000
AXPZ20 KNHC 062157
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
2205 UTC TUE OCT 06 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.               
 
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...            
THE MONSOON TROUGH EXTENDS FROM 09N84W TO 09N94W TO 12N105W TO A 
1008 MB LOW PRES LOCATED NEAR 08N113 TO 09N120W THEN RESUMES AT 
10N128W TO 08N135W TO BEYOND 09N140W. A CLUSTER OF MODERATE TO 
STRONG CONVECTION IS NOTED N OF 04N BETWEEN 78W AND 82W... 
INCLUDING PARTS OF THE GULF OF PANAMA. SCATTERED MODERATE 
ISOLATED STRONG CONVECTION CAN BE FOUND FROM 05N TO 07N BETWEEN 
90W AND 95W.

...DISCUSSION... 
                                            
TROPICAL CYCLONE OHO...CURRENTLY LOCATED WELL SOUTHEAST OF 
HAWAII IS FORECAST TO CONTINUE MOVING TOWARD THE NORTHEAST WITH 
STEADILY INCREASING FORWARD SPEED THROUGH THURSDAY MORNING. ON 
THE FORECAST TRACK...OHO WILL REMAIN W OF THE FORECAST AREA BUT 
WILL BRING AN INCREASE IN WINDS AND SEAS ACROSS THE WESTERN PART 
OF THE FORECAST REGION ON WED. MARINE GUIDANCE SUGGESTS 
INCREASING WINDS OF 20-30 KT AND BUILDING SEAS OF 9-14 FT IN 
MIXED SWELL NW OF A LINE FROM 30N135W TO 22N140W BY WED NIGHT. 
SEAS ARE EXPECTED TO FURTHER BUILD TO 10-19 FT NW OF A LINE FROM 
30N135W TO 25N140W BY EARLY THU AFTERNOON WITH THE HIGHEST SEAS 
NEAR 30N140W. 

GULF OF CALIFORNIA...A FRONTAL TROUGH IS ANALYZED ACROSS THE 
NORTHERN PORTION OF THE GULF AND EXTENDS FROM 32N113W TO 
29N114W. NW WINDS OF 15-20 KT ARE NOTED W OF TROUGH AXIS WITH 
SEAS OF 3-4 FT. THE TROUGH WILL SHIFT EASTWARD INTO MAINLAND 
MEXICO TONIGHT WITH WINDS DIMINISHING TO 10-15 KT.  

A 1022 MB HIGH PRES LOCATED N OF AREA NEAR 33N123W EXTENDS A 
RIDGE ACROSS THE N WATERS. THE PRES GRADIENT BETWEEN THE RIDGE 
AND A 1010 MB LOW PRES LOCATED NEAR 19N122W IS PRODUCING AN AREA 
OF MAINLY FRESH WINDS WITH SEAS TO 9 FT WITHIN 150 NM NW AND 120 
E QUADRANTS OF LOW CENTER. THIS SYSTEM IS FORECAST TO OPEN UP 
INTO A TROUGH IN ABOUT 24 HOURS WITH SEAS SUBSIDING BELOW 8 FT. 

GULF OF TEHUANTEPEC...A FAIRLY TIGHT PRESSURE GRADIENT IS IN 
PLACE ACROSS THE AREA BETWEEN A RIDGE ALONG THE WEST AND 
NORTHWESTERN COAST OF THE GULF OF MEXICO AND LOWER PRESSURE 
ASSOCIATED WITH THE MONSOON TROUGH. THIS IS COMBINING WITH 
NOCTURNAL DRAINAGE FLOW AND SUPPORTING A PLUME OF FRESH TO 
STRONG NORTHERLY WINDS ACROSS THE GULF OF TEHUANTEPEC THAT IS 
FORECAST TO EXTEND TO NEAR 12.5N97W BY EARLY WED MORNING. THESE 
WINDS WILL BUILD SEAS TO 8-10 FT. SIMILAR CONDITIONS ARE 
EXPECTED AGAIN WED NIGHT INTO THU MORNING. 

GULF OF PAPAGAYO...HIGH PRESSURE RIDGING WILL PREVAIL ACROSS THE 
INTERIOR OF CENTRAL AMERICA. THIS COMBINED WITH LOWER PRESSURES 
ASSOCIATED WITH THE MONSOON TROUGH WILL INDUCE A GAP WIND EVENT 
ACROSS THIS GULF. THE MOST RECENT ASCAT PASS SHOWED NE-E WINDS 
OF MAINLY 20 KT ACROSS THIS AREA. WINDS THERE ARE EXPECTED TO 
PULSE TO AROUND 20 KT EACH OF THE NEXT FEW NIGHTS. 

A 1008 MB AREA OF LOW PRESSURE REMAINS EMBEDDED IN THE MONSOON 
TROUGH NEAR 08N113W PRODUCING DISORGANIZED SHOWERS AND 
THUNDERSTORMS. SATELLITE IMAGERY INDICATES SCATTERED MODERATE 
CONVECTION FROM 06N TO 11N BETWEEN 111W AND 115W. A BAND OF 
SIMILAR CONVECTION IS ALSO NOTED TO THE NE OF THE LOW CENTER AND 
WITHIN AROUND 90 NM SE OF LINE FROM 16N107W TO 12N113W.  
ENVIRONMENTAL CONDITIONS ARE EXPECTED TO BE CONDUCIVE FOR 
GRADUAL DEVELOPMENT OF THIS SYSTEM LATER THIS WEEK WHILE THE LOW 
MOVES WEST-NORTHWESTWARD.

CROSS-EQUATORIAL SW SWELL DOMINATES MOST OF THE FORECAST WATERS 
E OF 120W GENERATING AN AREA OF 8-9 FT SEAS S OF 06N BETWEEN 
105W AND 120W. THE CROSS EQUATORIAL SW SWELL WILL PERSIST ACROSS 
THE S CENTRAL WATERS THROUGH 48 HOURS AS A NEW SET PROPAGATES 
ACROSS THE EQUATOR.

$$
GR