000 AXNT20 KNHC 081755 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT FRI JUN 08 2012 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...TROPICAL WAVES... A WEAK AND LOW-AMPLITUDE TROPICAL WAVE IS ALONG 38W FROM 06N TO 13N. A SURGE OF DEEP LAYER MOISTURE IS PRESENT IN ASSOCIATION WITH THIS WAVE IN THE TOTAL PRECIPITABLE WATER IMAGERY. HOWEVER...THE MOST RECENT WINDSAT PASS SHOWS MAINLY MODERATE TO FRESH TRADE WINDS ON EITHER SIDE OF THE WAVE AXIS. NO DEEP CONVECTION IS CURRENTLY ASSOCIATED WITH THIS FEATURE. THE WAVE IS FORECAST TO REACH THE TROPICAL N ATLC WATERS BY SUN MORNING AND MOVE INTO THE FAR EASTERN CARIBBEAN BY MON MORNING. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF SIERRA LEONE AT 8.5N13W. SEVERAL SCATTEROMETER PASSES AND VISIBLE SATELLITE PICTURE INDICATE THAT THE ITCZ EXTENDS FROM 8.5N13W TO 7N36W THEN RESUMES AT 7N41W TO THE COAST OF GUYANA. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS WITHIN 60-80 NM EITHER SIDE OF ITCZ AXIS E OF 30W. SIMILAR CONVECTION IS NOTED WITHIN 90-120 NM N OF THE AXIS W OF 30W TO THE COAST OF GUYANA. ...DISCUSSION... THE GULF OF MEXICO... A STATIONARY FRONT REMAINS OVER THE NORTH GULF WATERS PRODUCING SCATTERED TO NUMEROUS SHOWERS AND TSTMS...PARTICULARLY N OF 23N BETWEEN 87W AND 94W AND OVER THE NE GULF. A WEAK LOW PRES HAS DEVELOPED ALONG THE FRONTAL BOUNDARY NEAR 29N94W. A COLD FRONT EXTENDS FROM THIS LOW PRES ACROSS SOUTHERN TEXAS AND THE NORTHERN PORTION OF THE STATE OF COAHUILA IN MEXICO. THE FRONT WILL LINGER ACROSS THE AREA THROUGH SAT BEFORE LIFTING N AND DISSIPATING AS THE SUBTROPICAL RIDGE BEGINS TO BUILD ACROSS THE GULF REGION. AN UPPER LEVEL TROUGH OVER TEXAS SUPPORTS THIS FRONT. A DIFFLUENT PATTERN ALOFT BETWEEN THIS TROUGH AND A RIDGE EXTENDING FROM SE MEXICO TO THE BAHAMAS IS HELPING TO INDUCE THE AFOREMENTIONED CONVECTIVE ACTIVITY AS WELL AS A CLUSTER OF SHOWERS AND TSTMS THAT IS OVER THE BAY OF CAMPECHE MAINLY E OF 94W. SURFACE AND SCATTEROMETER DATA SHOW LIGHT AND VARIABLE WINDS OVER A LARGE AREA OF THE GULF. HOWEVER...WINDS AND SEAS WILL BE HIGHER NEAR THE TSTMS. A SURFACE TROUGH IS AHEAD OF THE FRONT AND EXTENDS FROM 28N94W TO NE MEXICO. THIS TROUGH WILL DISSIPATE BY SAT. THE CARIBBEAN SEA... HIGH PRES CENTERED NEAR 32N33W EXTENDS A RIDGE W-SW ACROSS THE ATLANTIC OCEAN INTO THE NE CARIBBEAN. PRES GRADIENT BETWEEN THIS RIDGE AND THE COLOMBIAN/PANAMANIAN LOW PRES...ANALYZED 1007 MB NEAR 10N75W ON THE 1200 UTC SURFACE MAP...IS RESULTING IN FRESH TO STRONG