000 AXNT20 KNHC 100535 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 AM EST SAT MAR 10 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 8N12W 4N20W 3N30W CROSSING THE EQUATOR NEAR 41W TO NE BRAZIL NEAR 3S46W. SCATTERED MODERATE CONVECTION IS WITHIN 90 NM EITHER SIDE OF THE AXIS BETWEEN 32W-41W...AND WITHIN 60 NM EITHER SIDE BETWEEN 17W-23W. SIMILAR CONVECTION IS OVER NE BRAZIL. ...DISCUSSION... GULF OF MEXICO... STRONG ZONAL PATTERN HAS SET UP IN THE GULF SANDWICHED BETWEEN A DIGGING SHORTWAVE TROUGH OVER THE CENTRAL/EASTERN U.S. AND WEAK RIDGING OVER CENTRAL AMERICA. THIS STRONG MID TO UPPER LEVEL FLOW IS SPREADING A PLUME OF MOISTURE ACROSS CENTRAL/SOUTHERN MEXICO AND THE GULF S OF 28N. HOWEVER...MOST OF THIS IS ONLY IN THE FORM OF BROKEN TO OVERCAST MID TO HIGH LEVEL CLOUDINESS. IN THE LOWER LEVELS...WEAK HIGH PRES RIDGING IS THE THEME EXTENDING SW FROM A STRONG HIGH OFF THE MID-ATLANTIC COAST. A VERY WEAK SFC TROUGH IS NEARLY STATIONARY ALONG 89W FROM 24N-30N. A SLIGHT WIND SHIFT OR PERTURBATION IN THE LIGHT ELY FLOW...AS DEPICTED IN QSCAT AND SHIP OBS...IS THE BASIS FOR THIS BOUNDARY. THERE ARE SCATTERED LOW TO MID LEVEL CLOUDS AND MAYBE AN ISOLATED SHOWER WITHIN 180 NM E OF THE TROUGH AXIS. LOOKING AHEAD THROUGH THE WEEKEND...THE WEAK TROUGH WILL GRADUALLY DISSIPATE AS STRONG HIGH PRES BUILDS N OF THE REGION. THE PRES GRADIENT ON THE S SIDE OF THE HIGH WILL INCREASE THE ELY WINDS SLIGHTLY ON SUN AND INTO EARLY NEXT WEEK. CARIBBEAN... QUIET WEATHER PERSISTS ACROSS MUCH OF THE BASIN THIS EVENING WITH PLENTY OF DRY STABLE AIR ALOFT IN PLACE. WEAK UPPER RIDGING GENERALLY DOMINATES THE REGION AS THE SHORTWAVE TROUGH HAS NOW PULLED E OF THE AREA. THERE ARE ONLY A COUPLE OF AREAS OF NOTABLE CLOUDINESS. ONE IS OVER THE COLOMBIA...PANAMA...COSTA RICA AND THE COASTAL WATERS WHERE THERE IS SMALL PATCHES OF WEAKENING CONVECTION MOSTLY ASSOCIATED WITH CLIMATOLOGICAL LOW PRES AND THE ITCZ. THE OTHER AREA OF CLOUDINESS IS OVER THE ISLAND OF HISPANIOLA WHERE INFLUENCE FROM A SFC TROUGH TO THE N AND LOCAL UPSLOPING CONDITIONS IS LIKELY PRODUCING A FEW SHOWERS OVER THE HIGH TERRAIN. OTHERWISE MAINLY FAIR WEATHER AND TYPICAL ISOLATED TRADE WIND SHOWERS ARE MOVING WWD ACROSS THE REGION. TRANQUIL WEATHER IS EXPECTED TO CONTINUE THROUGH THE WEEKEND WITH CONDITIONS DOMINATED BY MODERATE TO STRONG TRADE WINDS. WESTERN ATLANTIC... A LARGE AREA OF CLOUDS AND SCATTERED SHOWERS CONTINUE TO AFFECT THE REGION. THE SFC PATTERN CONTRIBUTING TO THIS UNSETTLED WEATHER IS SOMEWHAT COMPLEX. THE MAIN FEATURE IS A 1012 MB LOW PRES SYSTEM CENTERED N OF THE CENTRAL BAHAMAS NEAR 25N73W WITH A TROUGH EXTENDING SWD FROM THE LOW ACROSS HISPANIOLA. A COLD FRONT IS APPROACHING THE LOW ENTERING THE REGION NEAR 32N48W AND CONTINUING WSW TO 28N73W. THESE FEATURES MAY BE MERGING BASED ON THE LATEST SATELLITE DATA. THE MID AND UPPER FLOW IS MAINLY SWLY HELPING TO GENERATE AND ADVECT MOISTURE NEWARD N OF 21N E OF 70W. IR IMAGES SHOW A FEW PATCHES OF COLD CLOUD TOPS FROM 23N-26N BETWEEN 65W-70W WHERE LIFTING AND INSTABILITY IS GREATEST. IN ADDITION TO THE MOISTURE...ANOTHER CONCERN IS THE STRONG NELY WINDS AS A TIGHT PRES GRAD HAS NOW SET UP BETWEEN THE LOW AND A 1034 MB HIGH NEAR 39N68W. LOOKING AHEAD IN TIME...THE WEAK LOW IS EXPECTED TO INTENSIFY AND TRACK TO THE NE MOVING OUT OF THE AREA ON SUN BUT ITS TRAILING FRONT/TROUGH WILL REMAIN IN THE REGION LONGER. THIS WOULD INCREASE THE PRES GRAD FURTHER THROUGHOUT THE DAY AND FOR THAT REASON A GALE WARNING IS IN EFFECT FOR A PORTION OF THE FORECAST AREA. FOR DETAILS REFER TO THE HIGH SEAS FORECAST...AWIPS HEADER MIAHSFAT2. EASTERN ATLANTIC... STRONG HIGH PRES RIDGING CONTINUES TO DOMINATE 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 N OF 20 E OF 30W WHERE THE TIGHTEST PRES GRAD EXISTS. IN THE MID AND UPPER LEVELS...STRONG RIDGING IS ALSO THE RULE WITH THE AXIS ALIGNED MAINLY N-S ALONG 28W. ABUNDANT DRY SINKING AIR ALOFT IS WIDESPREAD AIDING IN THE FAIR WEATHER ACROSS THIS REGION. OVER THE NEXT FEW DAYS...THE STRONG RIDGING WILL RETREAT NE ALLOWING THE TRADES TO RELAX SLIGHTLY TODAY ESPECIALLY IN THE E ATLC. HOWEVER THEY ARE SET TO PICK UP AGAIN FROM W TO E SUN AND INTO NEXT WEEK AS STRONG HIGH PRES REBUILDS E ACROSS THE ATLC OCEAN. THE UPPER RIDGE IS FORECAST TO SHIFT W AS A SHARP TROUGH DEVELOPS IN THE E ATLC N OF THE REGION...THIS SHOULD ALLOW FAIR WEATHER TO CONTINUE FOR THE BULK OF THE AREA. $$ CANGIALOSI