000
AXPZ20 KNHC 190245
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL 
0405 UTC SAT OCT 19 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 
0200 UTC.

...SPECIAL FEATURES... 

A BROAD AREA OF LOW PRESSURE...EMBEDDED IN THE MONSOON TROUGH IS 
LOCATED NEAR 10.5N97W OR ABOUT 305 NM SOUTH-SOUTHWEST OF THE 
GULF OF TEHUANTEPEC. SHOWERS AND THUNDERSTORMS CONTINUE TO SHOW 
SIGNS OF ORGANIZATION IN ASSOCIATION WITH THIS SYSTEM. SATELLITE 
IMAGERY SHOWS SCATTERED MODERATE TO ISOLATED STRONG CONVECTION 
WITHIN 180 NM N SEMICIRCLE AND 210 NM SW QUADRANT OF LOW CENTER. 
CONDITIONS ARE EXPECTED TO BE CONDUCIVE FOR GRADUAL 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 KT. FOR 
NOW...MARINE GUIDANCE SUGGESTS INCREASING WINDS TO 20-25 KT AND 
BUILDING SEAS TO AROUND 9 FT SE OF LOW CENTER DURING THE NEXT 
COUPLE OF DAYS. 

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

THE MONSOON TROUGH EXTENDS FROM 11N86W TO 1009 MB LOW PRES NEAR 
10.5N97W TO 11N106W TO 1010 MB LOW PRES NEAR 10N112W TO 07N120W 
TO 07N130W. ITCZ CONTINUES FROM 07N130W TO 13N140W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION IS NOTED FROM 08N TO 14N 
BETWEEN 94W AND 99W AND FROM 07N TO 11N BETWEEN 99W AND 103W. 
SCATTERED MODERATE CONVECTION IS WITHIN 120 NM S OF TROUGH 
BETWEEN 108W AND 111W AND FROM 05N TO 08N BETWEEN 117W AND 120W.

...DISCUSSION...                                              

A 1029 MB HIGH PRESSURE CENTERED WELL N OF AREA EXTENDS A RIDGE 
ACROSS THE N WATERS MAINLY 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 REMNANT LOW OF PRISCILLA HAS WEAKENED INTO A TROUGH THAT 
EXTENDS ALONG 127W FROM 16N TO 20N. THE TROUGH WILL MOVE 
WESTWARD REACHING 130W BY SAT AFTERNOON AND 135W BY SUN 
AFTERNOON. 

ANOTHER AREA OF LOW PRESSURE REMAINS EMBEDDED IN THE MONSOON 
TROUGH AND IS CENTERED NEAR 10N112W. SCATTEROMETER DATA SHOWED 
AN ELONGATED CYCLONIC CIRCULATION WITH 15-20 KT S-SW WINDS SOUTH 
OF THE CIRCULATION CENTER. CONVECTION ASSOCIATED WITH THE LOW  
INCREASED SIGNIFICANTLY DURING THE DAY TODAY BUT HAS DIMINISHED 
THIS EVENING. MODEL GUIDANCE INDICATES THE LOW WILL DRIFT W 
THROUGH SUN WITH LITTLE CHANGE IN INTENSITY WITH SEAS BUILDING 
TO 6-8 FT SE OF THE CENTER IN A SW WIND FLOW. 

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