000 AXPZ20 KNHC 241607 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC WED SEP 24 2014 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1515 UTC. ...SPECIAL FEATURES... THE LOW PRESSURE CENTER BEING MONITORED OFFSHORE OF MEXICO THE PAST FEW DAYS HAS MAINTAINED SUFFICIENT CONVECTION NEAR THE CENTER TO BE CLASSIFIED A TROPICAL CYCLONE THIS MORNING... TROPICAL DEPRESSION EIGHTEEN-E. THE CENTER OF T.D. EIGHTEEN-E WAS LOCATED NEAR LATITUDE 15.0 NORTH...LONGITUDE 105.5 WEST...OR ABOUT 285 MILES...460 KM...SSW OF MANZANILLO MEXICO. THE DEPRESSION IS MOVING TOWARD THE WEST-NORTHWEST NEAR 14 MPH...22 KM/H. THIS GENERAL MOTION WITH SOME REDUCTION IN FORWARD SPEED IS FORECAST DURING THE NEXT COUPLE OF DAYS. SCATTERED MODERATE TO STRONG CONVECTION WAS OCCURRING WITHIN 240 NM ACROSS SW THE QUADRANT OF THE DEPRESSION...WHILE THE FIRST VISIBLE SATELLITE IMAGES THIS MORNING SHOW THE LOW LEVEL CENTER PARTIALLY EXPOSED ALONG THE N EDGE OF THIS CONVECTION. NORTHERLY UPPER LEVEL WINDS ARE CURRENTLY PRODUCING A SHEARED ENVIRONMENT AND IS EXPECTED TO CONTINUE FOR THE NEXT 24 HOURS OR SO. AFTER THAT TIME THE WIND SHEAR IS EXPECTED TO DIMINISH AND THE CYCLONE WILL HAVE AN OPPORTUNITY TO INTENSIFY...WHEN GRADUAL STRENGTHENING IS EXPECTED. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP3/WTPZ23 FOR MORE DETAILS. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH EXTENDS FROM 10N78W TO LOW PRES NEAR 10N87W 1010 MB TO 16N100W TO T.D. EIGHTEEN-E NEAR 15.0N 105.5W 1006 MB TO 07N120W...WHERE IT TRANSITIONS TO ITCZ...CONTINUING ON TO 05N130W TO BEYOND 06.5N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION NOTED FROM 03N TO 07N E OF 81W. SCATTERED MODERATE TO STRONG CONVECTION NOTED WITHIN 240 NM S OF TROUGH FROM 86W TO 91W...AND WITHIN 360 NM S OF TROUGH FROM 91W TO 97W. SCATTERED MODERATE ISOLATED STRONG CONVECTION NOTED WITHIN 90 NM N OF ITCZ BETWEEN 130W AND 135W. ...DISCUSSION... WEAK 1017 MB HIGH PRESSURE WAS CENTERED ACROSS N PORTIONS NEAR 27N130W AND WAS BEING NUDGED SE BY AN APPROACHING COLD FRONT MOVING INTO NW PORTIONS. THE FRONT EXTENDED FROM 30N134W TO 26.5N140W WITH MODERATE N TO NE WINDS BEHIND IT. LARGE NW SWELL GENERATED FROM THE LARGE AND POWERFUL STORM SYSTEM ACROSS THE NE PACIFIC HAS JUST BEGUN TO RAISE SEAS TO 8 FT BEHIND THIS COLD FRONT...AND WILL PROPAGATE SE THROUGHOUT THE NEXT FEW DAYS. THE FRONT IS EXPECTED TO WASH OUT ACROSS NE PORTIONS THU NIGHT TO FRI MORNING...BUT LEAVE A SHEAR LINE FROM 25N128.5W TO 22N140W. BUILDING HIGH PRESSURE IN THE WAKE OF THE FRONT WILL INCREASE THE NORTHERLY FLOW TO 15-20 KT ALONG THE PACIFIC COAST OF THE BAJA PENINSULA TO THE N OF 30N LATE THU...WITH THESE CONDITIONS SPREADING AS FAR S AS 27N ON FRI AFTERNOON...WITH THE GRADIENT BEGINNING TO RELAX FRI NIGHT. SEAS WILL BUILD TO 7-10 FT IN MIXING LONG PERIOD NW SWELL ACROSS THE DISCUSSION WATERS NW OF A LINE FROM 29N115W TO 16N140W THU NIGHT...THEN GRADUALLY SUBSIDE OVER THE WEEKEND. THE REMNANTS OF FORMER TROPICAL CYCLONE POLO ARE ANALYZED AS A 1010 MB LOW PRESSURE NEAR 20N116W. WINDS REMAIN 15-20 KT WITHIN ABOUT 180 NM W OF THE CENTER...WITH SEAS OF 5-7 FT. THE LOW IS FORECAST TO MOVE SW AND WEAKEN TO A OPEN TROUGH FROM 16N116W TO 20N118W ON THU. A LARGE CONVECTIVE CLUSTER DEVELOPED OVERNIGHT ALONG THE W COAST OF MEXICO AND THE ADJACENT COASTAL WATERS OUT TO ABOUT 200 NM FROM JALISCO NORTHWARD TO SOUTHERN SINALOA...AND WAS PRODUCING VERY HEAVY RAINFALL. THIS WEATHER HAS CONTINUED TO SHIFT NORTHWARD THIS MORNING INTO N PORTIONS OF SINALOA AND MUCH OF THE S END OF THE GULF OF CALIFORNIA. FREQUENT LIGHTNING...STRONG GUSTY WINDS...AND TORRENTIAL RAINFALL WILL ACCOMPANY THIS WEATHER. $$ STRIPLING