000
AXPZ20 KNHC 212117
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC WED AUG 21 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.
                                    
...SPECIAL FEATURES...

1007 MB LOW PRES IS EMBEDDED IN THE MONSOON TROUGH NEAR 
15.5N111W. NUMEROUS MODERATE AND SCATTERED STRONG CONVECTION IS 
LOCATED WITHIN 240 NM IN THE W SEMICIRCLE AND 180 NM IN THE N 
QUADRANT OF THE LOW. RECENT SCATTEROMETER PASSES INDICATED FRESH 
TO STRONG WINDS WITHIN 300 NM IN THE S QUADRANT AND 180 NM IN 
THE N QUADRANT OF THE LOW ALONG WITH 8 TO 10 FT SEAS. THIS LOW 
IS FORECAST TO MOVE TO THE N THEN N TO NW DURING THE NEXT 
SEVERAL DAYS. THE LOW HAS A HIGH CHANCE OF BECOMING A TROPICAL 
CYCLONE DURING THE NEXT 48 HOURS.

..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM 10N85W TO LOW PRES NEAR 
15.5N111W TO LOW PRES NEAR 14.5N122.5W TO 10N140W. NO ITCZ AXIS 
IS PRESENT. SCATTERED MODERATE CONVECTION IS FROM 04N TO 07N 
BETWEEN 79W AND 86W...FROM 06N TO 09N BETWEEN 94W AND 97W... 
FROM 05N TO 10N BETWEEN 98W AND 104W...WITHIN 120 NM EITHER SIDE 
OF THE MONSOON TROUGH BETWEEN 102W AND 108W...WITHIN 240 NM S OF 
THE MONSOON TROUGH BETWEEN 115W AND 120W...AND WITHIN 120 NM N 
OF THE MONSOON TROUGH BETWEEN 119W AND 125W. 

...DISCUSSION...

A LARGE UPPER LEVEL ANTICYCLONE IS LOCATED OVER 20N140W. VERY 
DRY AND STABLE AIR COVERS THE WATERS N OF 13N W OF 130W. AN 
UPPER LEVEL TROUGH EXTENDS FROM NEAR 32N125W THROUGH 23N125W TO 
13N130W WITH DRY AIR ALSO PRESENT W OF THE TROUGH TO 130W. DEEP 
TROPICAL MOISTURE/CONVECTIVE DEBRIS CONTINUES TO BE ADVECTED 
AHEAD OF THE TROUGH TO THE NE ACROSS THE BAJA CALIFORNIA 
PENINSULA AND FAR NW MEXICO W OF 110W.

AT THE SURFACE...1022 MB HIGH PRES IS NEAR 34N140W WITH A BROAD 
RIDGE AXIS EXTENDING TO THE SE TO NEAR 24N116W. 1014 MB LOW PRES 
NEAR 36N125W EXTENDS A TROUGH TO NEAR 30N126W. ASSOCIATED WINDS 
HAVE BEEN GENERATING 6-8 FT SEAS FROM 30N TO 32N BETWEEN 125W 
AND 135W ALTHOUGH SEAS SHOULD SUBSIDE AS THE FEATURES SHIFT TO 
THE E. S OF 30N...WINDS ARE PRIMARILY LIGHT TO MODERATE ACROSS 
THE REMAINDER OF THE DISCUSSION AREA...EXCEPT LOCALLY TO FRESH 
IN SOUTHERLY FLOW S OF THE MONSOON TROUGH.

A WEAK AND ILL-DEFINED 1011 MB AREA OF LOW PRES IS EMBEDDED IN 
THE MONSOON TROUGH NEAR 14.5N122.5W. CONVECTION NEAR THE LOW IS 
DISORGANIZED AND WINDS ARE MODERATE TO LOCALLY FRESH. THE LOW IS 
FORECAST TO DISSIPATE DURING THE NEXT 24 HOURS AS IT REMAINS 
NEARLY STATIONARY.

THE PRES GRADIENT IS FORECAST TO TIGHTEN IN THE GULF OF 
TEHUANTEPEC REGION BY LATE THU NIGHT ALLOWING FOR WINDS TO 
INCREASE TO FRESH TO STRONG IN THE GULF...DIMINISHING BY FRI 
AFTERNOON.
 
$$
LEWITSKY