000
AXPZ20 KNHC 110323
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC WED SEP 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0200 UTC.

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

MONSOON TROUGH AXIS CONTINUES ACROSS CENTRAL AMERICA... 
MEANDERING FROM PANAMA NORTHWESTWARD TO SOUTHEAST PORTIONS OF 
MEXICO NEAR 18.5N98W...WHERE IT BECOME ILL DEFINED...THEN 
RESUMES NEAR 16.5N103W TO 13N106.5W TO 11N136W...WHERE IT 
TRANSITIONS TO ITCZ CONTINUING ON BEYOND 10N140W. SCATTERED 
MODERATE TO STRONG CONVECTION NOTED FROM 05N TO 10N BETWEEN 83W 
AND 88W. SCATTERED MODERATE ISOLATED STRONG CONVECTION NOTED 
FROM 07N TO 14N BETWEEN 92.5W AND 107W. 

...DISCUSSION...

AN UPPER TROUGH HAS BECOME NEARLY STATIONARY JUST TO THE NW AND 
OF THE DISCUSSION AREA...WHILE A DEEP LAYERED CYCLONE 
ENCOMPASSED THE SOUTHWESTERN U.S. BETWEEN 109W AND 125W AND 
EXTENDED S INTO THE AREA ALONG 28.5N119W. UPPER LEVEL RIDGING 
PREVAILED TO THE SW OF THIS CYCLONE TO 140W...AND WAS AIDING IN 
PRODUCING A BROAD ZONE OF GENERALLY DRY AND STABLE ATMOSPHERIC 
CONDITIONS ACROSS THE NW ONE-THIRD OF THE AREA. SOUTHEAST OF THE 
DEEP LAYERED TROUGH IS A BROAD UPPER RIDGE COVERING ALL BUT NW 
MEXICO...AND EXTENDING FROM AN ANTICYCLONE NEAR 23N106W W-SW TO 
NEAR 15N130W. ANTICYCLONIC FLOW GENERALLY RESIDES ELSEWHERE TO 
THE E...AS SCATTERED MODERATE TO STRONG CONVECTION ACROSS THE 
REGION CONTINUE TO INDUCE BROAD ZONES OF DIVERGENCE 
ALOFT. 

ELSEWHERE AT LOW LEVELS...A BROAD TROUGH EXTENDS FROM THE GULF 
OF CALIFORNIA SW TO NEAR 16N116.5W. MID DAY SCATTEROMETER PASSES 
ACROSS THE AREA SHOWED A BROAD ZONE OF MODERATE SW WINDS S OF 
THE MONSOON TROUGH FROM 02.5N TO 10N BETWEEN E OF 112W...AND AN 
AREA OF 20-25 KT SW WINDS FROM 02N TO 08N BETWEEN 80W AND 
89W...WHICH WAS FUELING A LARGE CLUSTER OF DEEP CONVECTION. 
CONVECTION HAS SINCE DIMINISHED IN AREAL COVERAGE THIS EVENING 
SUGGESTING A REDUCTION IN LOW LEVEL WIND FLOW. 

GLOBAL MODELS INDICATE THAT THE SW MONSOONAL FLOW WILL 
STRENGTHEN BETWEEN 92W AND 105W DURING THE NEXT FEW DAYS AND 
GRADUALLY LEAD TO THE DEVELOPMENT OF A SURFACE LOW OFFSHORE AND 
TO THE SOUTHWEST OF THE GULF OF TEHUANTEPEC...WHERE IT MAY  
MEANDER FOR SEVERAL DAYS. THIS INCREASED SW FLOW WILL LEAD TO 
VERY ACTIVE CONVECTION ACROSS THIS AREA...AND LOCAL SEAS 
BUILDING 7-10 FT WITHIN 48 HOURS.

$$
STRIPLING