000
AXPZ20 KNHC 102159
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SUN OCT 10 2010

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2145 UTC.

...THE ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS ANALYZED FROM 09N85W TO 
07N95W TO LOW NEAR 08N103W 1011 MB TO 08N113W TO 08N121W TO LOW 
NEAR 11N133W 1012 MB TO 08N140W. SCATTERED MODERATE ISOLATED 
STRONG WITHIN 60 NM N OF AXIS BETWEEN 115W AND 117W. SCATTERED 
MODERATE WITHIN 60 NM S OF AXIS BETWEEN 130W AND 132W.

...DISCUSSION...

AN UPPER TROUGH EXTENDS FROM A WELL DEFINED CYCLONIC CIRCULATION
OVER NEBRASKA SW THROUGH 32N107W ACROSS CENTRAL BAJA CALIFORNIA
THEN CONTINUES AS A NARROW SHEAR AXIS THROUGH 25N125W TO AN 
UPPER LEVEL CYCLONE W OF THE AREA NEAR 19N147W. SMALL CYCLONIC
CIRCULATIONS ARE EMBEDDED WITHIN THE TROUGH NEAR 26N119W AND 
24N132W. VERY DRY AIR WAS NOTED WITHIN 150 NM EITHER SIDE OF THE 
TROUGH/SHEAR AXIS. AN UPPER ANTICYCLONE NEAR 33N125W WITH A 
RIDGE EXTENDING SW TO A COL NEAR 29N140W EXISTS TO THE N OF THE 
TROUGH NOTED ABOVE.

A TROPICAL ANTICYCLONE IS NOTED NEAR 9N128W WITH BROAD 
ANTICYCLONIC FLOW DOMINATING THE AREA S OF 20N W OF 122W. THE 
ASSOCIATED UPPER DIFFLUENCE IS ENHANCING CONVECTION ALONG THE 
ITCZ AXIS W OF 130W. AN UPPER ANTICYCLONE OVER THE CARIBBEAN 
NEAR PUERTO RICO HAS A RIDGE AXIS EXTENDING W ACROSS CENTRAL 
AMERICA AND THE ISTHMUS OF TEHUANTEPEC TO A CREST OVER THE 
TROPICAL PACIFIC NEAR 16N112W. AN UPPER TROUGH EXTENDING NW TO 
SE FROM 22N122W TO 13N115W TO 07N108W ESSENTIALLY SPLITS THE TWO 
RIDGES/ANTICYCLONES. THE UPPER LEVELS ARE VERY DRY S OF 23N E OF 
115W IN THE VICINITY OF MEXICO AND CENTRAL AMERICA.

AT THE SURFACE...BUILDING 1029 MB HIGH PRES IS CENTERED NEAR 
32N135W WITH A RIDGE EXTENDING SE THROUGH 25N125W TO NEAR 
18N110W. THE GRADIENT S OF THIS SURFACE RIDGE AND N OF THE ITCZ 
IS SUPPORTING NE TO E TRADES OF 20 TO LOCALLY 25 KT IN AN AREA 
FROM 10N TO 20N W OF 127W. THIS WAS CONFIRMED BY AN 1802 UTC 
ASCAT PASS. SEAS WERE 8 TO 11 FT IN MIXED SWELL. THE PARENT 
SURFACE HIGH IS EXPECTED TO SHIFT WELL N OF THE AREA...SOMEWHAT 
BLOCKING THE NEXT COLD FRONT...AND ALLOWING AN AREA OF N TO NE 
WINDS TO INCREASE TO 20 KT OVER THE ENTIRE AREA W OF 123W BY MON.

GAP WINDS...A 1622 UTC ASCAT PASS INDICATED NORTHERLY WINDS OF 
15 TO 20 KT OVER AND DOWNSTREAM OF THE GULF OF TEHUANTEPEC IN 
RESIDUAL DRAINAGE FLOW. THESE WINDS WILL PULSE TO 20 KT IN 
DIURNALLY INDUCED DRAINAGE FLOW MON MORNING BEFORE DIMINISHING 
TO 10 TO 15 KT TUE. WINDS INCREASE ONCE AGAIN TUE NIGHT INTO 
WED...POSSIBLY REACHING GALE FORCE THU.

$$
COBB