000
AXPZ20 KNHC 061515
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SAT SEP 05 2009

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN
FROM THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...SPECIAL FEATURES...

A 1008 MB LOW PRESSURE IS CENTERED NEAR 14N123W MOVING WNW AT 
AROUND 15 KT. NUMEROUS MODERATE WITH SCATTERED STRONG CONVECTION 
IS OCCURRING WITHIN 150 NM W SEMICIRCLE AND ALSO WITHIN 90 NM OF 
17N123W. IT APPEARS THAT A CENTER MAY BE FORMING CLOSER TO DEEP 
CONVECTION. 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 08N78W 
TO 09N105W TO 09N115W TO 10N140W. SCATTERED MODERATE CONVECTION 
IS WITHIN 60 NM EITHER SIDE OF THE ITCZ AXIS FROM 93W TO 100W. 
SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION IS WITHIN 60 
NM OF THE POINT 09N117W.

...DISCUSSION...

CONVECTION IS RESTRICTED TO THE ABOVE MENTIONED LOW NEAR 
14N123W, SEVERAL SMALL AREAS NEAR THE ITCZ AND DIMINISHING 
CONVECTION THAT HAS PROPAGATED OVER THE OCEAN FROM THE COASTAL 
AREAS OF NORTHERN NICARAGUA TO THE GULF OF TEHUANTEPEC.

AN UPPER ANTICYCLONE IS CENTERED NEAR 26N141W WITH ASSOCIATED 
RIDGE OVER THE AREA WEST OF A LINE THROUGH 32N135W 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 NORTH OF 18N. 

A SMALL DEEP LAYER CYCLONIC CIRCULATION IS CENTERED NEAR 21N107W 
AND EXTENDS OUT ABOUT 240 NM. THE AREA OVER THE OCEAN IS DRY AND 
CLEAR HOWEVER THE AREA OVER THE LAND HAS MULTI LEVEL BROKEN TO 
OVERCAST CLOUDS THAT ARE THE REMNANTS FROM CONVECTION OVER THE 
COASTAL REGIONS. AN ASSOCIATED TROUGH EXTENDS SOUTH TO NEAR 14N 
BETWEEN 105W AND 110W.

THE AREA SOUTH OF A LINE FROM NEAR 10N130W TO 19N125W TO 22N115W 
TO 21N111W TO 10N109W IS ANTICYCLONIC FLOW AND INCLUDES THE 
OUTFLOW FROM THE 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 
BROKEN TO OVERCAST STRATOCUMULUS IN THE LOWER LEVELS MOSTLY WEST 
OF 115W.

THE AREA EAST OF 105W IS BROADLY ANTICYCLONIC WITH DIMINISHING 
COASTAL CONVECTION AND SOME CONVECTION WITHIN THE ITCZ REGION.

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 26N114W...AND SHOULD FULLY DISSIPATE WITHIN THE NEXT 24 
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 16N131W AND IS ALSO FORECAST TO 
DISSIPATE IN ABOUT 12 TO 24 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