000
AXPZ20 KNHC 071011
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC WED OCT 07 2009

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 
0915 UTC.

...TROPICAL WAVE... 

A TROPICAL WAVE WAS ALONG 93W N OF 11N ACROSS THE EPAC EXTENDING 
NNW ACROSS MEXICO AND INTO THE SW GULF OF MEXICO ALONG 95W...AND 
WAS BEGINNING TO FRACTURE INTO TWO PIECES AS THE NORTHERN EXTENT 
OF THE WAVE MOVED NW AROUND THE SW PERIPHERY OF THE W ATLC 
RIDGE. THE WAVE IS ENTERING THE EASTERN END OF AN ELONGATED LOW 
TO MID LEVEL CYCLONIC GYRE...WHERE ABUNDANT DEEP LAYER MOISTURE 
IS NOTED IN TOTAL PRECIPITABLE WATER IMAGERY. THE GFS 
INITIALIZED A 20-25 KT LLVL JET MOVING ACROSS THE YUCATAN 
PENINSULA AT 00 UTC WHICH WAS AIDING IN PRODUCING 20 KT FLOW 
ALONG THE PACIFIC COASTS FROM NICARAGUA TO THE GULF OF 
TEHUANTEPEC. THIS WAS FORCING SCATTERED TO NUMEROUS CONVECTION 
ALONG THE N SEMICIRCLE OF THIS GYRE NWD TO THE COASTS. 

...ITCZ...

THE ITCZ AXIS WAS CENTERED ALONG 08N80W TO 12N95W TO 12N109W TO 
07N131W TO 09N140W. SCATTERED MODERATE CONVECTION WAS WITHIN 240 
NM S OF AXIS BETWEEN 89W AND 108W. ISOLATED TO SCATTERED 
MODERATE CONVECTION WAS WITHIN 120 NM S OF AXIS W OF 111W.

...DISCUSSION...

A BROAD ANTICYCLONIC CIRCULATION LOCATED OVER ERN MEXICO NEAR
24N99W EXTENDS A RIDGE SW TO 18N114W TO NEAR 14N124W. THIS RIDGE
WILL SHIFT E AND WEAKEN...AHEAD OF A MID TO UPPER LEVEL TROUGH
THAT STRETCHES FROM A MID/UPPER LEVEL UPPER LEVEL N OF THE AREA 
OFF THE SRN CALIFORNIA COAST SW TO 32N123W TO 27N125W...THEN S TO
A COL REGION NEAR 14N124W. A SWLY JET STREAM BRANCH BETWEEN THE
RIDGE AND TROUGH WAS SEEN IN WATER VAPOR IMAGERY WITH CORE WINDS 
OF UP TO 90 KT...WHICH WILL CONTINUE TO ADVECT UPPER LEVEL 
MOISTURE ACROSS MUCH OF BAJA CALIFORNIA...NRN MEXICO AND THE SW 
U.S.

A SURFACE RIDGE ENTERS THE REGION FROM A 1032 MB HIGH NEAR 
49N140W TO NEAR 20N114W. SHIP AND OVERNIGHT SCATTEROMETER DATA 
INDICATED 15-20 KT NW FLOW ALONG THE BAJA COAST...ACCELERATING 
TO 20-25 KT ALONG THE SRN END OF THE PENINSULA AND THE SE 
PERIPHERY OF THE RIDGE. 

OVER THE SRN PORTION...A 1010 MB LOW IS NOTED ALONG THE ITCZ 
NEAR 11N111W. THE LOW IS FORECAST TO SLOWLY MOVE WNW OVER THE 
NEXT COUPLE OF DAYS...AND ALTHOUGH WILL NOT DEVELOP 
SIGNIFICANTLY IT MAY ENHANCE TRADE WIND FLOW AS IT INTERACTS 
WITH THE RIDGE TO THE N. ANOTHER LOW WAS DETECTED BY AN 
OVERNIGHT QUIKSCAT PASS NEAR 09N99W. THIS BROAD LOW IS SUGGESTED 
BY GLOBAL MODELS TO BECOME ABSORBED INTO THE CYCLONIC GYRE 
ACROSS THAT AREA AND SHIFT NW WHILE BROADENING.

A BROAD SPECTRUM OF WIND WAVES AND SWELL IS CURRENTLY AFFECTING 
THE REGIONAL WATERS...WITH 8 FT SEAS MAINLY SW OF THE SURFACE 
RIDGE AXIS IN FRESH NELY WIND FLOW. WAVE MODELS SUGGESTS THAT 
SEAS WILL SUBSIDE BY A FEW FEET OVER THE NEXT 48 HOURS.

$$
STRIPLING