000
AXPZ20 KNHC 111605 RRA
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL 
1605 UTC SUN AUG 11 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 
0130 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...          
MONSOON TROUGH AXIS EXTENDS FROM COLOMBIA NEAR 09N74W TO ACROSS 
NRN COSTA RICA TO 09N89W TO 08N97W TO LOW PRES NEAR 13N121W 1009 
MB AND TO 12N112W WHERE IT IS NO LONGER IDENTIFIABLE. SCATTERED 
STRONG CONVECTION EXISTS FROM 06N-09N E OF 82W.

...DISCUSSION...

WATER VAPOR IMAGERY SHOWS AN ELONGATED UPPER LEVEL ANTICYCLONE 
NOW HAVING SHIFTED NE TO NEAR 26N115W WITH A RIDGE STRETCHING SW 
TO 20N140W...AND ANOTHER ONE NEWD TO EASTERN TEXAS. BROAD UPPER 
SW TO W FLOW IS SEEN N OF THE ANTICYCLONE AND ASSOCIATED 
RIDGES...PRODUCING VERY DRY AND STABLE CONDITIONS WITHIN THE 
RIDGE AND TO ITS NW. E TO NE WINDS ALOFT GENERALLY PREVAIL 
ACROSS THE REMAINDER OF THE AREA S AND SE OF THE 
RIDGE...CONTINUING TO PRODUCE A GENERALLY LIGHTLY SHEARED 
ENVIRONMENT.

AT THE SURFACE...A 1023 MB HIGH IS ANALYZED AT 32N139W WITH A 
RIDGE EXTENDING SE TO NEAR 21N116W. THE WEAK PRES GRADIENT 
BETWEEN THE HIGH AND PERSISTENT LOW PRES ALONG THE SIERRA MADRES 
OCCIDENTALES IS PRODUCING NNW WINDS NEAR 20 KT ALONG AND 
OFFSHORE OF THE W COAST OF BAJA CALIFORNIA TO ABOUT 116W...WHERE 
WAVE MODEL GUIDANCE AND A FEW SHIP OBSERVATIONS FROM THE PAST 24 
HOURS INDICATED PEAK SEAS ARE 5-6 FT. THESE CONDITIONS ARE 
FORECAST TO CHANGE VERY LITTLE OVER THE NEXT 24-48 HOURS. A  
DISSIPATING COLD FRONT IS OVER THE FAR NW CORNER OF THE AREA 
FROM 32N129W TO 28N140W. IT IS POSSIBLE TO CONTAIN ISOLATED 
SHOWERS. THE IS FORECAST TO DISSIPATE OVER THE NEXT 24 HOURS AS 
ANOTHER HIGH OF 1021 MB N OF THE AREA AT 36N141W MOVES SE TO 
NEAR 32N138W. THE PRES GRADIENT BETWEEN THE HIGH AND THE MONSOON 
TROUGH TO THE S IS MODEST AT BEST...AND IS AIDING IN PRODUCING 
SMALL AREAS OF FRESH NE TRADES TO THE N AND NW OF TWO LOW PRES 
CENTERS EMBEDDED ALONG THE MONSOON TROUGH...ONE OF 1009 MB AT 
13N121W...AND THE OTHER ONE WEAKER WITH A PRES OF 1010 MB AT 
12N136W. SCATTERED MODERATE/ISOLATED STRONG IS NOTED WITHIN 180 
NM IN THE SW QUADRANT OF THE LOW AT 13N121W...WHILE SIMILAR 
CONVECTION IS WITHIN 180 NM IN THE NW QUADRANT OF THE LOW AT 
12N136W. THE LOW AT 13N121W IS FORECAST TO MOVE TO NEAR 13N126W 
IN 24 HOURS...AND TO NEAR 13N131W IN 48W HOURS WITH MAJORITY OF 
THE GLOBAL MODELS DEPICTING THAT IT MAY ACTUALLY BE MORE OF 
TROUGH FEATURE NEAR 48 HOUR. 

SATELLITE IMAGERY FROM THROUGH THE MORNING HAS BEEN SHOWING 
CLUSTER OF SCATTERED TSTMS MOST PROMINENT OVER THE EASTERN 
PORTION OF THE AREA WHERE MORE DEEP ATMOSPHERIC MOISTURE IS 
PREVALENT. SCATTERED STRONG SCATTERED CONVECTION IS SEEN FROM 
15N TO 19N BETWEEN 103W AND 108W...AND ALSO WITHIN 45 NM OF 
13N91W. WIDELY SCATTERED SHOWERS AND TSTMS ARE ELSEWHERE E OF 
ABOUT 117W...WITH ISOLATED SHOWERS AND TSTMS ELSEWHERE FROM 06N 
TO 19N BETWEEN 117W AND 130W AND FROM 08N TO 17N W OF 130W. 
GLOBAL MODELS SUGGEST THAT A WEAK TROPICAL WAVE WILL MOVE ACROSS 
CENTRAL AMERICA ALONG DURING THE MIDDLE PART OF THE UPCOMING 
WEEK. IT WILL LIKELY BE ATTENDANT BY INCREASING MOISTURE AND 
CONVECTION.

NORTHERLY FLOW THROUGH THE CHIVELA PASS WILL PULSATE THROUGH TUE
ALLOWING FOR 15-20 KT ACROSS THE FAR NORTHERN GULF TEHUANTEPEC 
DURING THIS TIME PERIOD...HOWEVER WITH VERY LIMITED FETCH AND 
DURATION OF THESE WINDS SEAS THERE SHOULD REMAIN AT OR BELOW 5 
FT.

$$ 
AGUIRRE