000
AXPZ20 KNHC 130909
TWDEP 

TROPICAL WEATHER DISCUSSION      
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC THU SEP 13 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 104W/105W N OF 5N MOVING W 5-10 KT WITH A 
WEAK 1009 MB LOW ALONG THE AXIS NEAR 9N. INFRARED SATELLITE 
IMAGERY SHOWS A WELL-DEFINED LOW TO MID-LEVEL CIRCULATION NEAR 
9N104W BUT AN 0118 UTC QUIKSCAT PASS INDICATED THAT THE 
LOW-LEVEL CENTER COULD HAVE BEEN FARTHER N NEAR 10.5N104W. 
HOWEVER...AN AMBIGUITY ANALYSIS SHOWS THAT THE CENTER COULD BE 
FARTHER S NEAR THE MORE PRONOUNCED CIRCULATION. SCATTERED 
MODERATE CONVECTION FROM 7N-13N BETWEEN 105W-110W.

TROPICAL WAVE ALONG 135W S OF 15N MOVING W 10 KT. A WEAK 
CIRCULATION IS NOTED WITHIN THE ITCZ WITH A SLIGHT FLARE-UP IN 
DEEP CONVECTION. SEE ITCZ FOR RELATED CONVECTION.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 7N77W 11N94W 10N105W 16N111W 
10N140W. SCATTERED MODERATE/STRONG CONVECTION FROM 3N-8N E OF 
80W. SCATTERED MODERATE/STRONG FROM 7N-11N BETWEEN 94W-99W. 
SCATTERED MODERATE WITHIN 75 NM OF AXIS BETWEEN 109W-117W...AND 
BETWEEN 132W-138W.

...DISCUSSION...

E OF 110W...
TWO UPPER LEVEL ANTICYCLONES ARE LOCATED NEAR EASTERN AND 
WESTERN MEXICO...ONE NEAR 20N99W AND THE OTHER JUST W OF THE 
BAJA PENINSULA NEAR 27N115W. A SHARP UPPER TROUGH IS SANDWICHED 
BETWEEN THE TWO ANTICYCLONES AND EXTENDS FROM NEAR CHIHUAHUA SW 
TO A CLOSED LOW VERY CLOSE TO CABO SAN LUCAS NEAR 22N109W. 
SOUTHWESTERLY FLOW ALOFT ON THE E SIDE OF THE TROUGH IS DRAWING 
DEEP MOISTURE INLAND ACROSS CENTRAL MEXICO...AND THIS HAS CAUSED 
THE DEVELOPMENT OF SCATTERED MODERATE/STRONG CONVECTION OVER 
W/CENTRAL MEXICO FROM DURANGO SWD TO PUERTO VALLARTA AND 
GUADALAJARA AS THE AIR IS FORCED TO RISE OVER THE MOUNTAINS. TO 
THE S...THE UPPER LEVEL FLOW IS MAINLY EASTERLY TO NORTHEASTERLY 
AND SCATTERED CLUSTERS OF DEEP CONVECTION HAVE BEEN OCCURRING IN 
AREAS OF LOW-LEVEL CONVERGENCE ALONG THE ITCZ.

W OF 110W...
THE W PART OF THE PACIFIC DISCUSSION AREA IS DOMINATED BY AN 
UPPER HIGH NEAR 20N134W WITH A LARGE AREA OF MODERATE SUBSIDENCE 
EXTENDING FROM 13N-26N W OF 122W. DEEP-LAYERED MOISTURE IS 
INCREASING FROM E TO W BEHIND AN INVERTED UPPER TROUGH WHICH IS 
ALONG 124W. A PAIR OF 1010 MB SURFACE LOWS ARE EMBEDDED ALONG 
THE ITCZ NEAR 17N112W AND 15N120W BUT ARE CAUSING ONLY SPORADIC 
CONVECTION. ELSEWHERE...A WEAK SURFACE RIDGE LIES ACROSS THE NW 
PART OF THE AREA FROM 30N128W TO 26N140W WITH AN 80 KT UPPER 
LEVEL JET OVERHEAD ALONG 30N EXTENDING NE TO COASTAL CALIFORNIA.

$$
BERG