000
AXPZ20 KNHC 182125
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SUN SEP 18 2011

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 
2100 UTC.

...ITCZ/MONSOON TROUGH...

MONSOON TROUGH AXIS EXTENDS FROM 10N80W TO LOW PRES AT 10N93W TO 
07N103W...THEN RESUMES FROM LOW PRES AT 17N113W TO 13N120W TO 
10N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION N OF 04N E
OF 104W AND WITHIN 150 NM OF LINE 21N110W TO 12N120W TO 09N140W.

...DISCUSSION... 

HIGH PRES RIDGE N OF AREA EXTENDS FROM 36N130W THROUGH A 1026 MB 
HIGH NEAR 33N135W TO A 1025 MB HIGH NEAR 32N152W. THE RIDGE IS 
SUPPORTING 15 KT TRADE WINDS N OF THE MONSOON TROUGH TO AROUND 
25N. SCATTEROMETER DATA INDICATES STRONG LOW LEVEL CONVERGENCE 
ALONG 10N BETWEEN 115W AND 140W ASSOCIATED WITH THE MONSOON 
TROUGH. FRESH S TO SW FLOW IS EVIDENT S OF THE TROUGH BETWEEN 
125W AND 135W. THE CONVERGENT FLOW IS CONTINUING TO GENERATE 
ACTIVE CONVECTION IN SCATTERED MODERATE SHOWERS AND TSTMS IN 
THIS AREA AS WELL ALONG THE MONSOON TROUGH.

A WEAK LOW PRES CENTER IS EVIDENT FROM SATELLITE DATA NEAR 10N94W
WITH AN ESTIMATED PRES OF 1011 MB. GLOBAL MODELS CONTINUE TO SHOW
THIS LOW PRES AREA STEADILY DEVELOPING OVER THE NEXT FEW DAYS IN 
THIS AREA AND DRIFTING W ALONG THE MONSOON TROUGH AXIS. THE MAIN 
IMPACT OF THIS WILL BE SW WINDS REACHING 20 KT WITHIN 180-240 NM 
S OF THE MONSOON TROUGH MAINLY BETWEEN 110W AND 130W OVER THE 
NEXT FEW DAYS...WITH SEAS BUILDING TO 9 FT. EXPECTED DEVELOPMENT
HAS BEEN VERY SLOW AND THE FORECAST TENDENCY WILL BE TO REMAIN 
BELOW GUIDANCE ON WINDS AND SEAS ASSOCIATED WITH THIS FEATURE. 

WIND REPORTS AND ASCAT PASS CONFIRM ENHANCED N FLOW THROUGH THE 
TEHUANTEPEC GULF...WITH MAX WINDS AROUND 20 KT. THIS IS A LITTLE 
LESS THAN EXPECTED...BUT GIVEN THE DEVELOPMENT OF WEAK LOW PRES 
TO THE SOUTH...EXPECT OCCASIONAL 20 KT FLOW THROUGH TEHUANTEPEC 
THROUGH TUE...WITH DIURNAL MAXIMUM TO 25 KT IN THE MORNING.

$$
MUNDELL