000 AXNT20 KNHC 091803 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST FRI MAR 09 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 1745 UTC. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 7N11W 4N20W 3N35W EQ44W TO THE NE COAST OF BRAZIL NEAR 2S46W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS WITHIN 150 NM S OF THE AXIS E OF 14W. SCATTERED MODERATE IS ALSO WITHIN 60 NM EITHER SIDE OF THE AXIS BETWEEN 27W-29W...AND WITHIN 150 NM EITHER SIDE OF AXIS W OF 34W. ...DISCUSSION... GULF OF MEXICO... AS INDICATED IN THE PREVIOUS DISCUSSION...A VERY WEAK TROUGH HAS FORMED IN THE MIDDLE GULF ALONG 27N88W 23N88W. THE 1200 UTC QUIKSCAT PASS SHOWED THIS BOUNDARY WELL...WHICH IS PRODUCING A REGION OF LOW AND MID CLOUDS WITH POSSIBLE SHOWERS WITHIN 60 NM OF THE AXIS. OTHERWISE THE SYNOPTIC SFC PATTERN ACROSS THE GULF IS DOMINATED BY WEAK RIDGING...WITH A 1021 MB CENTER PLACED NEAR THE COAST OF SRN LOUISIANA NEAR 29N92W AT 1500 UTC. RIDGING CONTINUES IN THE UPPER LEVELS WITH BROAD W TO WNW FLOW OVER THE BASIN. UPPER LEVEL SWLY FLOW ON THE WRN PERIPHERY OF THE RIDGE IS ADVECTING HIGH LEVEL MOISTURE FROM THE EPAC ACROSS CENTRAL MEXICO AND INTO THE GULF MAINLY S OF 26N. MODERATE DRY AIR EXISTS BOTH N OF THE UPPER MOISTURE PLUME. THE WEAK PATTERN AT THE SFC IS KEEPING WINDS AND SEAS FAIRLY LIGHT AND THEY ARE EXPECTED TO REMAIN THAT WAY THROUGH SAT AS THE SFC PRES GRADIENT CHANGES LITTLE. MAINLY FAIR WEATHER IS ALSO EXPECTED TO CONTINUE UNDER WEAK HIGH PRES...THOUGH SHOWERS MAY LINGER NEAR THE WEAK TROUGH IN THE MIDDLE GULF THROUGH SAT. CARIBBEAN... MUCH OF THE CARIB IS QUIET THIS AFTERNOON WITH PLENTY OF DRY STABLE AIR ALOFT IN PLACE. UPPER RIDGING GENERALLY DOMINATES THE BASIN W OF 70W WITH A SHORTWAVE TROUGH FROM THE ATLC TO THE E. THERE IS A FAIR AMOUNT OF MID TO UPPER LEVEL MOISTURE AND A FEW SMALL POCKETS OF MODERATE CONVECTION OVER COLOMBIA PRODUCED BY SFC LIFT ALONG THE ITCZ. MOST OF THIS MOISTURE IS CONTAINED S OF 12N. AT THE SFC MODERATE TO FRESH TRADES CONTINUE TO ADVECT THEIR TYPICAL PATCHES OF LOW LEVEL MOISTURE WWD. THERE IS A LITTLE MORE ORGANIZATION TO THE CLOUDS OVER THE YUCATAN PENINSULA AND THE CHANNEL ASSOCIATED WITH THE REMNANTS OF A WEAK SFC TROUGH. TRANQUIL WEATHER IS EXPECTED TO CONTINUE THROUGH THE WEEKEND WITH CONDITIONS DOMINATED BY MODERATE TRADES. WESTERN ATLANTIC... A COMPLEX SURFACE PATTERN AND UNSETTLED WEATHER CONTINUES TO DOMINATE MUCH OF THE WRN ATLC. A 1013 MB LOW REMAINS NEAR THE SE BAHAMAS NEAR 24N74W. A TROUGH EXTENDS THROUGH THIS LOW ALONG 29N63W 25N73W THEN THROUGH ERN CUBA. A COLD FRONT ENTERS THE AREA NEAR 32N60W AND CONTINUES WSW TO NEAR 30N78W. ASSOCIATED DEEP LAYER CLOUDINESS WITH EMBEDDED CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 25=4N-31W BETWEEN 52W-74W. THE SFC FEATURES ARE BEING OBSCURED BUT IN PART SUPPORTED BY THE UPPER SHORTWAVE TROUGH EXTENDING S ALONG 63W. THE FRONT AND TROUGH/LOW WILL LIKELY GRADUALLY MESH TOGETHER OVER THE NEXT DAY OR SO. THE OVERALL PICTURE FROM THE RESULT WILL BE THAT HIGH PRESSURE PUSHING OFF THE MID ATLANTIC COAST WILL INTERACT THE THE LOW TO ITS SOUTH TO SET UP INCREASING WINDS/SEAS IN MUCH OF THE AREA THROUGH EARLY SAT. THIS WILL CONTINUE TO PRODUCE UNSETTLED WEATHER IN THE AREA THROUGH TOMORROW...AND SEND MODERATE ELY SWELL TO THE SE U.S. COAST THROUGH EARLY NEXT WEEK. EASTERN ATLANTIC... A STRONG 1039 MB HIGH PRES SYSTEM LOCATED ABOUT 300 NM W OF PORTUGAL IS DOMINATING THE SFC PATTERN ACROSS THE ATLC E OF 45W. THIS HIGH IS PRODUCING MODERATE TO STRONG TRADE WINDS ACROSS A GOOD PORTION OF THE DISCUSSION AREA PARTICULARLY E OF 30W WHERE THE TIGHTEST PRES GRAD EXISTS. THE UPPER LEVEL TROUGH THAT HAS BEEN DRIFTING N IN THE AREA HAS NOW JUST ABOUT DISSIPATED. ONLY PATCHES OF MID AND HIGH LEVEL CLOUDS ARE LEFT N OF 22N BETWEEN 20W-29W. ELSEWHERE FAIRLY DRY AIR ALOFT DOMINATES PROVIDING STABLE CONDITIONS. THE WEAK TROUGH IS EMBEDDED IN LARGE SCALE UPPER RIDGING THAT IS BEGINNING TO TAKE OVER. OVER THE NEXT COUPLE OF DAYS...THE STRONG SFC HIGH IS FORECAST TO RETREAT NE ALLOWING THE TRADES TO RELAX SLIGHTLY THIS WEEKEND IN THE E ATLC. HOWEVER THEY ARE SET TO PICK UP AGAIN SUN AND INTO NEXT WEEK AS STRONG HIGH PRES REBUILDS E ACROSS THE ATLC. $$ WILLIS