000 AXPZ20 KNHC 191604 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC MON OCT 19 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... MAJOR HURRICANE OLAF IS CENTERED NEAR 9.9N 137.7W AT 1500 UTC MOVING WEST OR 280 DEGREES AT 12 KT. ESTIMATED MINIMUM CENTRAL PRESSURE HAS LOWERED TO 967 MB. THE MAXIMUM SUSTAINED WIND SPEED IS 100 KT WITH GUSTS TO 105 KT. LATEST SATELLITE IMAGERY SHOWS THAT OLAF HAS CONTINUED TO INTENSIFY AS NOTED IN ITS MORE SYMMETRICAL CLOUD PATTERN. IN ADDITION...A SMALL EYE FEATURE IS APPARENT IN IR IMAGERY. NUMEROUS STRONG CONVECTION IS WITHIN 90 NM OF THE CENTER...WITH SCATTERED MODERATE TO STRONG CONVECTION WITHIN FROM 06N-12N BETWEEN 134W-139W. SCATTERED MODERATE/ ISOLATED STRONG CONVECTION IS SEEN FROM 04N-06N BETWEEN 133W- 140W. OLAF IS FORECAST TO INTENSIFY AS IT MOVE W OF 140W TONIGHT...THEN BEGIN TO SLOWLY WEAKEN THEREAFTER. PLEASE SEE LATEST FORECAST ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP4/WTPZ24 KNHC FOR MORE DETAILS ON OLAF. GULF OF TEHUANTEPEC...LOW PRESSURE IS S OF THE GULF ALONG THE MONSOON TROUGH NEAR 13N94W 1007 MB. N-NE GALE FORCE WINDS OF 30- 35 KT ARE WITHIN 15 NM EITHER SIDE OF A LINE FROM 16N95W TO 15N95W INCLUDING THE GULF WITH SEAS OF 9-13 FT. THE VERY TIGHT EXISTING PRESSURE GRADIENT LEADING TO THESE GALE FORCE WINDS WILL CONTINUE THROUGH TUE MORNING BEFORE ABATING TUE AFTERNOON. THESE WINDS ARE THEN FORECAST TO INCREASE BACK UP TO GALE FORCE BY EARLY ON WED AS THE LOW INTENSIFIES AS THE GLOBAL MODELS CONTINUE TO SUGGEST THE LOW COULD DEVELOP INTO A TROPICAL CYCLONE AROUND MID-WEEK. THERE IS CURRENTLY A MEDIUM CHANCE FOR TROPICAL CYCLOGENESIS WITHIN THE NEXT 48 HOURS. ABUNDANT TROPICAL MOISTURE ACROSS THE NORTHERN HALF OF CENTRAL AMERICA AND SOUTHERN MEXICO ASSOCIATED WITH THE MONSOON GYRE IN WHICH THE LOW IS EMBEDDED WITHIN WILL INCREASE THE POTENTIAL FOR ACTIVE WEATHER OVER THIS AREA FOR THE NEXT COUPLE OF DAYS. REGARDLESS OF TROPICAL CYCLONE FORMATION...THIS SYNOPTIC SETUP HAS INCREASED THE POTENTIAL FOR LOCALLY HEAVY RAINFALL WHICH MAY LEAD TO FLASH FLOODING AND DANGEROUS MUDSLIDES OVER PORTIONS OF CENTRAL AMERICA AND SOUTHERN MEXICO OVER THE NEXT COUPLE OF DAYS. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS FROM 14N92W TO LOW PRES NEAR 13N94W 1007 MB TO 10N102W TO 09N110W TO 08N120W. SCATTERED MODERATE TO STRONG CONVECTION IS OVER FORECAST WATERS FROM 11N-15N BETWEEN 89W-94W...AND ALSO N OF 13N BETWEEN 97W-101W. ...DISCUSSION... WATER VAPOR IMAGERY SHOWS ABUNDANT SUBSIDENCE AND DRY AIR N OF A LINE FROM 20N106W TO 19N120W TO 20N130W TO 14N140W...WHILE VERY DEEP TROPICAL MOISTURE REMAINS CONFINED TO S OF THIS SAME LINE. A SHARP UPPER TROUGH IS MOVING QUICKLY EASTWARD OVER THE FAR NE CORNER OF THE DISCUSSION AREA. A 1026 MB SUBTROPICAL HIGH PRESSURE CENTER NEAR 34N138W EXTENDS A RIDGE SE TO THE ISLAS REVILLAGIGEDO. OVERNIGHT SCATTEROMETER DATA REVEALED MODERATE TO FRESH N-NW WINDS ALONG THE PACIFIC COAST OF THE BAJA CALIFORNIA PENINSULA N OF ABOUT 26N...TO THE N OF THE RIDGE. THE TIGHTEST PRESSURE GRADIENT IS FORECAST TO SHIFT N THROUGH EARLY WED AS TROUGHING BUILDS OVER THE INTERIOR WESTERN UNITED STATES. INCREASING WINDS N OF THE AREA WILL USHER NW SWELL INTO THE NE PORTION OF THE FORECAST AREA WHERE IT WILL MERGE WITH THE LONGER PERIOD NW SWELL ALREADY IN PLACE. 7-9 FT SEAS IN THIS LONGER PERIOD SWELL CURRENTLY SPAN THE AREA N OF 25N W OF 118W. THE AREA WILL DECREASE IN COVERAGE TO N OF 26N BETWEEN 118W-127W BY EARLY ON WED...AND TO LESS THAN 8 F AROUND 12Z WED. THE BUILDING SUBTROPICAL HIGH HAS HELPED EXPAND THE 20-33 KT WINDS OVER THE NORTHERN PART OF OLAF TO WITHIN 420 NM N QUADRANT. THE RIDGE WILL SHIFT SLIGHTLY TO THE W OVER THE NEXT 48 HOURS IN TANDEM WITH HURRICANE OLAF...MAINTAINING THIS PRESSURE GRADIENT. OUTSIDE OF THE CIRCULATION ASSOCIATED WITH OLAF...MODERATE TO FRESH TRADE WINDS PREVAIL OVER MUCH OF THE DISCUSSION AREA N OF 15N W OF 115W INDUCED BY TIGHT PRESSURE THERE AS UPPER TROUGH MOVES EASTWARD THROUGH THERE...AND TIGHT SURFACE PRESSURE GRADIENT REMAINS THERE BETWEEN THE AFOREMENTIONED RIDGE AND LOW PRESSURE OVER THE WESTERN U.S. THIS AREA OF MODERATE TO FRESH TRADE WINDS WILL SHIFT SLIGHTLY WESTWARD AS THE RIDGE AXIS SHIFTS WESTWARD THROUGH EARLY WED. THE 18-20 SECOND PERIOD SW SWELL THAT IS CURRENTLY AFFECTING THE PACIFIC COAST OVER THE ENTIRE FORECAST COULD MAKE FOR DANGEROUS CONDITIONS ENTERING AND EXITING PORTS AND WILL INCREASE THE THREAT OF RIP CURRENTS TODAY. CONDITIONS ARE FORECAST TO IMPROVE DURING TUE AS THE SWELL SUBSIDES. $$ AGUIRRE