000
AXPZ20 KNHC 171605
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL 
1605 UTC THU OCT 17 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 
1500 UTC.

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

THE MONSOON TROUGH EXTENDS FROM 10N86W TO LOW PRES NEAR 09.5N90W 
TO 10N109W TO 09N122W TO 11N134W TO 10N140W. SCATTERED MODERATE 
ISOLATED STRONG CONVECTION IS FROM 09N TO 13N BETWEEN 88W AND 
93W. SCATTERED MODERATE CONVECTION WITHIN 45 NM S OF THE TROUGH 
BETWEEN 122W AND 127W...AND WITHIN 60 NM EITHER SIDE OF THE AXIS 
W OF 133W.

...DISCUSSION...                                                 

A LARGE ANTICYCLONE CENTERED OVER THE S CENTRAL GULF OF MEXICO 
EXTENDS A RIDGE ACROSS SOUTHERN MEXICO TO NEAR 10N116W. A MID- 
LEVEL TROUGH EXTENDS SW FROM NORTHERN BAJA CALIFORNIA TO NEAR 
20N128W. POST-TROPICAL REMNANT LOW PRISCILLA HAS A WELL-DEFINED 
LOW LEVEL CIRCULATION CENTERED NEAR 19N123W...BUT LACKS DEEP 
CONVECTION MOVING OVER COOL WATER IN A HIGH SHEAR ENVIRONMENT 
ASSOCIATED WITH THE MID-LEVEL TROUGH MENTIONED ABOVE. ASCAT AND 
OSCAT DATA BETWEEN 0500 AND 0900 UTC SHOWED SMALL AREA OF WINDS 
TO 25 KT IN THE NW QUADRANT OF THE LOW. THE SYSTEM APPEARS TO BE 
RAPIDLY WEAKENING. MAX WINDS ARE AROUND 20 KT WITH SEAS TO 7 FT. 
CLUSTERS OF CONVECTION ASSOCIATED WITH THE CONVERGENCE ZONE ARE 
FOUND ROUGHLY ALONG 10N ACROSS THE ENTIRE BASIN. 

RELATIVELY BENIGN MARINE CONDITIONS CHARACTERIZE THE FORECAST 
AREA WITH WIDESPREAD GENTLE TO MODERATE WINDS AND 4-6 FT SEAS. A 
RIDGE DOMINATES NW PORTION OF THE REGION...REACHING FROM 32N138W 
TO 25N114W. WEAK LOW PRES AREA IS EMBEDDED IN THE MONSOON TROUGH 
CENTERED NEAR 10N110W. THE LOW IS EXPECTED TO MOVE W WITH LITTLE 
CHANGE IN INTENSITY THROUGH SAT. AN AREA OF LOW PRES ASSOCIATED 
WITH REMNANTS OF A TROP WAVE THAT MOVED THROUGH CENTRAL AMERICA 
THE PAST DAY OR SO IS CENTERED NEAR 9.5N90W. THE LOW IS EXPECTED 
TO MOVE SLOWLY NW SOUTH OF GUATEMALA AND MEXICO THIS WEEKEND AND 
GRADUALLY INTENSIFY. LATEST SET OF MODEL GUIDANCE SHOWS THE LOW 
REMAINING BELOW TROP DEPRESSION INTENSITY THROUGH MON. 

MOST SIGNIFICANT LONG-TERM MARINE IMPACT WILL BE ARRIVAL OF LONG 
PERIOD NW SWELL INTO NW PORTION SUN AND MON. WAVE MODEL GUIDANCE 
SHOWS LEADING EDGE OF SWELL TRAIN WITH 22-23 SEC PERIOD...WHICH 
WILL PRODUCE UNUSUALLY LARGE SURF HEIGHTS AS IT REACHES SHALLOW 
WATER ALONG THE PACIFIC COAST NEXT WEEK.
 
$$ 
MUNDELL