000
AXPZ20 KNHC 091604
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC TUE NOV 08 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 
1545 UTC.

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

THE MONSOON TROUGH EXTENDS SW ACROSS COSTA RICA FROM 9N84W
TO THE E PACIFIC AT 7N97W TO 12N117W TO 9N129W WHERE LOW LEVEL
WINDS INDICATE A TRANSITION TO THE ITCZ TO 10N140W.  A LOW LEVEL 
TROUGH IS ORIENTATED NNE TO SW FROM 15N118W TO 12N120W...AND IS 
ACCOMPANIED BY SCATTERED MODERATE ISOLATED STRONG CONVECTION 
WITHIN 45 NM EITHER SIDE OF ITS AXIS. SCATTERED STRONG CONVECTION
IS ALONG AND WITHIN 120 NM S OF THE TROUGH BETWEEN 120W AND 
124W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS WITHIN 
120 NM S OF THE ITCZ BETWEEN 131W AND 138W.

...DISCUSSION...

A LONG WAVE TROUGH IS OVER THE FAR NE PORTION OF THE AREA N OF
17N AND E OF 119W. A SHORT WAVE TROUGH WITHIN THE LONG WAVE
TROUGH IS RAPIDLY SHIFTING E OF THE AREA FROM 15N TO 25N E OF 
115N. A BAND OF UPPER MOISTURE IS RACING E ACROSS THE NORTHERN 
BAJA CALIFORNIA PENINSULA...THE NORTHERN GULF OF CALIFORNIA AND 
EXTREME NORTHERN OLD MEXICO THIS MORNING. MODERATE SUBSIDENCE
ALLOWING FOR DRY STABLE CONDITIONS IS CONFINED TO N OF 25N AND
E OF 123W.

AN UPPER LEVEL CYCLONE CONTINUES OVER THE DEEP TROPICS NEAR 
1N105W AND SEPARATES UPPER ANTICYCLONIC FLOW OVER THE TROPICAL 
E PACIFIC. TO THE W AN UPPER ANTICYLONE IS CENTERED NEAR 12N128W 
WITH A SHORT WAVE RIDGE AMPLIFYING N BEYOND 32N128W TO ALONG THE 
WESTERN SEABOARD OF THE CONUS. AN UPPER ANTICYCLONE IS CENTERED 
NEAR 13N92W WITH A RIDGE EXTENDING NE ACROSS THE EASTERN GULF OF 
MEXICO AND THE SE CONUS. BROAD UPPER DIFFLUENCE IS ENHANCING THE 
PREVIOUSLY DESCRIBED CONVECTION ALONG THE LOW LEVEL TROUGH AND 
ALONG THE ITCZ BETWEEN 120W AND 140W. THE DEBRIS MOISTURE IS 
ADVECTED N MERGING WITH ADDITIONAL MOISTURE ORIGINATING FROM 
ITCZ CONVECTION WELL W OF THE AREA THAT HAS SPREAD E INTO THE 
DISCUSSION AREA. THE RESULT IS VERY DEEP MOISTURE THROUGH THE 
ATMOSPHERE FROM 5N TO 28N AND W OF 123W. SOME OF THIS MOISTURE 
CONTINUES E ALONG THE BASE OF THE UPPER TROUGH...AND WILL SPREAD 
E ACROSS THE SOUTHERN BAJA PENINSULA AND GULF OF CALIFORNIA 
TODAY. DEBRIS MOISTURE FROM CONVECTION ALONG THE MONSOON TROUGH 
FANS OUT OVER THE AREA FROM THE EQUATOR TO 9N AND TO E OF 90W. 
OF SIGNIFICANCE IS A STRONG UPPER SHORTWAVE IS APPROACHING THE 
NW PORTION WITH ITS AXIS CURRENTLY FROM 32N139W TO 28N146W.  

AT THE LOW LEVELS A SURFACE HIGH NEAR 32N125W 1022 MB IS MOVING 
SE WITH A RIDGE EXTENDING SE TO NEAR 16N108W. SOUTHERLY WINDS 
ARE INCREASING TO 15 TO 20 KT OVER THE WATERS N OF 29N W OF 138W 
IN ADVANCE OF A SURFACE COLD FRONT THAT WILL MOVE INTO THE AREA 
EARLY THIS AFTERNOON ACCOMPANIED BY NW WINDS AT 20 TO 25 KT AND 
SEAS 8 TO 10 FT. SOUTHERLY WINDS WILL ALSO INCREASE TO 20 TO 25 
KT OVER THE WATERS N OF 28N WITHIN 240 NM E OF THE FRONT. 
ALTHOUGH THE GRADIENT WILL RELAX ON THU AND FRI...LARGE NW 
SWELLS... RESULTING IN COMBINED SEAS TO 20 FT...WILL PROPAGATE 
SE INTO THE NW WATERS. NE TO E TRADE WINDS AT 15 TO 20 KT AND 
SEAS 9 TO 11 FT IN MIXED NE AND NW SWELL...IS OBSERVED S OF THE 
RIDGE IN THE AREA FROM 8N TO 25N W OF 115W. MIXED N SWELL IS 
FOUND OVER THE REMAINDER OF FORECAST WATERS W OF 110W WITH SEAS 
7 TO 10 FT IN THE N SWELL WHICH IS MIXING WITH SOUTHERLY SWELL 
IN WATERS S OF 12N.

GULF OF TEHUANTEPEC...N WINDS AT 15 TO 20 KT WILL SURGE THROUGH 
THE CHIVELA PASS INTO THE GULF OF TEHUANTEPEC TONIGHT RAPIDLY 
INCREASING TO GALE FORCE THU AFTERNOON...AND JUST BELOW STORM 
FORCE THU NIGHT. WINDS WILL DIMINISH BELOW GALE FORCE FRI NIGHT 
AND FURTHER DIMINISH BELOW 20 KT SAT.

$$
AGUIRRE