000
AXPZ20 KNHC 101530
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SUN OCT 10 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 
1530 UTC.

...THE ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS ANALYZED FROM 09N83W TO 
07N96W TO LOW PRES 1011 MB NEAR 08N102W TO 07N107W TO 09N115W TO 
LOW PRES 1011 MB NEAR 08N120W TO LOW PRES 1010 MB NEAR 11N133W 
TO 09N140W. SCATTERED MODERATE CONVECTION NOTED WITHIN 30 NM S 
AND 90 NM N OF AXIS BETWEEN 93W AND 96W...AND BETWEEN 114W AND 
122W. SCATTERED MODERATE ISOLATED STRONG CONVECTION NOTED WITHIN 
120 NM N AND 60 NM S OF AXIS W OF 127W.

...DISCUSSION...

AN UPPER TROUGH EXTENDS FROM A WELL DEFINED CYCLONIC CIRCULATION
OVER NEBRASKA SW THROUGH 32N108W ACROSS NRN BAJA CALIFORNIA THEN
CONTINUES AS A NARROW SHEAR AXIS THROUGH 25N125W TO AN UPPER 
LEVEL CYCLONE W OF THE AREA NEAR 21N146W. A SECOND UPPER CYCLONE 
APPEARS TO BE DEVELOPING WITHIN THE TROUGH NEAR 27N121W. VERY 
DRY AIR WAS NOTED WITHIN 150 NM EITHER SIDE OF THE TROUGH AXIS. 
AN UPPER ANTICYCLONE NEAR 33N127W WITH A RIDGE EXTENDING SW TO 
29N140W EXISTS TO THE N OF THE TROUGH NOTED ABOVE.

A TROPICAL ANTICYCLONE IS NOTED NEAR THE EQUATOR ALONG 130W WITH 
BROAD ANTICYCLONIC FLOW DOMINATING THE AREA S OF 20N W OF 125W. 
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 15N115W. AN UPPER TROUGH EXTENDING NW TO 
SE FROM 22N122W TO 15N120W TO 05N118W 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 1028 MB HIGH PRES IS CENTERED NEAR 
31N135W WITH A RIDGE SW TO BEYOND 28N140W...AND A RIDGE SE TO 
NEAR 18N110W. THE GRADIENT S OF THIS SURFACE RIDGE AND N OF THE 
ITCZ IS SUPPORTING NE TO E TRADES OF 20 TO 25 KT WITH SEAS TO 12 
FT IN MIXED SWELL. THE PARENT SURFACE HIGH IS EXPECTED TO SHIFT 
N OF THE AREA...SOMEWHAT BLOCKING THE NEXT COLD FRONT...AND 
ALLOWING THE NE WINDS TO INCREASE TO 20 KT OVER THE ENTIRE AREA 
W OF 123W BY MON.

GAP WINDS...A 0350 UTC ASCAT PASS INDICATED NORTHERLY WINDS OF 
20 KT ARE NOTED OVER AND DOWNSTREAM OF THE GULF OF TEHUANTEPEC 
TO NEAR 13N97W. THESE WINDS WILL CONTINUE TO DIMINISH TO 15 KT
LATER TODAY WITH LITTLE CHANGE THROUGH MON. HIGH PRES WILL BUILD 
OVER THE N CENTRAL GULF OF MEXICO TUE NIGHT AND WED WITH 
NORTHERLY WINDS INCREASING TO 20 TO 30 KT IN THE GULF OF 
TEHUANTEPEC BY WED.
 
$$
COBB