000 AXPZ20 KNHC 311539 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC SUN MAY 31 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 1530 UTC. ...SPECIAL FEATURE... HURRICANE ANDRES WAS CENTERED NEAR 15.5N 118.1W AT 31/1500 UTC MOVING NW OR 290 DEG AT 7 KT. ESTIMATED MINIMAL CENTRAL PRESSURE WAS 968 MB. MAXIMUM SUSTAINED WIND SPEED WAS 90 KT WITH GUSTS TO 110 KT. NUMEROUS MODERATE TO STRONG CONVECTION WAS WITHIN 90 NM OF CENTER. SCATTERED MODERATE CONVECTION WAS FOUND ELSEWHERE IN A PLUME OF SW WINDS CONVERGING INTO ANDRES...IN AN AREA BOUNDED FROM 09N120W TO 15N112W TO 10N110W TO 03N120W TO 09N120W. ANDRES IS FORECAST TO WEAKEN OVER THE NEXT TWO DAYS AS IT MOVES OVER COLDER WATERS...DIPPING BELOW HURRICANE FORCE BY EARLY TUE MORNING. SWELLS GENERATED BY ANDRES ARE REACHING THE COAST OF MEXICO BETWEEN MANZANILLO AND PUNTA EUGENIA AND ARE EXPECTED TO AFFECT THE COAST OF BAJA CALIFORNIA TODAY...WITH 6-8 FT SEAS FOUND IN THIS AREA. THE BROAD AREA OF SWELL RELATED TO ANDRES WILL ENVELOP MOST OF THE FORECAST WATERS N OF 10N BETWEEN 110W AND 130W OVER THE NEXT COUPLE OF DAYS. REFER TO LATEST NHC PUBLIC/ FORECAST ADVISORIES UNDER AWIPS/WMO HEADERS MIATCPEP1/MIATCMEP1 AND WTPZ31/WTPZ21 KNHC FOR MORE DETAILS. AN AREA OF LOW PRESSURE CONTINUES TO BECOME BETTER ORGANIZED NEAR 12N102W WITH MEAN SEA LEVEL PRESSURE ESTIMATED TO BE NEAR 1007 MB. NW SHEAR RELATED TO OUTFLOW FROM ANDRES IS IMPACTING THIS LOW...AND NUMEROUS MODERATE TO STRONG CONVECTION IS NOTED WITHIN 90 NM SE SEMICIRCLE OF THE LOW PRES. AN EARLIER ASCAT SATELLITE PASS INDICATED WINDS OF 20 TO 25 KT WITHIN 60 NM ON THE NORTHERN QUADRANT OF THE LOW PRESSURE. THE STRONG UPPER WINDS RELATED TO ANDRES WILL INHIBIT SIGNIFICANT DEVELOPMENT OF THIS LOW PRES AREA THROUGH MONDAY. THESE WINDS WILL DIMINISH BY TUE...ALLOWING FURTHER DEVELOPMENT OF THE LOW...POSSIBLY BECOMING TROPICAL DEPRESSION BY MID WEEK AS IT DRIFTS NORTH AND BECOMES STATIONARY. FORECAST TRACK AT THIS STAGE CONTINUES TO FOLLOW THE ECMWF WHICH IS CLOSER TO THE EC AND GFS ENSEMBLE MEANS. ...TROPICAL WAVES/LOWS... THE LOW PRES NEAR 12N102W DEVELOPED OVER THE PAST 24 TO 36 HOURS ALONG A TROPICAL WAVE IN THE VICINITY. RIDGING IN THE WAKE ANDRES HAS PREVENTED THE TROPICAL WAVE FROM MOVING WESTWARD...AND GIVEN THE DEVELOPMENT OF THE LOW PRES...THE WAVE HAS BEEN REMOVED FROM THE ANALYSIS. A 1009 MB LOW PRESSURE SYSTEM WAS ANALYZED NEAR 06N93W. NO SIGNIFICANT DEEP CONVECTION WAS NOTED NEAR THE LOW. THIS SYSTEM IS EXPECTED TO ENCOUNTER INCREASING NORTHWESTERLY FLOW ALOFT OVER THE NEXT TWO DAYS. THIS SHOULD INHIBIT FURTHER DEVELOPMENT OF THE SYSTEM. IT IS FORECAST TO DISSIPATE BY MON MORNING. A 1007 MB LOW PRES AREA WAS ANALYZED NEAR 09N130W. SCATTERED MODERATE CONVECTION WAS NOTED WITHIN 120 NM NW SEMICIRCLE OF THIS LOW. EARLIER SCATTEROMETER DATA SHOWED ONLY MODERATE TO FRESH TRADE WINDS E OF 140W BETWEEN THE LOW PRES AND WEAK RIDGING N OF THE AREA. HOWEVER ALTIMETER PASSES FROM SEVERAL HOURS AGO CONFIRMED WAVE MODEL GUIDANCE INITIALIZATIONS SHOWING SEAS TO AT LEAST 8 FT WITHIN 180 NM N OF THE LOW PRES IN A MIX OF SW SWELL WITH TRADE WIND RELATED SEAS. