000 AXPZ20 KNHC 171604 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC SAT OCT 17 2015 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 1545 UTC. ...SPECIAL FEATURES... TROPICAL STORM OLAF IS CENTERED NEAR 9.4N 129.5W AT 1500 UTC MOVING WEST OR 270 DEGREES AT 11 KT. ESTIMATED MINIMUM CENTRAL PRESSURE HAS LOWERED TO 999 MB. MAXIMUM SUSTAINED WIND SPEED HAS INCREASED TO 50 KT WITH GUSTS TO 60 KT. LATEST SATELLITE IMAGERY SHOW A PRIMARY BAND BAND OF CONFINED TO THE WESTERN SEMICIRCLE CONSISTING OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION WITHIN 30 NM OF 07N130W TO 09N133W TO 11N132W TO 12N131W. THE CENTER APPEARS TO BE UNDER A SMALL CDO (CENTRAL DENSE OVERCAST) FEATURE. SCATTERED STRONG CONVECTION IS NOTED WITHIN 90 NM OF THE CENTER IN THE SW QUADRANT. SCATTERED MODERATE CONVECTION IS 120 NM OF THE CENTER IN THE NE QUADRANT. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 30 NM OF 07N127W AND ALSO WITHIN 07N128W. OLAF IS FORECAST TO CONTINUE TO INTENSIFY AS IT MOVES IN A GENERAL WESTWARD MOTION OVER THE NEXT COUPLE OF DAYS. THE 15 UTC NHC ADVISORY HAS IT ATTAINING MINIMAL HURRICANE INTENSITY EARLY ON SUN NEAR 10N 133W. PLEASE SEE LATEST FORECAST ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP4/WTPZ24 KNHC FOR MORE DETAILS ON OLAF. GULF OF TEHUANTEPEC...WINDS OF MINIMAL GALE FORCE CONTINUE TO FUNNEL THROUGH THE CHIVELA PASS AND INTO THE GULF OF TEHUANTEPEC. WINDS WILL REMAIN AT NEAR GALE FORCE OR MINIMAL GALE FORCE OVER THE NEXT COUPLE OF DAYS. MAXIMUM SEAS OF 10-14 FT ARE EXPECTED WITH THIS EVENT. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH HAS MARKEDLY LIFTED NORTHWARD SINCE YESTERDAY AS A BROAD AREA OF LOW PRESSURE S OF SOUTHEASTERN MEXICO CONTINUES TO GATHER MOMENTUM. THE AXIS OF THE TROUGH IS ANALYZED FROM 14N90W TO 10N99W TO 09N103W TO 10N111W. SCATTERED STRONG CONVECTION IS OBSERVED WITHIN 120 NM SE AND S OF THE TROUGH BETWEEN 90W-91W...WITHIN 60 NM OF THE TROUGH BETWEEN 91W-93W. SCATTERED MODERATE TO STRONG CONVECTION EXISTS FROM 11N-15N BETWEEN 93W-95W...AND FROM 10N-15N BETWEEN 95W- 100W. SCATTERED MODERATE CONVECTION S OF THE TROUGH FROM 04N-08N BETWEEN 100W- 107W. ...DISCUSSION... A WEAK COLD FRONT IS ANALYZED FROM NEAR 32N128W TO 29N133W TO 27N140W. A 1023 MB HIGH CENTER IS NW OF THE AREA NEAR 34N146W WITH A RIDGE EXTENDING SE TO BEHIND THE FRONT. THE PRESSURE GRADIENT BETWEEN THE HIGH TO THE N AND TROPICAL STORM OLAF TO THE S IS DRIVING MAINLY MODERATE TRADE WINDS OVER MUCH OF THE WESTERN HALF OF THE FORECAST AREA. THE COLD FRONT WILL CONTINUE TO WEAKEN AS MOVES E TO SE THROUGH THIS EVENING...AND DISSIPATE BY EARLY SUN MORNING. 8-10 FT SEAS IN NW SWELL MAINLY BEHIND THE FRONT WILL CONTINUE TO PROPAGATE SOUTHEASTWARD WHILE GRADUALLY SUBSIDE TO 8 FT BY EARLY ON MON. STRONGER HIGH PRESSURE WILL BUILD SOUTHWARD OVER THE NORTHERN WATERS ONCE THE FRONT DISSIPATES. THIS WILL HELP EXPAND THE AREA OF 20-33 KT WINDS AROUND TROPICAL STORM OLAF. SW SWELL WITH PERIODS IN THE 19-21 SECOND RANGE WILL PASS GALAPAGOS ISLANDS THIS AFTERNOON...REACH THE PACIFIC COAST S OF MAZATLAN MEXICO OVERNIGHT TONIGHT...AND STRETCH N ALONG THE PACIFIC COAST OF THE BAJA CALIFORNIA PENINSULA AFTER SUNRISE SUN. THIS LONG-PERIOD SWELL COULD MAKE FOR DANGEROUS CONDITIONS ENTERING AND EXITING PORTS AND WILL INCREASE THE THREAT OF RIP CURRENTS. THE SW SWELL IS CONTRIBUTING TO THE 7-9 FT SEAS CURRENTLY FOUND OVER MUCH OF THE AREA S OF 10N BETWEEN 89W AND 129W. THE SWELL W OF 105W WILL SUBSIDE...WITH SEAS LESS THAN 8 FT EXPECTED BY SUN AFTERNOON. A DEVELOPING CENTRAL AMERICAN LOW PRESSURE GYRE...AS REFERENCED ABOVE UNDER ITCZ/MONSOON TROUGH...WILL HELP MAINTAIN WINDS OF NEAR GALE TO MINIMUM GALE FORCE FOR THE FORECAST PERIOD OVER THE GULF OF TEHUANTEPEC. THIS GYRE WILL HELP INCREASE SW MONSOON FLOW OVER THE EASTERN WATERS AND MAINTAIN SEAS IN THE 7-9 FT RANGE S OF THE GULF OF TEHUANTEPEC TO 04N. THE INCREASED MONSOON FLOW WILL ADVECT ABUNDANT TROPICAL MOISTURE INTO THE EASTERN WATERS AND PORTIONS OF CENTRAL AMERICA AND SOUTHERN MEXICO WITH ADDED ENERGY FROM A TROPICAL WAVE PRESENTLY MOVING THROUGH SOUTHEASTERN MEXICO AND THE CENTRAL PART OF GUATEMALA. THIS WILL LEAD TO ACTIVE WEATHER OVER THIS AREA FOR THE NEXT SEVERAL DAYS. THE GLOBAL MODELS CONTINUE TO HINT THAT THE INTERACTION OF THE GALE FORCE WINDS WITH THE MONSOON TROUGH WILL HELP TO GENERATE A MORE DEFINITIVE LOW PRESSURE SYSTEM S OF THE GULF OF TEHUANTEPEC SUN. THIS LOW WILL HAVE THE POTENTIAL TO DEVELOP INTO A TROPICAL CYCLONE NEXT WEEK. REGARDLESS OF TROPICAL CYCLONE FORMATION ...THIS SYNOPTIC SETUP WILL BRING THE POTENTIAL FOR HEAVY RAINFALL AND MAY LEAD TO FLASH FLOODING AND DANGEROUS MUDSLIDES OVER PORTIONS OF CENTRAL AMERICA AND SOUTHERN MEXICO. $$ AGUIRRE