000
AXPZ20 KNHC 220242
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC THU AUG 22 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0230 UTC.
                                    
...SPECIAL FEATURES...

1006 MB LOW PRES IS EMBEDDED IN THE MONSOON TROUGH NEAR 16N111W. 
ASSOCIATED CONVECTION IS DESCRIBED IN THE SECTION BELOW. EARLIER 
SCATTEROMETER PASSES INDICATED FRESH TO STRONG WINDS WITHIN 300 
NM IN THE SE SEMICIRCLE AND 60 NM IN THE NE QUADRANT OF THE 
LOW...WITH 8 TO 11 FT SEAS PRESUMED TO BE ACCOMPANYING THESE 
WINDS. THE LOW IS FORECAST TO MOVE TO THE N THEN 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 09N85W TO 11N100W TO LOW PRES 
NEAR 11.5N111W TO LOW PRES NEAR 15N121W TO 12N140W. NO ITCZ AXIS 
IS PRESENT. SCATTERED MODERATE CONVECTION IS WITHIN 150 NM S OF 
THE MONSOON TROUGH BETWEEN 90W AND 94W...AND BETWEEN 96W AND 
99W...WITHIN 210 NM S OF THE MONSOON TROUGH BETWEEN 100W AND 
108W...FROM 12N TO 18N BETWEEN 111W AND 118W...AND WITHIN 150 NM 
N OF THE MONSOON TROUGH BETWEEN 118W AND 124W.

...DISCUSSION...

A LARGE UPPER LEVEL ANTICYCLONE IS LOCATED OVER 19N140W. VERY 
DRY AND STABLE AIR COVERS THE WATERS N OF 12N W OF 130W. AN 
UPPER LEVEL TROUGH EXTENDS FROM NEAR 32N124W THROUGH 24N124W TO 
19N127W 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...1020 MB HIGH PRES IS NEAR 35N138W WITH A BROAD 
RIDGE AXIS EXTENDING TO THE SE TO NEAR 26N120W. 1011 MB LOW PRES 
NEAR 34N126W 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 1008 MB AREA OF LOW PRES IS EMBEDDED IN 
THE MONSOON TROUGH NEAR 15N121W. 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 
STATIONARY OR RETROGRADES TO THE E DUE TO THE EVOLUTION OF THE 
1006 MB LOW DESCRIBED ABOVE.

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