000
AXPZ20 KNHC 120332
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC TUE OCT 12 2010

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN
FROM THE EQUATOR TO 32N...EAST OF 140W.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0315 UTC.

...THE ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS CENTERED ALONG 8N78W
8N91W 7N98W TO 1008 MB LOW PRES NEAR 8N106W TO 1008 MB LOW PRES
11N120W TO 8N131W TO 10N140W. SCATTERED CONVECTION IS WITHIN 
120 NM S OF THE AXIS BETWEEN 119W-123W...AND 60 NM OF THE AXIS
BETWEEN 124W-127W.

...DISCUSSION...

AN UPPER TROUGH EXTENDS FROM A WELL DEFINED CYCLONIC CIRCULATION 
OVER NEBRASKA SW TO ACROSS NW MEXICO WHERE IT ENDS AT A COL 
REGION AT 29N112W. A MID/UPPER LEVEL ANTICYCLONE IS N OF THE COL 
REGION OVER FAR SW NEVADA MOVING SE. A RIDGE EXTENDS W FROM THE 
ANTICYCLONE TO 32N124W AND SW TO 31N133W. A NEARLY STATIONARY 
SMALL UPPER LEVEL CYCLONIC CIRCULATION IS NEAR 27N123W WITH A 
NARROW TROUGH SE TO 25N115W TO 20N111W AND CONTINUES SE TO 
11N112W. SATELLITE WATER VAPOR IMAGERY SHOWS MODERATE SUBSIDENCE 
WITH VERY STABLE ATMOSPHERIC CONDITIONS ALONG AND NE OF THE 
TROUGH. A NARROW UPPER TROUGH EXTENDS FROM 32N125W TO W OF THE 
REGION AT 24N140W.

OVER THE TROPICAL ZONE...BROAD ANTICYCLONIC FLOW COVERS THE AREA 
S OF 22N W OF 110W. UPPER DIFFLUENCE BETWEEN THE ABOVE AND THE
EASTERN PERIPHERY OF THE ANTICYCLONIC FLOW AREA IS HELPING TO 
SUPPORT CONVECTION ALONG THE ITCZ BETWEEN 119W-123W. DIFFLUENCE 
ON THE BACK SIDE OF THE ANTICYCLONIC AREA IS AIDING ITCZ 
CONVECTION BETWEEN 124W-127W. A LARGE UPPER ANTICYCLONE CENTERED
OVER THE N CENTRAL CARIBBEAN SEA HAS A RIDGE AXIS EXTENDING W 
ACROSS CENTRAL AMERICA...THEN NW TO CENTRAL GULF OF CALIFORNIA.
A LARGE PLUME OF UPPER LEVEL MOISTURE IS RIDING OVER THE BROAD 
ANTICYCLONIC AREA FROM 13N TO 25N W OF 110W WHERE IT DISSOLVES 
IN DRY AIR ALOFT ASSOCIATED WITH MODERATE SUBSIDENCE E OF THE 
ABOVE MENTIONED UPPER TROUGH. NEAR THE COAST COSTA 
RICA...ISOLATED WEAK CONVECTION IS NOTED BUT WEAKENING AS IT 
MOVES W. SLIGHTER STRONGER TSTM CLUSTERS MOVING W ARE NOTED 
ALONG AND WITHIN ABOUT 30 NM OF THE COLOMBIAN COAST FROM 5N TO 
THE BORDER OF PANAMA.

AT THE SURFACE...A RIDGE EXTENDS FROM 32N132W TO 24N122W. HIGH 
PRES COVERS THE AREA N OF 21N W OF 122W. THE PRES GRADIENT S OF 
THE RIDGE AND N OF THE ITCZ IS SUPPORTING NE TO E TRADES OF 20 
KT IN AN AREA FROM 12N TO 22N W OF 125W WHERE SEAS ARE IN THE 
RANGE OF 8 TO 11 FT PRIMARILY IN NE SWELL. THE RIDGE IS FORECAST 
WEAKEN THROUGH THE NEXT 48 HOURS ALLOWING FOR WINDS WITHIN THIS
AREA TO DIMINISH TO 20 KT FROM 12N TO 18N W OF 129W WITH SEAS
TO 8 FT IN S SWELL.

GAP WINDS...N WINDS OF 20 KT THROUGH THE GULF OF TEHUANTEPEC IN 
ABOUT 24 HOURS ARE EXPECTED TO LEAD THE ONSET OF THE NEXT GALE
EVENT THROUGH THE GULF STARTING IN 36 HOURS AT WHICH TIME WINDS
ARE FORECAST TO INCREASE TO 25 TO 35 KT FROM THE N AND NE WITH
SEAS BUILDING 8 TO 11 FT. WITH HIGH PRES BUILDING SE ACROSS
SOUTHEASTERN MEXICO...THE PRES GRADIENT WILL THEN FURTHER 
INCREASE THROUGH THE ISTHMUS OF TEHUANTEPEC ALLOWING FOR WINDS 
TO INCREASE TO 30 TO 40 KT WITH SEAS BUILDING TO 18 FT. THESE 
CONDITIONS MAY INCREASE FURTHER JUST BEYOND 48 HOURS.

$$
AGUIRRE