000
AXPZ20 KNHC 091604
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SAT OCT 09 2010

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

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...THE ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS ANALYZED FROM 09N83W TO 
06N100W TO LOW PRES 1012 MB NEAR 08.5N115.5W TO 11N122W TO LOW 
PRES 1012 MB NEAR 10.5N127.5W TO 09N140W. SCATTERED MODERATE TO 
STRONG WITHIN 60 NM OF AXIS BETWEEN 128W AND 134W. SCATTERED 
MODERATE CONVECTION NOTED WITHIN 120 NM OF THE AXIS BETWEEN 121W 
AND 128W.

...DISCUSSION...

UPPER LEVEL FLOW ACROSS THE REGION N OF 20N HAS BECOME MORE 
POSITIVELY TILTED DURING THE PAST 24 HOURS AS A LONGWAVE UPPER 
TROUGH HAS SHIFTED INTO THE NE PACIFIC. AN UPPER TROUGH EXTENDS 
FROM AN UPPER CYCLONE OVER THE GREAT PLAINS THROUGH 32N117W AND 
CONTINUES SW TO A MID LEVEL LOW NEAR 21N143W. CONVERGENCE 
OCCURRING WITHIN THIS NARROW TROUGH IS LEADING TO DEEP LAYERED 
SUBSIDENCE WITHIN 200 NM OF THE TROUGH AXIS. W TO SW UPPER LEVEL 
FLOW IS OCCURRING S AND SE OF THIS TROUGH TO 115W...AND IS 
AIDING IN CREATING A FAVORABLE UPPER ENVIRONMENT FOR DEEP 
CONVECTION ALONG THE ITCZ W OF 130W. AN UPPER ANTICYCLONE IS 
CENTERED AT 31N136W WITH A RIDGE EXTENDING NE TO THE OFFSHORE 
WATERS OF THE PACIFIC U.S. COASTS...AND SW TO JUST N OF THE 
HAWAIIAN ISLANDS. THIS RIDGE SEPARATES THE AFOREMENTIONED TROUGH 
AND THE LONGWAVE TROUGH MOVING INTO THE NE PACIFIC. TO THE 
E...AN UPPER RIDGE EXTENDS W ACROSS THE SOUTHERN CARIBBEAN AND 
CENTRAL AMERICA ALONG 13N THEN TURNS W-NW TO 17N117W. VERY 
MODEST CONVECTION IS OCCURRING ALONG THE ITCZ ACROSS THE FAR 
EPAC S OF THIS RIDGE...AND MAINLY BETWEEN 105W AND 115W.

AT THE LOW LEVELS...A 1026 MB HIGH IS CENTERED NEAR 31N130W WITH 
A RIDGE SW TO BEYOND 26N140W...AND A RIDGE SE TO NEAR 17N112W. 
THE LOW LEVEL PRES GRADIENT BETWEEN THIS HIGH AND THE ITCZ IS 
SUPPORTING NE TO E TRADES AT 15-25 KT WITH SEAS TO ABOUT 11 FT 
IN MIXED SWELL. THE RIDGE WILL SLIP A LITTLE FURTHER S AND 
COLLAPSE LATE SUN...ALLOWING A COLD FRONT TO ENTER THE AREA AND 
SWEEP RAPIDLY E ACROSS WATERS N OF 27N THROUGH MON. THIS WILL 
INCREASE THE AREA OF NE WINDS TO ALL WATERS N OF 10N W OF 125W 
BY SUN NIGHT. TO THE E OF THE RIDGE...NWLY FLOW HAS INCREASED 
ALONG THE W COAST OF BAJA CALIFORNIA TO NEAR 20 KT...AS WELL AS 
INSIDE THE GULF OF CALIFORNIA. THESE WINDS WILL DIMINISH BY SUN 
EVENING AS THE HIGH COLLAPSES.

GAP WINDS...NORTHERLY WINDS AT 20 TO 25 ARE NOTED OVER AND 
DOWNSTREAM OF THE GULF OF TEHUANTEPEC. EXPECT THESE WINDS TO 
GRADUALLY DIMINISH TO 20 KT TONIGHT...THEN BRIEFLY INCREASE TO 
20 TO 25 KT SUN MORNING...AND THEN GRADUALLY DIMINISH TO 15 TO 
20 KT BY MON MORNING. MODERATE NE OFFSHORE TRADEWINDS WILL 
CONTINUE BLOWING OFF THE PACIFIC COASTS E OF 90W THROUGH SUN 
MORNING BEFORE WEAKENING IN RESPONSE TO AN ELONGATED LOW 
ATTEMPTING TO ORGANIZE IN THE W CARIBBEAN.
  
$$
STRIPLING