000
AXPZ20 KNHC 302157
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC FRI JUL 30 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 
2100 UTC.

...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE IS ANALYZED ALONG A LINE FROM 
10N86W TO 09N95W TO 17N109W TO 09N125W TO 12N137W TO 09N140W. 
SCATTERED MODERATE FROM 06N TO 08N BETWEEN 83W AND 86W. 
SCATTERED MODERATE ISOLATED STRONG FROM 11N TO 16N BETWEEN 105W. 
SCATTERED MODERATE FROM 08N TO 12N BETWEEN 115W AND 125W...AND 
FROM 10N TO 12N BETWEEN 134W AND 138W.

...DISCUSSION...

AN UPPER LEVEL TROUGH AXIS IS LOCATED NORTHWEST OF THE 
DISCUSSION AREA WITH TROUGHING AND A 30 TO 50 KT UPPER LEVEL JET 
IMPACTING THE NW CORNER OF THE AREA NW OF 32N125W TO 23N140W. 
ELSEWHERE...UPPER LEVEL ANTICYCLONIC FLOW COVERS MUCH OF THE 
AREA TO THE NORTH OF 10N W OF 120W WITH AN UPPER LEVEL RIDGE 
AXIS EXTENDING FROM AN ANTICYCLONE OVER ARIZONA THROUGH THE 
NORTHERN BAJA PENINSULA TO 20N130W. A WEAK UPPER LEVEL LOW AND 
ASSOCIATED TROUGHING LIES FROM 26N118W THROUGH THE UPPER LOW 
NEAR 23N117W TO 20N113W. THIS PATTERN IS EXPECTED TO BECOME MORE 
AMPLIFIED AND RETROGRADE SLIGHTLY WESTWARD DURING THE NEXT 
COUPLE OF DAYS. DRY AIR IN SUBSIDENCE CAN BE FOUND IN MOST OF 
THE REGION N OF A LINE FROM 12N140W TO 15N125W TO 32N117W...BUT 
SOME MOISTURE ALOFT IS BEGINNING TO CROSS THIS LINE FROM THE SE 
AND MOVE INTO THE ENTRANCE REGION OF THE AFOREMENTIONED UPPER 
JET IN THE VICINITY OF 20N128W. BROAD SURFACE ANTICYCLONIC FLOW 
COVERS THE AREA TO THE NORTH OF 15N AND WEST OF 115W. A SURFACE 
TROUGH IS ANALYZED FROM 19N110W TO 12N112W. SOUTHERLY SWELLS TO 
9 FEET ARE LOCATED SOUTH OF 10N W OF 100W AND INTO CENTRAL 
WATERS S OF 15N.

MODERATE EASTERLY TO NORTHEASTERLY WINDS ALOFT COVER THE EASTERN 
PORTION OF THE DISCUSSION AREA. AT THE SURFACE...A 1011 MB LOW 
IS EMBEDDED IN THE ITCZ NEAR 09N94W WITH CONVECTION WELL N OF 
THE CENTER. SOME OF THE COMPUTER MODEL GUIDANCE SUGGESTS THAT 
SHORTWAVE ENERGY OVER THE ISTHMUS OF TEHUANTEPEC WILL SEEP 
SOUTHWARD THROUGH THE GULF OF TEHUANTEPEC INTO THE WESTERN SIDE 
OF THIS PACIFIC LOW. THE PASSAGE OF THE SHORTWAVE ENERGY HAS 
BROUGHT N TO NE WINDS IN THE RANGE OF 20 TO 25 KT IN THE GULF OF 
TEHUANTEPEC THAT ARE FORECAST TO DIMINISH BELOW 20 KT BY LATE 
SATURDAY.

$$
FORMOSA