000
AXPZ20 KNHC 032232
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SAT SEP 03 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 
2130 UTC.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM 15N104W TO 14N125W TO 13N140W.  
SCATTERED MODERATE FROM 06N TO 08N BETWEEN 91W AND 95W...FROM 
09N TO 11N BETWEEN 102W AND 108W AND WITHIN 140 NM S OF MONSOON 
TROUGH BETWEEN 124W AND 136W.

...DISCUSSION...
BLOCKING PATTERN ALOFT PERSISTS ACROSS THE AREA TODAY. A BROAD 
MIDDLE TO UPPER LEVEL TROUGH COVERS THE AREA N OF 18N BETWEEN 
122W AND 142W WITH A CUT-OFF LOW NEAR 28N130W. UPPER LEVEL RIDGE 
EXTENDS FROM AN UPPER ANTICYCLONE CENTERED NEAR 25N112W ESE 
ACROSS MEXICO TO THE BAY OF CAMPECHE. A MIDDLE LEVEL TROUGH 
ASSOCIATED WITH THE REMNANTS OF THE FORMER T.D. EIGHT-E NARROWS 
THE RIDGE NEAR THE MOUTH OF THE GULF OF CALIFORNIA. SOUTH OF 
THIS RIDGE...NE TO E FLOW ALOFT PERSISTS...YIELDING MODERATE 
VERTICAL WIND SHEAR ACROSS THE DEEP TROPICS...BUT HAD INCREASED 
TO 30 KT OF SHEAR DUE SOUTH OF THE HIGH CENTER ALONG 110W. A 
SIGNIFICANT PATTERN CHANGE ACROSS THE AREA IS EXPECTED NEXT WEEK 
AS THE UPPER TROUGH WILL EVENTUALLY WEAKEN AND LIFT OUT TO THE 
NE. 

AT THE SURFACE...HIGH PRES REMAINS CENTERED WELL N OF THE 
DISCUSSION AREA...WITH A 1023 MB HIGH NEAR 44N135W AND A SECOND 
1023 MB HIGH NEAR 33N152W. A NEARLY STATIONARY 1012 MB LOW ALONG 
THE COAST OF NORTHERN CALIFORNIA WITH A DYING FRONTAL TROUGH 
EXTENDS WELL SW AND SEPARATES THE TWO HIGH CENTERS. A WEAK 
SURFACE RIDGE THUS EXTENDS ESE ACROSS THE AREA FROM THE HIGH 
NEAR 33N152W TO NEAR 27N117W PRODUCING A MILD PRESSURE GRADIENT 
ACROSS THE LOCAL AREA. TRADEWINDS REMAIN BELOW 20 KT E OF 140W 
UNDER THE INFLUENCE OF THIS WEAK RIDGE...WITH SEAS 7 TO 9 FT IN 
A MIX OF LONG PERIOD SRN HEMI SLY SWELL AND MODERATE NLY SWELL. 

THE REMNANTS OF T.D. EIGHT-E ARE EVIDENT ON VISIBLE SATELLITE 
IMAGERY ACROSS THE MOUTH OF THE GULF OF CALIFORNIA NEAR 
22N108W...PRODUCING SCATTERED MODERATE CONVECTION...AND REMAINS 
EMBEDDED WITHIN THE S END OF THE SEMIPERMANENT BAJA CALIFORNIA 
TROUGH. THIS FEATURE IS EXPECTED TO DRIFT SLOWLY WNW ACROSS THE 
S TIP OF BAJA DURING THE NEXT 24 HOURS AND GRADUALLY WEAKEN. A 
BROAD CYCLONIC LOW TO MID LEVEL GYRE ASSOCIATED WITH THIS FORMER 
T.D. CONTINUES TO TRANSPORT TROPICAL MOISTURE FROM THE EPAC N  
AND NE ACROSS ALL BUT NORTHERN MEXICO AND INTO THE GULF OE 
MEXICO...WHERE IT IS ALSO FEEDING INTO TROPICAL STORM LEE. 
EXPECT THIS MOIST PATTERN TO CONTINUE THROUGH MONDAY.

FURTHER SOUTH...BROAD MONSOONAL FLOW IS OCCURRING ACROSS THE 
AREA S THROUGH E OF THE MONSOON TROUGH TO THE COASTS OF CENTRAL 
AMERICA AND COLOMBIA...AND IS GENERALLY LESS THAN 20 KT BUT WITH 
A FEW VERY SMALL AREAS NEAR 20 KT DEPICTED BY AFTERNOON 
SCATTEROMETER PASSES. AN ELONGATED ZONE OF VERY FAVORABLE LOW 
LEVEL CONVERGENCE WAS YIELDING SCATTERED MODERATE CONVECTION 
FROM 08N-11N BETWEEN 90W AND 120W...AND FROM 11N-14N W OF 122W. 
THIS SYNOPTIC PATTERN WILL GENERALLY HOLD THROUGH THE NEXT FEW 
DAYS.

$$
STRIPLING