000 AXPZ20 KNHC 120319 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC WED AUG 12 2009 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0330 UTC. ...SPECIAL FEATURES... TROPICAL DEPRESSION NINE-E WAS LOCATED NEAR LATITUDE 14.9N 130.2W OR ABOUT 1345 MILES...2165 KM...WEST-SOUTHWEST OF THE SOUTHERN TIP OF BAJA CALIFORNIA. THE DEPRESSION WAS MOVING TOWARD THE WEST...265 DEGREES...11 KNOTS. THIS GENERAL MOTION SHOULD CONTINUE FOR THE NEXT COUPLE OF DAYS. MAXIMUM SUSTAINED WINDS WERE NEAR 25 KT WITH GUSTS TO 35 KT. ESTIMATED MINIMUM CENTRAL PRESSURE WAS 1007 MB. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP4/WTPZ24 KNHC FOR MORE DETAILS. CONVECTION CONTINUES TO BE LIMITED WITH THE DEPRESSION AS IT IS PASSING THROUGH THE BASE OF A SHARP UPPER LEVEL TROUGH...AND ENCOUNTERING UPPER LEVEL CONVERGENCE. SCATTERED MODERATE CONVECTION WAS NOTED OCCURRING 25-120 NM FROM THE CENTER IN THE NW QUADRANT. SLOW STRENGTHENING IS POSSIBLE ON WEDNESDAY AND THURSDAY...AND THE DEPRESSION COULD BECOME A TROPICAL STORM DURING THAT TIME AS IT MOVES AWAY FROM THE UPPER TROUGH AND BEGINS TO MOVE UNDERNEATH AN UPPER LEVEL RIDGE. A 1008 MB LOW PRES CENTER NEAR 14N113W IS EMBEDDED WITH A TROPICAL WAVE...MOVING W AT 15 KT. THE LOW POSTION WAS RELOCATED TO THE NW BASED ON THE LATEST SATELLITE IMAGERY. CONVECTION IS BECOMING A LITTLE BETTER ORGANIZED AS THE WAVE/LOW COMPLEX MOVES INTO A MORE FAVORABLE ENVIRONMENT TO THE WEST. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS NOTED WITHIN 240 NM S SEMICIRCLE AND WITHIN 180 NM IN THE NW QUADRANT ALONG THE WAVE. CONVECTION UPPER-LEVEL CONDITIONS ARE EXPECTED TO BECOME MORE FAVORABLE FOR DEVELOPMENT OF THIS SYSTEM DURING THE NEXT COUPLE OF DAYS. THERE IS A MEDIUM CHANCE...30 TO 50 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. ...TROPICAL WAVES... A TROPICAL WAVE IS MOVING THROUGH THE BAY OF PANAMA NEAR 79W MOVING W AT 15 KT. NO SIGNIFCIANT CONVECTION IS NOTED WITH THIS WAVE...EXCEPT A SMALL CLUSTER OVER NW COLOMBIA. A TROPICAL WAVE ORIENTED NW TO SE FROM 20N115W TO 09N108W MOVING W AT 15 KT. THE 1008 MB LOW MENTIONED ABOVE IS EMBEDDED WITH THIS WAVE NEAR 14N113W. CONVECTION IS BECOMING A LITTLE MORE ORGANIZED A THE WAVE MOVES INTO THE SE SIDE OF AN UPPER TROUGH TO THE WEST OF THE AREA. ...ITCZ... THE INTERTROPICAL CONVERGENCE ZONE WAS ANALYZED ALONG 07N78W TO 12N110W TO 09N125W TO 13N140W. SCATTERED MODERATE CONVECTION IS NOTED WITHIN 120 NM S OF AXIS AND WITHIN 90 NM N OF AXIS BETWEEN 120W AND 130W. ...DISCUSSION... E OF 110W...A AN UPPER TROUGH IS ORIENTED NORTH TO SOUTH ALONG 95W THROUGH A CLOSED UPPER LOW IS CENTERED NEAR 13N95W N OF 10N. DIVERGENCE ALOFT TO THE EAST OF THE UPPER TROUGH IS ENHANCING CLUSTERS OF CONVECTION OVER NORTHERN CENTRAL AMERICA AND SOUTHERN MEXICO...AS WELL AS POSSIBLE AIDING THE DEVELOPMENT OF A WEAK SURFACE TROUGH OVER GUATEMALA AND YUCATAN. NORTHERLY FLOW TO THE WEST OF THIS SURFACE IS FUNNELING THROUGH THE ISTHMUS OF TEHUANTEPEC...WITH WINDS TO 25 KT NOTED ON AN 16Z ASCAT PASS. THE UPPER TROUGH WEAKENS AND SHIFTS WEST THROUGH WED...ALLOWING THE TEHUANTPEC WINDS TO DIMINISH. FRESH