000
AXPZ20 KNHC 051603
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SAT OCT 05 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1545 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...           

THE MONSOON TROUGH PASSES THROUGH PANAMA NEAR 08N78W TO 12N90W 
TO 13N100W...TO A 1008 MB LOW PRESSURE CENTER THAT IS NEAR  
13N113W...TO 11N119W. THE ITCZ CONTINUES FROM 11N119W TO 10N126W 
AND 10N140W. CONVECTIVE PRECIPITATION...NUMEROUS STRONG FROM 13N 
TO 16N BETWEEN 97W AND 99W. SCATTERED MODERATE ISOLATED STRONG 
FROM 08N TO 10N BETWEEN 128W AND 140W. SCATTERED MODERATE 
ISOLATED STRONG FROM 10N TO 15N BETWEEN 113W AND 118W...NEAR THE 
1008 MB LOW PRESSURE CENTER. SCATTERED MODERATE FROM 12N TO 15N 
BETWEEN 121W AND 125W.

...DISCUSSION...

A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH THE NORTHERN 
PART OF BAJA CALIFORNIA NEAR 31N116W...TO 32N126W TO 28N131W TO 
23N138W TO 15N137W. COMPARATIVELY DRIER AIR IN SUBSIDENCE...AS 
DEPICTED IN WATER VAPOR IMAGERY...SURROUNDS THE AREA OF THE 
CYCLONIC WIND FLOW WITH THE TROUGH.
 
AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTER IS NEAR 21N111W. 
ANTICYCLONIC WIND FLOW COVERS THE AREA FROM THE EQUATOR TO 30N 
BETWEEN 110W AND 130W. A MIDDLE LEVEL TO UPPER LEVEL INVERTED 
TROUGH IS ALONG 99W/100W TO THE SOUTH OF 11N.

A SURFACE RIDGE PASSES THROUGH 32N127W TO 28N117W AND 20N110W. 
THE WIND SPEEDS THAT ARE TO THE EAST OF THE RIDGE RANGE FROM 5 
KNOTS TO 10 KNOTS. LONG PERIOD NORTHERLY SWELLS CONTINUE TO 
MERGE WITH CROSS EQUATORIAL LONG PERIOD SOUTHERLY SWELL... 
RESULTING IN COMBINED SEA HEIGHTS RANGING FROM 6 FEET TO 8 FEET 
OF 6-8 FT ACROSS THE DISCUSSION ARETO THE NORTH OF 20N BETWEEN 
115W AND 140W. THE NORTHERLY SWELLS WILL SUBSIDE TODAY WITH 
COMBINED SEAS HEIGHTS OF 5 FEET TO 6 FEET BY THIS EVENING. 

A SURFACE LOW IS EMBEDDED IN THE MONSOON TROUGH NEAR 13N113W. 
CURRENTLY NORTHEASTERLY WINDS RANGING FROM 15 KNOTS TO 20 KNOTS 
ARE WITHIN 240 NM OF THE CENTER IN THE NORTHWESTERN QUADRANT... 
AND SOUTHEASTERLY WINDS OF 15 KT ARE WITHIN 420 NM OF THE CENTER 
IN THE SOUTHEASTERN SEMICIRCLE OF CENTER. SEA HEIGHTS IN THESE 
AREAS RANGE FROM 6 FEET TO 8 FEET PRIMARILY DUE TO MIXING 
NORTHWESTERLY AND LONG PERIOD CROSS-EQUATORIAL SOUTHEASTERLY 
SWELL. THE LOW PRESSURE CENTER IS FORECAST TO MOVE SLOWLY 
WESTWARD...TO NEAR 13N116W LATE TONIGHT...AND NEAR 13N120W LATE 
SUNDAY NIGHT WITH WIND SPEEDS DIMINISHING TO 10 KNOTS TO 15 
KNOTS AND SEA HEIGHTS SUBSIDING TO LOWER THAN 8 FEET AT THE 
END OF THE FORECAST PERIOD.
 
GULF OF CALIFORNIA...NORTHWESTERLY 20 KNOT TO 30 KT WINDS...WITH 
SEAS HEIGHTS RANGING FROM 5 FEET TO 8 FEET...ARE OCCURRING 
ACROSS THE OPEN FETCH WATERS TO THE NORTH OF 29N. THE GRADIENT 
WILL RELAX SOME LATER TODAY. NORTHWESTERLY WIND SPEEDS OF 20 
KNOTS TO 25 KNOTS WILL SPREAD SOUTHWARD ACROSS THE GULF 
WATERS...TO THE NORTH OF 25N DURING THE FIRST 24 HOURS OF THE 
FORECAST PERIOD. THE GRADIENT WILL WEAKEN MORE...AND THE WIND 
SPEEDS WILL DIMINISH TO 10 TO 15 KNOTS ACROSS THE ENTIRE GULF OF 
CALIFORNIA DURING THE TIME FROM 24 HOURS INTO THE END OF THE 48 
HOUR FORECAST PERIOD. THE SEAS WILL SUBSIDE GRADUALLY TO 2 FEET 
OR LESS.

GULF OF TEHUANTEPEC...LIGHT AND VARIABLE WINDS ARE EXPECTED TO 
CONTINUE ACROSS THE TEHUANTEPEC AREA THROUGH SUN EVENING. 
NORTHERLY 15-20 KNOT DRAINAGE FLOW IS EXPECTED TO OCCUR ACROSS 
THE GULF OF TEHUANTEPEC WATERS LATE EACH NIGHT BEGINNING ON SUN 
NIGHT.

$$
MT