000 AXPZ20 KNHC 190929 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC SAT MAY 19 2007 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0845 UTC. ...ITCZ... INTERTROPICAL CONVERGENCE ZONE ALONG 7N78W 9N87W 8N96W 10N117W 8N133W 8N140W. SCATTERED MODERATE AND STRONG CONVECTION WITHIN 60 NM EITHER SIDE OF A LINE FROM 7N85W TO 8N95W TO 9N102W TO 7N108W AND FROM 9N100W TO 8N108W TO 10N119W. ISOLATED MODERATE NEAR 6N117W 7N120W 7N121W 8N134W 8N137W AND 8.5N140W. MODERATE CONVECTION WITHIN 60 NM OF THE COAST FROM 3N78W TO 8N80W TO 7N82W. SCATTERED STRONG CONVECTION FROM 11N87W TO 13N89W. ISOLATED STRONG NEAR 14N93W. ...DISCUSSION... A SHORTWAVE TROUGH IN THE MID LEVELS CONTINUES NEAR 30N120W AND MAKING LITTLE HEADWAY. A FLAT MID LEVEL RIDGE COVERS THE AREA S OF 20N AND BULGES NWD ALONG 108W OVER NW MEXICO AND THE SW CONUS. THE SHORTWAVE IS IN THE SRN BRANCH BUT DURING THE PAST 24 TO 36 HRS HAS TAPPED INTO THE NRN BRANCH OF THE WESTERLIES. THIS IS HELPING IT MOVE SOME BUT THE MAIN THRUST OF THE NRN BRANCH HAS SHIFTED FROM NWLY TO WLY WITH LESS PUSH THAN LAST NIGHT. A MID LEVEL RIDGE IS BEGINNING TO BUILD ALONG 138W BUT HAS LITTLE SUPPORT UPSTREAM TO HELP IT OUT. ON THE SURFACE TONIGHT A GALE WARNING ISSUED EARLIER FOR THE GULF OF TEHUANTEPEC IS NOT SUPPORTED AT 06Z AND WILL BE DROPPED. A SHIP OBS SHOWS 25 KT..QUIKSCAT AT 0014 PASS SHOWS 20 TO 25 KT AND SSMI AT 0606Z SHOWS 20 TO 25 KT AND THE GFS MODEL 00Z RUN HAS 25 KT AT 06Z. OTHERWISE A 1026 MB HIGH CENTER ANCHORES THE PACIFIC RIDGE AND MAINTAINS NE TRADES 20 TO 25 KT S OF 22N W OF 125W. WINDS ALONG THE BAJA COAST ARE MOSTLY NWLY 15 TO 20 KT WITH SWELL TO 9 FT N OF 27N. LATER DAY 1 THE GFS MODEL SHOWS THE SHORTWAVE TROUGH OFF THE NW BAJA COAST DEVELOPING SOME AMPLITUDE APPARENTLY FROM THE NRN BRANCH. THE SHORTWAVE IS CAUGHT BETWEEN THE PERSISTENT RIDGE OVER THE SW CONUS ALONG 107W AND A SECOND MID LEVEL OPEN RIDGE ALONG 135W. ON THE SURFACE LATER DAY 1 A 1028 MB HIGH CENTER WILL MOVE LITTLE AND IS FORECAST TO BE NEAR 29N135W THUS LITTLE CHANGE TO NE TRADES AND WINDS ALONG THE BAJA COAST. GAP WINDS MOSTLY LIGHT EXCEPT FOR TEHUANTEPEC WHERE HIGH PRESSURE OVER THE SRN CONUS RIDGES SW OVER THE SW GULF OF MEXICO AND PRODUCES WINDS 20 TO 25 KT. FOR DAY 2 THE MID LEVEL SHORTWAVE TROUGH CONTINUES TO ALONG 115W AND IS MOVING SLOWLY EWD..STILL BLOCKED BY THE RIDGE OVER THE SW CONUS. THERE ARE SIGNS THIS RIDGE IS BREAKING DOWN WHICH WILL ALLOW THE TROUGH TO MOVE EWD. ALSO THE RIDGE BACK ALONG 134W IS FORECAST TO GAIN AMPLITUDE WHICH WILL HELP THE TROUGH MOVE EWD. THE RIDGE IS PROBABLY STRENGTHENING AS THE NEXT TROUGH IN THE NRN BRANCH APPROACHES. THIS HINTED AT BY THE MID LEVEL HEIGHTS BEGINNING TO FALL NEAR 150W. ON THE SURFACE DAY 2 THE PACIFIC RIDGE IS FORECAST TO STRENGTHEN SLIGHTLY TO 1029 MB WHICH WILL MAINTAIN NE TRADES ABOUT THE SAME. WINDS ALONG THE IMMEDIATE BAJA COAST ARE FORECAST TO WEAKEN SOME PROBABLY SINCE THE HIGH CENTER IS FORECAST TO DRIFT WWD TO NEAR 29N139W. GAP WINDS MOSTLY LIGHT AS HIGH PRESSURE OVER THE GULF OF MEXICO SLIDES EWD. GFS MODEL SHOWS SOME INCREASE IN SW WINDS S OF 4N E OF 95W WHICH COULD BE CLIMATOLOGICAL WITH THE MONSOONAL TROUGH STRENGTHENING FOR THE TROPICAL SEASON. $$ RRG