000 AXNT20 KNHC 102339 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST SAT FEB 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 6N10W 2N18W EQ24W EQ40W INTO NORTHEASTERN BRAZIL AT 2S46W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 120 NM N OF THE AXIS BETWEEN 13W-15W. ISOLATED MODERATE IS WITHIN 180 NM EITHER SIDE BETWEEN 30W-40W. ...DISCUSSION... THE GULF OF MEXICO... THE FRONTAL BOUNDARY THAT HAS BEEN QUASI-STATIONARY OVER THE PAST 12-24 HOURS IS NOW MAKING SOME PROGRESS SWD AS AN UPPER SHORTWAVE TROUGH HAS MOVED E INTO THE W GULF GIVING THE BOUNDARY SOME SUPPORT/FORCING. AS OF 21 UTC...THE COLD FRONT WAS ANALYZED FROM THE TAMPA BAY AREA ACROSS THE GULF TO CENTRAL MEXICO ALONG 28N82W 27N92W 24N98W THEN CONTINUING NWD STATIONARY ALONG THE E SLOPES OF THE SIERRA MADRE...CLEARLY DEFINED BY THICK LOW CLOUDS BANKED UP AGAINST THE TOPOGRAPHY. DEEP MOISTURE IS ALMOST NON-EXISTENT NEAR THE FRONT ACROSS FLORIDA AND MOST OF THE GULF. THE EXCEPTION IS W OF 94W...WHERE BRO DOPPLER RADAR AND IR PICTURES INDICATE A SWATH OF NUMEROUS SHOWERS AND TSTMS FROM 23N-27N. THIS ACTIVITY HAS FIRED UP DUE TO THE CLOSE PROXIMITY OF THE UPPER SHORTWAVE AXIS WHICH LIES ABOVE 99W OR SO. THE SFC FLOW IS RATHER UNIFORM N-NELY AS HIGH PRES HAS BUILT SE OVER THE CENTRAL U.S. THIS HAS MADE THE FRONT DIFFICULT TO FIND PURELY LOOKING AT WIND DIR...BUT A TEMP/DEWPT GRAD IS QUITE CLEAR IN THE REGION WITH BUOYS/SHIPS REPORTING TEMPS IN THE UPPER 40'S AND 50'S F N OF THE FRONT AND UPPER 60'S AND 70'S F S. NWP MODELS SHOW THE FRONT CONTINUING ITS SWD PROGRESSION THRU THE NIGHT...THEN BECOMING DIFFUSE AND LIFTING BACK N IN RESPONSE TO THE NEXT COLD FRONT WHICH IS EXPECTED TO MOVE OFF THE TX COAST EARLY TUE. THE CARIBBEAN SEA... A LARGE STRONG UPPER LEVEL RIDGE REMAINS PARKED E OF THE AREA IN THE TROPICAL ATLC WITH RIDGING STRETCHING NE ACROSS THE CARIB ALONG 13N67W 22N73W. ABUNDANT DRY STABLE AIR/SUBSIDENCE CONTINUES TO SUPPRESS ANY SIGNIFICANT DEEP CONVECTION FROM FORMING. IN THE LOW LEVELS...THERE ARE A COUPLE FEATURES WORTH MENTIONING. ONE OF THESE IS A SFC TROUGH ANALYZED FAIRLY HORIZONTALLY FROM THE YUCATAN PENINSULA TO WRN CUBA. THIS TROUGH IS ESSENTIALLY A CONVERGENCE ZONE BETWEEN THE N-NELY FLOW IN THE GULF AND E-SELY TRADES IN THE NW CARIB. BROKEN LOW AND MID LEVEL CLOUDS ARE LOCATED WITHIN 90 NM EITHER SIDE OF THE TROUGH AXIS WITH A FEW STATIONS REPORTING LIGHT/MODERATE RAIN IN THE REGION. THE OTHER SFC FEATURE IS A WEAK TROUGH WHICH EXTENDS FROM A FRONTAL LOW IN THE ATLC INTO THE DOMINICAN REPUBLIC. ONLY PATCHY LOW CLOUDS AND ISOLATED SHOWERS ARE LIKELY OVER HISPANIOLA ...ALTHOUGH THERE IS ALWAYS A CHANCE FOR MORE ACTIVE WEATHER IN MOUNTAINOUS AREAS. TRADE WINDS ARE MODERATE...THESE SHOULD REMAIN THAT WAY TOMORROW AND THEN PICK UP ON MON AS A HIGH PRES RIDGE...CURRENTLY OVER THE CENTRAL U.S...BUILDS SE N OF THE AREA. THE ATLANTIC OCEAN... TWO COLD FRONTS ARE LOCATED IN THE WRN/CENTRAL ATLC THIS EVENING. ONE ENTERS THE AREA NEAR 32N69W AND EXTENDS ACROSS CENTRAL FL AND THE GULF. THIS BOUNDARY...AT LEAST THE PART IN THE ATLC...IS WEAK WITH MINIMAL SHOWER ACTIVITY AND ILL-DEFINED LOW CLOUD STRUCTURE. THE OTHER IS FURTHER E ENTERING THE AREA NEAR 32N45W EXTENDING TO A WEAK LOW NEAR 23N63W. A SFC TROUGH CONTINUES FROM THE LOW TO THE DOMINICAN REPUBLIC. THIS BOUNDARY IS A LITTLE BETTER DEFINED WITH BROKEN CLOUDS AND LIKELY ISOLATED TO SCATTERED SHOWERS WITHIN 120 NM EITHER SIDE OF THE FRONT. THE DEEP MOISTURE IS CONFINED WITHIN 240 NM E OF THE FRONT N OF 29N. ALOFT...AN EXTENSIVE RIDGE IS CONTROLLING MUCH OF THE WEATHER ANCHORED IN THE TROPICAL ATLC NEAR 9N57W. WIDESPREAD DRY SINKING AIR COVERS NEARLY ALL OF THE REGION S OF 26N W OF 30W. IN THE E ATLC...THE REMNANTS OF A ONCE VIGOROUS LARGE UPPER LEVEL LOW CONTINUES TO WEAKEN NEAR 14N28W. SWLY UPPER LEVEL FLOW TO THE E OF LOW/TROUGH AXIS IS STILL DRAWING SOME TROPICAL HIGH LEVEL MOISTURE...ALTHOUGH IT IS MUCH THINNER AND COVERS A SMALLER AREA THAN DAYS PRIOR...MAINLY FROM 10N-16N E OF 25W. THE SFC PATTERN REMAINS DOMINATED BY A 1029 MB HIGH NEAR MADEIRA ISLANDS MAINTAINING FAIR WEATHER. GFS SHOWS THIS RIDGE GRADUALLY BECOMING ERODED BY A LOW PRES/FRONTAL SYSTEM OVER THE NEXT COUPLE DAYS. $$ CANGIALOSI