000
AXPZ20 KNHC 202130
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL 
2205 UTC FRI SEP 20 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.

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

A MONSOON TROUGH EXTENDS FROM 16N97W TO 12N102W TO 12N124W... 
THEN TRANSITIONS TO AN ITCZ TO 10N140W. NO SIGNIFICANT 
CONVECTION.

...DISCUSSION...

WATER VAPOR IMAGERY SHOWS MODERATE TO STRONG SUBSIDENCE MAINLY W 
OF 110W ASSOCIATED WITH A LARGE MID-LEVEL ANTICYCLONE ANCHORED 
NEAR 24N120W THAT DOMINATES THE REGION. DRY STABLE MID-LEVEL AIR 
IS PREVENTING CONVECTION FROM DEVELOPING IN THE TROPICS. A COLD 
FRONT FROM 33N129W TO 27N145W BECOMING VERY DIFFUSE W OF 135W. 
THE FRONT WILL STALL FROM SOUTHERN CALIFORNIA TO 29N128W BY SAT 
EVENING THEN DISSIPATE. HIGH PRES WILL BUILD EASTWARD N OF THE 
FRONT THROUGH SUN AND TIGHTEN THE PRES GRADIENT N OF 30N NEAR 
SOUTHERN CALIFORNIA. NLY WINDS WILL INCREASE WITH SEAS EXPECTED 
TO BUILD TO 8 FT NEAR THE COAST OF NORTHERN BAJA CALIFORNIA SUN. 
A WEAK PRES PATTERN EXISTS ELSEWHERE ACROSS THE AREA. CONVECTIVE 
ACTIVITY REMAINS MARKEDLY LESS THAN USUAL. THERE ARE A FEW SMALL 
CLUSTERS OF CONVECTION ALONG THE COASTS OF MEXICO AND CENTRAL 
AMERICA...BUT MINIMAL SHOWERS ELSEWHERE. NO SIGNIFICANT INCREASE 
IN CONVECTION AND MARINE CONDITIONS IS EXPECTED THROUGH SAT.

$$
MUNDELL