000 AXPZ20 KNHC 090332 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC THU OCT 09 2008 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 0315 UTC. ...SPECIAL FEATURES... AT 09/0300 UTC HURRICANE NORBERT IS CENTERED NEAR 17.1N 111.8W OR ABOUT 420 NM SOUTH-SOUTHWEST OF THE SOUTHERN TIP OF BAJA CALIFORNIA...MOVING NORTHWEST OR 305 DEGREES AT 8 KT. ESTIMATED SURFACE PRESSURE IS 948 MB. MAXIMUM SUSTAINED WINDS ARE 115 KT WITH GUSTS TO 140 KT...A CATEGORY FOUR ON THE SAFFIR-SIMPSON SCALE. A GRADUAL TURN TOWARD THE NORTH IS EXPECTED ON THURSDAY FOLLOWED BY A TURN TOWARD THE NORTH-NORTHEAST ON FRIDAY TOWARD THE SOUTHERN COAST OF BAJA CALIFORNIA. SOME WEAKENING IS EXPECTED STARTING BY FRIDAY AS THE HURRICANE ENCOUNTERS INCREASING SHEAR AND SLIGHTLY COOLER WATERS. REFER TO LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP5/WTPZ25 KNHC AND INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPEP5/ WTPZ35 KNHC FOR MORE DETAILS. AT 09/0300 UTC TROPICAL DEPRESSION SIXTEEN-E IS CENTERED NEAR 12.2N 91.8W OR ABOUT 205 MILES WEST-SOUTHWEST OF SAN SALVADOR EL SALVADOR AND ABOUT 395 MILES SOUTHEAST OF PUERTO ANGEL MEXICO. T.D SIXTEEN-E IS MOVING WEST-NORTHWEST OR 285 DEGREES AT 10 KT. ESTIMATED SURFACE PRESSURE IS 1006 MB. MAXIMUM SUSTAINED WINDS ARE 30 KT WITH GUSTS TO 40 KT. CONVECTION LOOKS BETTER ORGANIZED ON SATELLITE IMAGERY...WITH DISTINCT CONVECTIVE BANDS WRAPPING AROUND THE SOUTHERN EDGE OF THE STORM. WARM SEA SURFACE TEMPERATURES AND FAVORABLE WINDS ALOFT WILL ALLOW T.D. SIXTEEN-E TO INTENSIFY TO A STRONG TROPICAL STORM THROUGH FRI...AS IT SHIFTS WESTWARD ALONG THE SOUTHERN MEXICAN COAST. REFER TO LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP1/WTPZ21 KNHC AND INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPEP1/ WTPZ31 KNHC FOR MORE DETAILS. ...ITCZ... ITCZ AXIS ALONG 12N97W TO 11N105W TO 09N113W TO 12N125W TO 11N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 75 NM EITHER SIDE OF AXIS BETWEEN 93W AND 96W. ...DISCUSSION... E OF 115W...SCATTEROMETER DATA AND SHIP OBSERVATIONS SHOW PERSISTENT S TO SW CROSS-EQUATORIAL FLOW INTO THE ITCZ...CONVERGING INTO T.D. 16-E. HOWEVER...THESE WINDS ARE LIGHTER THAN THEY WERE PREVIOUSLY AND THIS HAS RESULTED IN ONLY MODEST CONVECTION ALONG THE ITCZ AT THIS TIME. A SHIP OBSERVATION NEAR THE GUATEMALAN COAST TO THE NORTH T.D. 16-E INDICATED SEAS WERE NOT QUITE REACHING 12 FT AROUND THE STORM. FURTHER NORTH...A JASON ALTIMETER PASS FROM 22Z PASSED DIRECTLY OVER HURRICANE NORBERT. THIS AND SHIP OBSERVATION TO THE NE OF THE HURRICANE SHOWED 12 FT SEAS EXPANDING TO AS FAR AS 300 NM FROM THE CENTER. MAIN INFLUENCE ALOFT REMAINS AN UPPER ANTICYCLONE EXTENDING FROM CENTRAL MEXICO TO THE YUCATAN PENINSULA. NORBERT IS POSITIONED ON THE FAR WESTERN EDGE OF THIS UPPER RIDGE...EXPERIENCING DIVERGENT FLOW ALOFT AND LOW SHEAR FOR THE MOMENT. AN UPPER LOW OVER NORTHERN HONDURAS HAD BEEN THE MAIN DRIVER FOR THE SURFACE LOW THAT IS NOW T.D. 16-E...BUT THIS HAS SHIFTED NORTHWARD AND THE DEPRESSION REMAINS UNDER LIGHT TO MODERATE NE SHEAR ALOFT SOUTH OF THE UPPER ANTICYCLONE. MEANWHILE STRONG HIGH PRES OVER THE CENTRAL PACIFIC IS RESULTING IN A SURGE OF NORTHERLY WINDS DOWN THE CALIFORNIA COAST. THESE WINDS WILL PUSH DOWN THE NORTHERN BAJA COAST BY FRI NIGHT JUST AS NORBERT MOVES NORTHEAST TOWARD SOUTHERN BAJA. THIS WILL RESULT IN CONFUSED SEAS OFF THE CENTRAL BAJA COAST BETWEEN SOUTHERLY SWELL FROM NORBERT AND THE NORTHERLY WINDS AND SWELL. W OF 115W...THE REMNANT LOW OF MARIE CONTINUES TO SPIN NEAR 16N127W...DRIFTING WSW. WHILE NO CONVECTION IS NOTED WITH THIS SYSTEM...THERE IS ENOUGH OF A GRADIENT BETWEEN THE LOW AND HIGH PRES TO THE NORTH TO SUPPORT 20 TO 25 KT ON THE NW SIDE OF THE LOW...WITH SEAS TO 8 TO 10 FT. THE TIGHT GRADIENT ON THE SE PERIPHERY OF THE HIGH PRES WILL ALLOW A SURGE OF FRESH TO STRONG NORTHERLY WINDS TO PUSH INTO THE AREA N OF 20N THROUGH FRI...WITH LONG PERIOD SWELL UP TO 17 FT. THE REMNANT OF MARIE SHIFTS SOUTH AND DISSIPATES AHEAD OF THIS SURGE. ELSEWHERE...DEEP LAYER MOISTURE REMAINS TO LIMITED TO SUPPORT ANY ORGANIZED CONVECTION AT THIS TIME. $$ CHRISTENSEN