000
AXPZ20 KNHC 062116
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SAT SEP 05 2009

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.

...SPECIAL FEATURES...

A 1008 MB LOW PRESSURE IS CENTERED NEAR 15N124W MOVING WNW AT 
AROUND 15 KT. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION 
IS OCCURRING WITHIN 120 NM OF CENTER EXCEPT 240 NM NE QUADRANT.
THIS SYSTEM CONTINUES TO SHOW SIGNS OF ORGANIZATION AND HAS A 
HIGH CHANCE OF BECOMING A TROPICAL CYCLONE IN THE NEXT 48 HOURS. 
COMPUTER MODELS ALSO SUGGEST AN INCREASE IN WINDS AND SEAS 
ASSOCIATED WITH THIS LOW...PARTICULARLY ON THE NORTHERN 
SEMICIRCLE DUE TO THE PRESSURE GRADIENT BETWEEN THE LOW AND A 
RIDGE TO THE NORTH. FOR NOW...EXPECT WINDS OF 20-30 KT AND SEAS 
IN THE 8 TO 12 FT RANGE.

...THE ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS ALONG THE LINE FROM 07N77W 
TO 09N100W TO 10N120W TO 10N140W. SCATTERED MODERATE CONVECTION 
IS WITHIN 60 NM EITHER SIDE OF THE ITCZ AXIS FROM 96W TO 102W. 

...DISCUSSION...

CONVECTION IS RESTRICTED TO THE ABOVE MENTIONED LOW NEAR 14N123W 
AND A COUPLE OF SMALL AREAS NEAR THE ITCZ. OVERNIGHT CONVECTION 
ALONG THE CENTRAL AMERICA COAST HAS PROPAGATED OVER THE OCEAN 
FROM THE COASTAL AREAS AND CAN BE EXPECTED AGAIN TONIGHT MOST 
LIKELY FROM NORTHERN COSTA RICA TO THE MEXICAN COAST NEAR 105W.

AN DEEP LAYER ANTICYCLONE IS CENTERED OVER THE NORTHWEST PART OF 
THE AREA WITH ASSOCIATED RIDGE OVER THE AREA WEST OF A LINE 
THROUGH 32N133W TO THE ITCZ NEAR 130W. THIS AREA IS DRY AND 
CLOUD FREE IN THE MIDDLE AND UPPER LEVELS WITH MOSTLY OVERCAST 
STRATOCUMULUS IN THE LOWER LEVELS FROM 20N TO 28N AND BROKEN TO 
SCATTERED ELSEWHERE N OF 15N.

A SMALL DEEP LAYER CYCLONIC CIRCULATION IS CENTERED NEAR 
21.5N106.5W AND EXTENDS OUT ABOUT 240 NM. THE AREA IS DRY AND 
CLEAR HOWEVER THE AREA OVER THE LAND HAS DEVELOPING CONVECTION 
WHICH WILL CONTINUE INTO THE NIGHT. AN ASSOCIATED TROUGH EXTENDS 
SOUTH TO NEAR 14N BETWEEN 105W AND 110W.

THE AREA SOUTH OF A LINE FROM NEAR 10N130W TO 19N127W TO 22N117W 
TO 20N110W TO 10N109W IS ANTICYCLONIC FLOW AND INCLUDES THE 
OUTFLOW FROM THE SURFACE LOW NEAR 14N123W. THIS AREA IS MOIST IN 
THE DEEP LAYER WITH AREAS OF MULTI LEVEL CLOUDS. EMBEDDED 
CONVECTION IS CONFINED TO NEAR THE LOW.

THE REMAINDER OF THE AREA WEST OF 105W IS A BROAD TROUGH. THIS 
AREA IS DRY AND CLOUD FREE IN THE MIDDLE AND UPPER LEVELS WITH 
SCATTERED TO BROKEN STRATOCUMULUS IN THE LOWER LEVELS MOSTLY 
WEST OF 115W.

THE AREA EAST OF 105W IS BROADLY ANTICYCLONIC WITH AREAS OF 
MULTI LEVEL CLOUDS AND SOME EMBEDDED CONVECTION.

A SURFACE RIDGE COVERS THE NORTHERN FORECAST WATERS MAINLY N OF 
20N WEST OF 118W...WITH NORTHEAST TRADEWINDS OF 20 KNOTS BETWEEN 
16N AND 25N WEST OF 130W AND SEAS TO 8 FT. THESE WINDS MAY 
INCREASE IN ABOUT 48 HOURS AHEAD OF THE DEVELOPING LOW NEAR 
14N123W.

THE REMNANTS OF JIMENA ARE STILL PRESENT AS A LOW-LEVEL SWIRL  
NEAR 25N115W...AND SHOULD FULLY DISSIPATE WITHIN THE NEXT 12 
HOURS OR SO. PART OF THE CLOUDINESS ASSOCIATED WITH THIS FEATURE 
CONTINUES TO AFFECT THE SOUTHERN BAJA CALIFORNIA AND COASTAL 
WATERS.

THE REMNANTS OF KEVIN ALSO CONTINUE AS A LOW-LEVEL SWIRL IN THE 
STRATOCUMULUS CLOUDS NEAR 16N133W AND IS ALSO FORECAST TO 
DISSIPATE IN ABOUT 12 HOURS. 

LONG PERIOD SWELLS FROM THE NW ARE EXPECTED TO INVADE THE N 
WATERS IN ABOUT 24 HOURS RAISING SEAS TO 9 FT LATE MON INTO 
EARLY TUE. 

$$
LL