EASTERLY TRADES ACROSS THE SOUTH-CENTRAL CARIBBEAN AND MODERATE TO FRESH TRADES ELSEWHERE. SURFACE DATA ALONG WITH THE MOST RECENT ASCAT PASS INDICATE THE PRESENCE OF 20-30 KT ELY WINDS ACROSS THE S-CENTRAL CARIBBEAN. THE PRES GRADIENT WILL RELAX SOME BY SAT AS A FRONTAL SYSTEM MOVES S ACROSS THE SW N ATLC. ALOFT...AN UPPER LEVEL RIDGE EXTENDS FROM SE MEXICO ACROSS THE NW CARIBBEAN AND CUBA INTO THE BAHAMAS. E OF THIS RIDGE... THERE IS AN INVERTED TROUGH STRETCHING FROM HISPANIOLA TO EASTERN PANAMA. THE REMAINDER OF THE CARIBBEAN SEA IS UNDER THE INFLUENCE OF AN UPPER LEVEL RIDGE. THIS RIDGE IS SUPPORTING SOME SHOWER AND TSTM ACTIVITY OVER PARTS OF NORTHERN VENEZUELA AND COLOMBIA. SHALLOW MOISTURE EMBEDDED IN THE TRADE WIND FLOW WILL CONTINUE TO MOVE ACROSS THE REGION PRODUCING ISOLATED TO SCATTERED PASSING SHOWERS. OF NOTE...AT 1030 AM AST...THE TEMPERATURE AT LMM INTERNATIONAL AIRPORT IN SAN JUAN PUERTO RICO REACHED 90S WITH EAST-SOUTHEAST LOW LEVEL FLOW OVER THE AREA. THIS IS THE 10TH CONSECUTIVE DAY WITH TEMPERATURES REACHING 90S OR MORE AT THE AIRPORT. THE ATLANTIC OCEAN... MOST OF THE AREA IS DOMINATED BY A HIGH PRES CENTERED NEAR 32N33W. THIS SYSTEM EXTENDS A RIDGE MAINLY WWD REACHING THE SE BAHAMAS. ON THE SOUTHERN PERIPHERY OF THE RIDGE...MAINLY FRESH TRADE WINDS CAN BE FOUND. A STATIONARY FRONT ENTERS THE FORECAST REGION NEAR 31N73W THEN CONTINUES WWD ACROSS N FLORIDA INTO THE GULF OF MEXICO. DOPPLER RADAR SHOWS A BAND OF SHOWERS AND TSTMS AHEAD OF THE FRONT OVER S-CENTRAL FLORIDA NEAR LAKE OKEECHOBEE. THIS BAND MOSTLY ZONAL WLY FLOW ALOFT OVER THE EASTERN GULF OF MEXICO IS TRANSPORTING ABUNDANT TROPICAL MOISTURE ACROSS THE STATE OF FLORIDA INTO THE SW N ATLC. A FRONTAL WAVE OR WEAK LOW IS FORECAST BY THE COMPUTER MODELS TO FORM ALONG THE STATIONARY FRONT IN ABOUT 24 HOURS. AS THE LOW PRES DEVELOPS AND MOVES E-NE THE ATLANTIC PORTION OF THE FRONT WILL MOVE SOUTH AS A COLD FRONT REACHING FROM 31N58W TO THE CENTRAL BAHAMAS BY SAT EVENING. AN UPPER-LEVEL LOW IS SPINNING NEAR 24N43W...BUT IT IS NOT CAUSING ANY SIGNIFICANT WEATHER. ONLY FEW SHOWERS ARE ASSOCIATED WITH THIS LOW. MODERATE TO STRONG MID TO UPPER LEVEL SUBSIDENCE AND IMPLIED DRY AIR-MASS IS NOTED N OF THE ITCZ AXIS TO 20N BETWEEN THE COAST OF AFRICA AND THE LESSER ANTILLES. IN ADDITION...THE SAHARAN AIR LAYER FROM CIMMS SHOWS AFRICAN DUST SPREADING WWD ACROSS THE AREA IN THE HEELS OF THE TROPICAL WAVE LOCATED NEAR 38W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GR