000
AXPZ20 KNHC 120922
TWDEP 

TROPICAL WEATHER DISCUSSION      
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC WED SEP 12 2007

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 
0845 UTC.

...TROPICAL WAVES...

TROPICAL WAVE ALONG 101W N OF 6N MOVING W 5 KT. THERE IS WEAK 
ROTATION IN THE LOW-LEVEL CLOUD FIELD AND A N-S LINE OF 
SHOWERS/TSTMS HAS RECENTLY DEVELOPED ALONG THE WAVE AXIS. 
SCATTERED MODERATE CONVECTION FROM 8N-14N BETWEEN 99W-103W.

TROPICAL WAVE ALONG 131W/132W N OF 5N MOVING W 5 KT. A FAIRLY 
WELL-DEVELOPED CIRCULATION IS NOTED WITHIN THE ITCZ WITH A 
FLARE-UP IN DEEP CONVECTION. SEE ITCZ FOR RELATED CONVECTION.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 8N77W 16N110W 9N133W 9N140W. 
SCATTERED MODERATE CONVECTION N OF 6N BETWEEN 79W-83W. SCATTERED 
MODERATE FROM 8N-14N BETWEEN 94W-106W. SCATTERED MODERATE FROM 
13N-18N BETWEEN 105W-112W. SCATTERED MODERATE WITHIN 120 NM OF 
AXIS W OF 122W.

...DISCUSSION...

MEXICO...
A MID-LEVEL RIDGE EXTENDS ACROSS THE NORTHERN TIER OF MEXICO 
CONNECTED TO A MID-LEVEL HIGH JUST W OF BAJA CALIFORNIA NEAR 
30N118W. THE RIDGE DOES NOT EXTEND VERY DEEP HOWEVER AND THERE 
IS AN UPPER LEVEL LOW CENTERED NEAR 23N105W...OR VERY NEAR 
MAZATLAN. THIS LOW...COUPLED WITH AN UPPER HIGH OVER THE W GULF 
OF MEXICO...IS DRAWING TROPICAL MOISTURE NWD ACROSS MUCH OF THE 
COUNTRY WHICH HELPED TO SPARK TSTM ACTIVITY LAST EVENING. SOME 
LEFTOVER TSTMS EXTEND OVER THE STATES OF GUERRERO...OAXACA...AND 
CHIAPAS OVER THE SOUTHERN PART AS WELL AS OVER THE STATES OF 
SONORA AND SINALOA INTO THE GULF OF CALIFORNIA.

TROPICAL PACIFIC...
MAINLY E TO NE UPPER LEVEL FLOW EXTENDS FROM THE CENTRAL 
AMERICAN LANDMASS OVER THE ADJACENT PACIFIC WATERS TO THE 
EQUATOR. DEEP MOISTURE IS LOCATED MAINLY N OF 7N WITH 
SHOWERS/TSTMS DEVELOPING IN PATCHES NEAR TROPICAL WAVES AND 
ALONG THE ITCZ. STRONG SOUTHERLY LOW-LEVEL FLOW REACHES AS FAR N 
AS 9N E OF 110W WITH BROKEN/OVERCAST STRATUS EXTENDING DOWN 
ACROSS THE EQUATOR. FARTHER W...THE UPPER LEVEL EASTERLY FLOW 
CONTINUES TO 140W WITH A NE-SW BAND OF DEEP MOISTURE COINCIDING 
WITH THE ITCZ. A QUIKSCAT PASS FROM LAST EVENING INDICATED AN 
AREA OF LOW PRES...1010 MB...LOCATED NEAR 15N114W BUT THERE IS 
RELATIVELY LITTLE NEARBY CONVECTION. A MID-LEVEL CIRCULATION WAS 
NOTED NEAR 14N118W EARLIER BUT MOST OF THE ASSOCIATED CONVECTION 
HERE HAS ALSO WEAKENED. A LARGE AREA OF MODERATE/STRONG 
SUBSIDENCE HAS PLUNGED S TO 12N W OF 120W AND THUS SKIES ARE 
MOSTLY CLEAR WITH A LINEAR ITCZ.

SUBTROPICAL PACIFIC...
A DEEP-LAYERED CLOSED LOW IS CENTERED N OF THE AREA WITH THE 
UPPER LEVEL SIGNATURE NEAR 35N137W AND AN 80 KT WESTERLY JET 
STREAK EXTENDING FROM 29N140W TO 30N130W. A WEAK 1013 MB SURFACE 
LOW IS LOCATED BENEATH THE UPPER FEATURE NEAR 35N136W WITH A 
SURFACE TROUGH REACHING INTO THE FAR NW PART OF THE AREA. 
ELSEWHERE...AN UPPER RIDGE AXIS EXTENDS FROM NW MEXICO TO AN 
UPPER HIGH NEAR 23N130W TO 21N140W. LARGE-SCALE SUBSIDENCE AND 
DRY AIR IS KEEPING SKIES MOSTLY CLOUD-FREE FROM BAJA TO 140W.

$$
BERG