000
AXPZ20 KNHC 120925
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SAT OCT 12 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 
0900 UTC.

...SPECIAL FEATURES...

1007 MB LOW PRES IS EMBEDDED IN THE MONSOON TROUGH NEAR 
14.5N108W...OR SEVERAL HUNDRED MILES SW OF MANZANILLO MEXICO. 
DISORGANIZED SCATTERED MODERATE AND ISOLATED STRONG CONVECTION 
IS FROM 16N TO 20N BETWEEN 106W AND 112W. CURRENTLY ASSOCIATED 
WINDS AND SEAS ARE BELIEVED TO BE 20 KT OR LESS AND LESS THAN 8 
FT WITH NO RECENT SCATTEROMETER OR ALTIMETER PASSES...HOWEVER 
EXPECT WINDS TO INCREASE TO FRESH TO STRONG WITH SEAS BUILDING 
TO 8-11 FT DURING THE NEXT 24 HOURS AND CONTINUING THROUGH 48 
HOURS. SW FLOW S OF THE MONSOON TROUGH WILL ALSO INCREASE TO 
FRESH TO STRONG ALONG WITH 8-10 FT SEAS TO THE SW OF THE LOW. 
THIS LOW HAS A MEDIUM CHANCE OF BECOME A TROPICAL CYCLONE DURING 
THE NEXT 48 HOURS.

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

THE MONSOON TROUGH EXTENDS FROM 08N77W TO LOW PRES NEAR 14N108W 
TO LOW PRES NEAR 14N116W TO 07N132W...THEN RESUMES FROM 13N131W 
TO 08N138W. THE ITCZ AXIS EXTENDS FROM 08N138W TO BEYOND 
08N140W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS 
WITHIN 120 NM S OF THE MONSOON TROUGH BETWEEN 85W AND 93W...AND 
ALSO WITHIN 210 NM W OF A LINE FROM 10N106W TO 18N116W.

...DISCUSSION...

AN UPPER LEVEL TROUGH CUTS DEEP INTO THE BASIN FROM 32N117W TO 
15N127W WITH A DRY...STABLE...AND SUBSIDING AIR MASS W OF THE 
AXIS. A STUBBORN AND NEARLY STATIONARY MID TO UPPER LEVEL 
DOWNSTREAM RIDGE OVER CENTRAL MEXICO NEAR 20N100W IS BLOCKING 
ANY FURTHER EASTWARD MOVEMENT OF THE UPPER TROUGH...AND IS IN 
TURN SQUEEZED ON ITS WESTERN PERIPHERY WITH INCREASING SOUTHERLY 
WINDS ALOFT OVER THE ABOVE MENTIONED SURFACE LOW NEAR 14.5N108W 
HINDERING DEVELOPMENT OF THE LOW. THE RIDGE IS ALSO ALLOWING FOR 
TROPICAL MOISTURE ALONG AND NEAR THE MONSOON TROUGH TO FAN OUT 
ACROSS THE WATERS MAINLY S OF 22N E OF 120W. ELSEWHERE ALOFT... 
A BROAD ANTICYCLONE IS OVER THE SW PORTION NEAR 10N135W WITH DRY 
AND STABLE CONDITIONS S OF 20N W OF 130W. AN UPPER RIDGE EXTENDS 
NW-N THROUGH 20N140W TO 32N140W WITH DEEP TROPICAL MOISTURE W OF 
THE DISCUSSION WATERS BEING ADVECTED TO THE NE OVER THE FAR NW 
CORNER N OF 20N W OF 135W.

ELSEWHERE AT THE SURFACE...HIGH PRES RIDGING EXTENDS FROM 
32N140W TO NEAR THE SOUTHERN TIP OF THE BAJA CALIFORNIA 
PENINSULA NEAR 21N110W. 1011 MB LOW PRES...THE REMNANTS OF 
NARDA...IS NEAR 14N132W. FRESH TO STRONG WINDS AND 8-11 FT SEAS 
ARE OCCURRING WITHIN 240 NM IN THE N QUADRANT OF THE LOW...WHILE 
AN AREA OF 8-10 FT N-NE SWELL SURROUNDS THE LOW OVER AN AREA 
BOUNDED BY A LINE FROM 25N131W TO 23N140W TO 13N136W TO 17N126W 
TO 25N131W. A TIGHT PRES GRADIENT BETWEEN THE RIDGING TO THE N 
AND THE LOW WILL ALLOW FOR FRESH TO STRONG WINDS TO PERSIST 
THROUGH TODAY...DIMINISHING TO 20 KT OR LESS BY LATE SUN AS THE 
LOW STARTS TO OPEN UP INTO A TROUGH.
 
$$
LEWITSKY