TO STRONG TRADES ARE FILTERING FROM THE SW CARIBBEAN INTO THE GULF OF PAPAGAYO. LITTLE CHANGE IS EXPECTED THROUGH THE REMAINDER OF THE WEEK. FURTHER SOUTH...SOUTHERLY CROSS-EQUATORIAL FLOW IS FAIRLY IS WEAK...BUT THIS IS EXPECTED TO PICK UP SLIGHTLY WED INTO THU...WITH THE COORESPONDING LOW LEVEL CONVERGENCE AIDING CONVECTION ALONG THE ITCZ E OF 110W. W OF 110W...AN UPPER TROUGH EXTENDS FROM 30N125W TO 16N126W. UPPER DIVERGENCE BETWEEN THE TROUGH AND AN UPPER ANTICYCLONE CENTERED OVER THE SOUTHERN TIP OF THE BAJA PENINSULA IS AIDING CONVECTION ALONG THE 1008 MB LOW AND TROPICAL WAVE COMPLEX ALONG 113W. CONVECTION IS LIKELY TO PERSIST NEAR THIS COMPLEX THROUGH WED AS IT DRIFTS WESTWARD INTO THE FAVORABLE SE SIDE OF THE TROUGH. THE UPPER TROUGH WILL DAMPEN OUT BY THU...LEAVING THE FORECAST HINGED ON THE POTENTIAL DEVELOPMENT OF THE 1008 MB LOW CENTER AS IT MIGRATES WEST. SURFACE RIDGING N OF THE AREA WILL ALLOW FOR A TIGHT GRADIENT WITH THE SURFACE LOW...KEEPING FRESH EAST WINDS IN THE FORECAST MAINLY BETWEEN 15N AND 22N THROUGH THE REMAINDER OF THE WEEK. FURTHER WEST...DRY DEEP LAYER SUBSIDENCE W OF 125W IS SUPPRESSING COVECTION NEAR T.D. NINE-E. SPORADIC CONVECTION ALONG THE ITCZ WILL REMAIN ACTIVE NONETHELESS DUE TO 20 KT SOUTHERLY FLOW ACROSS THE EQUATOR. EXTENDING FROM WEST TO EAST...A RIDGE-TROUGH-RIDGE-TROUGH UPPER PATTERN COVERS THE TROPICAL EASTERN PACIFIC THIS AFTERNOON... STARTING FROM AN ANTICYCLONE JUST SE OF THE BIG ISLAND OF HAWAII. THE TWO NARROW UPPER TROUGHS WERE NORTH TO SOUTH ALIGNED...ONE QUASISTATIONARY ALONG 124/125W...AND THE OTHER A TUTT LIKE LOW WITH BROAD TROUGH EXTENDING NE INTO THE ERN GULF OF MEXICO...SHIFTING W ALONG 93/94W. EAST TO NORTHEASTERLY UPPER FLOW S OF THE RIDGES AND THE WRN MOST UPPER TROUGH WAS BLOWING ACROSS THE EQUATOR...AND WAS ACTING TO PRODUCE A LARGE AREA OF UPPER DIFFLUENCE BETWEEN 105W AND 130W...VENTING AND ENHANCING ITCZ CONVECTION ACROSS THIS REGION. AT THE SURFACE...THE EASTERN PACIFIC SEMIPERMANENT HIGH WAS CENTERED NEAR 33N141W WITH RIDGE EXTENDING SE TO BAJA CALIFORNIA. THE MODERATE TO STRONG GRADIENT ALONG THE W COAST OF THE U.S. AND TO BAJA CALIFORNIA OF RECENT WEEKS HAS WEAKENED IN THE PAST FEW DAYS...AND WINDS ALONG THE SRN CALIFORNIA AND THE BAJA HAVE DROPPED BELOW 20 KT. S OF THE RIDGE...MODERATE SIZED ZONES OF 20 KT WINDS WITH POCKETS TO 25 KT...WERE OCCURRING ACROSS THE NRN PERIPHERY OF EACH OF THE TROPICAL WAVES. GAP WINDS... NE TO E WINDS OF 20 KT CONTINUE TO FUNNEL THROUGH THE GULF OF PAPAGAYO RAISING SEAS TO 8 FT. THIS WAS OCCURRING BEHIND AN ELONGATED LOW TO MID LEVEL JET ASSOCIATED WITH THE TROPICAL WAVE BETWEEN 113W AND 108W...AND WAS ALSO CONTRIBUTING TO NLY GAP FLOW OF 20-30 KT THROUGH THE GULF OF TEHUANTEPEC. THE GAP WINDS THROUGH PAPAGAYO ARE FORECAST TO CONTINUE THROUGH THE NEXT COUPLE OF DAYS...WITH THE TEHUANTEPEC PLUME WILL LIKELY CONTINUE NEAR 20 KT OR GREATER FOR THE NEXT 24 TO 36 HOURS. CROSS-EQUATORIAL SE SWELLS CONTINUE TO AFFECT THE SOUTHERN PORTION OF THE FORECAST AREA. THESE CONDITIONS ARE EXPECTED TO GRADUALLY SUBSIDE DURING THE NEXT 24 TO 48 HOURS. $$ STRIPLING