000 AXPZ20 KNHC 200958 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC THU JUN 20 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0945 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH AXIS FROM 10N85W TO 11N100W TO 1008 MB LOW PRES NEAR 11N110W TO 09N128W WHERE IT TRANSITIONS TO THE ITCZ TO 09N140W. SCATTERED MODERATE TO STRONG CONVECTION EXISTS WITHIN 120 NM S OF THE AXIS BETWEEN 92W-97W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 120 NM S OF THE AXIS BETWEEN 115W-126W...AND ALSO WITHIN 60 NM OF THE AXIS BETWEEN 107W-115W. ...DISCUSSION... WATER VAPOR IMAGERY SHOWS AN UPPER TROUGH NOW HAVING SHIFTED TO THE FAR NE PART OF THE AREA. IN ITS WAKE...W TO NW FLOW UPPER FLOW IS PRESENT N OF 27N AND W TO NEAR 135W/136W WHERE MID TO UPPER RIDGING IS EVIDENT. THIS RIDGING EXTENDS SE TO AN UPPER ANTICYCLONE AT 18N134W. THE UPPER FLOW BECOMES SWLY W OF 136W AHEAD OF AN EWD ADVANCING UPPER TROUGH W OF THE AREA. ANOTHER UPPER ANTICYCLONE IS SEEN NEAR 21N123W. BOTH OF THE ANTICYCLONE ARE JOINED BY A RIDGE THAT EXTENDS ENE TO OVER SRN BAJA CALIFORNIA...AND TO SW OF THE AREA AT 15N140W. ASSOCIATED ANTICYCLONIC FLOW COVERS THE AREA FROM 13N TO 27N. WITH THIS ANTICYCLONIC FLOW IN PLACE...RESULTANT MODERATE TO STRONG SUBSIDENCE IS KEEPING DRY AND VERY STABLE ATMOSPHERIC CONDITIONS THROUGHOUT THIS PORTION OF THE AREA AS NOTED BY THE MOSTLY CLEAR SKIES PRESENT THERE. BROKEN HIGH CLOUDS ARE SEEN STREAMING EWD INTO THE NW CORNER OF THE AREA ACROSS THE RIDGE DESCRIBED ABOVE AS THE UPPER TROUGH W OF THE AREA TAPS THE DEEP TROPICAL CENTRAL PACIFIC REGION. THESE HIGH CLOUDS REACH TO NEAR 130W BEFORE THEY EVAPORATE IN THE MODERATE TO STRONG AIR ALOFT. AN UPPER TROUGH EXTENDS FROM AN UPPER CYCLONE CENTERED NEAR 16N112W TO 15N100W. THIS IS SUPPORTING A 1008 MB SURFACE LOW EMBEDDED WITHIN THE MONSOON TROUGH AT 11N108W. E OF THE LOW...THE LATEST AVAILABLE ASCAT PASSES INDICATED A SURGE OF MODERATE TO FRESH SW FLOW INTO THE MONSOON TROUGH...AND PROVIDING FURTHER FUEL TO CONVECTION ASSOCIATED WITH THE MONSOON TROUGH. TO THE SE AND S OF THE UPPER LOW AT 16N112W...MID/UPPER LEVEL RIDGING IS PRESENT. A SMALL UPPER LEVEL LOW IS SEEN OVER THE GULF OF TEHUANTEPEC. THE LOW IS PROVIDING A FAVORABLE ENVIRONMENT FOR DEEP LAYER ATMOSPHERIC MOISTURE TO EXIST OVER THE FAR ERN PART OF THE AREA AS THE UPPER FLOW PATTERN BECOMES DIFFLUENT THERE. SCATTERED STRONG CONVECTION IN CLUSTERS IS SEEN WITHIN 30 NM OF 13N90W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS ELSEWHERE WITHIN 90 NM OF THE COAST OF CENTRAL AMERICA FROM 09N TO 14N. THIS CONVECTION SHOULD LINGER INTO THE NEXT 24-48 HRS WITH TIMES ON BETWEEN WHERE IT WILL WEAKEN THEN REDEVELOP. OVER THE NEXT 48 HRS...THE NWP MODELS ARE IN REASONABLE AGREEMENT THAT THE LOW NEAR 11N110W WILL DRIFT SLOWLY W. MEANWHILE...A SECOND SURFACE LOW IS EXPECTED TO FORM NEAR 12N100W THROUGH SAT PER MODEL GUIDANCE...AND EVENTUALLY INTERACT WITH THE LOW NEAR 11N110W BEYOND 48 HRS. BOTH OF THESE FEATURES WILL BE EMBEDDED WITHIN A BROAD AREA OF LOW PRES EXPECTED TO MATERIALIZED OVER THE ERN PORTION OF THE AREA THROUGH THE NEXT FEW DAYS. ELSEWHERE AT THE SURFACE...A NEARLY STATIONARY 1028 MB HIGH PRES CENTER IS ANALYZED JUST NW OF THE FORECAST WATERS AT 33N140W WITH A RIDGE EXTENDING SEWD TO NEAR 21N121W. THE PRES GRADIENT TO ITS E IN COMBINATION WITH LOWER PRES OVER THE WRN U.S. W COAST IS ALLOWING FOR MAINLY FRESH TO STRONG WINDS NEAR THE COAST OF CALIFORNIA WITH A PORTION OF THESE WINDS TO GALE FORCE FROM 30N TO 36N BETWEEN 120W-123W. NW TO N SWELLS GENERATED BY THESE WINDS ARE SPREADING S INTO THE NE PORTION OF THE AREA TO N OF 22N BETWEEN 118W AND 124W WHERE NW-N WINDS OF 20-25 KT AND SEAS OF 9-10 FT ARE PRESENT IN AS NOTED IN THE 0438 UTC ASCAT PASS FROM THIS MORNING. THESE WINDS ARE FORECAST TO LOWER TO 20 KT OR LESS IN 24 HRS WITH SEAS TO 9 FT IN NW TO N SWELL N OF 26N BETWEEN 118W AND 124W IN 48 HRS. BY 48 HRS...THIS AREA OF SWELLS WILL BE CONFINED TO N OF 28N BETWEEN 118W-122W. A WEAK SURFACE TROUGH IS SUGGESTED BY PARTIAL ASCAT DATA AND IN THE LOW CLOUD MOTION TO BE LOCATED FROM NEAR 11N134W TO 09N135W. THE ASCAT DATA INDICATED NE 20 KT WINDS W OF THE TROUGH. SEAS THERE ARE 8 FT IN A NE SWELL. THE NWP MODELS SUGGEST THAT THE TROUGH WILL TRANSLATE EWD THROUGH LATE FRI NIGHT WHERE IT SHOULD EXTEND FROM 11N137W TO 09N138W. AT THAT TIME THE GRADIENT TO ITS W SHOULD ALLOW FOR NE WINDS OF 20-25 KT WITH SEAS TO 9 FT. $$ AGUIRRE