000
AXPZ20 KNHC 182121
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL 
2205 UTC FRI OCT 18 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 
2045 UTC.

...SPECIAL FEATURES... 

SHOWERS AND THUNDERSTORMS HAVE BECOME SOMEWHAT MORE ORGANIZED 
TODAY IN ASSOCIATION WITH A BROAD AREA OF LOW PRESSURE LOCATED 
NEAR 10.5N96W OR ABOUT 300 NM SOUTH-SOUTHWEST OF THE GULF OF 
TEHUANTEPEC. CONDITIONS ARE EXPECTED TO BE CONDUCIVE FOR SOME 
SLOW DEVELOPMENT OF THIS SYSTEM DURING THE NEXT SEVERAL DAYS. 
THE LATEST NHC TROPICAL WEATHER OUTLOOK GIVES THIS LOW PRES AREA 
A MEDIUM CHANCE OF DEVELOPING INTO A TROPICAL CYCLONE DURING THE 
48 HOURS WHILE IT MOVES WESTWARD TO WEST-NORTHWESTWARD AT 5 TO 
10 MPH. 

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

THE MONSOON TROUGH EXTENDS FROM 11N86W TO 1009 MB LOW PRES NEAR 
10.5N96W TO A 1010 MB LOW PRES NEAR 09N112W TO 07N120W TO A 1012 
MB LOW PRES NEAR 11N140W. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION IS NOTED FROM 09N TO 14N BETWEEN 95W AND 102W. 
NUMEROUS MODERATE TO SCATTERED STRONG CONVECTION IS FROM 08N TO 
12N BETWEEN 108W AND 112W...AND FROM 08N TO 10N BETWEEN 112W AND 
115W.

...DISCUSSION...                                              

A 1029 MB HIGH PRESSURE CENTERED WELL N OF THE AREA NEAR 48N134W 
EXTENDS A RIDGE ACROSS THE WATERS N OF 20N...INCLUDING BAJA 
CALIFORNIA. A VERY WEAK PRES GRADIENT IS NOTED BETWEEN THE RIDGE 
AND THE MONSOON TROUGH. AS A RESULT...RELATIVELY BENIGN MARINE 
CONDITIONS PREVAIL OVER MOST OF THE DISCUSSION AREA...WITH 
WIDESPREAD GENTLE TO MODERATE WINDS AND 4-6 FT SEAS.

THE SWIRL OF LOW CLOUDS ASSOCIATED WITH REMNANT LOW PRISCILLA IS 
CENTERED NEAR 18N126W. THE LOW IS EXPECTED TO WEAKEN INTO A 
TROUGH LATER TODAY. THE TROUGH WILL MOVE WESTWARD REACHING 130W 
BY SAT AFTERNOON AND 135W BY SUN AFTERNOON. LATEST SCATTEROMETER 
PASSES INDICATE WINDS OF 20 KT IN THE NW QUADRANT OF THE REMNANT 
LOW WITH SEAS TO 7 FT. 

AN AREA OF LOW PRESSURE CENTERED NEAR 9N112W HAS BECOME BETTER 
ORGANIZED OVER THE PAST 12-24 HOURS. AN OSCAT PASS AT 0725 UTC 
SHOWED AN ELONGATED CYCLONIC CIRCULATION WITH 15-20 KT S-SW 
WINDS SOUTH OF THE CIRCULATION CENTER. CONVECTION ASSOCIATED 
WITH THE LOW HAS INCREASED SIGNIFICANTLY TODAY. MODEL GUIDANCE 
INDICATES THE LOW WILL DRIFT W THROUGH SUN WITH LITTLE CHANGE IN 
INTENSITY AND SEAS BUILDING TO 6-8 FT SE OF THE CENTER.

LOOKING AHEAD...VERY LONG PERIOD NW SWELL ASSOCIATED WITH STRONG 
LOW PRES SYSTEM LOCATED NW OF AREA WILL SWEEP INTO NW WATERS SUN 
AND SPREAD SOUTHEASTWARD MON THROUGH WED. WAVE MODEL GUIDANCE 
SHOWS THE 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.
 
$$ 
GR