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS WAS ANALYZED FROM 10N120W TO 07N125W TO 10N137W TO 09N140W. SCATTERED MODERATE CONVECTION WAS OBSERVED WITHIN 150 NM S OF THE AXIS BETWEEN 120W AND 135W. ...DISCUSSION... N OF 15N E OF 120W...THE CENTER OF HURRICANE ANDRES IS 240 NM SW OF CLARION ISLAND...AND IS AT ITS CLOSET POINT OF APPROACH. A PAIR OF ALTIMETER PASSES OVER THE PAST SEVERAL HOURS INDICATED SEAS TO 8 FT REACHING AS FAR AS 480 NM N OF THE CENTER...PRIMARILY DUE TO FRESH SWELL GENERATED FROM ANDRES. WAVE MODEL GUIDANCE INDICATES 5 TO 7 FT SEAS PROPAGATING THROUGH THE REMAINDER OF THE AREA OUTSIDE THE GULF OF CALIFORNIA THROUGH MID WEEK. AS ANDRES CONTINUES TO MOVE W-NW AND WEAKENS...ATTENTION TURNS TO THE LOW PRES NEAR 12N102W. INFLUENCE FROM ANDRES WILL REQUIRE THE LOW TO REMAIN NEARLY STATIONARY WITH A SLOW NORTHWARD DRIFT...BEFORE DEVELOPING FURTHER BY MID WEEK ROUGHLY 360 NM OFF ACAPULCO. IN THE MEAN TIME...THE LOW PRES WILL LIKELY ENHANCE NIGHTLY SHOWERS AND THUNDERSTORMS FORMING WITHIN 200 NM OF THE MEXICAN COAST BETWEEN 95W AND 105W. THE DEEPENING LOW PRES WILL ALSO ENHANCE OVERNIGHT GAP WIND PULSES INTO THE GULF OF TEHUANTEPEC TONIGHT AND POSSIBLY AGAIN MON NIGHT WITH SEAS BRIEFLY BUILDING TO 8 FT. S OF 15N E OF 110W...AREAS OF SHOWERS AND THUNDERSTORMS OFF THE COASTS OF PANAMA AND COSTA RICA WILL DIMINISH LATER TODAY...BUT WILL LIKELY REDEVELOP OVERNIGHT. SOME ENHANCEMENT OF THIS CONVECTION NEAR PANAMA AND LIKELY OFF COLOMBIA IS POSSIBLY TONIGHT ASSOCIATED WITH A TROPICAL WAVE CURRENTLY MOVING INTO THE SW CARIBBEAN. MODERATE SOUTHERLY WINDS ARE CONVERGING ALONG ROUGHLY 05N...ENHANCING CONVECTION AS WELL...PRIMARILY SOUTH OF THE DEVELOPING LOW PRES NEAR 12N102W FROM 05N TO 07N BETWEEN 100W AND 105W. THIS CONVECTION WILL LIKELY PERSIST AND POSSIBLY INCREASE IN AREAL COVERAGE INTO MID WEEK AS THE LOW PRES SLOWLY DEVELOPS AND DRIFTS NORTHWARD. FRESH WINDS THROUGH THE GULF OF PAPAGAYO OVERNIGHT WERE ALLOWING SEAS TO 7 FT. WHILE THIS HAS DIMINISHED IT WILL LIKELY REOCCUR TONIGHT AND MON NIGHT. ELSEWHERE...AN UPPER TROUGH IS MOVING EASTWARD THROUGH 130W N OF 25N ACROSS A 1016 MB SURFACE HIGH CENTERED NEAR 27N129W. THE HIGH PRES HAS BEEN WEAKENED BY THE PASSAGE OF THE UPPER TROUGH AND THE ADVANCEMENT OF HURRICANE ANDRES FROM THE SOUTHEAST. RECENT SCATTEROMETER PASSES DO NOT INDICATE SIGNIFICANT TRADE WIND FLOW BETWEEN THE HIGH PRES AND THE MONSOON TROUGH FARTHER SOUTH IN THE DEEP TROPICS. A STATIONARY FRONT FROM 30N133W TO 25N140W IS DISSIPATING. RIDGING WILL BUILD NW OF THE AREA BEHIND THE EXITING UPPER TROUGH. THIS WILL ENHANCE THE PRES GRADIENT BETWEEN RELATED SURFACE RIDGING AND THE ADVANCING ANDRES OVER THE NEXT 2-3 DAYS...ALTHOUGH ANDRES WILL BE WEAKENING...RESULTING IN A BROAD AREA OF 15 TO 20 KT NE WINDS AHEAD OF ANDRES. THE ASSOCIATED WIND WAVES WILL MIX WITH SWELL GENERATED FROM THE STALLING ANDRES TO PRODUCE A LARGE ARE OF 8 TO 10 FT COMBINED SEAS FROM ROUGHLY 10N TO 25N W OF 130W BY LATE MON...EXPANDING NORTHWARD THROUGH TUE. $$ CHRISTENSEN