000
AXPZ20 KNHC 202145
TWDEP 

TROPICAL WEATHER DISCUSSION      
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC FRI JUL 20 2007

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 
2130 UTC.

...TROPICAL WAVES...

TROPICAL WAVE 96W/97W S OF 16N MOVING W 15 KT WITH A 1010 MB LOW 
ALONG THE AXIS NEAR 10N96W. A BROAD LOW-LEVEL CIRCULATION IS 
NOTED S OF THE GULF OF TEHUANTEPEC BUT MOST DEEP CONVECTION IS 
CURRENTLY DISPLACED MORE THAN 100 NM AWAY FROM THE CENTER. 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM 10N-15N 
BETWEEN 93W-103W. SCATTERED MODERATE FROM 5N-9N BETWEEN 93W-104W.

TROPICAL WAVE ALONG 120W S OF 16N MOVING W 10 KT. THE WAVE IS 
EMBEDDED WITHIN THE EXTENDED NE/SW ORIENTED ITCZ AXIS...AND 
THERE IS NO CLEAR INDICATION OF ITS EXACT POSITION. SHOWERS/ 
TSTMS ORIENTED ALONG THE ITCZ.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 8N77W 10N96W 6N103W THEN FROM 
20N109W 10N120W 5N135W 9N140W. SCATTERED MODERATE/ISOLATED 
STRONG CONVECTION WITHIN 120 NM OF AXIS BETWEEN 78W-88W. 
SCATTERED MODERATE 60 NM OF AXIS BETWEEN 113W-119W. WIDELY 
SCATTERED SHOWERS/TSTMS ELSEWHERE WITHIN 120 NM OF AXIS BETWEEN 
107W-135W.

...DISCUSSION...

E OF 105W...
A BROAD SURFACE LOW ASSOCIATED WITH A TROPICAL WAVE SSW OF THE 
GULF OF TEHUANTEPEC IS BECOMING MORE ORGANIZED WITH THE 
LOW-LEVEL CIRCULATION BECOMING MORE WELL-DEFINED. DEEP 
CONVECTION IS GENERALLY REMOVED FROM THE CENTER BY ABOUT 100 NM 
OR SO...BUT VISIBLE SATELLITE IMAGERY SHOWS THAT SOME BANDING 
MAY BE FORMING. THIS SYSTEM LIES JUST W OF A SMALL UPPER TROUGH 
AXIS ALONG 91W/92W WHICH IN EFFECT IS PRODUCING NE/E FLOW AND 
SUFFICIENT UPPER DIFFLUENCE OVER THE LOW. ELSEWHERE...SEVERAL 
CYCLONIC AND ANTICYCLONIC CIRCULATIONS ARE NOTED OVER 
MEXICO...THE NW CARIBBEAN...AND NW SOUTH AMERICA BUT THEY ARE 
FAR ENOUGH REMOVED FROM THE PACIFIC WATERS TO HAVE LITTLE EFFECT.

W OF 105W...
THE MOST STRIKING FEATURE AT THE MOMENT IS THE NWD EXTENSION OF 
THE ITCZ WHICH STRETCHES FROM 6N130W IN THE DEEP TROPICS NE TO 
THE COAST OF MEXICO ROUGHLY NEAR MAZATLAN. BROAD S/SW FLOW FEEDS 
INTO THE AXIS WITH MOISTURE BEING DRAWN NWD INTO SRN PARTS OF 
THE GULF OF CALIFORNIA. AS A RESULT...SCATTERED SHOWERS AND 
TSTMS ARE MOVING INLAND FROM MAZATLAN NWD INTO NW MEXICO...AIDED 
BY THE USUAL DAYTIME HEATING OVER LAND. A MID/UPPER LOW LOCATED 
JUST W OF BAJA CALIFORNIA NEAR 25N115W IS ALSO HELPING TO PULL 
THE DEEP TROPICAL MOISTURE NWD TOWARDS LAND. ELSEWHERE THE 
WEATHER IS QUITE TRANQUIL. AN UPPER TROUGH ALONG THE W COAST OF 
THE UNITED STATES HAS WEAKENED THE SUBTROPICAL RIDGE AND THUS 
THE TRADES ARE CURRENTLY IN A WEAKENED STATE.

$$
BERG