000 AXPZ20 KNHC 091613 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC WED OCT 09 2013 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 1500 UTC. ...SPECIAL FEATURES... TROPICAL DEPRESSION NARDA WAS CENTERED AT 16.9N 128.5N AT 1500 UTC MOVING W OR 270 DEG AT 2 KT. MAXIMUM SUSTAINED WINDS ARE 25 KT GUSTING TO 35 KT WITH A CENTRAL SURFACE PRESSURE OF 1008 MB. NARDA CONTINUES TO WEAKENING AS IT DRIFTS W TOWARD COOLER WATERS AND DRIER MORE STABLE AIR...AND WILL LIKELY BE A REMNANT LOW LACKING SIGNIFICANT CONVECTION LATER TODAY AS IT BEGINS TO MOVE MORE W-SW. CURRENTLY ONLY A SMALL CLUSTER OF SCATTERED MODERATE CONVECTION IS NOTED WITHIN 120 NM OF OVER THE SE QUADRANT. REFER TO NARDA FORECAST ADVISORY UNDER WMO/AWIPS HEADERS WTPZ24 KNHC/ MIATCMEP4 FOR ADDITIONAL DETAILS. A BROAD AREA OF DISORGANIZED CONVECTION OCCURRING OFF THE MEXICAN COAST GENERALLY SOUTH OF ACAPULCO THE PAST 24 HOURS HAS BECOME MUCH BETTER ORGANIZED IN THE PAST SEVERAL HOURS...WITH A LARGE CLUSTER OF DEEP CONVECTION CENTERED ON A SURFACE LOW WITHIN THE MONSOON TROUGH NEAR 13.5N99.5W. SCATTERED MODERATE TO STRONG CONVECTION WAS OCCURRING WITHIN 120 NM N AND 60 NM S SEMICIRCLES OF THE CENTER. THIS FEATURE REMAINS EMBEDDED IN A VERY MOIST AND UNSTABLE ENVIRONMENT AND UNDERNEATH THE UPPER RIDGE. ENVIRONMENT AND OCEANIC CONDITIONS APPEAR VERY FAVORABLE FOR A TROPICAL CYCLONE TO FORM FROM THIS SYSTEM IN THE NEXT FEW DAYS...AND IS INDICATED BY GLOBAL MODELS. THIS SYSTEM HAS A MEDIUM CHANCE OF BECOMING A TROPICAL CYCLONE IN THE NEXT 48 HOURS AS IT MOVE NW. GLOBAL MODELS SUGGEST AN EVENTUAL TRAJECTORY TOWARDS THE S TIP OF BAJA CALIFORNIA IN A FEW DAYS. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH EXTENDS FROM COLOMBIA NEAR 09.5N72W TO 09N83.5W TO 13N94W...WHERE IT HAS FRACTURED...THEN RESUMES FROM 11.5N101W TO 10.5N103W TO 11.5N112W TO 07.5N117W TO 08.5N122W...WHERE IT FRACTURES AGAIN...THEN RESUMES FROM 13N130W TO BEYOND 10.5N140W. SCATTERED STRONG CONVECTION NOTED WITHIN 60 NM N AND 270 NM S OF TROUGH E OF 85W. SCATTERED MODERATE ISOLATED STRONG CONVECTION NOTED WITHIN 90 NM N AND 210 NM S OF TROUGH BETWEEN 87W AND 94W. SCATTERED MODERATE ISOLATED STRONG CONVECTION NOTED WITHIN 60 NM N AND 90 NM S OF TROUGH BETWEEN 101W AND 119W. SCATTERED MODERATE TO STRONG CONVECTION WAS ALSO NOTED FROM 10N TO 16N BETWEEN 113W AND 121W. ...DISCUSSION... STRONG NLY FLOW ALOFT OCCURRING IN THE BACKSIDE OF A DEEP LAYERED CYCLONE ACROSS THE PACIFIC NW OF THE U.S. IS FORCING THE ASSOCIATED TROUGH THAT EXTENDS INTO THE DISCUSSION AREA TO SINK S...AND NOW EXTENDS FROM NEAR THE MEXICAN BORDER NEAR TIJUANA SW TO 26N124.5W THEN SNAKES W-NW AS A NARROW TROUGH TO BEYOND 29N150W. BROAD CYCLONIC FLOW THUS COVERS THE ARE TO THE S OF THIS TROUGH AXIS TO ALMOST 20N. A GENERAL RIDGE-TROUGH-RIDGE PATTERN PREVAIL ACROSS THE AREA S OF THIS...WITH RIDGES ANCHORED ON UPPER ANTICYCLONES NEAR 08N145W AND 17N98W. COMPLEX MIDDLE TO UPPER TROUGHING RESIDES BETWEEN THE TWO HIGHS BETWEEN 127W AND 140W. THE EASTERN MOST RIDGE IS WELL ESTABLISHED AND EXTENDS WWD TO 127W AND CONTINUES TO PROVIDE A FAVORABLE ENVIRONMENT ALOFT FOR ACTIVE CONVECTION IN THE VICINITY OF THE MONSOON TROUGH. GULF OF TEHUANTEPEC...WINDS AND SEAS HAVE SUBSIDED SLIGHTLY IN THE PAST 12 HOURS...WITH A RECENT WINDSAT PASS SUGGESTING NE WINDS AROUND 20 KT...AND SEAS 6-8 FT...CURRENTLY EXTEND AS FAR SW AS 13.5N98W...WHICH CONTINUE TO ACT AS INFLOW TO THE DEVELOPING LOW CENTER NEAR 13.5N99.5W. THE GRADIENT WILL CONTINUE TO RELAX TODAY AND THE LOW WILL SHIFT NW...WITH WINDS DIMINISHING BELOW 20 KT BY LATE AFTERNOON. GULF OF CALIFORNIA...SW 10-15 KT WINDS ARE EXPECTED TO INCREASE TO 20-25 KT ACROSS THE GULF WATERS N OF 29N THIS AFTERNOON AND CONTINUE THROUGH SUNRISE THU...WITH SEAS BUILDING BRIEFLY 6 TO 8 FT. A WEAK FRONTAL TROUGH WILL MOVE INTO THE NORTHERN GULF OF CALIFORNIA WATERS ON THU AFTERNOON WITH THE ASSOCIATED LIGHT NW WINDS SPREADING S ACROSS THE ENTIRE GULF OF CALIFORNIA BY THU EVENING. THESE NW WINDS WILL INCREASE TO BRIEFLY 10-15 KT OVER THE UPCOMING WEEKEND. ELSEWHERE AT THE SURFACE...A RIDGE EXTENDS FROM A 1035 MB HIGH NEAR 39N145W TO 21N111W. N-NE WINDS AT 15-20 KT...WITH SEAS TO 9 FT IN MIXED LONG PERIOD N AND S SWELL...ARE CURRENTLY OBSERVED ON SCATTEROMETER DATA ACROSS THE AREA N OF A LINE FROM 30N120W TO 27.5N124W TO 30N122W. ALTHOUGH THE GRADIENT WILL RELAX AND SUPPORT MOSTLY 10-15 KT WINDS TONIGHT...THE LONG PERIOD N SWELL WILL PROPAGATE S TO ALONG 25N BETWEEN 115-135W WITH COMBINED SEAS OF 8-11 FT ON THU...THEN BEGIN TO SUBSIDE AND BELOW 8 FT BY LATE FRI. STRIPLING