000 AXPZ20 KNHC 122158 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC WED AUG 12 2009 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2130 UTC. ...SPECIAL FEATURES... AT 200 PM PDT...2100 UTC...THE CENTER OF TROPICAL DEPRESSION NINE-E WAS LOCATED NEAR LATITUDE 14.1 NORTH...LONGITUDE 133.2 WEST OR ABOUT 1640 MILES WEST-SOUTHWEST OF THE SOUTHERN TIP OF BAJA CALIFORNIA. THE DEPRESSION WAS MOVING TOWARD THE WEST-SOUTHWEST NEAR 13 MPH. MAXIMUM SUSTAINED WINDS WERE NEAR 35 MPH...55 KM/HR...WITH HIGHER GUSTS. ESTIMATED MINIMUM CENTRAL PRESSURE WAS 1007 MB...29.74 INCHES. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP4/WTPZ24 KNHC FOR MORE DETAILS. THE DEPRESSION IS CURRENTLY MOVING UNDERNEATH THE SOUTHERN END OF AN UPPER LEVEL TROUGH...WHERE MID TO UPPER LEVEL CONVERGENCE IS PRODUCING A DRY STABLE ENVIRONMENT ACROSS THE WESTERN PERIPHERY OF THE DEPRESSION. DUE TO THIS... THUNDERSTORM ACTIVITY REMAINS ISOLATED AND LIMITED...CURRENTLY TO THE EASTERN SEMICIRCLE. LITTLE CHANGE IN OVERALL STRENGTH OF THIS SYSTEM IS EXPECTED IN THE NEXT 24 HOURS...AS IT MOVES WEST TO WEST-SOUTHWEST...AND GRADUALLY SLOW AS IT INTERACTS WITH A WEAK LOW LEVEL LOW CURRENTLY TO ITS WEST. AT 200 PM PDT...2100 UTC...THE CENTER OF NEW TROPICAL DEPRESSION TEN-E WAS LOCATED NEAR LATITUDE 15.8 NORTH...LONGITUDE 117.8 WEST OR ABOUT 710 MILES SOUTHWEST OF THE SOUTHERN TIP OF BAJA CALIFORNIA. THE DEPRESSION WAS MOVING TOWARD THE WEST-NORTHWEST NEAR 17 MPH. MAXIMUM SUSTAINED WINDS WERE NEAR 35 MPH...55 KM/HR...WITH HIGHER GUSTS. ESTIMATED MINIMUM CENTRAL PRESSURE WAS 1005 MB...29.68 INCHES. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP5/WTPZ25 KNHC FOR MORE DETAILS. LARGE WELL DEFINED BANDS OF SHOWERS AND THUNDERSTORMS CONTINUE TO GROW ACROSS THE WESTERN SEMICIRCLE OF THE DEPRESSION...AND HAVE BEGUN TO DEVELOP NEAR THE CENTER OF THE LOW LEVEL CIRCULATION...WHILE SMALLER ISOLATED BANDS WERE OCCURRING IN THE SOUTHEAST QUADRANT. THIS SYSTEM IS UNDERNEATH AN UPPER LEVEL ANTICYCLONE THAT IS PRODUCING DIVERGENT FLOW ALOFT AND SHOULD ALLOW FOR SUSTAINED THUNDERSTORMS...AND GRADUAL CONTINUED INTENSIFICATION OF THE DEPRESSION. THERE IS A GOOD CHANCE OF THIS SYSTEM TO BECOME A TROPICAL STORM TONIGHT OR THURSDAY. THIS DEPRESSION IS EXPECTED TO CONTINUE TO MOVE WEST-NORTHWEST DURING THE NEXT 24 HOURS AND GRADUALLY MOVE MORE WESTWARD IN A FEW DAYS. ...TROPICAL WAVES... A TROPICAL WAVE WAS ANALYZED ALONG 86W MOVING W NEAR 15 KT. ATMOSPHERIC SIGNALS ASSOCIATED WITH THIS WAVE WERE NOT CLEAR. TPW PRODUCTS SUGGESTED LOWER LATITUDE MOISTURE NEAR THIS WAVE BEING ENTRAINED IN THE MONSOONAL CIRCULATION OF S AMERICA... WHILE MOISTURE FARTHER N WAS CONTINUING TO ADVECT WESTWARD ACROSS CENTRAL AMERICA AND INTO THE EPAC BEYOND 90W. THIS SUGGESTED A STRONGLY EITHER A POSITIVE TILT TO THIS WAVE...WITH A LOW LEVEL JET IN THE FORM OF THE PAPAGAYO PLUME AIDING IN LOCATION...OR A WAVE FARTHER WEST AND PAST 90W. ...ITCZ... THE INTERTROPICAL CONVERGENCE ZONE WAS ANALYZED ALONG THE LINE... 07N78W TO 07N100W TO 14N115W TO 09N130W TO 08N140W. SCATTERED MODERATE WITHIN 210 NM S OF AXIS BETWEEN 80W AND 