000
AXPZ20 KNHC 260926
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC MON JUL 26 2010

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...ITCZ...

AXIS ANALYZED ALONG 08N79W TO 09N87W TO 08N100W TO 12N110W TO 
11N118W TO 12N139W. SCATTERED MODERATE TO STRONG CONVECTION IS 
WITHIN 120 NM S OF THE AXIS BETWEEN 89W AND 95W...WITHIN 75 NM 
EITHER SIDE OF THE AXIS BETWEEN 95W AND 103W...AND WITHIN 210 NM 
S OF THE AXIS BETWEEN 108W AND 113W.

...DISCUSSION...

AN UPPER LEVEL TROUGH PERSISTS OVER THE NORTHERN PORTION FROM 
32N124W TO 24N130W TO 22N140W. THE TROUGH IS DRIFTING EASTWARD 
BY AN UPPER RIDGE BUILDING IN FROM W OF THE DISCUSSION AREA 
ENTERING AT 19N140W TO 21N130W. AN UPPER ANTICYCLONE IS CENTERED
NEAR CENTRAL BAJA CALIFORNIA NEAR 26N115W WITH AN UPPER RIDGE 
AXIS EXTENDING SW TO 22N125W WHERE A COL SEPARATES THIS RIDGE 
FROM THE ABOVE MENTIONED RIDGE AND THE UPPER TROUGH...WITH 
ANOTHER RIDGE AXIS EXTENDING FROM THE ANTICYCLONE E-SE ACROSS 
MEXICO AND CONTINUING SE ACROSS CENTRAL AMERICA. MODERATE TO 
STRONG SUBSIDENCE DOMINATES THE REGION N OF 20N W OF 115W AND 
FROM 14N TO 20N W OF 125W.

A NEW UPPER ANTICYCLONE IS POSITIONED NEAR 11N119W WITH A RIDGE 
AXIS EXTENDING NW-N TO THE AFOREMENTIONED COL NEAR 21N127W. 
MAINLY ZONAL FLOW/UPPER LEVEL EASTERLIES EXIST ACROSS THE 
REMAINDER OF THE DISCUSSION AREA WHICH ARE ADVECTING ABUNDANT 
CONVECTIVE DEBRIS WITHIN 180 NM OF THE COAST OFFSHORE OF MEXICO 
AND ALL OF CENTRAL AMERICA...AND ALSO WESTWARD ACROSS THE ITCZ 
IN THE E PACIFIC TO 135W.

ELSEWHERE AT THE SURFACE...BROAD 1030 MB HIGH PRES WELL NW-N OF 
THE AREA HAS A RIDGE EXTENDING SE-S INTO THE AREA NEAR 28N140W 
WITH THE REMNANTS OF AN OLD COLD FRONT NOW IN THE FORM OF A WEAK 
FRONTAL TROUGH EXTENDING FROM 32N122W TO 25N130W. A TROUGH IS 
ALONG THE W GULF OF CALIFORNIA/E BAJA PENINSULA AND NW WINDS TO 
20 KT CONTINUE TO BE FUNNELED UP ALONG THE W COAST OF THE BAJA 
PENINSULA FROM 24N TO 28N. IN ADDITION A TIGHT PRES GRADIENT 
EXISTS OVER THE GULF OF CALIFORNIA WHERE S-SW WINDS OF 20 KT ARE 
POSSIBLE THROUGH 24 HOURS THEN DIMINISHING TO LESS THAN 20 KT 
THEREAFTER.

AN ELONGATED AND WEAK LOW TO MID LEVEL CYCLONIC CIRCULATION IS 
EMBEDDED ALONG THE ITCZ BETWEEN 105W AND 115W. COMPUTER MODEL 
SOLUTIONS VARY WITH THE POSSIBLE DEVELOPMENT OF A LOW PRES AREA 
FROM THIS FEATURE DURING THE NEXT SEVERAL DAYS. IN THE MEANTIME 
DECENT ANTICYCLONIC FLOW ALOFT ON THE S SIDE OF THE ITCZ IS 
PROVIDING FORCING TO ALLOW FOR SIGNIFICANT MODERATE TO STRONG 
CONVECTION AT THE SURFACE. SOUTHERLY WINDS TO 20 KT ARE ALSO 
OCCURRING FROM 03N TO 07N BETWEEN 82W AND 108W IN THIS SAME 
GENERAL AREA.

FRESH TO STRONG SOUTHEASTERLY TRADES ACROSS THE SUB-TROPICAL SE 
PACIFIC DURING THE PAST SEVERAL DAYS CONTINUE TO GENERATE LONG 
PERIOD SE SWELL ON THE ORDER OF 11-13 SECONDS ENTERING THE 
SOUTHERN PORTION OF THE DISCUSSION WATERS WITH SEAS OF 8-10 FT S 
OF 08N TO 10N. 

$$
LEWITSKY