EXTENDS EWD FROM THE LOW NEAR BERMUDA ALONG 32N/33N. ALL OF THESE ELEMENTS ARE AIDING IN PRODUCING A SWATH OF DEEP MOISTURE N OF 28N BETWEEN 56W-66W AND FROM 19N-28N BETWEEN 62W-68W. IN ADDITION...STRONG WINDS ARE A HIGH CONCERN AS A TIGHT SFC PRESSURE GRADIENT EXISTS BETWEEN THE LOW AND A 1037 MB HIGH NEAR 39N48W. UP TO GALE FORCE WINDS ARE OCCURRING N OF 29N BETWEEN 58W-64W. LOOKING AHEAD...THE LOW PRES SYSTEM IS EXPECTED TO CONTINUE DEEPENING AS IT TRACKS RATHER QUICKLY TO THE N...EXPECTED TO BE WELL N OF THE DISCUSSION AREA TONIGHT. HOWEVER...THE ASSOCIATED TRAILING TROUGH WILL REMAIN IN THE REGION FOR THE NEXT COUPLE OF DAYS. 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 PROMOTING THE CONTINUATION OF FAIR WEATHER. $$ CANGIALOSI