85W. SCATTERED MODERATE WITHIN 180 NM S OF AXIS FROM 100W TO 110W. ...DISCUSSION... A DEEP LAYERED HIGH PRES RIDGE COVERS THE AREA NORTH OF 24N AND WEST OF 130W...ANCHORED AT THE SURFACE BY A WEAK 1023 MB HIGH NEAR 35N 137W. THE AREA REMAINS VERY STABLE...WITH A BROAD FIELD OF STRATOCUMULUS CLOUDS TRAPPED IN THE MARINE LAYER BELOW STABLE AND STAGNANT MIDDLE LEVEL CONDITIONS. HIGH CLOUDS ARE BEING TRANSPORTED NORTHEASTWARD...NORTH OF 25N...AND ACROSS W PORTIONS OF THE AREA EMBEDDED IN THE SW FLOW AHEAD OF L/W UPPER LEVEL TROUGH NORTH THROUGH NORTHEAST OF THE HAWAIIAN ISLANDS. EAST OF THE RIDGE IS A SHARP MID TO UPPER LEVEL TROUGH WITH AXIS EXTENDING FROM NEAR 28N123W TO NEAR 13N130W...AND WAS IMPACTING THE CONVECTIVE DEVELOPMENT OF TROPICAL DEPRESSION NINE-E. NWLY FLOW DIVING INTO THE BACKSIDE OF THE TROUGH WAS PRODUCING SINKING AIR AND AN ELONGATED DRY SLOT W OF THE TROUGH AXIS. AT THE BASE OF THE TROUGH...CONVERGENCE WAS ALSO INHIBITING CONVECTION OCCURRING N OF THE ITCZ. FROM 125W TO 105W A LARGE RIDGE COVERS THE AREA...EXTENDING FROM AN UPPER HIGH JUST OFF SW BAJA CALIFORNIA...EXTENDING SW TO A SECOND SMALLER MESO HIGH THAT HAS DEVELOPED OVERHEAD OF TROPICAL DEPRESSION 10-E...THAN CONTINUED SW TO THE ITCZ. DIFFLUENT FLOW ALOFT BETWEEN 100W AND 115W WAS AIDING TO VENTILATE AND SUSTAIN DEEP CONVECTION ASSOCIATED WITH THE TROPICAL DEPRESSION AS WELL AS WITHIN 240-280 NM EITHER SIDE OF THE ITCZ. TO THE OF THIS RIDGE...AN UPPER TROUGH...WITH TUTT LIKE LOW SLOWLY CROSSING SRN MEXICO...HAS BROADENED AND EXPANDED TODAY BETWEEN 92W AND 108W...AND WAS COMBINING WITH THE HIGH PRESSURE RIDGE TO ITS W AND NW TO GREATLY ENHANCE CONVECTION NEAR AND EITHER SIDE OF THE ITCZ AS MENTION IN THE PARAGRAPH ABOVE. CONVECTION ACROSS THIS ZONE WILL REMAIN QUITE ACTIVE IN THE NEXT 18 TO 24 HOURS. EAST OF THIS UPPER LOW AND TROUGH WAS AN UPPER HIGH CENTERED ACROSS THE WRN CARIBBEAN EXTENDING S AND SW ACROSS COLOMBIA AND THE EXTREME EASTERN TROPICAL EPAC. DIFFLUENT FLOW ALOFT ACROSS NW COLOMBIA AND THE ADJACENT EPAC WITH AIDING IN THE MAINTENANCE OF DEEP CONVECTION...AS STRONG LLVL CONVERGENCE ASSOCIATED WITH 20-25 KT W-SW FLOW PREVAILED THERE S OF THE ITCZ/MONSOON TROUGH. WEST OF TROPICAL DEPRESSION 10-E WAS A STRING OF LOW LEVEL VORT CENTERS...OR WEAK LOW CENTERS...NEAR 14N141W...AND ANOTHER W OF THE AREA NEAR 13N149W...ALL MOVING W AT THE CLIMATOLOGICAL SPEED OF 10-15 KT. GAP WINDS... NE TO E WINDS OF 20 KT CONTINUE TO FUNNEL THROUGH THE GULF OF PAPAGAYO RAISING SEAS TO 8 FT. THESE WINDS ARE FORECAST TO CONTINUE THROUGH THE NEXT COUPLE OF DAYS. N WINDS OF 20 KT WILL CONTINUE IN THE GULF OF TEHUANTEPEC REGION THROUGH TONIGHT AND ARE THEN EXPECTED TO DIMINISH EARLY THURSDAY. A MIX OF CROSS-EQUATORIAL SE AND SW SWELLS CONTINUE TO BE THE DOMINANT WAVE ENERGY AFFECTING THESE EASTERN PACIFIC WATERS... WITH A NEW PULSE OF LONG PERIOD SRN HEMI SWELL TO REACH THE CENTRAL AMERICAN COAST LATE SAT. BROAD FIELDS OF 20 KT WINDS ACROSS THE NRN PORTIONS OF TROPICAL WAVES AND LOW TRANSITING THE BASIN CONTINUE TO RAISE SEAS A FEW FEET HIGHER...TO 8 FT AND GREATER ACROSS THESE ZONES. $$ STRIPLING