000
AXPZ20 KNHC 161608
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC TUE AUG 16 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...SPECIAL FEATURES...
TROPICAL STORM FERNANDA NEAR 12.3N 134.5W 1004 MB MOVING W OR 
270 DEG AT 7 KT. MAXIMUM SUSTAINED WINDS 40 KT GUSTS 50 KT. 
TROPICAL STORM FORCE WINDS WITHIN 30 NM OF CENTER. SEAS 12 FT OR 
GREATER WITHIN 30 NM N SEMICIRCLE WITH SEAS TO 13 FT. WITHIN 240 
NM NW AND 120 NM SE SEMICIRCLES WINDS 20 TO 33 KT. SEAS TO 10 FT.
SCATTERED MODERATE TO STRONG CONVECTION WITHIN 75 NM N SEMICIRCLE
AND SCATTERED TO NUMEROUS MODERATE TO STRONG CONVECTION WITHIN 
240 NM S SEMICIRCLE. FERNANDA IS EXPECTED TO MOVE WEST AND 
INTENSIFY DURING THE NEXT 24 HOURS. REFER TO FORECAST ADVISORIES 
ISSUED UNDER WMO HEADER WTPZ21 KNHC AND AWIPS HEADER MIATCMEP1 
FOR FURTHER DETAILS.

A 1006 MB LOW PRES IS EMBEDDED IN THE MONSOON TROUGH NEAR 14N98W.
WINDS OF 20 TO 25 KT ARE WITHIN 210 NM NE SEMICIRCLE WITH SEAS 
TO 10 FT. SCATTERED TO NUMEROUS MODERATE TO STRONG CONVECTION N 
OF 12N TO MEXICAN COAST BETWEEN 95W AND 103W. IT IS FORECAST TO 
MOVE NW S OF MEXICO OVER THE NEXT TWO DAYS AND HAS A HIGH CHANCE 
OF DEVELOPING INTO A TROPICAL CYCLONE.

...ITCZ/MONSOON TROUGH...
MONSOON TROUGH FROM 11N73W TO 09N86W TO LOW PRES 13.5N98W TO LOW 
PRES 12N111W TO 11N116W TO 13N128W. SCATTERED MODERATE TO STRONG 
CONVECTION WITHIN 270 NM S OF AXIS E OF 95W AND BETWEEN 103W AND 
123W.

...DISCUSSION...
A SURFACE RIDGE EXTENDS SE INTO THE DISCUSSION AREA FROM 32N140W 
TO NEAR 17N110W. WINDS ARE 10-15 KT ACROSS MOST OF THE REGION N 
OF 20N WITH SEAS 6 FT OR LESS. AN ACTIVE MONSOON STRETCHES ALL 
ACROSS THE DEEP TROPICS...WITH MULTIPLE CYCLONIC CIRCULATIONS... 
IN ADDITION TO TROPICAL STORM FERNANDA AND THE DEVELOPING LOW 
NEAR 14N98W...INDICATED ALONG THE TROUGH AXIS NEAR 12N111W AND 
09N88W. MODERATE EASTERLY UPPER LEVEL WINDS OVER THE MONSOON 
TROUGH E OF 120W ARE ACTING TO INHIBIT SIGNIFICANT DEVELOPMENT...
BUT LIGHTER WINDS N OF 15N ARE EXPECTED TO ALLOW THE LOW NEAR 14N
98W TO INTENSIFY AS IT MOVES NW S OF MEXICO...PARTICULARLY AS 
MODERATE TO FRESH W-SW WINDS CONTINUE TO SURGE INTO THE LOW 
LEVEL CENTER.

WW3 WAVE MODEL GUIDANCE SHOWS SEAS BUILDING TO 10 FT S OF THE 
MONSOON TROUGH TONIGHT E OF 115W. EXPECT THE TROUGH TO GRADUALLY 
SHIFT POLEWARD THROUGH WED...ALLOWING SEAS TO CONTINUE BUILDING 
TO 11-12 FT WITHIN 200 NM S OF THE AXIS WITH WINDS INCREASING TO 
20-25 KT AS THE MONSOON TROUGH DEEPENS OVER THE REGION E OF 115W.

$$
MUNDELL